root/libexec/ftpd/ftpd.c
/*      $NetBSD: ftpd.c,v 1.211 2025/06/27 21:36:23 andvar Exp $        */

/*
 * Copyright (c) 1997-2023 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Luke Mewburn.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Copyright (c) 1985, 1988, 1990, 1992, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Copyright (C) 1997 and 1998 WIDE Project.
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1985, 1988, 1990, 1992, 1993, 1994\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)ftpd.c      8.5 (Berkeley) 4/28/95";
#else
__RCSID("$NetBSD: ftpd.c,v 1.211 2025/06/27 21:36:23 andvar Exp $");
#endif
#endif /* not lint */

/*
 * FTP server.
 */
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include <sys/resource.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>

#define FTP_NAMES
#include <arpa/ftp.h>
#include <arpa/inet.h>
#include <arpa/telnet.h>

#include <ctype.h>
#include <dirent.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <fnmatch.h>
#include <glob.h>
#include <grp.h>
#include <limits.h>
#include <netdb.h>
#include <pwd.h>
#include <poll.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <time.h>
#include <tzfile.h>
#include <unistd.h>
#include <util.h>
#ifdef SUPPORT_UTMP
#include <utmp.h>
#endif
#ifdef SUPPORT_UTMPX
#include <utmpx.h>
#endif
#ifdef SKEY
#include <skey.h>
#endif
#ifdef KERBEROS5
#include <com_err.h>
#include <krb5/krb5.h>
#endif

#ifdef  LOGIN_CAP
#include <login_cap.h>
#endif

#ifdef USE_PAM
#include <security/pam_appl.h>
#endif

#include "pfilter.h"

#define GLOBAL
#include "extern.h"
#include "pathnames.h"
#include "version.h"

static sig_atomic_t     transflag;
static sig_atomic_t     urgflag;

int     data;
int     Dflag;
int     fflag;
int     sflag;
int     stru;                   /* avoid C keyword */
int     mode;
int     dataport;               /* use specific data port */
int     dopidfile;              /* maintain pid file */
int     doutmp;                 /* update utmp file */
int     dowtmp;                 /* update wtmp file */
int     doxferlog;              /* syslog/write wu-ftpd style xferlog entries */
int     xferlogfd;              /* fd to write wu-ftpd xferlog entries to */
int     getnameopts;            /* flags for use with getname() */
int     dropprivs;              /* if privileges should or have been dropped */
int     mapped;                 /* IPv4 connection on AF_INET6 socket */
off_t   file_size;
off_t   byte_count;
static char ttyline[20];

#ifdef USE_PAM
static int      auth_pam(void);
pam_handle_t    *pamh = NULL;
#endif

#ifdef SUPPORT_UTMP
static struct utmp utmp;        /* for utmp */
#endif
#ifdef SUPPORT_UTMPX
static struct utmpx utmpx;      /* for utmpx */
#endif

static const char *anondir = NULL;
static const char *confdir = _DEFAULT_CONFDIR;

static char     *curname;               /* current USER name */
static size_t   curname_len;            /* length of curname (include NUL) */

#if defined(KERBEROS) || defined(KERBEROS5)
int     has_ccache = 0;
int     notickets = 1;
char    *krbtkfile_env = NULL;
char    *tty = ttyline;
int     login_krb5_forwardable_tgt = 0;
#endif

int epsvall = 0;

/*
 * Timeout intervals for retrying connections
 * to hosts that don't accept PORT cmds.  This
 * is a kludge, but given the problems with TCP...
 */
#define SWAITMAX        90      /* wait at most 90 seconds */
#define SWAITINT        5       /* interval between retries */

int     swaitmax = SWAITMAX;
int     swaitint = SWAITINT;

enum send_status {
        SS_SUCCESS,
        SS_ABORTED,                     /* transfer aborted */
        SS_NO_TRANSFER,                 /* no transfer made yet */
        SS_FILE_ERROR,                  /* file read error */
        SS_DATA_ERROR                   /* data send error */
};

static int       bind_pasv_addr(void);
static int       checkuser(const char *, const char *, int, int, char **);
static int       checkaccess(const char *);
static int       checkpassword(const struct passwd *, const char *);
static void      do_pass(int, int, const char *);
static void      end_login(void);
static FILE     *getdatasock(const char *);
static char     *gunique(const char *);
static void      login_utmp(const char *, const char *, const char *,
                     struct sockinet *);
static void      logremotehost(struct sockinet *);
__dead static void       lostconn(int);
__dead static void       toolong(int);
__dead static void       sigquit(int);
static void      sigurg(int);
static int       handleoobcmd(void);
static int       receive_data(FILE *, FILE *);
static int       send_data(FILE *, FILE *, const struct stat *, int);
static struct passwd *sgetpwnam(const char *);
static int       write_data(int, char *, size_t, off_t *, struct timeval *,
                     int);
static enum send_status
                 send_data_with_read(int, int, const struct stat *, int);
static enum send_status
                 send_data_with_mmap(int, int, const struct stat *, int);
static void      logrusage(const struct rusage *, const struct rusage *);
static void      logout_utmp(void);

int     main(int, char *[]);

#if defined(KERBEROS)
int     klogin(struct passwd *, char *, char *, char *);
void    kdestroy(void);
#endif
#if defined(KERBEROS5)
int     k5login(struct passwd *, char *, char *, char *);
void    k5destroy(void);
#endif

int
main(int argc, char *argv[])
{
        int             ch, on = 1, tos, keepalive;
        socklen_t       addrlen;
#ifdef KERBEROS5
        krb5_error_code kerror;
#endif
        char            *p;
        const char      *xferlogname = NULL;
        long            l;
        struct sigaction sa;
        sa_family_t     af = AF_UNSPEC;

        connections = 1;
        ftpd_debug = 0;
        logging = 0;
        pdata = -1;
        Dflag = 0;
        fflag = 0;
        sflag = 0;
        dataport = 0;
        dopidfile = 1;          /* default: DO use a pid file to count users */
        doutmp = 0;             /* default: Do NOT log to utmp */
        dowtmp = 1;             /* default: DO log to wtmp */
        doxferlog = 0;          /* default: Do NOT syslog xferlog */
        xferlogfd = -1;         /* default: Do NOT write xferlog file */
        getnameopts = 0;        /* default: xlate addrs to name */
        dropprivs = 0;
        mapped = 0;
        usedefault = 1;
        emailaddr = NULL;
        hostname[0] = '\0';
        homedir[0] = '\0';
        gidcount = 0;
        is_oob = 0;
        version = FTPD_VERSION;

        /*
         * LOG_NDELAY sets up the logging connection immediately,
         * necessary for anonymous ftp's that chroot and can't do it later.
         */
        openlog("ftpd", LOG_PID | LOG_NDELAY, LOG_FTP);

        while ((ch = getopt(argc, argv,
            "46a:c:C:Dde:fh:HlL:nP:qQrst:T:uUvV:wWX")) != -1) {
                switch (ch) {
                case '4':
                        af = AF_INET;
                        break;

                case '6':
                        af = AF_INET6;
                        break;

                case 'a':
                        anondir = optarg;
                        break;

                case 'c':
                        confdir = optarg;
                        break;

                case 'C':
                        if ((p = strchr(optarg, '@')) != NULL) {
                                *p++ = '\0';
                                strlcpy(remotehost, p, MAXHOSTNAMELEN + 1);
                                if (inet_pton(AF_INET, p,
                                    &his_addr.su_addr) == 1) {
                                        his_addr.su_family = AF_INET;
                                        his_addr.su_len =
                                            sizeof(his_addr.si_su.su_sin);
#ifdef INET6
                                } else if (inet_pton(AF_INET6, p,
                                    &his_addr.su_6addr) == 1) {
                                        his_addr.su_family = AF_INET6;
                                        his_addr.su_len =
                                            sizeof(his_addr.si_su.su_sin6);
#endif
                                } else
                                        his_addr.su_family = AF_UNSPEC;
                        }
                        pw = sgetpwnam(optarg);
                        exit(checkaccess(optarg) ? 0 : 1);
                        /* NOTREACHED */

                case 'D':
                        Dflag = 1;
                        break;

                case 'd':
                case 'v':               /* deprecated */
                        ftpd_debug = 1;
                        break;

                case 'e':
                        emailaddr = optarg;
                        break;

                case 'f':
                        fflag = 1;
                        break;

                case 'h':
                        strlcpy(hostname, optarg, sizeof(hostname));
                        break;

                case 'H':
                        if (gethostname(hostname, sizeof(hostname)) == -1)
                                hostname[0] = '\0';
                        hostname[sizeof(hostname) - 1] = '\0';
                        break;

                case 'l':
                        logging++;      /* > 1 == extra logging */
                        break;

                case 'L':
                        xferlogname = optarg;
                        break;

                case 'n':
                        getnameopts = NI_NUMERICHOST;
                        break;

                case 'P':
                        errno = 0;
                        p = NULL;
                        l = strtol(optarg, &p, 10);
                        if (errno || *optarg == '\0' || *p != '\0' ||
                            l < IPPORT_RESERVED ||
                            l > IPPORT_ANONMAX) {
                                syslog(LOG_WARNING, "Invalid dataport %s",
                                    optarg);
                                dataport = 0;
                        }
                        dataport = (int)l;
                        break;

                case 'q':
                        dopidfile = 1;
                        break;

                case 'Q':
                        dopidfile = 0;
                        break;

                case 'r':
                        dropprivs = 1;
                        break;

                case 's':
                        sflag = 1;
                        break;

                case 't':
                case 'T':
                        syslog(LOG_WARNING,
                            "-%c has been deprecated in favour of ftpd.conf",
                            ch);
                        break;

                case 'u':
                        doutmp = 1;
                        break;

                case 'U':
                        doutmp = 0;
                        break;

                case 'V':
                        if (EMPTYSTR(optarg) || strcmp(optarg, "-") == 0)
                                version = NULL;
                        else
                                version = ftpd_strdup(optarg);
                        break;

                case 'w':
                        dowtmp = 1;
                        break;

                case 'W':
                        dowtmp = 0;
                        break;

                case 'X':
                        doxferlog |= 1;
                        break;

                default:
                        if (optopt == 'a' || optopt == 'C')
                                exit(1);
                        syslog(LOG_WARNING, "unknown flag -%c ignored", optopt);
                        break;
                }
        }
        if (EMPTYSTR(confdir))
                confdir = _DEFAULT_CONFDIR;

        pfilter_open();

        if (dowtmp) {
#ifdef SUPPORT_UTMPX
                ftpd_initwtmpx();
#endif
#ifdef SUPPORT_UTMP
                ftpd_initwtmp();
#endif
        }
        errno = 0;
        l = sysconf(_SC_LOGIN_NAME_MAX);
        if (l == -1 && errno != 0) {
                syslog(LOG_ERR, "sysconf _SC_LOGIN_NAME_MAX: %m");
                exit(1);
        } else if (l <= 0) {
                syslog(LOG_WARNING, "using conservative LOGIN_NAME_MAX value");
                curname_len = _POSIX_LOGIN_NAME_MAX;
        } else 
                curname_len = (size_t)l;
        curname = malloc(curname_len);
        if (curname == NULL) {
                syslog(LOG_ERR, "malloc: %m");
                exit(1);
        }
        curname[0] = '\0';

        if (Dflag) {
                int error, fd, i, n, *socks;
                struct pollfd *fds;
                struct addrinfo hints, *res, *res0;

                if (!fflag && daemon(1, 0) == -1) {
                        syslog(LOG_ERR, "failed to daemonize: %m");
                        exit(1);
                }
                (void)memset(&sa, 0, sizeof(sa));
                sa.sa_handler = SIG_IGN;
                sa.sa_flags = SA_NOCLDWAIT;
                sigemptyset(&sa.sa_mask);
                (void)sigaction(SIGCHLD, &sa, NULL);

                (void)memset(&hints, 0, sizeof(hints));
                hints.ai_flags = AI_PASSIVE;
                hints.ai_family = af;
                hints.ai_socktype = SOCK_STREAM;
                error = getaddrinfo(NULL, "ftp", &hints, &res0);
                if (error) {
                        syslog(LOG_ERR, "getaddrinfo: %s", gai_strerror(error));
                        exit(1);
                }

                for (n = 0, res = res0; res != NULL; res = res->ai_next)
                        n++;
                if (n == 0) {
                        syslog(LOG_ERR, "no addresses available");
                        exit(1);
                }
                socks = malloc(n * sizeof(int));
                fds = malloc(n * sizeof(struct pollfd));
                if (socks == NULL || fds == NULL) {
                        syslog(LOG_ERR, "malloc: %m");
                        exit(1);
                }

                for (n = 0, res = res0; res != NULL; res = res->ai_next) {
                        socks[n] = socket(res->ai_family, res->ai_socktype,
                            res->ai_protocol);
                        if (socks[n] == -1)
                                continue;
                        (void)setsockopt(socks[n], SOL_SOCKET, SO_REUSEADDR,
                            &on, sizeof(on));
                        if (bind(socks[n], res->ai_addr, res->ai_addrlen)
                            == -1) {
                                (void)close(socks[n]);
                                continue;
                        }
                        if (listen(socks[n], 12) == -1) {
                                (void)close(socks[n]);
                                continue;
                        }

                        fds[n].fd = socks[n];
                        fds[n].events = POLLIN;
                        n++;
                }
                if (n == 0) {
                        syslog(LOG_ERR, "%m");
                        exit(1);
                }
                freeaddrinfo(res0);

                if (pidfile(NULL) == -1)
                        syslog(LOG_ERR, "failed to write a pid file: %m");

                for (;;) {
                        if (poll(fds, n, INFTIM) == -1) {
                                if (errno == EINTR)
                                        continue;
                                syslog(LOG_ERR, "poll: %m");
                                exit(1);
                        }
                        for (i = 0; i < n; i++) {
                                if (fds[i].revents & POLLIN) {
                                        fd = accept(fds[i].fd, NULL, NULL);
                                        if (fd == -1) {
                                                syslog(LOG_ERR, "accept: %m");
                                                continue;
                                        }
                                        switch (fork()) {
                                        case -1:
                                                syslog(LOG_ERR, "fork: %m");
                                                break;
                                        case 0:
                                                goto child;
                                                /* NOTREACHED */
                                        }
                                        (void)close(fd);
                                }
                        }
                }
 child:
                (void)dup2(fd, STDIN_FILENO);
                (void)dup2(fd, STDOUT_FILENO);
                (void)dup2(fd, STDERR_FILENO);
                for (i = 0; i < n; i++)
                        (void)close(socks[i]);
        }

        memset((char *)&his_addr, 0, sizeof(his_addr));
        addrlen = sizeof(his_addr.si_su);
        if (getpeername(0, (struct sockaddr *)&his_addr.si_su, &addrlen) < 0) {
                syslog((errno == ENOTCONN) ? LOG_NOTICE : LOG_ERR,
                    "getpeername (%s): %m",argv[0]);
                exit(1);
        }
        his_addr.su_len = addrlen;
        memset((char *)&ctrl_addr, 0, sizeof(ctrl_addr));
        addrlen = sizeof(ctrl_addr.si_su);
        if (getsockname(0, (struct sockaddr *)&ctrl_addr, &addrlen) < 0) {
                syslog(LOG_ERR, "getsockname (%s): %m",argv[0]);
                exit(1);
        }
        ctrl_addr.su_len = addrlen;
#ifdef INET6
        if (his_addr.su_family == AF_INET6
         && IN6_IS_ADDR_V4MAPPED(&his_addr.su_6addr)) {
#if 1
                /*
                 * IPv4 control connection arrived to AF_INET6 socket.
                 * I hate to do this, but this is the easiest solution.
                 *
                 * The assumption is untrue on SIIT environment.
                 */
                struct sockinet tmp_addr;
                const int off = sizeof(struct in6_addr) - sizeof(struct in_addr);

                tmp_addr = his_addr;
                memset(&his_addr, 0, sizeof(his_addr));
                his_addr.su_family = AF_INET;
                his_addr.su_len = sizeof(his_addr.si_su.su_sin);
                memcpy(&his_addr.su_addr, &tmp_addr.su_6addr.s6_addr[off],
                    sizeof(his_addr.su_addr));
                his_addr.su_port = tmp_addr.su_port;

                tmp_addr = ctrl_addr;
                memset(&ctrl_addr, 0, sizeof(ctrl_addr));
                ctrl_addr.su_family = AF_INET;
                ctrl_addr.su_len = sizeof(ctrl_addr.si_su.su_sin);
                memcpy(&ctrl_addr.su_addr, &tmp_addr.su_6addr.s6_addr[off],
                    sizeof(ctrl_addr.su_addr));
                ctrl_addr.su_port = tmp_addr.su_port;
#else
                while (fgets(line, sizeof(line), fd) != NULL) {
                        if ((cp = strchr(line, '\n')) != NULL)
                                *cp = '\0';
                        reply(-530, "%s", line);
                }
                (void) fflush(stdout);
                (void) fclose(fd);
                reply(530,
                    "Connection from IPv4 mapped address is not supported.");
                exit(0);
#endif

                mapped = 1;
        } else
#endif /* INET6 */
                mapped = 0;
#ifdef IP_TOS
        if (!mapped && his_addr.su_family == AF_INET) {
                tos = IPTOS_LOWDELAY;
                if (setsockopt(0, IPPROTO_IP, IP_TOS, (char *)&tos,
                               sizeof(int)) < 0)
                        syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
        }
#endif
        /* if the hostname hasn't been given, attempt to determine it */ 
        if (hostname[0] == '\0') {
                if (getnameinfo((struct sockaddr *)&ctrl_addr.si_su,
                    ctrl_addr.su_len, hostname, sizeof(hostname), NULL, 0, 
                        getnameopts) != 0)
                        (void)gethostname(hostname, sizeof(hostname));
                hostname[sizeof(hostname) - 1] = '\0';
        }

        /* set this here so klogin can use it... */
        (void)snprintf(ttyline, sizeof(ttyline), "ftp%d", getpid());

        (void) freopen(_PATH_DEVNULL, "w", stderr);

        memset(&sa, 0, sizeof(sa));
        sa.sa_handler = SIG_DFL;
        sa.sa_flags = SA_RESTART;
        sigemptyset(&sa.sa_mask);
        (void) sigaction(SIGCHLD, &sa, NULL);

        sa.sa_handler = sigquit;
        sa.sa_flags = SA_RESTART;
        sigfillset(&sa.sa_mask);        /* block all sigs in these handlers */
        (void) sigaction(SIGHUP, &sa, NULL);
        (void) sigaction(SIGINT, &sa, NULL);
        (void) sigaction(SIGQUIT, &sa, NULL);
        (void) sigaction(SIGTERM, &sa, NULL);
        sa.sa_handler = lostconn;
        (void) sigaction(SIGPIPE, &sa, NULL);
        sa.sa_handler = toolong;
        (void) sigaction(SIGALRM, &sa, NULL);
        sa.sa_handler = sigurg;
        (void) sigaction(SIGURG, &sa, NULL);

        /* Try to handle urgent data inline */
#ifdef SO_OOBINLINE
        if (setsockopt(0, SOL_SOCKET, SO_OOBINLINE, (char *)&on, sizeof(on)) < 0)
                syslog(LOG_WARNING, "setsockopt: %m");
#endif
        /* Set keepalives on the socket to detect dropped connections.  */
#ifdef SO_KEEPALIVE
        keepalive = 1;
        if (setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, (char *)&keepalive,
            sizeof(int)) < 0)
                syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
#endif

#ifdef  F_SETOWN
        if (fcntl(fileno(stdin), F_SETOWN, getpid()) == -1)
                syslog(LOG_WARNING, "fcntl F_SETOWN: %m");
#endif
        logremotehost(&his_addr);
        /*
         * Set up default state
         */
        data = -1;
        type = TYPE_A;
        form = FORM_N;
        stru = STRU_F;
        mode = MODE_S;
        tmpline[0] = '\0';
        hasyyerrored = 0;

#ifdef KERBEROS5
        kerror = krb5_init_context(&kcontext);
        if (kerror) {
                syslog(LOG_ERR, "%s when initializing Kerberos context",
                    error_message(kerror));
                exit(0);
        }
#endif /* KERBEROS5 */

        init_curclass();
        curclass.timeout = 300;         /* 5 minutes, as per login(1) */
        curclass.type = CLASS_REAL;

        /* If logins are disabled, print out the message. */
        if (display_file(_PATH_NOLOGIN, 530)) {
                reply(530, "System not available.");
                exit(0);
        }
        (void)display_file(conffilename(_NAME_FTPWELCOME), 220);
                /* reply(220,) must follow */
        if (EMPTYSTR(version))
                reply(220, "%s FTP server ready.", hostname);
        else
                reply(220, "%s FTP server (%s) ready.", hostname, version);

        if (xferlogname != NULL) {
                xferlogfd = open(xferlogname, O_WRONLY | O_APPEND | O_CREAT,
                    0660);
                if (xferlogfd == -1)
                        syslog(LOG_WARNING, "open xferlog `%s': %m",
                            xferlogname);
                else
                        doxferlog |= 2;
        }

        ftp_loop();
        /* NOTREACHED */
}

static void
lostconn(int signo __unused)
{

        if (ftpd_debug)
                syslog(LOG_DEBUG, "lost connection");
        dologout(1);
}

static void
toolong(int signo __unused)
{

                /* XXXSIGRACE */
        reply(421,
            "Timeout (" LLF " seconds): closing control connection.",
            (LLT)curclass.timeout);
        if (logging)
                syslog(LOG_INFO, "User %s timed out after " LLF " seconds",
                    (pw ? pw->pw_name : "unknown"), (LLT)curclass.timeout);
        dologout(1);
}

static void
sigquit(int signo)
{

        if (ftpd_debug)
                syslog(LOG_DEBUG, "got signal %d", signo);
        dologout(1);
}

static void
sigurg(int signo __unused)
{
        
        urgflag = 1;
}


/*
 * Save the result of a getpwnam.  Used for USER command, since
 * the data returned must not be clobbered by any other command
 * (e.g., globbing).
 */
static struct passwd *
sgetpwnam(const char *name)
{
        static struct passwd save;
        struct passwd *p;

        if ((p = getpwnam(name)) == NULL)
                return (p);
        if (save.pw_name) {
                free((char *)save.pw_name);
                memset(save.pw_passwd, 0, strlen(save.pw_passwd));
                free((char *)save.pw_passwd);
                free((char *)save.pw_gecos);
                free((char *)save.pw_dir);
                free((char *)save.pw_shell);
        }
        save = *p;
        save.pw_name = ftpd_strdup(p->pw_name);
        save.pw_passwd = ftpd_strdup(p->pw_passwd);
        save.pw_gecos = ftpd_strdup(p->pw_gecos);
        save.pw_dir = ftpd_strdup(p->pw_dir);
        save.pw_shell = ftpd_strdup(p->pw_shell);
        return (&save);
}

static int      login_attempts; /* number of failed login attempts */
static int      askpasswd;      /* had USER command, ask for PASSwd */
static int      permitted;      /* USER permitted */

/*
 * USER command.
 * Sets global passwd pointer pw if named account exists and is acceptable;
 * sets askpasswd if a PASS command is expected.  If logged in previously,
 * need to reset state.  If name is "ftp" or "anonymous", the name is not in
 * _NAME_FTPUSERS, and ftp account exists, set guest and pw, then just return.
 * If account doesn't exist, ask for passwd anyway.  Otherwise, check user
 * requesting login privileges.  Disallow anyone who does not have a standard
 * shell as returned by getusershell().  Disallow anyone mentioned in the file
 * _NAME_FTPUSERS to allow people such as root and uucp to be avoided.
 */
void
user(const char *name)
{
        char    *class;
#ifdef  LOGIN_CAP
        login_cap_t *lc = NULL;
#endif
#ifdef USE_PAM
        int e;
#endif

        class = NULL;
        if (logged_in) {
                switch (curclass.type) {
                case CLASS_GUEST:
                        reply(530, "Can't change user from guest login.");
                        return;
                case CLASS_CHROOT:
                        reply(530, "Can't change user from chroot user.");
                        return;
                case CLASS_REAL:
                        if (dropprivs) {
                                reply(530, "Can't change user.");
                                return;
                        }
                        end_login();
                        break;
                default:
                        abort();
                }
        }

#if defined(KERBEROS)
        kdestroy();
#endif
#if defined(KERBEROS5)
        k5destroy();
#endif

        curclass.type = CLASS_REAL;
        askpasswd = 0;
        permitted = 0;

        if (strcmp(name, "ftp") == 0 || strcmp(name, "anonymous") == 0) {
                        /* need `pw' setup for checkaccess() and checkuser () */
                if ((pw = sgetpwnam("ftp")) == NULL)
                        reply(530, "User %s unknown.", name);
                else if (! checkaccess("ftp") || ! checkaccess("anonymous"))
                        reply(530, "User %s access denied.", name);
                else {
                        curclass.type = CLASS_GUEST;
                        askpasswd = 1;
                        reply(331,
                            "Guest login ok, type your name as password.");
                }
                if (!askpasswd) {
                        if (logging)
                                syslog(LOG_NOTICE,
                                    "ANONYMOUS FTP LOGIN REFUSED FROM %s",
                                    remoteloghost);
                        end_login();
                        goto cleanup_user;
                }
                name = "ftp";
        } else
                pw = sgetpwnam(name);

        strlcpy(curname, name, curname_len);

                        /* check user in /etc/ftpusers, and setup class */
        permitted = checkuser(_NAME_FTPUSERS, curname, 1, 0, &class);

                        /* check user in /etc/ftpchroot */
#ifdef  LOGIN_CAP
        lc = login_getpwclass(pw);
#endif
        if (checkuser(_NAME_FTPCHROOT, curname, 0, 0, NULL)
#ifdef  LOGIN_CAP       /* Allow login.conf configuration as well */
            || login_getcapbool(lc, "ftp-chroot", 0)
#endif
        ) {
                if (curclass.type == CLASS_GUEST) {
                        syslog(LOG_NOTICE,
            "Can't change guest user to chroot class; remove entry in %s",
                            _NAME_FTPCHROOT);
                        exit(1);
                }
                curclass.type = CLASS_CHROOT;
        }

                        /* determine default class */
        if (class == NULL) {
                switch (curclass.type) {
                case CLASS_GUEST:
                        class = ftpd_strdup("guest");
                        break;
                case CLASS_CHROOT:
                        class = ftpd_strdup("chroot");
                        break;
                case CLASS_REAL:
                        class = ftpd_strdup("real");
                        break;
                default:
                        syslog(LOG_ERR, "unknown curclass.type %d; aborting",
                            curclass.type);
                        abort();
                }
        }
                        /* parse ftpd.conf, setting up various parameters */
        parse_conf(class);
                        /* if not guest user, check for valid shell */
        if (pw == NULL)
                permitted = 0;
        else {
                const char      *cp, *shell;

                if ((shell = pw->pw_shell) == NULL || *shell == 0)
                        shell = _PATH_BSHELL;
                while ((cp = getusershell()) != NULL)
                        if (strcmp(cp, shell) == 0)
                                break;
                endusershell();
                if (cp == NULL && curclass.type != CLASS_GUEST)
                        permitted = 0;
        }

                        /* deny quickly (after USER not PASS) if requested */
        if (CURCLASS_FLAGS_ISSET(denyquick) && !permitted) {
                reply(530, "User %s may not use FTP.", curname);
                if (logging)
                        syslog(LOG_NOTICE, "FTP LOGIN REFUSED FROM %s, %s",
                            remoteloghost, curname);
                end_login();
                goto cleanup_user;
        }

                        /* if haven't asked yet (i.e, not anon), ask now */
        if (!askpasswd) {
                askpasswd = 1;
#ifdef USE_PAM
                e = auth_pam();         /* this does reply(331, ...) */
                do_pass(1, e, "");
                goto cleanup_user;
#else /* !USE_PAM */
#ifdef SKEY
                if (skey_haskey(curname) == 0) {
                        const char *myskey;

                        myskey = skey_keyinfo(curname);
                        reply(331, "Password [ %s ] required for %s.",
                            myskey ? myskey : "error getting challenge",
                            curname);
                } else
#endif
                        reply(331, "Password required for %s.", curname);
#endif /* !USE_PAM */
        }

 cleanup_user:
#ifdef LOGIN_CAP
        login_close(lc);
#endif
        /*
         * Delay before reading passwd after first failed
         * attempt to slow down passwd-guessing programs.
         */
        if (login_attempts)
                sleep((unsigned) login_attempts);

        if (class)
                free(class);
}

/*
 * Determine whether something is to happen (allow access, chroot)
 * for a user. Each line is a shell-style glob followed by
 * `yes' or `no'.
 *
 * For backward compatibility, `allow' and `deny' are synonymns
 * for `yes' and `no', respectively.
 *
 * Each glob is matched against the username in turn, and the first
 * match found is used. If no match is found, the result is the
 * argument `def'. If a match is found but without and explicit
 * `yes'/`no', the result is the opposite of def.
 *
 * If the file doesn't exist at all, the result is the argument
 * `nofile'
 *
 * Any line starting with `#' is considered a comment and ignored.
 *
 * Returns 0 if the user is denied, or 1 if they are allowed.
 *
 * NOTE: needs struct passwd *pw setup before use.
 */
static int
checkuser(const char *fname, const char *name, int def, int nofile,
            char **retclass)
{
        FILE    *fd;
        int      retval;
        char    *word, *perm, *class, *buf, *p;
        size_t   len, line;

        retval = def;
        if (retclass != NULL)
                *retclass = NULL;
        if ((fd = fopen(conffilename(fname), "r")) == NULL)
                return nofile;

        line = 0;
        for (;
            (buf = fparseln(fd, &len, &line, NULL, FPARSELN_UNESCCOMM |
                            FPARSELN_UNESCCONT | FPARSELN_UNESCESC)) != NULL;
            free(buf), buf = NULL) {
                word = perm = class = NULL;
                p = buf;
                if (len < 1)
                        continue;
                if (p[len - 1] == '\n')
                        p[--len] = '\0';
                if (EMPTYSTR(p))
                        continue;

                NEXTWORD(p, word);
                NEXTWORD(p, perm);
                NEXTWORD(p, class);
                if (EMPTYSTR(word))
                        continue;
                if (!EMPTYSTR(class)) {
                        if (strcasecmp(class, "all") == 0 ||
                            strcasecmp(class, "none") == 0) {
                                syslog(LOG_WARNING,
                "%s line %d: illegal user-defined class `%s' - skipping entry",
                                            fname, (int)line, class);
                                continue;
                        }
                }

                                        /* have a host specifier */
                if ((p = strchr(word, '@')) != NULL) {
                        unsigned char   net[16], mask[16], *addr;
                        int             addrlen, bits, bytes, a;

                        *p++ = '\0';
                                        /* check against network or CIDR */
                        memset(net, 0x00, sizeof(net));
                        if ((bits = inet_net_pton(his_addr.su_family, p, net,
                            sizeof(net))) != -1) {
#ifdef INET6
                                if (his_addr.su_family == AF_INET) {
#endif
                                        addrlen = 4;
                                        addr = (unsigned char *)&his_addr.su_addr;
#ifdef INET6
                                } else {
                                        addrlen = 16;
                                        addr = (unsigned char *)&his_addr.su_6addr;
                                }
#endif
                                bytes = bits / 8;
                                bits = bits % 8;
                                if (bytes > 0)
                                        memset(mask, 0xFF, bytes);
                                if (bytes < addrlen)
                                        mask[bytes] = 0xFF << (8 - bits);
                                if (bytes + 1 < addrlen)
                                        memset(mask + bytes + 1, 0x00,
                                            addrlen - bytes - 1);
                                for (a = 0; a < addrlen; a++)
                                        if ((addr[a] & mask[a]) != net[a])
                                                break;
                                if (a < addrlen)
                                        continue;

                                        /* check against hostname glob */
                        } else if (fnmatch(p, remotehost, FNM_CASEFOLD) != 0)
                                continue;
                }

                                        /* have a group specifier */
                if ((p = strchr(word, ':')) != NULL) {
                        gid_t   *groups, *ng;
                        int      gsize, i, found;

                        if (pw == NULL)
                                continue;       /* no match for unknown user */
                        *p++ = '\0';
                        groups = NULL;
                        gsize = 16;
                        do {
                                ng = realloc(groups, gsize * sizeof(gid_t));
                                if (ng == NULL)
                                        fatal(
                                            "Local resource failure: realloc");
                                groups = ng;
                        } while (getgrouplist(pw->pw_name, pw->pw_gid,
                                                groups, &gsize) == -1);
                        found = 0;
                        for (i = 0; i < gsize; i++) {
                                struct group *g;

                                if ((g = getgrgid(groups[i])) == NULL)
                                        continue;
                                if (fnmatch(p, g->gr_name, 0) == 0) {
                                        found = 1;
                                        break;
                                }
                        }
                        free(groups);
                        if (!found)
                                continue;
                }

                                        /* check against username glob */
                if (fnmatch(word, name, 0) != 0)
                        continue;

                if (perm != NULL &&
                    ((strcasecmp(perm, "allow") == 0) ||
                     (strcasecmp(perm, "yes") == 0)))
                        retval = 1;
                else if (perm != NULL &&
                    ((strcasecmp(perm, "deny") == 0) ||
                     (strcasecmp(perm, "no") == 0)))
                        retval = 0;
                else
                        retval = !def;
                if (!EMPTYSTR(class) && retclass != NULL)
                        *retclass = ftpd_strdup(class);
                free(buf);
                break;
        }
        (void) fclose(fd);
        return (retval);
}

/*
 * Check if user is allowed by /etc/ftpusers
 * returns 1 for yes, 0 for no
 *
 * NOTE: needs struct passwd *pw setup (for checkuser())
 */
static int
checkaccess(const char *name)
{

        return (checkuser(_NAME_FTPUSERS, name, 1, 0, NULL));
}

static void
login_utmp(const char *line, const char *name, const char *host,
    struct sockinet *haddr)
{
#if defined(SUPPORT_UTMPX) || defined(SUPPORT_UTMP)
        struct timeval tv;
        (void)gettimeofday(&tv, NULL);
#endif
#ifdef SUPPORT_UTMPX
        if (doutmp) {
                (void)memset(&utmpx, 0, sizeof(utmpx));
                utmpx.ut_tv = tv;
                utmpx.ut_pid = getpid();
                utmpx.ut_id[0] = 'f';
                utmpx.ut_id[1] = 't';
                utmpx.ut_id[2] = 'p';
                utmpx.ut_id[3] = '*';
                utmpx.ut_type = USER_PROCESS;
                (void)strncpy(utmpx.ut_name, name, sizeof(utmpx.ut_name));
                (void)strncpy(utmpx.ut_line, line, sizeof(utmpx.ut_line));
                (void)strncpy(utmpx.ut_host, host, sizeof(utmpx.ut_host));
                (void)memcpy(&utmpx.ut_ss, &haddr->si_su, haddr->su_len);
                ftpd_loginx(&utmpx);
        }
        if (dowtmp)
                ftpd_logwtmpx(line, name, host, haddr, 0, USER_PROCESS);
#endif
#ifdef SUPPORT_UTMP
        if (doutmp) {
                (void)memset(&utmp, 0, sizeof(utmp));
                (void)time(&utmp.ut_time);
                (void)strncpy(utmp.ut_name, name, sizeof(utmp.ut_name));
                (void)strncpy(utmp.ut_line, line, sizeof(utmp.ut_line));
                (void)strncpy(utmp.ut_host, host, sizeof(utmp.ut_host));
                ftpd_login(&utmp);
        }
        if (dowtmp)
                ftpd_logwtmp(line, name, host);
#endif
}

static void
logout_utmp(void)
{
#ifdef SUPPORT_UTMPX
        int okwtmpx = dowtmp;
#endif
#ifdef SUPPORT_UTMP
        int okwtmp = dowtmp;
#endif
        if (logged_in) {
#ifdef SUPPORT_UTMPX
                if (doutmp)
                        okwtmpx &= ftpd_logoutx(ttyline, 0, DEAD_PROCESS);
                if (okwtmpx)
                        ftpd_logwtmpx(ttyline, "", "", NULL, 0, DEAD_PROCESS);
#endif
#ifdef SUPPORT_UTMP
                if (doutmp)
                        okwtmp &= ftpd_logout(ttyline);
                if (okwtmp)
                        ftpd_logwtmp(ttyline, "", "");
#endif
        }
}

/*
 * Terminate login as previous user (if any), resetting state;
 * used when USER command is given or login fails.
 */
static void
end_login(void)
{
#ifdef USE_PAM
        int e;
#endif
        logout_utmp();
        show_chdir_messages(-1);                /* flush chdir cache */
        if (pw != NULL && pw->pw_passwd != NULL)
                memset(pw->pw_passwd, 0, strlen(pw->pw_passwd));
        pw = NULL;
        logged_in = 0;
        askpasswd = 0;
        permitted = 0;
        quietmessages = 0;
        gidcount = 0;
        curclass.type = CLASS_REAL;
        if (!dropprivs) {
                if (seteuid((uid_t)0) < 0) {
                        syslog(LOG_NOTICE, "end_login: can't seteuid 0: %m");
                        fatal("Can't reset privileges.");
                }
        }
#ifdef  LOGIN_CAP
        setusercontext(NULL, getpwuid(0), 0,
                       LOGIN_SETPRIORITY|LOGIN_SETRESOURCES|LOGIN_SETUMASK);
#endif
#ifdef USE_PAM
        if (pamh) {
                if ((e = pam_setcred(pamh, PAM_DELETE_CRED)) != PAM_SUCCESS)
                        syslog(LOG_ERR, "pam_setcred: %s",
                            pam_strerror(pamh, e));
                if ((e = pam_close_session(pamh,0)) != PAM_SUCCESS)
                        syslog(LOG_ERR, "pam_close_session: %s",
                            pam_strerror(pamh, e));
                if ((e = pam_end(pamh, e)) != PAM_SUCCESS)
                        syslog(LOG_ERR, "pam_end: %s", pam_strerror(pamh, e));
                pamh = NULL;
        }
#endif
}

void
pass(const char *passwd)
{
        do_pass(0, 0, passwd);
}

/*
 * Perform the passwd confirmation and login.
 *
 * If pass_checked is zero, confirm passwd is correct, & ignore pass_rval.
 * This is the traditional PASS implementation.
 *
 * If pass_checked is non-zero, use pass_rval and ignore passwd.
 * This is used by auth_pam() which has already parsed PASS.
 * This only applies to curclass.type != CLASS_GUEST.
 */
static void
do_pass(int pass_checked, int pass_rval, const char *passwd)
{
        int              rval;
        char             root[MAXPATHLEN];
#ifdef  LOGIN_CAP
        login_cap_t *lc = NULL;
#endif
#ifdef USE_PAM
        int e;
#endif

        rval = 1;

        if (logged_in || askpasswd == 0) {
                reply(503, "Login with USER first.");
                return;
        }
        askpasswd = 0;
        if (curclass.type != CLASS_GUEST) {
                        /* "ftp" is the only account allowed with no password */
                if (pw == NULL) {
                        rval = 1;       /* failure below */
                        goto skip;
                }
                if (pass_checked) {     /* password validated in user() */
                        rval = pass_rval;
                        goto skip;
                }
#ifdef USE_PAM
                syslog(LOG_ERR, "do_pass: USE_PAM shouldn't get here");
                rval = 1;
                goto skip;
#endif
#if defined(KERBEROS)
                if (klogin(pw, "", hostname, (char *)passwd) == 0) {
                        rval = 0;
                        goto skip;
                }
#endif
#if defined(KERBEROS5)
                if (k5login(pw, "", hostname, (char *)passwd) == 0) {
                        rval = 0;
                        goto skip;
                }
#endif
#ifdef SKEY
                if (skey_haskey(pw->pw_name) == 0) {
                        char *p;
                        int r;

                        p = ftpd_strdup(passwd);
                        r = skey_passcheck(pw->pw_name, p);
                        free(p);
                        if (r != -1) {
                                rval = 0;
                                goto skip;
                        }
                }
#endif
                if (!sflag)
                        rval = checkpassword(pw, passwd);
                else
                        rval = 1;

 skip:

                        /*
                         * If rval > 0, the user failed the authentication check
                         * above.  If rval == 0, either Kerberos or local
                         * authentication succeeded.
                         */
                if (rval) {
                        reply(530, "%s", rval == 2 ? "Password expired." :
                            "Login incorrect.");
                        pfilter_notify(1, rval == 2 ? "exppass" : "badpass");
                        if (logging) {
                                syslog(LOG_NOTICE,
                                    "FTP LOGIN FAILED FROM %s", remoteloghost);
                                syslog(LOG_AUTHPRIV | LOG_NOTICE,
                                    "FTP LOGIN FAILED FROM %s, %s",
                                    remoteloghost, curname);
                        }
                        pw = NULL;
                        if (login_attempts++ >= 5) {
                                syslog(LOG_NOTICE,
                                    "repeated login failures from %s",
                                    remoteloghost);
                                exit(0);
                        }
                        return;
                } else
                        pfilter_notify(0, "success");
        }

                        /* password ok; check if anything else prevents login */
        if (! permitted) {
                reply(530, "User %s may not use FTP.", pw->pw_name);
                if (logging)
                        syslog(LOG_NOTICE, "FTP LOGIN REFUSED FROM %s, %s",
                            remoteloghost, pw->pw_name);
                goto bad;
        }

        login_attempts = 0;             /* this time successful */
        if (setegid((gid_t)pw->pw_gid) < 0) {
                syslog(LOG_NOTICE, "user %s: can't setegid: %m", pw->pw_name);
                fatal("Can't drop privileges.");
        }
#ifdef  LOGIN_CAP
        if ((lc = login_getpwclass(pw)) != NULL) {
#ifdef notyet
                char    remote_ip[NI_MAXHOST];

                if (getnameinfo((struct sockaddr *)&his_addr, his_addr.su_len,
                        remote_ip, sizeof(remote_ip) - 1, NULL, 0,
                        NI_NUMERICHOST))
                                *remote_ip = 0;
                remote_ip[sizeof(remote_ip) - 1] = 0;
                if (!auth_hostok(lc, remotehost, remote_ip)) {
                        pfilter_notify(1, "bannedhost");
                        syslog(LOG_INFO|LOG_AUTH,
                            "FTP LOGIN FAILED (HOST) as %s: permission denied.",
                            pw->pw_name);
                        reply(530, "Permission denied.");
                        pw = NULL;
                        return;
                }
                if (!auth_timeok(lc, time(NULL))) {
                        reply(530, "Login not available right now.");
                        pw = NULL;
                        return;
                }
#endif
        }
        setsid();
        setusercontext(lc, pw, 0,
                LOGIN_SETLOGIN|LOGIN_SETGROUP|LOGIN_SETPRIORITY|
                LOGIN_SETRESOURCES|LOGIN_SETUMASK);
#else
        (void) initgroups(pw->pw_name, pw->pw_gid);
                        /* cache groups for cmds.c::matchgroup() */
#endif
#ifdef USE_PAM
        if (pamh) {
                if ((e = pam_open_session(pamh, 0)) != PAM_SUCCESS) {
                        syslog(LOG_ERR, "pam_open_session: %s",
                            pam_strerror(pamh, e));
                } else if ((e = pam_setcred(pamh, PAM_ESTABLISH_CRED))
                    != PAM_SUCCESS) {
                        syslog(LOG_ERR, "pam_setcred: %s",
                            pam_strerror(pamh, e));
                }
        }
#endif
        gidcount = getgroups(0, NULL);
        if (gidlist)
                free(gidlist);
        gidlist = malloc(gidcount * sizeof *gidlist);
        gidcount = getgroups(gidcount, gidlist);

        /* open utmp/wtmp before chroot */
        login_utmp(ttyline, pw->pw_name, remotehost, &his_addr);

        logged_in = 1;

        connections = 1;
        if (dopidfile)
                count_users();
        if (curclass.limit != -1 && connections > curclass.limit) {
                if (! EMPTYSTR(curclass.limitfile))
                        (void)display_file(conffilename(curclass.limitfile),
                            530);
                reply(530,
                    "User %s access denied, connection limit of " LLF
                    " reached.",
                    pw->pw_name, (LLT)curclass.limit);
                syslog(LOG_NOTICE,
                    "Maximum connection limit of " LLF
                    " for class %s reached, login refused for %s",
                    (LLT)curclass.limit, curclass.classname, pw->pw_name);
                goto bad;
        }

        homedir[0] = '/';
        switch (curclass.type) {
        case CLASS_GUEST:
                        /*
                         * We MUST do a chdir() after the chroot. Otherwise
                         * the old current directory will be accessible as "."
                         * outside the new root!
                         */
                format_path(root,
                    curclass.chroot ? curclass.chroot :
                    anondir ? anondir :
                    pw->pw_dir);
                format_path(homedir,
                    curclass.homedir ? curclass.homedir :
                    "/");
                if (EMPTYSTR(homedir))
                        homedir[0] = '/';
                if (EMPTYSTR(root) || chroot(root) < 0) {
                        syslog(LOG_NOTICE,
                            "GUEST user %s: can't chroot to %s: %m",
                            pw->pw_name, root);
                        goto bad_guest;
                }
                if (chdir(homedir) < 0) {
                        syslog(LOG_NOTICE,
                            "GUEST user %s: can't chdir to %s: %m",
                            pw->pw_name, homedir);
 bad_guest:
                        fatal("Can't set guest privileges.");
                }
                break;
        case CLASS_CHROOT:
                format_path(root,
                    curclass.chroot ? curclass.chroot :
                    pw->pw_dir);
                format_path(homedir,
                    curclass.homedir ? curclass.homedir :
                    "/");
                if (EMPTYSTR(homedir))
                        homedir[0] = '/';
                if (EMPTYSTR(root) || chroot(root) < 0) {
                        syslog(LOG_NOTICE,
                            "CHROOT user %s: can't chroot to %s: %m",
                            pw->pw_name, root);
                        goto bad_chroot;
                }
                if (chdir(homedir) < 0) {
                        syslog(LOG_NOTICE,
                            "CHROOT user %s: can't chdir to %s: %m",
                            pw->pw_name, homedir);
 bad_chroot:
                        fatal("Can't change root.");
                }
                break;
        case CLASS_REAL:
                        /* only chroot REAL if explicitly requested */
                if (! EMPTYSTR(curclass.chroot)) {
                        format_path(root, curclass.chroot);
                        if (EMPTYSTR(root) || chroot(root) < 0) {
                                syslog(LOG_NOTICE,
                                    "REAL user %s: can't chroot to %s: %m",
                                    pw->pw_name, root);
                                goto bad_chroot;
                        }
                }
                format_path(homedir,
                    curclass.homedir ? curclass.homedir :
                    pw->pw_dir);
                if (EMPTYSTR(homedir) || chdir(homedir) < 0) {
                        if (chdir("/") < 0) {
                                syslog(LOG_NOTICE,
                                    "REAL user %s: can't chdir to %s: %m",
                                    pw->pw_name,
                                    !EMPTYSTR(homedir) ?  homedir : "/");
                                reply(530,
                                    "User %s: can't change directory to %s.",
                                    pw->pw_name,
                                    !EMPTYSTR(homedir) ? homedir : "/");
                                goto bad;
                        } else {
                                reply(-230,
                                    "No directory! Logging in with home=/");
                                homedir[0] = '/';
                        }
                }
                break;
        }
#ifndef LOGIN_CAP
        setsid();
        setlogin(pw->pw_name);
#endif
        if (dropprivs ||
            (curclass.type != CLASS_REAL && 
            ntohs(ctrl_addr.su_port) > IPPORT_RESERVED + 1)) {
                dropprivs++;
                if (setgid((gid_t)pw->pw_gid) < 0) {
                        syslog(LOG_NOTICE, "user %s: can't setgid: %m", pw->pw_name);
                        fatal("Can't drop privileges.");
                }
                if (setuid((uid_t)pw->pw_uid) < 0) {
                        syslog(LOG_NOTICE, "user %s: can't setuid: %m", pw->pw_name);
                        fatal("Can't drop privileges.");
                }
        } else {
                if (seteuid((uid_t)pw->pw_uid) < 0) {
                        syslog(LOG_NOTICE, "user %s: can't seteuid: %m", pw->pw_name);
                        fatal("Can't drop privileges.");
                }
        }
        setenv("HOME", homedir, 1);

        if (curclass.type == CLASS_GUEST && passwd[0] == '-')
                quietmessages = 1;

                        /*
                         * Display a login message, if it exists.
                         * N.B. reply(230,) must follow the message.
                         */
        if (! EMPTYSTR(curclass.motd))
                (void)display_file(conffilename(curclass.motd), 230);
        show_chdir_messages(230);
        if (curclass.type == CLASS_GUEST) {
                char *p;

                reply(230, "Guest login ok, access restrictions apply.");
#if defined(HAVE_SETPROCTITLE)
                snprintf(proctitle, sizeof(proctitle),
                    "%s: anonymous/%s", remotehost, passwd);
                setproctitle("%s", proctitle);
#endif /* defined(HAVE_SETPROCTITLE) */
                if (logging)
                        syslog(LOG_INFO,
                        "ANONYMOUS FTP LOGIN FROM %s, %s (class: %s, type: %s)",
                            remoteloghost, passwd,
                            curclass.classname, CURCLASSTYPE);
                        /* store guest password reply into pw_passwd */
                REASSIGN(pw->pw_passwd, ftpd_strdup(passwd));
                for (p = pw->pw_passwd; *p; p++)
                        if (!isgraph((unsigned char)*p))
                                *p = '_';
        } else {
                reply(230, "User %s logged in.", pw->pw_name);
#if defined(HAVE_SETPROCTITLE)
                snprintf(proctitle, sizeof(proctitle),
                    "%s: %s", remotehost, pw->pw_name);
                setproctitle("%s", proctitle);
#endif /* defined(HAVE_SETPROCTITLE) */
                if (logging)
                        syslog(LOG_INFO,
                            "FTP LOGIN FROM %s as %s (class: %s, type: %s)",
                            remoteloghost, pw->pw_name,
                            curclass.classname, CURCLASSTYPE);
        }
        (void) umask(curclass.umask);
#ifdef  LOGIN_CAP
        login_close(lc);
#endif
        return;

 bad:
#ifdef  LOGIN_CAP
        login_close(lc);
#endif
                        /* Forget all about it... */
        end_login();
}

void
retrieve(const char *argv[], const char *name)
{
        FILE *fin, *dout;
        struct stat st;
        int (*closefunc)(FILE *) = NULL;
        int dolog, sendrv, closerv, stderrfd, isconversion, isdata, isls;
        struct timeval start, finish, td, *tdp;
        struct rusage rusage_before, rusage_after;
        const char *dispname;
        const char *error;

        sendrv = closerv = stderrfd = -1;
        isconversion = isdata = isls = dolog = 0;
        tdp = NULL;
        dispname = name;
        fin = dout = NULL;
        error = NULL;
        if (argv == NULL) {             /* if not running a command ... */
                dolog = 1;
                isdata = 1;
                fin = fopen(name, "r");
                closefunc = fclose;
                if (fin == NULL)        /* doesn't exist?; try a conversion */
                        argv = do_conversion(name);
                if (argv != NULL) {
                        isconversion++;
                        syslog(LOG_DEBUG, "get command: '%s' on '%s'",
                            argv[0], name);
                }
        }
        if (argv != NULL) {
                char temp[MAXPATHLEN];

                if (strcmp(argv[0], INTERNAL_LS) == 0) {
                        isls = 1;
                        stderrfd = -1;
                } else {
                        (void)snprintf(temp, sizeof(temp), "%s", TMPFILE);
                        stderrfd = mkstemp(temp);
                        if (stderrfd != -1)
                                (void)unlink(temp);
                }
                dispname = argv[0];
                fin = ftpd_popen(argv, "r", stderrfd);
                closefunc = ftpd_pclose;
                st.st_size = -1;
                st.st_blksize = BUFSIZ;
        }
        if (fin == NULL) {
                if (errno != 0) {
                        perror_reply(550, dispname);
                        if (dolog)
                                logxfer("get", -1, name, NULL, NULL,
                                    strerror(errno));
                }
                goto cleanupretrieve;
        }
        byte_count = -1;
        if (argv == NULL
            && (fstat(fileno(fin), &st) < 0 || !S_ISREG(st.st_mode))) {
                error = "Not a plain file";
                reply(550, "%s: %s.", dispname, error);
                goto done;
        }
        if (restart_point) {
                if (type == TYPE_A) {
                        off_t i;
                        int c;

                        for (i = 0; i < restart_point; i++) {
                                if ((c=getc(fin)) == EOF) {
                                        error = strerror(errno);
                                        perror_reply(550, dispname);
                                        goto done;
                                }
                                if (c == '\n')
                                        i++;
                        }
                } else if (lseek(fileno(fin), restart_point, SEEK_SET) < 0) {
                        error = strerror(errno);
                        perror_reply(550, dispname);
                        goto done;
                }
        }
        dout = dataconn(dispname, st.st_size, "w");
        if (dout == NULL)
                goto done;

        (void)getrusage(RUSAGE_SELF, &rusage_before);
        (void)gettimeofday(&start, NULL);
        sendrv = send_data(fin, dout, &st, isdata);
        (void)gettimeofday(&finish, NULL);
        (void)getrusage(RUSAGE_SELF, &rusage_after);
        closedataconn(dout);            /* close now to affect timing stats */
        timersub(&finish, &start, &td);
        tdp = &td;
 done:
        if (dolog) {
                logxfer("get", byte_count, name, NULL, tdp, error);
                if (tdp != NULL)
                        logrusage(&rusage_before, &rusage_after);
        }
        closerv = (*closefunc)(fin);
        if (sendrv == 0) {
                FILE *errf;
                struct stat sb;

                if (!isls && argv != NULL && closerv != 0) {
                        reply(-226,
                            "Command returned an exit status of %d",
                            closerv);
                        if (isconversion)
                                syslog(LOG_WARNING,
                                    "retrieve command: '%s' returned %d",
                                    argv[0], closerv);
                }
                if (!isls && argv != NULL && stderrfd != -1 &&
                    (fstat(stderrfd, &sb) == 0) && sb.st_size > 0 &&
                    ((errf = fdopen(stderrfd, "r")) != NULL)) {
                        char *cp, line[LINE_MAX];

                        reply(-226, "Command error messages:");
                        rewind(errf);
                        while (fgets(line, sizeof(line), errf) != NULL) {
                                if ((cp = strchr(line, '\n')) != NULL)
                                        *cp = '\0';
                                reply(0, "  %s", line);
                        }
                        (void) fflush(stdout);
                        (void) fclose(errf);
                                /* a reply(226,) must follow */
                }
                reply(226, "Transfer complete.");
        }
 cleanupretrieve:
        if (stderrfd != -1)
                (void)close(stderrfd);
        if (isconversion)
                free(argv);
}

void
store(const char *name, const char *fmode, int unique)
{
        FILE *fout, *din;
        struct stat st;
        int (*closefunc)(FILE *);
        struct timeval start, finish, td, *tdp;
        const char *desc, *error;

        din = NULL;
        desc = (*fmode == 'w') ? "put" : "append";
        error = NULL;
        if (unique && stat(name, &st) == 0 &&
            (name = gunique(name)) == NULL) {
                logxfer(desc, -1, name, NULL, NULL,
                    "cannot create unique file");
                goto cleanupstore;
        }

        if (restart_point)
                fmode = "r+";
        fout = fopen(name, fmode);
        closefunc = fclose;
        tdp = NULL;
        if (fout == NULL) {
                perror_reply(553, name);
                logxfer(desc, -1, name, NULL, NULL, strerror(errno));
                goto cleanupstore;
        }
        byte_count = -1;
        if (restart_point) {
                if (type == TYPE_A) {
                        off_t i;
                        int c;

                        for (i = 0; i < restart_point; i++) {
                                if ((c=getc(fout)) == EOF) {
                                        error = strerror(errno);
                                        perror_reply(550, name);
                                        goto done;
                                }
                                if (c == '\n')
                                        i++;
                        }
                        /*
                         * We must do this seek to "current" position
                         * because we are changing from reading to
                         * writing.
                         */
                        if (fseek(fout, 0L, SEEK_CUR) < 0) {
                                error = strerror(errno);
                                perror_reply(550, name);
                                goto done;
                        }
                } else if (lseek(fileno(fout), restart_point, SEEK_SET) < 0) {
                        error = strerror(errno);
                        perror_reply(550, name);
                        goto done;
                }
        }
        din = dataconn(name, (off_t)-1, "r");
        if (din == NULL)
                goto done;
        (void)gettimeofday(&start, NULL);
        if (receive_data(din, fout) == 0) {
                if (unique)
                        reply(226, "Transfer complete (unique file name:%s).",
                            name);
                else
                        reply(226, "Transfer complete.");
        }
        (void)gettimeofday(&finish, NULL);
        closedataconn(din);             /* close now to affect timing stats */
        timersub(&finish, &start, &td);
        tdp = &td;
 done:
        logxfer(desc, byte_count, name, NULL, tdp, error);
        (*closefunc)(fout);
 cleanupstore:
        ;
}

static FILE *
getdatasock(const char *fmode)
{
        int             on, s, t, tries;
        in_port_t       port;

        on = 1;
        if (data >= 0)
                return (fdopen(data, fmode));
        if (! dropprivs) {
                if (seteuid((uid_t)0) < 0) {
                        syslog(LOG_NOTICE, "getdatasock: can't seteuid 0: %m");
                        fatal("Can't reset privileges.");
                }
        }
        s = socket(ctrl_addr.su_family, SOCK_STREAM, 0);
        if (s < 0)
                goto bad;
        if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
            (char *) &on, sizeof(on)) < 0)
                goto bad;
        if (setsockopt(s, SOL_SOCKET, SO_KEEPALIVE,
            (char *) &on, sizeof(on)) < 0)
                goto bad;
                        /* anchor socket to avoid multi-homing problems */
        data_source = ctrl_addr;
                        /*
                         * By default source port for PORT connections is
                         * ctrlport-1 (see RFC959 section 5.2).
                         * However, if privs have been dropped and that
                         * would be < IPPORT_RESERVED, use a random port
                         * instead.
                         */
        if (dataport)
                port = dataport;
        else
                port = ntohs(ctrl_addr.su_port) - 1;
        if (dropprivs && port < IPPORT_RESERVED)
                port = 0;               /* use random port */
        data_source.su_port = htons(port);

        for (tries = 1; ; tries++) {
                if (bind(s, (struct sockaddr *)&data_source.si_su,
                    data_source.su_len) >= 0)
                        break;
                if (errno != EADDRINUSE || tries > 10)
                        goto bad;
                sleep(tries);
        }
        if (! dropprivs) {
                if (seteuid((uid_t)pw->pw_uid) < 0) {
                        syslog(LOG_NOTICE, "user %s: can't seteuid: %m", pw->pw_name);
                        fatal("Can't drop privileges.");
                }
        }
#ifdef IP_TOS
        if (!mapped && ctrl_addr.su_family == AF_INET) {
                on = IPTOS_THROUGHPUT;
                if (setsockopt(s, IPPROTO_IP, IP_TOS, (char *)&on,
                               sizeof(int)) < 0)
                        syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
        }
#endif
        return (fdopen(s, fmode));
 bad:
                /* Return the real value of errno (close may change it) */
        t = errno;
        if (! dropprivs) {
                if (seteuid((uid_t)pw->pw_uid) < 0) {
                        syslog(LOG_NOTICE, "user %s: can't seteuid: %m", pw->pw_name);
                        fatal("Can't drop privileges.");
                }
        }
        if (s >= 0)
                (void) close(s);
        errno = t;
        return (NULL);
}

FILE *
dataconn(const char *name, off_t size, const char *fmode)
{
        char sizebuf[32];
        FILE *file;
        int retry, tos, keepalive, conerrno;

        file_size = size;
        byte_count = 0;
        if (size != (off_t) -1)
                (void)snprintf(sizebuf, sizeof(sizebuf), " (" LLF " byte%s)",
                    (LLT)size, PLURAL(size));
        else
                sizebuf[0] = '\0';
        if (pdata >= 0) {
                struct sockinet from;
                int s;
                socklen_t fromlen = sizeof(from.su_len);

                (void) alarm(curclass.timeout);
                s = accept(pdata, (struct sockaddr *)&from.si_su, &fromlen);
                (void) alarm(0);
                if (s < 0) {
                        reply(425, "Can't open data connection.");
                        (void) close(pdata);
                        pdata = -1;
                        return (NULL);
                }
                (void) close(pdata);
                pdata = s;
                switch (from.su_family) {
                case AF_INET:
#ifdef IP_TOS
                        if (!mapped) {
                                tos = IPTOS_THROUGHPUT;
                                (void) setsockopt(s, IPPROTO_IP, IP_TOS,
                                    (char *)&tos, sizeof(int));
                        }
                        break;
#endif
                }
                /* Set keepalives on the socket to detect dropped conns. */
#ifdef SO_KEEPALIVE
                keepalive = 1;
                (void) setsockopt(s, SOL_SOCKET, SO_KEEPALIVE,
                    (char *)&keepalive, sizeof(int));
#endif
                reply(150, "Opening %s mode data connection for '%s'%s.",
                     type == TYPE_A ? "ASCII" : "BINARY", name, sizebuf);
                return (fdopen(pdata, fmode));
        }
        if (data >= 0) {
                reply(125, "Using existing data connection for '%s'%s.",
                    name, sizebuf);
                usedefault = 1;
                return (fdopen(data, fmode));
        }
        if (usedefault)
                data_dest = his_addr;
        usedefault = 1;
        retry = conerrno = 0;
        do {
                file = getdatasock(fmode);
                if (file == NULL) {
                        char hbuf[NI_MAXHOST];
                        char pbuf[NI_MAXSERV];
                        conerrno = errno;
                        if (getnameinfo((struct sockaddr *)&data_source.si_su,
                            data_source.su_len, hbuf, sizeof(hbuf), pbuf,
                            sizeof(pbuf), NI_NUMERICHOST | NI_NUMERICSERV))
                                strlcpy(hbuf, "?", sizeof(hbuf));
                        reply(425, "Can't create data socket (%s,%s): %s.",
                              hbuf, pbuf, strerror(conerrno));
                        return (NULL);
                }
                data = fileno(file);
                conerrno = 0;
                if (connect(data, (struct sockaddr *)&data_dest.si_su,
                    data_dest.su_len) == 0)
                        break;
                conerrno = errno;
                (void) fclose(file);
                file = NULL;
                data = -1;
                if (conerrno == EADDRINUSE) {
                        sleep((unsigned) swaitint);
                        retry += swaitint;
                } else {
                        break;
                }
        } while (retry <= swaitmax);
        if (conerrno != 0) {
                perror_reply(425, "Can't build data connection");
                return (NULL);
        }
        reply(150, "Opening %s mode data connection for '%s'%s.",
             type == TYPE_A ? "ASCII" : "BINARY", name, sizebuf);
        return (file);
}

void
closedataconn(FILE *fd)
{

        if (fd == NULL)
                return;
        (void)fclose(fd);
        data = -1;
        if (pdata >= 0)
                (void)close(pdata);
        pdata = -1;
}

int
write_data(int fd, char *buf, size_t size, off_t *bufrem,
    struct timeval *then, int isdata)
{
        struct timeval now, td;
        ssize_t c;

        while (size > 0) {
                c = size;
                if (curclass.writesize) {
                        if (curclass.writesize < c)
                                c = curclass.writesize;
                }
                if (curclass.rateget) {
                        if (*bufrem < c)
                                c = *bufrem;
                }
                (void) alarm(curclass.timeout);
                c = write(fd, buf, c);
                if (c <= 0)
                        return (1);
                buf += c;
                size -= c;
                byte_count += c;
                if (isdata) {
                        total_data_out += c;
                        total_data += c;
                }
                total_bytes_out += c;
                total_bytes += c;
                if (curclass.rateget) {
                        *bufrem -= c;
                        if (*bufrem == 0) {
                                (void)gettimeofday(&now, NULL);
                                timersub(&now, then, &td);
                                if (td.tv_sec == 0) {
                                        usleep(1000000 - td.tv_usec);
                                        (void)gettimeofday(then, NULL);
                                } else
                                        *then = now;
                                *bufrem = curclass.rateget;
                        }
                }
        }
        return (0);
}

static enum send_status
send_data_with_read(int filefd, int netfd, const struct stat *st, int isdata)
{
        struct timeval then;
        off_t bufrem;
        ssize_t readsize;
        char *buf;
        int c, error;

        if (curclass.readsize > 0)
                readsize = curclass.readsize;
        else
                readsize = st->st_blksize;
        if ((buf = malloc(readsize)) == NULL) {
                perror_reply(451, "Local resource failure: malloc");
                return (SS_NO_TRANSFER);
        }

        if (curclass.rateget) {
                bufrem = curclass.rateget;
                (void)gettimeofday(&then, NULL);
        } else
                bufrem = readsize;
        for (;;) {
                (void) alarm(curclass.timeout);
                c = read(filefd, buf, readsize);
                if (c == 0)
                        error = SS_SUCCESS;
                else if (c < 0)
                        error = SS_FILE_ERROR;
                else if (write_data(netfd, buf, c, &bufrem, &then, isdata))
                        error = SS_DATA_ERROR;
                else if (urgflag && handleoobcmd())
                        error = SS_ABORTED;
                else
                        continue;

                free(buf);
                return (error);
        }
}

static enum send_status
send_data_with_mmap(int filefd, int netfd, const struct stat *st, int isdata)
{
        struct timeval then;
        off_t bufrem, filesize, off, origoff;
        ssize_t mapsize, winsize;
        int error, sendbufsize, sendlowat;
        void *win;

        bufrem = 0;
        if (curclass.sendbufsize) {
                sendbufsize = curclass.sendbufsize;
                if (setsockopt(netfd, SOL_SOCKET, SO_SNDBUF,
                    &sendbufsize, sizeof(int)) == -1)
                        syslog(LOG_WARNING, "setsockopt(SO_SNDBUF, %d): %m",
                            sendbufsize);
        }

        if (curclass.sendlowat) {
                sendlowat = curclass.sendlowat;
                if (setsockopt(netfd, SOL_SOCKET, SO_SNDLOWAT,
                    &sendlowat, sizeof(int)) == -1)
                        syslog(LOG_WARNING, "setsockopt(SO_SNDLOWAT, %d): %m",
                            sendlowat);
        }

        winsize = curclass.mmapsize;
        filesize = st->st_size;
        if (ftpd_debug)
                syslog(LOG_INFO, "mmapsize = " LLF ", writesize = " LLF,
                    (LLT)winsize, (LLT)curclass.writesize);
        if (winsize <= 0)
                goto try_read;

        off = lseek(filefd, (off_t)0, SEEK_CUR);
        if (off == -1)
                goto try_read;

        origoff = off;
        if (curclass.rateget) {
                bufrem = curclass.rateget;
                (void)gettimeofday(&then, NULL);
        } else
                bufrem = winsize;
        while (1) {
                mapsize = MIN(filesize - off, winsize);
                if (mapsize == 0)
                        break;
                win = mmap(NULL, mapsize, PROT_READ,
                    MAP_FILE|MAP_SHARED, filefd, off);
                if (win == MAP_FAILED) {
                        if (off == origoff)
                                goto try_read;
                        return (SS_FILE_ERROR);
                }
                (void) madvise(win, mapsize, MADV_SEQUENTIAL);
                error = write_data(netfd, win, mapsize, &bufrem, &then,
                    isdata);
                (void) madvise(win, mapsize, MADV_DONTNEED);
                munmap(win, mapsize);
                if (urgflag && handleoobcmd())
                        return (SS_ABORTED);
                if (error)
                        return (SS_DATA_ERROR);
                off += mapsize;
        }
        return (SS_SUCCESS);

 try_read:
        return (send_data_with_read(filefd, netfd, st, isdata));
}

/*
 * Transfer the contents of "instr" to "outstr" peer using the appropriate
 * encapsulation of the data subject to Mode, Structure, and Type.
 *
 * NB: Form isn't handled.
 */
static int
send_data(FILE *instr, FILE *outstr, const struct stat *st, int isdata)
{
        int      c, filefd, netfd, rval;

        urgflag = 0;
        transflag = 1;
        rval = -1;

        switch (type) {

        case TYPE_A:
 /* XXXLUKEM: rate limit ascii send (get) */
                (void) alarm(curclass.timeout);
                while ((c = getc(instr)) != EOF) {
                        if (urgflag && handleoobcmd())
                                goto cleanup_send_data;
                        byte_count++;
                        if (c == '\n') {
                                if (ferror(outstr))
                                        goto data_err;
                                (void) putc('\r', outstr);
                                if (isdata) {
                                        total_data_out++;
                                        total_data++;
                                }
                                total_bytes_out++;
                                total_bytes++;
                        }
                        (void) putc(c, outstr);
                        if (isdata) {
                                total_data_out++;
                                total_data++;
                        }
                        total_bytes_out++;
                        total_bytes++;
                        if ((byte_count % 4096) == 0)
                                (void) alarm(curclass.timeout);
                }
                (void) alarm(0);
                fflush(outstr);
                if (ferror(instr))
                        goto file_err;
                if (ferror(outstr))
                        goto data_err;
                rval = 0;
                goto cleanup_send_data;

        case TYPE_I:
        case TYPE_L:
                filefd = fileno(instr);
                netfd = fileno(outstr);
                switch (send_data_with_mmap(filefd, netfd, st, isdata)) {

                case SS_SUCCESS:
                        break;

                case SS_ABORTED:
                case SS_NO_TRANSFER:
                        goto cleanup_send_data;

                case SS_FILE_ERROR:
                        goto file_err;

                case SS_DATA_ERROR:
                        goto data_err;
                }
                rval = 0;
                goto cleanup_send_data;

        default:
                reply(550, "Unimplemented TYPE %d in send_data", type);
                goto cleanup_send_data;
        }

 data_err:
        (void) alarm(0);
        perror_reply(426, "Data connection");
        goto cleanup_send_data;

 file_err:
        (void) alarm(0);
        perror_reply(551, "Error on input file");
        goto cleanup_send_data;

 cleanup_send_data:
        (void) alarm(0);
        transflag = 0;
        urgflag = 0;
        if (isdata) {
                total_files_out++;
                total_files++;
        }
        total_xfers_out++;
        total_xfers++;
        return (rval);
}

/*
 * Transfer data from peer to "outstr" using the appropriate encapsulation of
 * the data subject to Mode, Structure, and Type.
 *
 * N.B.: Form isn't handled.
 */
static int
receive_data(FILE *instr, FILE *outstr)
{
        int     c, netfd, filefd, rval;
        int     volatile bare_lfs;
        off_t   byteswritten;
        char    *buf;
        ssize_t readsize;
        struct sigaction sa, sa_saved;
        struct stat st;

        memset(&sa, 0, sizeof(sa));
        sigfillset(&sa.sa_mask);
        sa.sa_flags = SA_RESTART;
        sa.sa_handler = lostconn;
        (void) sigaction(SIGALRM, &sa, &sa_saved);

        bare_lfs = 0;
        urgflag = 0;
        transflag = 1;
        rval = -1;
        byteswritten = 0;
        buf = NULL;

#define FILESIZECHECK(x) \
                        do { \
                                if (curclass.maxfilesize != -1 && \
                                    (x) > curclass.maxfilesize) { \
                                        errno = EFBIG; \
                                        goto file_err; \
                                } \
                        } while (0)

        switch (type) {

        case TYPE_I:
        case TYPE_L:
                netfd = fileno(instr);
                filefd = fileno(outstr);
                (void) alarm(curclass.timeout);
                if (curclass.readsize)
                        readsize = curclass.readsize;
                else if (fstat(filefd, &st) != -1)
                        readsize = (ssize_t)st.st_blksize;
                else
                        readsize = BUFSIZ;
                if ((buf = malloc(readsize)) == NULL) {
                        perror_reply(451, "Local resource failure: malloc");
                        goto cleanup_recv_data;
                }
                if (curclass.rateput) {
                        while (1) {
                                int d;
                                struct timeval then, now, td;
                                off_t bufrem;

                                (void)gettimeofday(&then, NULL);
                                errno = c = d = 0;
                                for (bufrem = curclass.rateput; bufrem > 0; ) {
                                        if ((c = read(netfd, buf,
                                            MIN(readsize, bufrem))) <= 0)
                                                goto recvdone;
                                        if (urgflag && handleoobcmd())
                                                goto cleanup_recv_data;
                                        FILESIZECHECK(byte_count + c);
                                        if ((d = write(filefd, buf, c)) != c)
                                                goto file_err;
                                        (void) alarm(curclass.timeout);
                                        bufrem -= c;
                                        byte_count += c;
                                        total_data_in += c;
                                        total_data += c;
                                        total_bytes_in += c;
                                        total_bytes += c;
                                }
                                (void)gettimeofday(&now, NULL);
                                timersub(&now, &then, &td);
                                if (td.tv_sec == 0)
                                        usleep(1000000 - td.tv_usec);
                        }
                } else {
                        while ((c = read(netfd, buf, readsize)) > 0) {
                                if (urgflag && handleoobcmd())
                                        goto cleanup_recv_data;
                                FILESIZECHECK(byte_count + c);
                                if (write(filefd, buf, c) != c)
                                        goto file_err;
                                (void) alarm(curclass.timeout);
                                byte_count += c;
                                total_data_in += c;
                                total_data += c;
                                total_bytes_in += c;
                                total_bytes += c;
                        }
                }
 recvdone:
                if (c < 0)
                        goto data_err;
                rval = 0;
                goto cleanup_recv_data;

        case TYPE_E:
                reply(553, "TYPE E not implemented.");
                goto cleanup_recv_data;

        case TYPE_A:
                (void) alarm(curclass.timeout);
 /* XXXLUKEM: rate limit ascii receive (put) */
                while ((c = getc(instr)) != EOF) {
                        if (urgflag && handleoobcmd())
                                goto cleanup_recv_data;
                        byte_count++;
                        total_data_in++;
                        total_data++;
                        total_bytes_in++;
                        total_bytes++;
                        if ((byte_count % 4096) == 0)
                                (void) alarm(curclass.timeout);
                        if (c == '\n')
                                bare_lfs++;
                        while (c == '\r') {
                                if (ferror(outstr))
                                        goto data_err;
                                if ((c = getc(instr)) != '\n') {
                                        byte_count++;
                                        total_data_in++;
                                        total_data++;
                                        total_bytes_in++;
                                        total_bytes++;
                                        if ((byte_count % 4096) == 0)
                                                (void) alarm(curclass.timeout);
                                        byteswritten++;
                                        FILESIZECHECK(byteswritten);
                                        (void) putc ('\r', outstr);
                                        if (c == '\0' || c == EOF)
                                                goto contin2;
                                }
                        }
                        byteswritten++;
                        FILESIZECHECK(byteswritten);
                        (void) putc(c, outstr);
 contin2:       ;
                }
                (void) alarm(0);
                fflush(outstr);
                if (ferror(instr))
                        goto data_err;
                if (ferror(outstr))
                        goto file_err;
                if (bare_lfs) {
                        reply(-226,
                            "WARNING! %d bare linefeeds received in ASCII mode",
                            bare_lfs);
                        reply(0, "File may not have transferred correctly.");
                }
                rval = 0;
                goto cleanup_recv_data;

        default:
                reply(550, "Unimplemented TYPE %d in receive_data", type);
                goto cleanup_recv_data;
        }
#undef FILESIZECHECK

 data_err:
        (void) alarm(0);
        perror_reply(426, "Data Connection");
        goto cleanup_recv_data;

 file_err:
        (void) alarm(0);
        perror_reply(452, "Error writing file");
        goto cleanup_recv_data;

 cleanup_recv_data:
        (void) alarm(0);
        (void) sigaction(SIGALRM, &sa_saved, NULL);
        if (buf)
                free(buf);
        transflag = 0;
        urgflag = 0;
        total_files_in++;
        total_files++;
        total_xfers_in++;
        total_xfers++;
        return (rval);
}

void
statcmd(void)
{
        struct sockinet *su = NULL;
        static char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
        unsigned char *a, *p;
        int ispassive, af;
        off_t otbi, otbo, otb;

        a = p = NULL;

        reply(-211, "%s FTP server status:", hostname);
        reply(0, "Version: %s", EMPTYSTR(version) ? "<suppressed>" : version);
        hbuf[0] = '\0';
        if (!getnameinfo((struct sockaddr *)&his_addr.si_su, his_addr.su_len,
                        hbuf, sizeof(hbuf), NULL, 0, NI_NUMERICHOST)
            && strcmp(remotehost, hbuf) != 0)
                reply(0, "Connected to %s (%s)", remotehost, hbuf);
        else
                reply(0, "Connected to %s", remotehost);

        if (logged_in) {
                if (curclass.type == CLASS_GUEST)
                        reply(0, "Logged in anonymously");
                else
                        reply(0, "Logged in as %s%s", pw->pw_name,
                            curclass.type == CLASS_CHROOT ? " (chroot)" : "");
        } else if (askpasswd)
                reply(0, "Waiting for password");
        else
                reply(0, "Waiting for user name");
        cprintf(stdout, "    TYPE: %s", typenames[type]);
        if (type == TYPE_A || type == TYPE_E)
                cprintf(stdout, ", FORM: %s", formnames[form]);
        if (type == TYPE_L) {
#if NBBY == 8
                cprintf(stdout, " %d", NBBY);
#else
                        /* XXX: `bytesize' needs to be defined in this case */
                cprintf(stdout, " %d", bytesize);
#endif
        }
        cprintf(stdout, "; STRUcture: %s; transfer MODE: %s\r\n",
            strunames[stru], modenames[mode]);
        ispassive = 0;
        if (data != -1) {
                reply(0, "Data connection open");
                su = NULL;
        } else if (pdata != -1) {
                reply(0, "in Passive mode");
                if (curclass.advertise.su_len != 0)
                        su = &curclass.advertise;
                else
                        su = &pasv_addr;
                ispassive = 1;
                goto printaddr;
        } else if (usedefault == 0) {
                su = (struct sockinet *)&data_dest;

                if (epsvall) {
                        reply(0, "EPSV only mode (EPSV ALL)");
                        goto epsvonly;
                }
 printaddr:
                                                        /* PASV/PORT */
                if (su->su_family == AF_INET) {
                        a = (unsigned char *) &su->su_addr;
                        p = (unsigned char *) &su->su_port;
#define UC(b) (((int) b) & 0xff)
                        reply(0, "%s (%d,%d,%d,%d,%d,%d)",
                                ispassive ? "PASV" : "PORT" ,
                                UC(a[0]), UC(a[1]), UC(a[2]), UC(a[3]),
                                UC(p[0]), UC(p[1]));
                }

                                                        /* LPSV/LPRT */
            {
                int alen, i;

                alen = 0;
                switch (su->su_family) {
                case AF_INET:
                        a = (unsigned char *) &su->su_addr;
                        p = (unsigned char *) &su->su_port;
                        alen = sizeof(su->su_addr);
                        af = 4;
                        break;
#ifdef INET6
                case AF_INET6:
                        a = (unsigned char *) &su->su_6addr;
                        p = (unsigned char *) &su->su_port;
                        alen = sizeof(su->su_6addr);
                        af = 6;
                        break;
#endif
                default:
                        af = 0;
                        break;
                }
                if (af) {
                        cprintf(stdout, "    %s (%d,%d",
                            ispassive ? "LPSV" : "LPRT", af, alen);
                        for (i = 0; i < alen; i++)
                                cprintf(stdout, ",%d", UC(a[i]));
                        cprintf(stdout, ",%d,%d,%d)\r\n",
                            2, UC(p[0]), UC(p[1]));
#undef UC
                }
            }

                /* EPRT/EPSV */
 epsvonly:
                af = af2epsvproto(su->su_family);
                hbuf[0] = '\0';
                if (af > 0) {
                        struct sockinet tmp;

                        tmp = *su;
#ifdef INET6
                        if (tmp.su_family == AF_INET6)
                                tmp.su_scope_id = 0;
#endif
                        if (getnameinfo((struct sockaddr *)&tmp.si_su,
                            tmp.su_len, hbuf, sizeof(hbuf), sbuf, sizeof(sbuf),
                            NI_NUMERICHOST | NI_NUMERICSERV) == 0)
                                reply(0, "%s (|%d|%s|%s|)",
                                    ispassive ? "EPSV" : "EPRT",
                                    af, hbuf, sbuf);
                }
        } else
                reply(0, "No data connection");

        if (logged_in) {
                reply(0,
                    "Data sent:        " LLF " byte%s in " LLF " file%s",
                    (LLT)total_data_out, PLURAL(total_data_out),
                    (LLT)total_files_out, PLURAL(total_files_out));
                reply(0,
                    "Data received:    " LLF " byte%s in " LLF " file%s",
                    (LLT)total_data_in, PLURAL(total_data_in),
                    (LLT)total_files_in, PLURAL(total_files_in));
                reply(0,
                    "Total data:       " LLF " byte%s in " LLF " file%s",
                    (LLT)total_data, PLURAL(total_data),
                    (LLT)total_files, PLURAL(total_files));
        }
        otbi = total_bytes_in;
        otbo = total_bytes_out;
        otb = total_bytes;
        reply(0, "Traffic sent:     " LLF " byte%s in " LLF " transfer%s",
            (LLT)otbo, PLURAL(otbo),
            (LLT)total_xfers_out, PLURAL(total_xfers_out));
        reply(0, "Traffic received: " LLF " byte%s in " LLF " transfer%s",
            (LLT)otbi, PLURAL(otbi),
            (LLT)total_xfers_in, PLURAL(total_xfers_in));
        reply(0, "Total traffic:    " LLF " byte%s in " LLF " transfer%s",
            (LLT)otb, PLURAL(otb),
            (LLT)total_xfers, PLURAL(total_xfers));

        if (logged_in && !CURCLASS_FLAGS_ISSET(private)) {
                struct ftpconv *cp;

                reply(0, "%s", "");
                reply(0, "Class: %s, type: %s",
                    curclass.classname, CURCLASSTYPE);
                reply(0, "Check PORT/LPRT commands: %sabled",
                    CURCLASS_FLAGS_ISSET(checkportcmd) ? "en" : "dis");
                if (! EMPTYSTR(curclass.display))
                        reply(0, "Display file: %s", curclass.display);
                if (! EMPTYSTR(curclass.notify))
                        reply(0, "Notify fileglob: %s", curclass.notify);
                reply(0, "Idle timeout: " LLF ", maximum timeout: " LLF,
                    (LLT)curclass.timeout, (LLT)curclass.maxtimeout);
                reply(0, "Current connections: %d", connections);
                if (curclass.limit == -1)
                        reply(0, "Maximum connections: unlimited");
                else
                        reply(0, "Maximum connections: " LLF,
                            (LLT)curclass.limit);
                if (curclass.limitfile)
                        reply(0, "Connection limit exceeded message file: %s",
                            conffilename(curclass.limitfile));
                if (! EMPTYSTR(curclass.chroot))
                        reply(0, "Chroot format: %s", curclass.chroot);
                reply(0, "Deny bad ftpusers(5) quickly: %sabled",
                    CURCLASS_FLAGS_ISSET(denyquick) ? "en" : "dis");
                if (! EMPTYSTR(curclass.homedir))
                        reply(0, "Homedir format: %s", curclass.homedir);
                if (curclass.maxfilesize == -1)
                        reply(0, "Maximum file size: unlimited");
                else
                        reply(0, "Maximum file size: " LLF,
                            (LLT)curclass.maxfilesize);
                if (! EMPTYSTR(curclass.motd))
                        reply(0, "MotD file: %s", conffilename(curclass.motd));
                reply(0,
            "Modify commands (CHMOD, DELE, MKD, RMD, RNFR, UMASK): %sabled",
                    CURCLASS_FLAGS_ISSET(modify) ? "en" : "dis");
                reply(0, "Upload commands (APPE, STOR, STOU): %sabled",
                    CURCLASS_FLAGS_ISSET(upload) ? "en" : "dis");
                reply(0, "Sanitize file names: %sabled",
                    CURCLASS_FLAGS_ISSET(sanenames) ? "en" : "dis");
                reply(0, "PASV/LPSV/EPSV connections: %sabled",
                    CURCLASS_FLAGS_ISSET(passive) ? "en" : "dis");
                if (curclass.advertise.su_len != 0) {
                        char buf[50];   /* big enough for IPv6 address */
                        const char *bp;

                        bp = inet_ntop(curclass.advertise.su_family,
                            (void *)&curclass.advertise.su_addr,
                            buf, sizeof(buf));
                        if (bp != NULL)
                                reply(0, "PASV advertise address: %s", bp);
                }
                if (curclass.portmin && curclass.portmax)
                        reply(0, "PASV port range: " LLF " - " LLF,
                            (LLT)curclass.portmin, (LLT)curclass.portmax);
                if (curclass.rateget)
                        reply(0, "Rate get limit: " LLF " bytes/sec",
                            (LLT)curclass.rateget);
                else
                        reply(0, "Rate get limit: disabled");
                if (curclass.rateput)
                        reply(0, "Rate put limit: " LLF " bytes/sec",
                            (LLT)curclass.rateput);
                else
                        reply(0, "Rate put limit: disabled");
                if (curclass.mmapsize)
                        reply(0, "Mmap size: " LLF, (LLT)curclass.mmapsize);
                else
                        reply(0, "Mmap size: disabled");
                if (curclass.readsize)
                        reply(0, "Read size: " LLF, (LLT)curclass.readsize);
                else
                        reply(0, "Read size: default");
                if (curclass.writesize)
                        reply(0, "Write size: " LLF, (LLT)curclass.writesize);
                else
                        reply(0, "Write size: default");
                if (curclass.recvbufsize)
                        reply(0, "Receive buffer size: " LLF,
                            (LLT)curclass.recvbufsize);
                else
                        reply(0, "Receive buffer size: default");
                if (curclass.sendbufsize)
                        reply(0, "Send buffer size: " LLF,
                            (LLT)curclass.sendbufsize);
                else
                        reply(0, "Send buffer size: default");
                if (curclass.sendlowat)
                        reply(0, "Send low water mark: " LLF,
                            (LLT)curclass.sendlowat);
                else
                        reply(0, "Send low water mark: default");
                reply(0, "Umask: %.04o", curclass.umask);
                for (cp = curclass.conversions; cp != NULL; cp=cp->next) {
                        if (cp->suffix == NULL || cp->types == NULL ||
                            cp->command == NULL)
                                continue;
                        reply(0, "Conversion: %s [%s] disable: %s, command: %s",
                            cp->suffix, cp->types, cp->disable, cp->command);
                }
        }

        reply(211, "End of status");
}

void
fatal(const char *s)
{

        reply(451, "Error in server: %s\n", s);
        reply(221, "Closing connection due to server error.");
        dologout(0);
        /* NOTREACHED */
}

/*
 * reply() --
 *      depending on the value of n, display fmt with a trailing CRLF and
 *      prefix of:
 *      n < -1          prefix the message with abs(n) + "-"    (initial line)
 *      n == 0          prefix the message with 4 spaces        (middle lines)
 *      n >  0          prefix the message with n + " "         (final line)
 */
void
reply(int n, const char *fmt, ...)
{
        char    msg[MAXPATHLEN * 2 + 100];
        size_t  b;
        va_list ap;

        if (n == 0)
                b = snprintf(msg, sizeof(msg), "    ");
        else if (n < 0)
                b = snprintf(msg, sizeof(msg), "%d-", -n);
        else
                b = snprintf(msg, sizeof(msg), "%d ", n);
        va_start(ap, fmt);
        vsnprintf(msg + b, sizeof(msg) - b, fmt, ap);
        va_end(ap);
        cprintf(stdout, "%s\r\n", msg);
        (void)fflush(stdout);
        if (ftpd_debug)
                syslog(LOG_DEBUG, "<--- %s", msg);
}

static void
logremotehost(struct sockinet *who)
{

#if defined(HAVE_SOCKADDR_SNPRINTF)
        char abuf[MAXHOSTNAMELEN];
#endif

        struct sockaddr *sa = (struct sockaddr *)&who->si_su;
        if (getnameinfo(sa, who->su_len, remotehost, sizeof(remotehost), NULL,
            0, getnameopts))
                strlcpy(remotehost, "?", sizeof(remotehost));
#if defined(HAVE_SOCKADDR_SNPRINTF)
        sockaddr_snprintf(abuf, sizeof(abuf), "%a", sa);
        snprintf(remoteloghost, sizeof(remoteloghost), "%s(%s)", remotehost,
            abuf);
#else
        strlcpy(remoteloghost, remotehost, sizeof(remoteloghost));
#endif
        
#if defined(HAVE_SETPROCTITLE)
        snprintf(proctitle, sizeof(proctitle), "%s: connected", remotehost);
        setproctitle("%s", proctitle);
#endif /* defined(HAVE_SETPROCTITLE) */
        if (logging)
                syslog(LOG_INFO, "connection from %s to %s",
                    remoteloghost, hostname);
}

/*
 * Record logout in wtmp file and exit with supplied status.
 * NOTE: because this is called from signal handlers it cannot
 *       use stdio (or call other functions that use stdio).
 */
void
dologout(int status)
{
        /*
        * Prevent reception of SIGURG from resulting in a resumption
        * back to the main program loop.
        */
        transflag = 0;
        logout_utmp();
        if (logged_in) {
#ifdef KERBEROS
                if (!notickets && krbtkfile_env)
                        unlink(krbtkfile_env);
#endif
        }
        /* beware of flushing buffers after a SIGPIPE */
        if (xferlogfd != -1)
                close(xferlogfd);
        _exit(status);
}

void
abor(void)
{

        if (!transflag)
                return;
        tmpline[0] = '\0';
        is_oob = 0;
        reply(426, "Transfer aborted. Data connection closed.");
        reply(226, "Abort successful");
        transflag = 0;          /* flag that the transfer has aborted */
}

void
statxfer(void)
{

        if (!transflag)
                return;
        tmpline[0] = '\0';
        is_oob = 0;
        if (file_size != (off_t) -1)
                reply(213,
                    "Status: " LLF " of " LLF " byte%s transferred",
                    (LLT)byte_count, (LLT)file_size,
                    PLURAL(byte_count));
        else
                reply(213, "Status: " LLF " byte%s transferred",
                    (LLT)byte_count, PLURAL(byte_count));
}

/*
 * Call when urgflag != 0 to handle Out Of Band commands.
 * Returns non zero if the OOB command aborted the transfer
 * by setting transflag to 0. (c.f., "ABOR").
 */
static int
handleoobcmd(void)
{
        char *cp;
        int ret;

        if (!urgflag)
                return (0);
        urgflag = 0;
        /* only process if transfer occurring */
        if (!transflag)
                return (0);
        cp = tmpline;
        ret = get_line(cp, sizeof(tmpline)-1, stdin);
        if (ret == -1) {
                reply(221, "You could at least say goodbye.");
                dologout(0);
        } else if (ret == -2) {
                /* Ignore truncated command */
                /* XXX: abort xfer with "500 command too long", & return 1 ? */
                return 0;
        }
                /*
                 * Manually parse OOB commands, because we can't
                 * recursively call the yacc parser...
                 */
        if (strcasecmp(cp, "ABOR\r\n") == 0) {
                abor();
        } else if (strcasecmp(cp, "STAT\r\n") == 0) {
                statxfer();
        } else {
                /* XXX: error with "500 unknown command" ? */
        }
        return (transflag == 0);
}

static int
bind_pasv_addr(void)
{
        static int passiveport;
        int port, len;

        len = pasv_addr.su_len;
        if (curclass.portmin == 0 && curclass.portmax == 0) {
                pasv_addr.su_port = 0;
                return (bind(pdata, (struct sockaddr *)&pasv_addr.si_su, len));
        }

        if (passiveport == 0) {
                srand(getpid());
                passiveport = rand() % (curclass.portmax - curclass.portmin)
                    + curclass.portmin;
        }

        port = passiveport;
        while (1) {
                port++;
                if (port > curclass.portmax)
                        port = curclass.portmin;
                else if (port == passiveport) {
                        errno = EAGAIN;
                        return (-1);
                }
                pasv_addr.su_port = htons(port);
                if (bind(pdata, (struct sockaddr *)&pasv_addr.si_su, len) == 0)
                        break;
                if (errno != EADDRINUSE)
                        return (-1);
        }
        passiveport = port;
        return (0);
}

/*
 * Note: a response of 425 is not mentioned as a possible response to
 *      the PASV command in RFC959. However, it has been blessed as
 *      a legitimate response by Jon Postel in a telephone conversation
 *      with Rick Adams on 25 Jan 89.
 */
void
passive(void)
{
        socklen_t len;
        int recvbufsize;
        char *p, *a;

        if (pdata >= 0)
                close(pdata);
        pdata = socket(AF_INET, SOCK_STREAM, 0);
        if (pdata < 0 || !logged_in) {
                perror_reply(425, "Can't open passive connection");
                return;
        }
        pasv_addr = ctrl_addr;

        if (bind_pasv_addr() < 0)
                goto pasv_error;
        len = pasv_addr.su_len;
        if (getsockname(pdata, (struct sockaddr *) &pasv_addr.si_su, &len) < 0)
                goto pasv_error;
        pasv_addr.su_len = len;
        if (curclass.recvbufsize) {
                recvbufsize = curclass.recvbufsize;
                if (setsockopt(pdata, SOL_SOCKET, SO_RCVBUF, &recvbufsize,
                               sizeof(int)) == -1)
                        syslog(LOG_WARNING, "setsockopt(SO_RCVBUF, %d): %m",
                               recvbufsize);
        }
        if (listen(pdata, 1) < 0)
                goto pasv_error;
        if (curclass.advertise.su_len != 0)
                a = (char *) &curclass.advertise.su_addr;
        else
                a = (char *) &pasv_addr.su_addr;
        p = (char *) &pasv_addr.su_port;

#define UC(b) (((int) b) & 0xff)

        reply(227, "Entering Passive Mode (%d,%d,%d,%d,%d,%d)", UC(a[0]),
                UC(a[1]), UC(a[2]), UC(a[3]), UC(p[0]), UC(p[1]));
        return;

 pasv_error:
        (void) close(pdata);
        pdata = -1;
        perror_reply(425, "Can't open passive connection");
        return;
}

/*
 * convert protocol identifier to/from AF
 */
int
lpsvproto2af(int proto)
{

        switch (proto) {
        case 4:
                return AF_INET;
#ifdef INET6
        case 6:
                return AF_INET6;
#endif
        default:
                return -1;
        }
}

int
af2lpsvproto(int af)
{

        switch (af) {
        case AF_INET:
                return 4;
#ifdef INET6
        case AF_INET6:
                return 6;
#endif
        default:
                return -1;
        }
}

int
epsvproto2af(int proto)
{

        switch (proto) {
        case 1:
                return AF_INET;
#ifdef INET6
        case 2:
                return AF_INET6;
#endif
        default:
                return -1;
        }
}

int
af2epsvproto(int af)
{

        switch (af) {
        case AF_INET:
                return 1;
#ifdef INET6
        case AF_INET6:
                return 2;
#endif
        default:
                return -1;
        }
}

/*
 * 228 Entering Long Passive Mode (af, hal, h1, h2, h3,..., pal, p1, p2...)
 * 229 Entering Extended Passive Mode (|||port|)
 */
void
long_passive(const char *cmd, int pf)
{
        socklen_t len;
        char *p, *a;

        if (!logged_in) {
                syslog(LOG_NOTICE, "long passive but not logged in");
                reply(503, "Login with USER first.");
                return;
        }

        if (pf != PF_UNSPEC && ctrl_addr.su_family != pf) {
                /*
                 * XXX: only EPRT/EPSV ready clients will understand this
                 */
                if (strcmp(cmd, "EPSV") != 0)
                        reply(501, "Network protocol mismatch"); /*XXX*/
                else
                        epsv_protounsupp("Network protocol mismatch");

                return;
        }
 
        if (pdata >= 0)
                close(pdata);
        pdata = socket(ctrl_addr.su_family, SOCK_STREAM, 0);
        if (pdata < 0) {
                perror_reply(425, "Can't open passive connection");
                return;
        }
        pasv_addr = ctrl_addr;
        if (bind_pasv_addr() < 0)
                goto pasv_error;
        len = pasv_addr.su_len;
        if (getsockname(pdata, (struct sockaddr *) &pasv_addr.si_su, &len) < 0)
                goto pasv_error;
        pasv_addr.su_len = len;
        if (listen(pdata, 1) < 0)
                goto pasv_error;
        p = (char *) &pasv_addr.su_port;

#define UC(b) (((int) b) & 0xff)

        if (strcmp(cmd, "LPSV") == 0) {
                struct sockinet *advert;

                if (curclass.advertise.su_len != 0)
                        advert = &curclass.advertise;
                else
                        advert = &pasv_addr;
                switch (advert->su_family) {
                case AF_INET:
                        a = (char *) &advert->su_addr;
                        reply(228,
    "Entering Long Passive Mode (%d,%d,%d,%d,%d,%d,%d,%d,%d)",
                                4, 4, UC(a[0]), UC(a[1]), UC(a[2]), UC(a[3]),
                                2, UC(p[0]), UC(p[1]));
                        return;
#ifdef INET6
                case AF_INET6:
                        a = (char *) &advert->su_6addr;
                        reply(228,
    "Entering Long Passive Mode (%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d)",
                                6, 16,
                                UC(a[0]), UC(a[1]), UC(a[2]), UC(a[3]),
                                UC(a[4]), UC(a[5]), UC(a[6]), UC(a[7]),
                                UC(a[8]), UC(a[9]), UC(a[10]), UC(a[11]),
                                UC(a[12]), UC(a[13]), UC(a[14]), UC(a[15]),
                                2, UC(p[0]), UC(p[1]));
                        return;
#endif
                }
#undef UC
        } else if (strcmp(cmd, "EPSV") == 0) {
                switch (pasv_addr.su_family) {
                case AF_INET:
#ifdef INET6
                case AF_INET6:
#endif
                        reply(229, "Entering Extended Passive Mode (|||%d|)",
                            ntohs(pasv_addr.su_port));
                        return;
                }
        } else {
                /* more proper error code? */
        }

 pasv_error:
        (void) close(pdata);
        pdata = -1;
        perror_reply(425, "Can't open passive connection");
        return;
}

int
extended_port(const char *arg)
{
        char *tmp = NULL;
        char *result[3];
        char *p, *q;
        char delim;
        struct addrinfo hints;
        struct addrinfo *res = NULL;
        int i;
        unsigned long proto;

        tmp = ftpd_strdup(arg);
        p = tmp;
        delim = p[0];
        p++;
        memset(result, 0, sizeof(result));
        for (i = 0; i < 3; i++) {
                q = strchr(p, delim);
                if (!q || *q != delim)
                        goto parsefail;
                *q++ = '\0';
                result[i] = p;
                p = q;
        }

                        /* some more sanity checks */
        errno = 0;
        p = NULL;
        (void)strtoul(result[2], &p, 10);
        if (errno || !*result[2] || *p)
                goto parsefail;
        errno = 0;
        p = NULL;
        proto = strtoul(result[0], &p, 10);
        if (errno || !*result[0] || *p)
                goto protounsupp;
         
        memset(&hints, 0, sizeof(hints));
        hints.ai_family = epsvproto2af((int)proto);
        if (hints.ai_family < 0)
                goto protounsupp;
        hints.ai_socktype = SOCK_STREAM;
        hints.ai_flags = AI_NUMERICHOST;
        if (getaddrinfo(result[1], result[2], &hints, &res))
                goto parsefail;
        if (res->ai_next)
                goto parsefail;
        if (sizeof(data_dest) < res->ai_addrlen)
                goto parsefail;
        memcpy(&data_dest.si_su, res->ai_addr, res->ai_addrlen);
        data_dest.su_len = res->ai_addrlen;
#ifdef INET6
        if (his_addr.su_family == AF_INET6 &&
            data_dest.su_family == AF_INET6) {
                        /* XXX: more sanity checks! */
                data_dest.su_scope_id = his_addr.su_scope_id;
        }
#endif

        if (tmp != NULL)
                free(tmp);
        if (res)
                freeaddrinfo(res);
        return 0;

 parsefail:
        reply(500, "Invalid argument, rejected.");
        usedefault = 1;
        if (tmp != NULL)
                free(tmp);
        if (res)
                freeaddrinfo(res);
        return -1;

 protounsupp:
        epsv_protounsupp("Protocol not supported");
        usedefault = 1;
        if (tmp != NULL)
                free(tmp);
        return -1;
}

/*
 * 522 Protocol not supported (proto,...)
 * as we assume address family for control and data connections are the same,
 * we do not return the list of address families we support - instead, we
 * return the address family of the control connection.
 */
void
epsv_protounsupp(const char *message)
{
        int proto;

        proto = af2epsvproto(ctrl_addr.su_family);
        if (proto < 0)
                reply(501, "%s", message);      /* XXX */
        else
                reply(522, "%s, use (%d)", message, proto);
}

/*
 * Generate unique name for file with basename "local".
 * The file named "local" is already known to exist.
 * Generates failure reply on error.
 *
 * XXX: this function should under go changes similar to
 *      the mktemp(3)/mkstemp(3) changes.
 */
static char *
gunique(const char *local)
{
        static char new[MAXPATHLEN];
        struct stat st;
        char *cp;
        int count;

        cp = strrchr(local, '/');
        if (cp)
                *cp = '\0';
        if (stat(cp ? local : ".", &st) < 0) {
                perror_reply(553, cp ? local : ".");
                return (NULL);
        }
        if (cp)
                *cp = '/';
        for (count = 1; count < 100; count++) {
                (void)snprintf(new, sizeof(new) - 1, "%s.%d", local, count);
                if (stat(new, &st) < 0)
                        return (new);
        }
        reply(452, "Unique file name cannot be created.");
        return (NULL);
}

/*
 * Format and send reply containing system error number.
 */
void
perror_reply(int code, const char *string)
{
        int save_errno;

        save_errno = errno;
        reply(code, "%s: %s.", string, strerror(errno));
        errno = save_errno;
}

static char *onefile[] = {
        NULL,
        0
};

void
send_file_list(const char *whichf)
{
        struct stat st;
        DIR *dirp;
        struct dirent *dir;
        FILE *volatile dout;
        char **volatile dirlist;
        char *dirname, *p;
        char *notglob;
        int volatile simple;
        int volatile freeglob;
        glob_t gl;

        dirp = NULL;
        dout = NULL;
        notglob = NULL;
        simple = 0;
        freeglob = 0;
        urgflag = 0;

        p = NULL;
        if (strpbrk(whichf, "~{[*?") != NULL) {
                int flags = GLOB_BRACE|GLOB_NOCHECK|GLOB_TILDE|GLOB_LIMIT;

                memset(&gl, 0, sizeof(gl));
                freeglob = 1;
                if (glob(whichf, flags, 0, &gl)) {
                        reply(450, "Not found");
                        goto cleanup_send_file_list;
                } else if (gl.gl_pathc == 0) {
                        errno = ENOENT;
                        perror_reply(450, whichf);
                        goto cleanup_send_file_list;
                }
                dirlist = gl.gl_pathv;
        } else {
                notglob = ftpd_strdup(whichf);
                onefile[0] = notglob;
                dirlist = onefile;
                simple = 1;
        }
                                        /* XXX: } for vi sm */

        while ((dirname = *dirlist++) != NULL) {
                int trailingslash = 0;

                if (stat(dirname, &st) < 0) {
                        /*
                         * If user typed "ls -l", etc, and the client
                         * used NLST, do what the user meant.
                         */
                        /* XXX: nuke this support? */
                        if (dirname[0] == '-' && *dirlist == NULL &&
                            transflag == 0) {
                                const char *argv[] = { INTERNAL_LS, "", NULL };

                                argv[1] = dirname;
                                retrieve(argv, dirname);
                                goto cleanup_send_file_list;
                        }
                        perror_reply(450, whichf);
                        goto cleanup_send_file_list;
                }

                if (S_ISREG(st.st_mode)) {
                        /*
                         * XXXRFC:
                         *      should we follow RFC959 and not work
                         *      for non directories?
                         */
                        if (dout == NULL) {
                                dout = dataconn("file list", (off_t)-1, "w");
                                if (dout == NULL)
                                        goto cleanup_send_file_list;
                                transflag = 1;
                        }
                        cprintf(dout, "%s%s\n", dirname,
                            type == TYPE_A ? "\r" : "");
                        continue;
                } else if (!S_ISDIR(st.st_mode))
                        continue;

                if (dirname[strlen(dirname) - 1] == '/')
                        trailingslash++;

                if ((dirp = opendir(dirname)) == NULL)
                        continue;

                while ((dir = readdir(dirp)) != NULL) {
                        char nbuf[MAXPATHLEN];

                        if (urgflag && handleoobcmd()) {
                                (void) closedir(dirp);
                                goto cleanup_send_file_list;
                        }

                        if (ISDOTDIR(dir->d_name) || ISDOTDOTDIR(dir->d_name))
                                continue;

                        (void)snprintf(nbuf, sizeof(nbuf), "%s%s%s", dirname,
                            trailingslash ? "" : "/", dir->d_name);

                        /*
                         * We have to do a stat to ensure it's
                         * not a directory or special file.
                         */
                        /*
                         * XXXRFC:
                         *      should we follow RFC959 and filter out
                         *      non files ?   lukem - NO!, or not until
                         *      our ftp client uses MLS{T,D} for completion.
                         */
                        if (simple || (stat(nbuf, &st) == 0 &&
                            S_ISREG(st.st_mode))) {
                                if (dout == NULL) {
                                        dout = dataconn("file list", (off_t)-1,
                                                "w");
                                        if (dout == NULL) {
                                                (void) closedir(dirp);
                                                goto cleanup_send_file_list;
                                        }
                                        transflag = 1;
                                }
                                p = nbuf;
                                if (nbuf[0] == '.' && nbuf[1] == '/')
                                        p = &nbuf[2];
                                cprintf(dout, "%s%s\n", p,
                                    type == TYPE_A ? "\r" : "");
                        }
                }
                (void) closedir(dirp);
        }

        if (dout == NULL)
                reply(450, "No files found.");
        else if (ferror(dout) != 0)
                perror_reply(451, "Data connection");
        else
                reply(226, "Transfer complete.");

 cleanup_send_file_list:
        closedataconn(dout);
        transflag = 0;
        urgflag = 0;
        total_xfers++;
        total_xfers_out++;
        if (notglob)
                free(notglob);
        if (freeglob)
                globfree(&gl);
}

char *
conffilename(const char *s)
{
        static char filename[MAXPATHLEN];

        if (*s == '/')
                strlcpy(filename, s, sizeof(filename));
        else
                (void)snprintf(filename, sizeof(filename), "%s/%s", confdir ,s);
        return (filename);
}

/*
 * logxfer --
 *      if logging > 1, then based on the arguments, syslog a message:
 *       if bytes != -1         "<command> <file1> = <bytes> bytes"
 *       else if file2 != NULL  "<command> <file1> <file2>"
 *       else                   "<command> <file1>"
 *      if elapsed != NULL, append "in xxx.yyy seconds"
 *      if error != NULL, append ": " + error
 *
 *      if doxferlog != 0, bytes != -1, and command is "get", "put",
 *      or "append", syslog and/or write a wu-ftpd style xferlog entry
 */
void
logxfer(const char *command, off_t bytes, const char *file1, const char *file2,
    const struct timeval *elapsed, const char *error)
{
        char             buf[MAXPATHLEN * 2 + 100];
        char             realfile1[MAXPATHLEN], realfile2[MAXPATHLEN];
        const char      *r1, *r2;
        char             direction;
        size_t           len;
        time_t           now;

        if (logging <=1 && !doxferlog)
                return;

        r1 = r2 = NULL;
        if ((r1 = realpath(file1, realfile1)) == NULL)
                r1 = file1;
        if (file2 != NULL)
                if ((r2 = realpath(file2, realfile2)) == NULL)
                        r2 = file2;

                /*
                 * syslog command
                 */
        if (logging > 1) {
                len = snprintf(buf, sizeof(buf), "%s %s", command, r1);
                if (bytes != (off_t)-1)
                        len += snprintf(buf + len, sizeof(buf) - len,
                            " = " LLF " byte%s", (LLT) bytes, PLURAL(bytes));
                else if (r2 != NULL)
                        len += snprintf(buf + len, sizeof(buf) - len,
                            " %s", r2);
                if (elapsed != NULL)
                        len += snprintf(buf + len, sizeof(buf) - len,
                            " in " LLF ".%.03ld seconds",
                            (LLT)elapsed->tv_sec,
                            (long)(elapsed->tv_usec / 1000));
                if (error != NULL)
                        len += snprintf(buf + len, sizeof(buf) - len,
                            ": %s", error);
                syslog(LOG_INFO, "%s", buf);
        }

                /*
                 * syslog wu-ftpd style log entry, prefixed with "xferlog: "
                 */
        if (!doxferlog || bytes == -1)
                return;

        if (strcmp(command, "get") == 0)
                direction = 'o';
        else if (strcmp(command, "put") == 0 || strcmp(command, "append") == 0)
                direction = 'i';
        else
                return;

        time(&now);
        len = snprintf(buf, sizeof(buf),
            "%.24s " LLF " %s " LLF " %s %c %s %c %c %s FTP 0 * %c\n",

/*
 * XXX: wu-ftpd puts ' (send)' or ' (recv)' in the syslog message, and removes
 *      the full date.  This may be problematic for accurate log parsing,
 *      given that syslog messages don't contain the full date.
 */
            ctime(&now),
            (LLT)
            (elapsed == NULL ? 0 : elapsed->tv_sec + (elapsed->tv_usec > 0)),
            remotehost,
            (LLT) bytes,
            r1,
            type == TYPE_A ? 'a' : 'b',
            "_",                /* XXX: take conversions into account? */
            direction, 

            curclass.type == CLASS_GUEST ?  'a' :
            curclass.type == CLASS_CHROOT ? 'g' :
            curclass.type == CLASS_REAL ?   'r' : '?',

            curclass.type == CLASS_GUEST ? pw->pw_passwd : pw->pw_name,
            error != NULL ? 'i' : 'c'
            );

        if ((doxferlog & 2) && xferlogfd != -1)
                write(xferlogfd, buf, len);
        if ((doxferlog & 1)) {
                buf[len-1] = '\n';      /* strip \n from syslog message */
                syslog(LOG_INFO, "xferlog: %s", buf);
        }
}

/*
 * Log the resource usage.
 *
 * XXX: more resource usage to logging?
 */
void
logrusage(const struct rusage *rusage_before,
    const struct rusage *rusage_after)
{
        struct timeval usrtime, systime;

        if (logging <= 1)
                return;

        timersub(&rusage_after->ru_utime, &rusage_before->ru_utime, &usrtime);
        timersub(&rusage_after->ru_stime, &rusage_before->ru_stime, &systime);
        syslog(LOG_INFO, LLF ".%.03ldu " LLF ".%.03lds %ld+%ldio %ldpf+%ldw",
            (LLT)usrtime.tv_sec, (long)(usrtime.tv_usec / 1000),
            (LLT)systime.tv_sec, (long)(systime.tv_usec / 1000),
            rusage_after->ru_inblock - rusage_before->ru_inblock,
            rusage_after->ru_oublock - rusage_before->ru_oublock,
            rusage_after->ru_majflt - rusage_before->ru_majflt,
            rusage_after->ru_nswap - rusage_before->ru_nswap);
}

/*
 * Determine if `password' is valid for user given in `pw'.
 * Returns 2 if password expired, 1 if otherwise failed, 0 if ok
 */
int
checkpassword(const struct passwd *pwent, const char *password)
{
        const char *orig;
        char    *new;
        time_t   change, expire, now;

        change = expire = 0;
        if (pwent == NULL)
                return 1;

        time(&now);
        orig = pwent->pw_passwd;        /* save existing password */
        expire = pwent->pw_expire;
        change = pwent->pw_change;
        if (change == _PASSWORD_CHGNOW)
                change = now;

        if (orig[0] == '\0')            /* don't allow empty passwords */
                return 1;

        new = crypt(password, orig);    /* encrypt given password */
        if (strcmp(new, orig) != 0)     /* compare */
                return 1;

        if ((expire && now >= expire) || (change && now >= change))
                return 2;               /* check if expired */

        return 0;                       /* OK! */
}

char *
ftpd_strdup(const char *s)
{
        char *new = strdup(s);

        if (new == NULL)
                fatal("Local resource failure: malloc");
                /* NOTREACHED */
        return (new);
}

/*
 * As per fprintf(), but increment total_bytes and total_bytes_out,
 * by the appropriate amount.
 */
void
cprintf(FILE *fd, const char *fmt, ...)
{
        off_t b;
        va_list ap;

        va_start(ap, fmt);
        b = vfprintf(fd, fmt, ap);
        va_end(ap);
        total_bytes += b;
        total_bytes_out += b;
}

#ifdef USE_PAM
/*
 * the following code is stolen from imap-uw PAM authentication module and
 * login.c
 */
typedef struct {
        const char *uname;      /* user name */
        int         triedonce;  /* if non-zero, tried before */
} ftpd_cred_t;

static int
auth_conv(int num_msg, const struct pam_message **msg,
    struct pam_response **resp, void *appdata)
{
        int i, ret;
        size_t n;
        ftpd_cred_t *cred = (ftpd_cred_t *) appdata;
        struct pam_response *myreply;
        char pbuf[FTP_BUFLEN];

        if (num_msg <= 0 || num_msg > PAM_MAX_NUM_MSG)
                return (PAM_CONV_ERR);
        myreply = calloc(num_msg, sizeof *myreply);
        if (myreply == NULL)
                return PAM_BUF_ERR;

        for (i = 0; i < num_msg; i++) {
                myreply[i].resp_retcode = 0;
                myreply[i].resp = NULL;
                switch (msg[i]->msg_style) {
                case PAM_PROMPT_ECHO_ON:        /* user */
                        myreply[i].resp = ftpd_strdup(cred->uname);
                        /* PAM frees resp. */
                        break;
                case PAM_PROMPT_ECHO_OFF:       /* authtok (password) */
                                /*
                                 * Only send a single 331 reply and
                                 * then expect a PASS.
                                 */
                        if (cred->triedonce) {
                                syslog(LOG_ERR,
                        "auth_conv: already performed PAM_PROMPT_ECHO_OFF");
                                goto fail;
                        }
                        cred->triedonce++;
                        if (msg[i]->msg[0] == '\0') {
                                (void)strlcpy(pbuf, "password", sizeof(pbuf));
                        } else {
                                        /* Uncapitalize msg */
                                (void)strlcpy(pbuf, msg[i]->msg, sizeof(pbuf));
                                if (isupper((unsigned char)pbuf[0]))
                                        pbuf[0] = tolower(
                                            (unsigned char)pbuf[0]);
                                        /* Remove trailing ':' and whitespace */
                                n = strlen(pbuf);
                                while (n-- > 0) {
                                        if (isspace((unsigned char)pbuf[n]) ||
                                            pbuf[n] == ':')
                                                pbuf[n] = '\0';
                                        else
                                                break;
                                }
                        }
                                /* Send reply, wait for a response. */
                        reply(331, "User %s accepted, provide %s.",
                            cred->uname, pbuf);
                        (void) alarm(curclass.timeout);
                        ret = get_line(pbuf, sizeof(pbuf)-1, stdin);
                        (void) alarm(0);
                        if (ret == -1) {
                                reply(221, "You could at least say goodbye.");
                                dologout(0);
                        } else if (ret == -2) {
                            /* XXX: should we do this reply(-530, ..) ? */
                                reply(-530, "Command too long.");
                                goto fail;
                        }
                                /* Ensure it is PASS */
                        if (strncasecmp(pbuf, "PASS ", 5) != 0) {
                                syslog(LOG_ERR,
                                    "auth_conv: unexpected reply '%.4s'", pbuf);
                                /* XXX: should we do this reply(-530, ..) ? */
                                reply(-530, "Unexpected reply '%.4s'.", pbuf);
                                goto fail;
                        }
                                /* Strip CRLF from "PASS" reply */
                        n = strlen(pbuf);
                        while (--n >= 5 &&
                            (pbuf[n] == '\r' || pbuf[n] == '\n'))
                            pbuf[n] = '\0';
                                /* Copy password into reply */
                        myreply[i].resp = ftpd_strdup(pbuf+5);
                                /* PAM frees resp. */
                        break;
                case PAM_TEXT_INFO:
                case PAM_ERROR_MSG:
                        break;
                default:                        /* unknown message style */
                        goto fail;
                }
        }

        *resp = myreply;
        return PAM_SUCCESS;

 fail:
        free(myreply);
        *resp = NULL;
        return PAM_CONV_ERR;
}

/*
 * Attempt to authenticate the user using PAM.  Returns 0 if the user is
 * authenticated, or 1 if not authenticated.  If some sort of PAM system
 * error occurs (e.g., the "/etc/pam.conf" file is missing) then this
 * function returns -1.  This can be used as an indication that we should
 * fall back to a different authentication mechanism.
 * pw maybe be updated to a new user if PAM_USER changes from curname.
 */
static int
auth_pam(void)
{
        const char *tmpl_user;
        const void *item;
        int rval;
        int e;
        ftpd_cred_t auth_cred = { curname, 0 };
        struct pam_conv conv = { &auth_conv, &auth_cred };
        struct sockaddr_storage ss;

        e = pam_start("ftpd", curname, &conv, &pamh);
        if (e != PAM_SUCCESS) {
                /*
                 * In OpenPAM, it's OK to pass NULL to pam_strerror()
                 * if context creation has failed in the first place.
                 */
                syslog(LOG_ERR, "pam_start: %s", pam_strerror(NULL, e));
                return -1;
        }

        e = pam_set_item(pamh, PAM_RHOST, remotehost);
        if (e != PAM_SUCCESS) {
                syslog(LOG_ERR, "pam_set_item(PAM_RHOST): %s",
                        pam_strerror(pamh, e));
                if ((e = pam_end(pamh, e)) != PAM_SUCCESS) {
                        syslog(LOG_ERR, "pam_end: %s", pam_strerror(pamh, e));
                }
                pamh = NULL;
                return -1;
        }

        memset(&ss, 0, sizeof(ss));
        memcpy(&ss, &his_addr.si_su, his_addr.su_len);
        e = pam_set_item(pamh, PAM_SOCKADDR, &ss);
        if (e != PAM_SUCCESS) {
                syslog(LOG_ERR, "pam_set_item(PAM_SOCKADDR): %s",
                        pam_strerror(pamh, e));
                if ((e = pam_end(pamh, e)) != PAM_SUCCESS) {
                        syslog(LOG_ERR, "pam_end: %s", pam_strerror(pamh, e));
                }
                pamh = NULL;
                return -1;
        }

        e = pam_authenticate(pamh, 0);
        if (ftpd_debug)
                syslog(LOG_DEBUG, "pam_authenticate: user '%s' returned %d",
                    curname, e);
        switch (e) {
        case PAM_SUCCESS:
                /*
                 * With PAM we support the concept of a "template"
                 * user.  The user enters a login name which is
                 * authenticated by PAM, usually via a remote service
                 * such as RADIUS or TACACS+.  If authentication
                 * succeeds, a different but related "template" name
                 * is used for setting the credentials, shell, and
                 * home directory.  The name the user enters need only
                 * exist on the remote authentication server, but the
                 * template name must be present in the local password
                 * database.
                 *
                 * This is supported by two various mechanisms in the
                 * individual modules.  However, from the application's
                 * point of view, the template user is always passed
                 * back as a changed value of the PAM_USER item.
                 */
                if ((e = pam_get_item(pamh, PAM_USER, &item)) ==
                    PAM_SUCCESS) {
                        tmpl_user = (const char *) item;
                        if (pw == NULL
                            || strcmp(pw->pw_name, tmpl_user) != 0) {
                                pw = sgetpwnam(tmpl_user);
                                if (ftpd_debug)
                                        syslog(LOG_DEBUG,
                                            "auth_pam: PAM changed "
                                            "user from '%s' to '%s'",
                                            curname, pw->pw_name);
                                (void)strlcpy(curname, pw->pw_name,
                                    curname_len);
                        }
                } else
                        syslog(LOG_ERR, "Couldn't get PAM_USER: %s",
                            pam_strerror(pamh, e));
                rval = 0;
                break;

        case PAM_AUTH_ERR:
        case PAM_USER_UNKNOWN:
        case PAM_MAXTRIES:
                rval = 1;
                break;

        default:
                syslog(LOG_ERR, "pam_authenticate: %s", pam_strerror(pamh, e));
                rval = -1;
                break;
        }

        if (rval == 0) {
                e = pam_acct_mgmt(pamh, 0);
                if (e != PAM_SUCCESS) {
                        syslog(LOG_ERR, "pam_acct_mgmt: %s",
                                                pam_strerror(pamh, e));
                        rval = 1;
                }
        }

        if (rval != 0) {
                if ((e = pam_end(pamh, e)) != PAM_SUCCESS) {
                        syslog(LOG_ERR, "pam_end: %s", pam_strerror(pamh, e));
                }
                pamh = NULL;
        }
        return rval;
}

#endif /* USE_PAM */