/*
 * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 */

#include "defs.h"
#include <signal.h>
#include <string.h>
#include <errno.h>
#include <limits.h>
#include <ctype.h>
#include <krb5defs.h>
#include <stdarg.h>

/*
 * If we want to write *to* the client rdist program, *from* the server
 * side (server-side child `rdist -Server' process exec'ed off of in.rshd),
 * we write to stdout/stderr, since there is a pipe connecting stdout/stderr
 * to the outside world (which is why we use `wrem' and not `rem').
 */
int wrem = 1;

#define ack()   (void) write(wrem, "\0\n", 2)
#define err()   (void) write(wrem, "\1\n", 2)

/*
 * Set when a desread() is reqd. in response()
 */

struct  linkbuf *ihead;         /* list of files with more than one link */
extern char     buf[RDIST_BUFSIZ];      /* general purpose buffer */
char    source[RDIST_BUFSIZ];   /* base source directory name */
char    destination[RDIST_BUFSIZ];      /* base destination directory name */
char    target[RDIST_BUFSIZ];   /* target/source directory name */
char    *tp;                    /* pointer to end of target name */
char    *Tdest;                 /* pointer to last T dest */
int     catname;                /* cat name to target name */
char    *stp[32];               /* stack of saved tp's for directories */
int     oumask;                 /* old umask for creating files */

extern  FILE *lfp;              /* log file for mailing changes */

void    cleanup(int);
struct linkbuf *savelink(struct stat *, int);
char    *strsub(char *, char *, char *);

static void comment(char *);
static void note(char *, ...);
static void hardlink(char *cmd);
void error(char *, ...);
void log(FILE *, char *, ...);
static void recursive_remove(struct stat *stp);
static void recvf(char *cmd, int type);
static void query(char *name);
static void sendf(char *rname, int opts);
static void rmchk(int opts);
static void dospecial(char *cmd);
static void clean(char *cp);

/*
 * Server routine to read requests and process them.
 * Commands are:
 *      Tname   - Transmit file if out of date
 *      Vname   - Verify if file out of date or not
 *      Qname   - Query if file exists. Return mtime & size if it does.
 */
void
server(void)
{
        char cmdbuf[RDIST_BUFSIZ];
        char *cp;

        signal(SIGHUP, cleanup);
        signal(SIGINT, cleanup);
        signal(SIGQUIT, cleanup);
        signal(SIGTERM, cleanup);
        signal(SIGPIPE, cleanup);

        rem = 0;
        oumask = umask(0);

        (void) sprintf(buf, "V%d\n", VERSION);
        (void) write(wrem, buf, strlen(buf));

        for (;;) {
                cp = cmdbuf;
                if (read(rem, cp, 1) <= 0)
                        return;
                if (*cp++ == '\n') {
                        error("server: expected control record\n");
                        continue;
                }
                do {
                        if (read(rem, cp, 1) != 1)
                                cleanup(0);
                } while (*cp++ != '\n' && cp < &cmdbuf[RDIST_BUFSIZ]);
                *--cp = '\0';
                cp = cmdbuf;
                switch (*cp++) {
                case 'T':  /* init target file/directory name */
                        catname = 1;    /* target should be directory */
                        goto dotarget;

                case 't':  /* init target file/directory name */
                        catname = 0;
                dotarget:
                        if (exptilde(target, sizeof (target), cp) == NULL)
                                continue;
                        tp = target;
                        while (*tp)
                                tp++;
                        ack();
                        continue;

                case 'R':  /* Transfer a regular file. */
                        recvf(cp, S_IFREG);
                        continue;

                case 'D':  /* Transfer a directory. */
                        recvf(cp, S_IFDIR);
                        continue;

                case 'K':  /* Transfer symbolic link. */
                        recvf(cp, S_IFLNK);
                        continue;

                case 'k':  /* Transfer hard link. */
                        hardlink(cp);
                        continue;

                case 'E':  /* End. (of directory) */
                        *tp = '\0';
                        if (catname <= 0) {
                                error("server: too many 'E's\n");
                                continue;
                        }
                        tp = stp[--catname];
                        *tp = '\0';
                        ack();
                        continue;

                case 'C':  /* Clean. Cleanup a directory */
                        clean(cp);
                        continue;

                case 'Q':  /* Query. Does the file/directory exist? */
                        query(cp);
                        continue;

                case 'S':  /* Special. Execute commands */
                        dospecial(cp);
                        continue;

#ifdef notdef
                /*
                 * These entries are reserved but not currently used.
                 * The intent is to allow remote hosts to have master copies.
                 * Currently, only the host rdist runs on can have masters.
                 */
                case 'X':  /* start a new list of files to exclude */
                        except = bp = NULL;
                case 'x':  /* add name to list of files to exclude */
                        if (*cp == '\0') {
                                ack();
                                continue;
                        }
                        if (*cp == '~') {
                                if (exptilde(buf, sizeof (buf), cp) == NULL)
                                        continue;
                                cp = buf;
                        }
                        if (bp == NULL)
                                except = bp = expand(makeblock(NAME, cp),
                                    E_VARS);
                        else
                                bp->b_next = expand(makeblock(NAME, cp),
                                    E_VARS);
                        while (bp->b_next != NULL)
                                bp = bp->b_next;
                        ack();
                        continue;

                case 'I':  /* Install. Transfer file if out of date. */
                        opts = 0;
                        while (*cp >= '0' && *cp <= '7')
                                opts = (opts << 3) | (*cp++ - '0');
                        if (*cp++ != ' ') {
                                error("server: options not delimited\n");
                                return;
                        }
                        install(cp, opts);
                        continue;

                case 'L':  /* Log. save message in log file */
                        log(lfp, cp);
                        continue;
#endif

                case '\1':
                        nerrs++;
                        continue;

                case '\2':
                        return;

                default:
                        error("server: unknown command '%s'\n", cp);
                        continue;
                case '\0':
                        continue;
                }
        }
}

/*
 * Update the file(s) if they are different.
 * destdir = 1 if destination should be a directory
 * (i.e., more than one source is being copied to the same destination).
 */
void
install(char *src, char *dest, int destdir, int opts)
{
        char *rname;
        char destcopy[RDIST_BUFSIZ];

        if (dest == NULL) {
                opts &= ~WHOLE; /* WHOLE mode only useful if renaming */
                dest = src;
        }

        if (nflag || debug) {
                printf("%s%s%s%s%s %s %s\n", opts & VERIFY ? "verify":"install",
                    opts & WHOLE ? " -w" : "",
                    opts & YOUNGER ? " -y" : "",
                    opts & COMPARE ? " -b" : "",
                    opts & REMOVE ? " -R" : "", src, dest);
                if (nflag)
                        return;
        }

        rname = exptilde(target, sizeof (target), src);
        if (rname == NULL)
                return;
        tp = target;
        while (*tp)
                tp++;
        /*
         * If we are renaming a directory and we want to preserve
         * the directory heirarchy (-w), we must strip off the leading
         * directory name and preserve the rest.
         */
        if (opts & WHOLE) {
                while (*rname == '/')
                        rname++;
                destdir = 1;
        } else {
                rname = rindex(target, '/');
                if (rname == NULL)
                        rname = target;
                else
                        rname++;
        }
        if (debug)
                printf("target = %s, rname = %s\n", target, rname);
        /*
         * Pass the destination file/directory name to remote.
         */
        if (snprintf(buf, sizeof (buf), "%c%s\n", destdir ? 'T' : 't', dest) >=
            sizeof (buf)) {
                error("%s: Name too long\n", dest);
                return;
        }
        if (debug)
                printf("buf = %s", buf);
        (void) deswrite(rem, buf, strlen(buf), 0);

        if (response() < 0)
                return;

        strcpy(source, src);
        if (destdir) {
                strcpy(destcopy, dest);
                Tdest = destcopy;
                strcpy(destination, rname);
        } else {
                strcpy(destination, dest);
        }
        sendf(rname, opts);
        Tdest = 0;
}

#define protoname()     (pw ? pw->pw_name : user)
#define protogroup()    (gr ? gr->gr_name : group)
/*
 * Transfer the file or directory in target[].
 * rname is the name of the file on the remote host.
 */
void
sendf(char *rname, int opts)
{
        struct subcmd *sc;
        struct stat stb;
        int sizerr, f, u, len;
        off_t i;
        DIR *d;
        struct dirent *dp;
        char *otp, *cp;
        extern struct subcmd *subcmds;
        static char user[15], group[15];

        if (debug)
                printf("sendf(%s, %x%s)\n", rname, opts, printb(opts, OBITS));

        if (except(target))
                return;
        if ((opts & FOLLOW ? stat(target, &stb) : lstat(target, &stb)) < 0) {
                error("%s: %s\n", target, strerror(errno));
                return;
        }
        if (index(rname, '\n')) {
                error("file name '%s' contains an embedded newline - "
                    "can't update\n", rname);
                return;
        }
        if ((u = update(rname, opts, &stb)) == 0) {
                if ((stb.st_mode & S_IFMT) == S_IFREG && stb.st_nlink > 1)
                        (void) savelink(&stb, opts);
                return;
        }

        if (pw == NULL || pw->pw_uid != stb.st_uid)
                if ((pw = getpwuid(stb.st_uid)) == NULL) {
                        log(lfp, "%s: no password entry for uid %d \n",
                            target, stb.st_uid);
                        pw = NULL;
                        sprintf(user, ":%d", stb.st_uid);
                }
        if (gr == NULL || gr->gr_gid != stb.st_gid)
                if ((gr = getgrgid(stb.st_gid)) == NULL) {
                        log(lfp, "%s: no name for group %d\n",
                            target, stb.st_gid);
                        gr = NULL;
                        sprintf(group, ":%d", stb.st_gid);
                }
        if (u == 1) {
                if (opts & VERIFY) {
                        log(lfp, "need to install: %s\n", target);
                        goto dospecial;
                }
                log(lfp, "installing: %s\n", target);
                opts &= ~(COMPARE|REMOVE);
        }

        switch (stb.st_mode & S_IFMT) {
        case S_IFDIR:
                if ((d = opendir(target)) == NULL) {
                        error("%s: %s\n", target, strerror(errno));
                        return;
                }
                if (snprintf(buf, sizeof (buf), "D%o %04o 0 0 %s %s %s\n",
                    opts, stb.st_mode & 07777, protoname(), protogroup(),
                    rname) >= sizeof (buf)) {
                        error("%s: Name too long\n", rname);
                        closedir(d);
                        return;
                }
                if (debug)
                        printf("buf = %s", buf);
                (void) deswrite(rem, buf, strlen(buf), 0);
                if (response() < 0) {
                        closedir(d);
                        return;
                }

                if (opts & REMOVE)
                        rmchk(opts);

                otp = tp;
                len = tp - target;
                while (dp = readdir(d)) {
                        if ((strcmp(dp->d_name, ".") == 0)||
                            (strcmp(dp->d_name, "..") == 0))
                                continue;
                        if ((int)(len + 1 + strlen(dp->d_name)) >=
                            (int)(RDIST_BUFSIZ - 1)) {
                                error("%.*s/%s: Name too long\n", len, target,
                                    dp->d_name);
                                continue;
                        }
                        tp = otp;
                        *tp++ = '/';
                        cp = dp->d_name;
                        while (*tp++ = *cp++)
                                ;
                        tp--;
                        sendf(dp->d_name, opts);
                }
                closedir(d);
                (void) deswrite(rem, "E\n", 2, 0);
                (void) response();
                tp = otp;
                *tp = '\0';
                return;

        case S_IFLNK:
                if (u != 1)
                        opts |= COMPARE;
                if (stb.st_nlink > 1) {
                        struct linkbuf *lp;

                        if ((lp = savelink(&stb, opts)) != NULL) {
                                /* install link */
                                if (*lp->target == 0)
                                        len = snprintf(buf, sizeof (buf),
                                            "k%o %s %s\n", opts, lp->pathname,
                                            rname);
                                else
                                        len = snprintf(buf, sizeof (buf),
                                            "k%o %s/%s %s\n", opts, lp->target,
                                            lp->pathname, rname);
                                if (len >= sizeof (buf)) {
                                        error("%s: Name too long\n", rname);
                                        return;
                                }
                                if (debug)
                                        printf("buf = %s", buf);
                                (void) deswrite(rem, buf, strlen(buf), 0);
                                (void) response();
                                return;
                        }
                }
                (void) snprintf(buf, sizeof (buf), "K%o %o %ld %ld %s %s %s\n",
                    opts, stb.st_mode & 07777, stb.st_size, stb.st_mtime,
                    protoname(), protogroup(), rname);
                if (debug)
                        printf("buf = %s", buf);
                (void) deswrite(rem, buf, strlen(buf), 0);
                if (response() < 0)
                        return;
                sizerr = (readlink(target, buf, RDIST_BUFSIZ) != stb.st_size);
                (void) deswrite(rem, buf, stb.st_size, 0);
                if (debug)
                        printf("readlink = %.*s\n", (int)stb.st_size, buf);
                goto done;

        case S_IFREG:
                break;

        default:
                error("%s: not a file or directory\n", target);
                return;
        }

        if (u == 2) {
                if (opts & VERIFY) {
                        log(lfp, "need to update: %s\n", target);
                        goto dospecial;
                }
                log(lfp, "updating: %s\n", target);
        }

        if (stb.st_nlink > 1) {
                struct linkbuf *lp;

                if ((lp = savelink(&stb, opts)) != NULL) {
                        /* install link */
                        if (*lp->target == 0)
                                len = snprintf(buf, sizeof (buf), "k%o %s %s\n",
                                    opts, lp->pathname, rname);
                        else
                                len = snprintf(buf, sizeof (buf),
                                    "k%o %s/%s %s\n", opts, lp->target,
                                    lp->pathname, rname);
                        if (len >= sizeof (buf)) {
                                error("%s: Name too long\n", rname);
                                return;
                        }
                        if (debug)
                                printf("buf = %s", buf);
                        (void) deswrite(rem, buf, strlen(buf), 0);
                        (void) response();
                        return;
                }
        }

        if ((f = open(target, 0)) < 0) {
                error("%s: %s\n", target, strerror(errno));
                return;
        }
        (void) snprintf(buf, sizeof (buf), "R%o %o %ld %ld %s %s %s\n", opts,
            stb.st_mode & 07777, stb.st_size, stb.st_mtime,
            protoname(), protogroup(), rname);
        if (debug)
                printf("buf = %s", buf);
        (void) deswrite(rem, buf, strlen(buf), 0);

        if (response() < 0) {
                (void) close(f);
                return;
        }

        sizerr = 0;

        for (i = 0; i < stb.st_size; i += RDIST_BUFSIZ) {
                int amt = RDIST_BUFSIZ;
                if (i + amt > stb.st_size)
                        amt = stb.st_size - i;
                if (sizerr == 0 && read(f, buf, amt) != amt)
                        sizerr = 1;
                (void) deswrite(rem, buf, amt, 0);
        }
        (void) close(f);
done:
        if (sizerr) {
                error("%s: file changed size\n", target);
                (void) deswrite(rem, "\1\n", 2, 0);
        } else
                (void) deswrite(rem, "\0\n", 2, 0);
        f = response();

        if (f < 0 || f == 0 && (opts & COMPARE))
                return;
dospecial:
        for (sc = subcmds; sc != NULL; sc = sc->sc_next) {
                if (sc->sc_type != SPECIAL)
                        continue;
                if (sc->sc_args != NULL && !inlist(sc->sc_args, target))
                        continue;
                log(lfp, "special \"%s\"\n", sc->sc_name);
                if (opts & VERIFY)
                        continue;
                (void) snprintf(buf, sizeof (buf), "SFILE=%s;%s\n", target,
                    sc->sc_name);
                if (debug)
                        printf("buf = %s", buf);
                (void) deswrite(rem, buf, strlen(buf), 0);
                while (response() > 0)
                        ;
        }
}

struct linkbuf *
savelink(struct stat *stp, int opts)
{
        struct linkbuf *lp;

        for (lp = ihead; lp != NULL; lp = lp->nextp)
                if (lp->inum == stp->st_ino && lp->devnum == stp->st_dev) {
                        lp->count--;
                        return (lp);
                }
        lp = (struct linkbuf *)malloc(sizeof (*lp));
        if (lp == NULL)
                log(lfp, "out of memory, link information lost\n");
        else {
                lp->nextp = ihead;
                ihead = lp;
                lp->inum = stp->st_ino;
                lp->devnum = stp->st_dev;
                lp->count = stp->st_nlink - 1;

                if (strlcpy(lp->pathname,
                    opts & WHOLE ? target : strsub(source, destination, target),
                    sizeof (lp->pathname)) >= sizeof (lp->pathname)) {
                        error("%s: target name too long\n", target);
                }

                if (Tdest) {
                        if (strlcpy(lp->target, Tdest,
                            sizeof (lp->target)) >= sizeof (lp->target))
                                error("%s: target name too long\n", Tdest);
                } else
                        *lp->target = 0;
        }
        return (NULL);
}

/*
 * Check to see if file needs to be updated on the remote machine.
 * Returns 0 if no update, 1 if remote doesn't exist, 2 if out of date
 * and 3 if comparing binaries to determine if out of date.
 */
int
update(char *rname, int opts, struct stat *stp)
{
        char *cp, *s;
        off_t size;
        time_t mtime;

        if (debug)
                printf("update(%s, %x%s, %x)\n", rname, opts,
                    printb(opts, OBITS), stp);

        /*
         * Check to see if the file exists on the remote machine.
         */
        if (snprintf(buf, sizeof (buf), "Q%s\n", rname) >= sizeof (buf)) {
                error("%s: Name too long\n", rname);
                return (0);
        }
        if (debug)
                printf("buf = %s", buf);
        (void) deswrite(rem, buf, strlen(buf), 0);
again:
        cp = s = buf;
more:
        do {
                if (desread(rem, cp, 1, 0) != 1)
                        lostconn();
        } while (*cp++ != '\n' && cp < &buf[RDIST_BUFSIZ]);

        if (cp <  &buf[RDIST_BUFSIZ])
                *cp = '\0';
        if (debug) {
                printf("update reply:  ");
                switch (*s) {
                        case 'Y':
                        case 'N':
                                putchar(*s);
                                break;
                        default:
                                if (iscntrl(*s)) {
                                        putchar('^');
                                        putchar('A' + *s - 1);
                                } else
                                        printf("%#x", *s & 0xff);
                                break;
                }
                printf("%s", &s[1]);
        }

        switch (*s++) {
        case 'Y':
                break;

        case 'N':  /* file doesn't exist so install it */
                return (1);

        case '\1':
                nerrs++;
                if (*s != '\n') {
                        if (!iamremote) {
                                fflush(stdout);
                                (void) write(2, s, cp - s);
                        }
                        if (lfp != NULL)
                                (void) fwrite(s, 1, cp - s, lfp);
                }
                if (cp == &buf[RDIST_BUFSIZ] && *(cp - 1) != '\n') {
                        /* preserve status code */
                        cp = s;
                        s = buf;
                        goto more;
                }
                return (0);

        case '\3':
                *--cp = '\0';
                if (lfp != NULL)
                        log(lfp, "update: note: %s\n", s);
                goto again;

        default:
                *--cp = '\0';
                error("update: unexpected response '%s'\n", s);
                return (0);
        }

        if (*s == '\n')
                return (2);

        if (opts & COMPARE)
                return (3);

        size = 0;
        while (isdigit(*s))
                size = size * 10 + (*s++ - '0');
        if (*s++ != ' ') {
                error("update: size not delimited\n");
                return (0);
        }
        mtime = 0;
        while (isdigit(*s))
                mtime = mtime * 10 + (*s++ - '0');
        if (*s != '\n') {
                error("update: mtime not delimited\n");
                return (0);
        }
        /*
         * File needs to be updated?
         */
        if (opts & YOUNGER) {
                if (stp->st_mtime == mtime)
                        return (0);
                if (stp->st_mtime < mtime) {
                        log(lfp, "Warning: %s: remote copy is newer\n", target);
                        return (0);
                }
        } else if (stp->st_mtime == mtime && stp->st_size == size)
                return (0);
        return (2);
}

/*
 * Query. Check to see if file exists. Return one of the following:
 *      N\n             - doesn't exist
 *      Ysize mtime\n   - exists and its a regular file (size & mtime of file)
 *      Y\n             - exists and its a directory or symbolic link
 *      ^Aerror message\n
 */
static void
query(char *name)
{
        struct stat stb;

        if (catname) {
                if (sizeof (target) - (tp - target) >= strlen(name) + 2) {
                        (void) sprintf(tp, "/%s", name);
                } else {
                        error("%.*s/%s: Name too long\n", tp - target,
                            target, name);
                        return;
                }
        }

        if (lstat(target, &stb) < 0) {
                if (errno == ENOENT)
                        (void) write(wrem, "N\n", 2);
                else
                        error("%s:%s: %s\n", host, target, strerror(errno));
                *tp = '\0';
                return;
        }

        switch (stb.st_mode & S_IFMT) {
        case S_IFREG:
                (void) sprintf(buf, "Y%ld %ld\n", stb.st_size, stb.st_mtime);
                (void) write(wrem, buf, strlen(buf));
                break;

        case S_IFLNK:
        case S_IFDIR:
                (void) write(wrem, "Y\n", 2);
                break;

        default:
                error("%s: not a file or directory\n", name);
                break;
        }
        *tp = '\0';
}

static void
recvf(char *cmd, int type)
{
        char *cp;
        int f, mode, opts, wrerr, olderrno;
        off_t i, size;
        time_t mtime;
        struct stat stb;
        struct timeval tvp[2];
        char *owner, *group;
        char new[RDIST_BUFSIZ];
        extern char *tmpname;

        cp = cmd;
        opts = 0;
        while (*cp >= '0' && *cp <= '7')
                opts = (opts << 3) | (*cp++ - '0');
        if (*cp++ != ' ') {
                error("recvf: options not delimited\n");
                return;
        }
        mode = 0;
        while (*cp >= '0' && *cp <= '7')
                mode = (mode << 3) | (*cp++ - '0');
        if (*cp++ != ' ') {
                error("recvf: mode not delimited\n");
                return;
        }
        size = 0;
        while (isdigit(*cp))
                size = size * 10 + (*cp++ - '0');
        if (*cp++ != ' ') {
                error("recvf: size not delimited\n");
                return;
        }
        mtime = 0;
        while (isdigit(*cp))
                mtime = mtime * 10 + (*cp++ - '0');
        if (*cp++ != ' ') {
                error("recvf: mtime not delimited\n");
                return;
        }
        owner = cp;
        while (*cp && *cp != ' ')
                cp++;
        if (*cp != ' ') {
                error("recvf: owner name not delimited\n");
                return;
        }
        *cp++ = '\0';
        group = cp;
        while (*cp && *cp != ' ')
                cp++;
        if (*cp != ' ') {
                error("recvf: group name not delimited\n");
                return;
        }
        *cp++ = '\0';

        if (type == S_IFDIR) {
                int     isdot;

                if (strcmp(cp, ".") == 0)
                        isdot = 1;
                else
                        isdot = 0;
                if (catname >= sizeof (stp) / sizeof (stp[0])) {
                        error("%s:%s: too many directory levels\n",
                            host, target);
                        return;
                }
                stp[catname] = tp;
                if (catname++) {
                        *tp++ = '/';
                        while (*tp++ = *cp++)
                                ;
                        tp--;
                }
                if (opts & VERIFY) {
                        ack();
                        return;
                }
                if (lstat(target, &stb) == 0) {
                        if (ISDIR(stb.st_mode)) {
                                if ((stb.st_mode & 07777) == mode) {
                                        ack();
                                        return;
                                }
                                sendrem("%s: Warning: remote mode %o != "
                                    "local mode %o", target,
                                    stb.st_mode & 07777, mode);
                                return;
                        }
                        errno = ENOTDIR;
                } else if (errno == ENOENT && (mkdir(target, mode) == 0 ||
                    chkparent(target) == 0 &&
                    (isdot == 1 || mkdir(target, mode) == 0))) {
                        if (chog(target, owner, group, mode) == 0)
                                ack();
                        return;
                }
                error("%s:%s: %s\n", host, target, strerror(errno));
                tp = stp[--catname];
                *tp = '\0';
                return;
        }

        if (catname) {
                if (sizeof (target) - (tp - target) >= strlen(cp) + 2) {
                        (void) sprintf(tp, "/%s", cp);
                } else {
                        error("%.*s/%s: Name too long\n", tp - target,
                            target, cp);
                        return;
                }
        }
        cp = rindex(target, '/');
        if (cp == NULL)
                strcpy(new, tmpname);
        else if (cp == target)
                (void) sprintf(new, "/%s", tmpname);
        else {
                *cp = '\0';

                /*
                 * sizeof (target) =  RDIST_BUFSIZ and sizeof (tmpname) = 11
                 * RDIST_BUFSIZ = 50*1024 is much greater than PATH_MAX that is
                 * allowed by the kernel, so it's safe to call snprintf() here
                 */
                (void) snprintf(new, sizeof (new), "%s/%s", target, tmpname);
                *cp = '/';
        }

        if (type == S_IFLNK) {
                int j;

                ack();
                cp = buf;
                for (i = 0; i < size; i += j) {
                        if ((j = read(rem, cp, size - i)) <= 0)
                                cleanup(0);
                        cp += j;
                }
                *cp = '\0';
                if (response() < 0) {
                        err();
                        return;
                }
                if (symlink(buf, new) < 0) {
                        if (errno != ENOENT || chkparent(new) < 0 ||
                            symlink(buf, new) < 0)
                                goto badn;
                }
                mode &= 0777;
                if (opts & COMPARE) {
                        char tbuf[MAXPATHLEN];

                        if ((i = readlink(target, tbuf, MAXPATHLEN)) >= 0 &&
                            i == size && strncmp(buf, tbuf, size) == 0) {
                                (void) unlink(new);
                                ack();
                                return;
                        }
                        if (opts & VERIFY)
                                goto differ;
                }
                goto fixup;
        }

        if ((f = creat(new, mode & ~06000)) < 0) {
                if (errno != ENOENT || chkparent(new) < 0 ||
                    (f = creat(new, mode & ~06000)) < 0)
                        goto badn;
        }

        ack();
        wrerr = 0;
        for (i = 0; i < size; i += RDIST_BUFSIZ) {
                int amt = RDIST_BUFSIZ;

                cp = buf;
                if (i + amt > size)
                        amt = size - i;
                do {
                        int j = read(rem, cp, amt);
                        if (j <= 0) {
                                (void) close(f);
                                (void) unlink(new);
                                cleanup(0);
                        }
                        amt -= j;
                        cp += j;
                } while (amt > 0);
                amt = RDIST_BUFSIZ;
                if (i + amt > size)
                        amt = size - i;
                if (wrerr == 0 && write(f, buf, amt) != amt) {
                        olderrno = errno;
                        wrerr++;
                }
        }
        (void) close(f);

        if (response() < 0) {
                err();
                (void) unlink(new);
                return;
        }
        if (wrerr) {
                error("%s:%s: %s\n", host, new, strerror(olderrno));
                (void) unlink(new);
                return;
        }
        if (opts & COMPARE) {
                FILE *f1, *f2;
                int c;

                if ((f1 = fopen(target, "r")) == NULL)
                        goto badt;
                if ((f2 = fopen(new, "r")) == NULL) {
                badn:
                        error("%s:%s: %s\n", host, new, strerror(errno));
                        (void) unlink(new);
                        return;
                }
                while ((c = getc(f1)) == getc(f2))
                        if (c == EOF) {
                                (void) fclose(f1);
                                (void) fclose(f2);
                                (void) unlink(new);
                                ack();
                                return;
                        }
                (void) fclose(f1);
                (void) fclose(f2);
                if (opts & VERIFY) {
                differ:
                        (void) unlink(new);
                        sendrem("need to update: %s", target);
                        return;
                }
        }

        /*
         * Set last modified time.  For type == S_IFDIR, the lstat above filled
         * in stb.  Otherwise, do it now.
         */
        if (type != S_IFDIR)
                (void) lstat(new, &stb);
        tvp[0].tv_sec = stb.st_atime;   /* old atime from target */
        tvp[0].tv_usec = 0;
        tvp[1].tv_sec = mtime;
        tvp[1].tv_usec = 0;
        if (utimes(new, tvp) < 0) {
                note("%s:utimes failed %s: %s", host, new, strerror(errno));
        }
        if (chog(new, owner, group, mode) < 0) {
                (void) unlink(new);
                return;
        }
fixup:
        if (rename(new, target) < 0) {
badt:
                error("%s:%s: %s\n", host, target, strerror(errno));
                (void) unlink(new);
                return;
        }
        if (opts & COMPARE) {
                sendrem("updated %s", target);
        } else
                ack();
}

/*
 * Creat a hard link to existing file.
 */
static void
hardlink(char *cmd)
{
        char *cp;
        struct stat stb;
        char *oldname;
        int opts, exists = 0;
        char oldnamebuf[RDIST_BUFSIZ];

        cp = cmd;
        opts = 0;
        while (*cp >= '0' && *cp <= '7')
                opts = (opts << 3) | (*cp++ - '0');
        if (*cp++ != ' ') {
                error("hardlink: options not delimited\n");
                return;
        }
        oldname = cp;
        while (*cp && *cp != ' ')
                cp++;
        if (*cp != ' ') {
                error("hardlink: oldname name not delimited\n");
                return;
        }
        *cp++ = '\0';

        if (catname) {
                if (sizeof (target) - (tp - target) >= strlen(cp) + 2) {
                        (void) sprintf(tp, "/%s", cp);
                } else {
                        error("%.*s/%s: Name too long\n", tp - target,
                            target, cp);
                        return;
                }
        }
        if (lstat(target, &stb) == 0) {
                int mode = stb.st_mode & S_IFMT;
                if (mode != S_IFREG && mode != S_IFLNK) {
                        error("%s:%s: not a regular file\n", host, target);
                        return;
                }
                exists = 1;
        }
        if (chkparent(target) < 0) {
                error("%s:%s: %s (no parent)\n",
                    host, target, strerror(errno));
                return;
        }
        if (opts & VERIFY) {
                struct stat nstb;

                if (exists && lstat(oldname, &nstb) == 0 &&
                    nstb.st_mode == stb.st_mode &&
                    nstb.st_ino == stb.st_ino &&
                    nstb.st_dev == stb.st_dev) {
                        ack();
                        return;
                } else {
                        sendrem("need to update: %s", target);
                        return;
                }
        }
        if (exists && (unlink(target) < 0)) {
                error("%s:%s: %s (unlink)\n",
                    host, target, strerror(errno));
                return;
        }
        if (*oldname == '~')
                oldname = exptilde(oldnamebuf, sizeof (oldnamebuf), oldname);
        if (link(oldname, target) < 0) {
                error("%s:can't link %s to %s\n",
                    host, target, oldname);
                return;
        }
        ack();
}

/*
 * Check to see if parent directory exists and create one if not.
 */
int
chkparent(char *name)
{
        char *cp;
        struct stat stb;

        cp = rindex(name, '/');
        if (cp == NULL || cp == name)
                return (0);
        *cp = '\0';
        if (lstat(name, &stb) < 0) {
                if (errno == ENOENT && chkparent(name) >= 0 &&
                    mkdir(name, 0777 & ~oumask) >= 0) {
                        *cp = '/';
                        return (0);
                }
        } else if (ISDIR(stb.st_mode)) {
                *cp = '/';
                return (0);
        }
        *cp = '/';
        return (-1);
}

/*
 * Change owner, group and mode of file.
 */
int
chog(char *file, char *owner, char *group, int mode)
{
        int i;
        uid_t uid, gid;
        extern char user[];

        /*
         * by default, set uid of file to the uid of the person running
         * this program.
         */
        uid = getuid();

        /*
         * We'll use available privileges so we just try to do what
         * the client specifies.  If the chown() fails we'll not
         * add the set-[ug]id bits; and if we want to add the set-[ug]id
         * bits and we're not permitted to do so, the OS will prevent us
         * from doing so.
         */
        if (*owner == ':') {
                uid = atoi(owner + 1);
        } else if (pw == NULL || strcmp(owner, pw->pw_name) != 0) {
                if ((pw = getpwnam(owner)) == NULL) {
                        if (mode & 04000) {
                                note("%s:%s: unknown login name, "
                                    "clearing setuid", host, owner);
                                mode &= ~04000;
                        }
                } else {
                        uid = pw->pw_uid;
                }
        } else {
                uid = pw->pw_uid;
        }

        if (*group == ':') {
                gid = atoi(group + 1);
                goto ok;
        }

        gid = -1;
        if (gr == NULL || strcmp(group, gr->gr_name) != 0) {
                if ((*group == ':' &&
                    (getgrgid(gid = atoi(group + 1)) == NULL)) ||
                    ((gr = getgrnam(group)) == NULL)) {
                        if (mode & 02000) {
                                note("%s:%s: unknown group", host, group);
                                mode &= ~02000;
                        }
                } else
                        gid = gr->gr_gid;
        } else
                gid = gr->gr_gid;
ok:
        if (chown(file, uid, gid) < 0 ||
            (mode & 07000) && chmod(file, mode) < 0) {
                note("%s: chown or chmod failed: file %s:  %s",
                    host, file, strerror(errno));
        }
        return (0);
}

/*
 * Check for files on the machine being updated that are not on the master
 * machine and remove them.
 */
static void
rmchk(int opts)
{
        char *cp, *s;
        struct stat stb;

        if (debug)
                printf("rmchk()\n");

        /*
         * Tell the remote to clean the files from the last directory sent.
         */
        (void) sprintf(buf, "C%o\n", opts & VERIFY);
        if (debug)
                printf("buf = %s", buf);
        (void) deswrite(rem, buf, strlen(buf), 0);
        if (response() < 0)
                return;
        for (;;) {
                cp = s = buf;
                do {
                        if (desread(rem, cp, 1, 0) != 1)
                                lostconn();
                } while (*cp++ != '\n' && cp < &buf[RDIST_BUFSIZ]);

                switch (*s++) {
                case 'Q': /* Query if file should be removed */
                        /*
                         * Return the following codes to remove query.
                         * N\n -- file exists - DON'T remove.
                         * Y\n -- file doesn't exist - REMOVE.
                         */
                        *--cp = '\0';
                        (void) sprintf(tp, "/%s", s);
                        if (debug)
                                printf("check %s\n", target);
                        if (except(target))
                                (void) deswrite(rem, "N\n", 2, 0);
                        else if (lstat(target, &stb) < 0)
                                (void) deswrite(rem, "Y\n", 2, 0);
                        else
                                (void) deswrite(rem, "N\n", 2, 0);
                        break;

                case '\0':
                        *--cp = '\0';
                        if (*s != '\0')
                                log(lfp, "%s\n", s);
                        break;

                case 'E':
                        *tp = '\0';
                        (void) deswrite(rem, "\0\n", 2, 0);
                        return;

                case '\1':
                case '\2':
                        nerrs++;
                        if (*s != '\n') {
                                if (!iamremote) {
                                        fflush(stdout);
                                        (void) write(2, s, cp - s);
                                }
                                if (lfp != NULL)
                                        (void) fwrite(s, 1, cp - s, lfp);
                        }
                        if (buf[0] == '\2')
                                lostconn();
                        break;

                default:
                        error("rmchk: unexpected response '%s'\n", buf);
                        (void) deswrite(rem, "\1\n", 2, 0);
                }
        }
}

/*
 * Check the current directory (initialized by the 'T' command to server())
 * for extraneous files and remove them.
 */
static void
clean(char *cp)
{
        DIR *d;
        struct dirent *dp;
        struct stat stb;
        char *otp;
        int len, opts;

        opts = 0;
        while (*cp >= '0' && *cp <= '7')
                opts = (opts << 3) | (*cp++ - '0');
        if (*cp != '\0') {
                error("clean: options not delimited\n");
                return;
        }
        if ((d = opendir(target)) == NULL) {
                error("%s:%s: %s\n", host, target, strerror(errno));
                return;
        }
        ack();

        otp = tp;
        len = tp - target;
        while (dp = readdir(d)) {
                if ((strcmp(dp->d_name, ".") == 0) ||
                    (strcmp(dp->d_name, "..") == 0))
                        continue;
                if ((int)(len + 1 + strlen(dp->d_name)) >=
                    (int)(RDIST_BUFSIZ - 1)) {
                        error("%s:%s/%s: Name too long\n",
                            host, target, dp->d_name);
                        continue;
                }
                tp = otp;
                *tp++ = '/';
                cp = dp->d_name;
                while (*tp++ = *cp++)
                        ;
                tp--;
                if (lstat(target, &stb) < 0) {
                        error("%s:%s: %s\n", host, target, strerror(errno));
                        continue;
                }
                (void) snprintf(buf, sizeof (buf), "Q%s\n", dp->d_name);
                (void) write(wrem, buf, strlen(buf));
                cp = buf;
                do {
                        if (read(rem, cp, 1) != 1)
                                cleanup(0);
                } while (*cp++ != '\n' && cp < &buf[RDIST_BUFSIZ]);
                *--cp = '\0';
                cp = buf;
                if (*cp != 'Y')
                        continue;
                if (opts & VERIFY) {
                        sendrem("need to remove: %s", target);
                } else
                        (void) recursive_remove(&stb);
        }
        closedir(d);
        (void) write(wrem, "E\n", 2);
        (void) response();
        tp = otp;
        *tp = '\0';
}

/*
 * Remove a file or directory (recursively) and send back an acknowledge
 * or an error message.
 */
static void
recursive_remove(struct stat *stp)
{
        DIR *d;
        struct dirent *dp;
        char *cp;
        struct stat stb;
        char *otp;
        int len;

        switch (stp->st_mode & S_IFMT) {
        case S_IFREG:
        case S_IFLNK:
                if (unlink(target) < 0)
                        goto bad;
                goto removed;

        case S_IFDIR:
                break;

        default:
                error("%s:%s: not a plain file\n", host, target);
                return;
        }

        if ((d = opendir(target)) == NULL)
                goto bad;

        otp = tp;
        len = tp - target;
        while (dp = readdir(d)) {
                if ((strcmp(dp->d_name, ".") == 0) ||
                    (strcmp(dp->d_name, "..") == 0))
                        continue;
                if ((int)(len + 1 + strlen(dp->d_name)) >=
                    (int)(RDIST_BUFSIZ - 1)) {
                        error("%s:%s/%s: Name too long\n",
                            host, target, dp->d_name);
                        continue;
                }
                tp = otp;
                *tp++ = '/';
                cp = dp->d_name;
                while (*tp++ = *cp++)
                        ;
                tp--;
                if (lstat(target, &stb) < 0) {
                        error("%s:%s: %s\n", host, target, strerror(errno));
                        continue;
                }
                recursive_remove(&stb);
        }
        closedir(d);
        tp = otp;
        *tp = '\0';
        if (rmdir(target) < 0) {
bad:
                error("%s:%s: %s\n", host, target, strerror(errno));
                return;
        }
removed:
        sendrem("removed %s", target);
}

/*
 * Execute a shell command to handle special cases.
 */
static void
dospecial(char *cmd)
{
        int fd[2], status, pid, i;
        char *cp, *s;
        char sbuf[RDIST_BUFSIZ];

        if (pipe(fd) < 0) {
                error("%s\n", strerror(errno));
                return;
        }
        if ((pid = fork()) == 0) {
                /*
                 * Return everything the shell commands print.
                 */
                (void) close(0);
                (void) close(1);
                (void) close(2);
                (void) open("/dev/null", 0);
                (void) dup(fd[1]);
                (void) dup(fd[1]);
                (void) close(fd[0]);
                (void) close(fd[1]);
                execl("/bin/sh", "sh", "-c", cmd, 0);
                _exit(127);
        }
        (void) close(fd[1]);
        s = sbuf;
        *s++ = '\0';
        while ((i = read(fd[0], buf, RDIST_BUFSIZ)) > 0) {
                cp = buf;
                do {
                        *s++ = *cp++;
                        if (cp[-1] != '\n') {
                                if (s < &sbuf[RDIST_BUFSIZ - 1])
                                        continue;
                                *s++ = '\n';
                        }
                        /*
                         * Throw away blank lines.
                         */
                        if (s == &sbuf[2]) {
                                s--;
                                continue;
                        }
                        (void) write(wrem, sbuf, s - sbuf);
                        s = &sbuf[1];
                } while (--i);
        }
        if (s > &sbuf[1]) {
                *s++ = '\n';
                (void) write(wrem, sbuf, s - sbuf);
        }
        while ((i = wait(&status)) != pid && i != -1)
                ;
        if (i == -1)
                status = -1;
        (void) close(fd[0]);
        if (status)
                error("shell returned %d\n", status);
        else
                ack();
}

void
log(FILE *fp, char *fmt, ...)
{
        va_list ap;

        /* Print changes locally if not quiet mode */
        if (!qflag) {
                va_start(ap, fmt);
                vprintf(fmt, ap);
                va_end(ap);
        }

        /* Save changes (for mailing) if really updating files */
        va_start(ap, fmt);
        if (!(options & VERIFY) && fp != NULL)
                vfprintf(fp, fmt, ap);
        va_end(ap);
}

void
error(char *fmt, ...)
{
        va_list ap;
        static FILE *fp;

        nerrs++;
        if (iamremote) {
                if (!fp && !(fp = fdopen(rem, "w")))
                        return;
                va_start(ap, fmt);
                (void) fprintf(fp, "%crdist: ", 0x01);
                (void) vfprintf(fp, fmt, ap);
                fflush(fp);
                va_end(ap);
        } else {
                va_start(ap, fmt);
                fflush(stdout);
                (void) fprintf(stderr, "rdist: ");
                (void) vfprintf(stderr, fmt, ap);
                fflush(stderr);
                va_end(ap);
        }
        if (lfp != NULL) {
                va_start(ap, fmt);
                (void) fprintf(lfp, "rdist: ");
                (void) vfprintf(lfp, fmt, ap);
                fflush(lfp);
                va_end(ap);
        }
}

void
fatal(char *fmt, ...)
{
        va_list ap;
        static FILE *fp;

        nerrs++;
        if (iamremote) {
                if (!fp && !(fp = fdopen(rem, "w")))
                        return;
                va_start(ap, fmt);
                (void) fprintf(fp, "%crdist: ", 0x02);
                (void) vfprintf(fp, fmt, ap);
                fflush(fp);
                va_end(ap);
        } else {
                va_start(ap, fmt);
                fflush(stdout);
                (void) fprintf(stderr, "rdist: ");
                (void) vfprintf(stderr, fmt, ap);
                fflush(stderr);
                va_end(ap);
        }
        if (lfp != NULL) {
                va_start(ap, fmt);
                (void) fprintf(lfp, "rdist: ");
                (void) vfprintf(lfp, fmt, ap);
                fflush(lfp);
                va_end(ap);
        }
        cleanup(0);
}

int
response(void)
{
        char *cp, *s;
        char resp[RDIST_BUFSIZ];

        if (debug)
                printf("response()\n");

        cp = s = resp;
more:
        do {
                if (desread(rem, cp, 1, 0) != 1)
                        lostconn();
        } while (*cp++ != '\n' && cp < &resp[RDIST_BUFSIZ]);

        switch (*s++) {
        case '\0':
                *--cp = '\0';
                if (*s != '\0') {
                        log(lfp, "%s\n", s);
                        return (1);
                }
                return (0);
        case '\3':
                *--cp = '\0';
                log(lfp, "Note: %s\n", s);
                return (response());

        default:
                s--;
                /* FALLTHROUGH */
        case '\1':
        case '\2':
                nerrs++;
                if (*s != '\n') {
                        if (!iamremote) {
                                fflush(stdout);
                                (void) write(2, s, cp - s);
                        }
                        if (lfp != NULL)
                                (void) fwrite(s, 1, cp - s, lfp);
                }
                if (cp == &resp[RDIST_BUFSIZ] && *(cp - 1) != '\n') {
                        /* preserve status code */
                        cp = s;
                        s = resp;
                        goto more;
                }
                if (resp[0] == '\2')
                        lostconn();
                return (-1);
        }
}

/*
 * Remove temporary files and do any cleanup operations before exiting.
 */
void
cleanup(int arg __unused)
{
        (void) unlink(Tmpfile);
        exit(1);
}

static void
note(char *fmt, ...)
{
        va_list ap;
        static char buf[RDIST_BUFSIZ];

        va_start(ap, fmt);
        (void) vsnprintf(buf, sizeof (buf) - 1, fmt, ap);
        comment(buf);
        va_end(ap);
}

static void
comment(char *s)
{
        char three = '\3';
        char nl = '\n';
        struct iovec iov[3];

        iov[0].iov_base = &three;
        iov[0].iov_len = sizeof (char);
        iov[1].iov_base = s;
        iov[1].iov_len = strlen(s);
        iov[2].iov_base = &nl;
        iov[2].iov_len = sizeof (char);
        (void) writev(rem, iov, 3);
}

/*
 * Send message to other end.
 * N.B.: uses buf[].
 */
void
sendrem(char *fmt, int a1, int a2, int a3)
{
        int len;

        buf[0] = '\0';
        len = snprintf(buf + 1, sizeof (buf) - 1, fmt, a1, a2, a3) + 2;
        if (len > sizeof (buf))
                len = sizeof (buf);
        buf[len - 1] = '\n';
        (void) write(wrem, buf, len);
}

/*
 * strsub(old, new, s)
 *
 * Return a pointer to a new string created by replacing substring old
 * with substring new in string s.  String s is assumed to begin with
 * substring old.
 */
char *
strsub(char *old, char *new, char *s)
{
        static char pbuf[PATH_MAX];
        char *p, *q, *r, *plim;

        /* prepend new to pbuf */
        for (p = pbuf, q = new, plim = pbuf + sizeof (pbuf) - 1;
        /* CSTYLED */
            *q && (p < plim);)
                *p++ = *q++;
        /* p now points to the byte in pbuf where more copying should begin */

        /* skip over the part of s which begins with old */
        for (r = old, q = s; *r; q++, r++)
                ;
        /* q now points to the byte in s where more copying should begin */

        while (*q && (p < plim))
                *p++ = *q++;
        *p = '\0';

        return (pbuf);
}