/*      $OpenBSD: recvjob.c,v 1.26 2015/01/16 06:40:18 deraadt Exp $    */
/*      $NetBSD: recvjob.c,v 1.14 2001/12/04 22:52:44 christos Exp $    */

/*
 * Copyright (c) 1983, 1993
 *      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.
 */

/*
 * Receive printer jobs from the network, queue them and
 * start the printer daemon.
 */
#include <sys/types.h>
#include <sys/mount.h>
#include <sys/stat.h>

#include <unistd.h>
#include <signal.h>
#include <fcntl.h>
#include <dirent.h>
#include <syslog.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <limits.h>
#include "lp.h"
#include "lp.local.h"
#include "extern.h"
#include "pathnames.h"

#define ack()   (void)write(STDOUT_FILENO, sp, 1);

static char      dfname[NAME_MAX];      /* data files */
static int       minfree;       /* keep at least minfree blocks available */
static char     *sp = "";
static char      tfname[NAME_MAX];      /* tmp copy of cf before linking */

static int        chksize(int);
static void       frecverr(const char *, ...)
        __attribute__((__format__(__printf__, 1, 2)));
static int        noresponse(void);
static void       rcleanup(int);
static int        read_number(char *);
static int        readfile(char *, int);
static int        readjob(void);


void
recvjob(void)
{
        struct stat stb;
        int status;

        /*
         * Perform lookup for printer name or abbreviation
         */
        if ((status = cgetent(&bp, printcapdb, printer)) == -2)
                frecverr("cannot open printer description file");
        else if (status == -1)
                frecverr("unknown printer %s", printer);
        else if (status == -3)
                fatal("potential reference loop detected in printcap file");
        
        if (cgetstr(bp, "lf", &LF) == -1)
                LF = _PATH_CONSOLE;
        if (cgetstr(bp, "sd", &SD) == -1)
                SD = _PATH_DEFSPOOL;
        if (cgetstr(bp, "lo", &LO) == -1)
                LO = DEFLOCK;

        (void)close(2);                 /* set up log file */
        PRIV_START;
        if (open(LF, O_WRONLY|O_APPEND, 0664) < 0) {
                syslog(LOG_ERR, "%s: %m", LF);
                (void)open(_PATH_DEVNULL, O_WRONLY);
        }
        PRIV_END;

        if (chdir(SD) < 0)
                frecverr("%s: %s: %m", printer, SD);
        if (stat(LO, &stb) == 0) {
                if (stb.st_mode & 010) {
                        /* queue is disabled */
                        putchar('\1');          /* return error code */
                        exit(1);
                }
        } else if (stat(SD, &stb) < 0)
                frecverr("%s: %s: %m", printer, SD);

        minfree = 2 * read_number("minfree");   /* scale KB to 512 blocks */
        signal(SIGTERM, rcleanup);
        signal(SIGPIPE, rcleanup);

        if (readjob())
                printjob();
}

/*
 * Read printer jobs sent by lpd and copy them to the spooling directory.
 * Return the number of jobs successfully transferred.
 */
static int
readjob(void)
{
        int size, nfiles;
        char *cp;

        ack();
        nfiles = 0;
        for (;;) {
                /*
                 * Read a command to tell us what to do
                 */
                cp = line;
                do {
                        if ((size = read(STDOUT_FILENO, cp, 1)) != 1) {
                                if (size < 0)
                                        frecverr("%s: Lost connection",
                                            printer);
                                return(nfiles);
                        }
                } while (*cp++ != '\n' && (cp - line + 1) < sizeof(line));
                if (cp - line + 1 >= sizeof(line))
                        frecverr("readjob overflow");
                *--cp = '\0';
                cp = line;
                switch (*cp++) {
                case '\1':      /* cleanup because data sent was bad */
                        rcleanup(0);
                        continue;

                case '\2':      /* read cf file */
                        size = 0;
                        while (*cp >= '0' && *cp <= '9')
                                size = size * 10 + (*cp++ - '0');
                        if (*cp++ != ' ')
                                break;
                        /*
                         * host name has been authenticated, we use our
                         * view of the host name since we may be passed
                         * something different than what gethostbyaddr()
                         * returns
                         */
                        strlcpy(cp + 6, from, sizeof(line) + line - cp - 6);
                        if (strchr(cp, '/'))
                                frecverr("readjob: %s: illegal path name", cp);
                        strlcpy(tfname, cp, sizeof(tfname));
                        tfname[0] = 't';
                        if (!chksize(size)) {
                                (void)write(STDOUT_FILENO, "\2", 1);
                                continue;
                        }
                        /*
                         * XXX
                         * We blindly believe what the remote host puts
                         * for the path to the df file.  In general this
                         * is OK since we don't allow paths with '/' in
                         * them.  Still, it would be better to sanity
                         * check the cf file sent to us and make the
                         * df name match the cf name we used.  That way
                         * we avoid any possible collisions.
                         */
                        if (!readfile(tfname, size)) {
                                rcleanup(0);
                                continue;
                        }
                        if (link(tfname, cp) < 0)
                                frecverr("link %s %s: %m", tfname, cp);
                        (void)unlink(tfname);
                        tfname[0] = '\0';
                        nfiles++;
                        continue;

                case '\3':      /* read df file */
                        size = 0;
                        while (*cp >= '0' && *cp <= '9')
                                size = size * 10 + (*cp++ - '0');
                        if (*cp++ != ' ')
                                break;
                        if (strchr(cp, '/'))
                                frecverr("readjob: %s: illegal path name", cp);
                        if (!chksize(size)) {
                                (void)write(STDOUT_FILENO, "\2", 1);
                                continue;
                        }
                        (void)strlcpy(dfname, cp, sizeof(dfname));
                        (void)readfile(dfname, size);
                        continue;
                }
                frecverr("protocol screwup: %s", line);
        }
}

/*
 * Read files send by lpd and copy them to the spooling directory.
 */
static int
readfile(char *file, int size)
{
        char *cp;
        char buf[BUFSIZ];
        int i, j, amt;
        int fd, err;

        if ((fd = open(file, O_CREAT|O_EXCL|O_WRONLY, FILMOD)) < 0)
                frecverr("readfile: %s: illegal path name: %m", file);
        ack();
        err = 0;
        for (i = 0; i < size; i += BUFSIZ) {
                amt = BUFSIZ;
                cp = buf;
                if (i + amt > size)
                        amt = size - i;
                do {
                        j = read(STDOUT_FILENO, cp, amt);
                        if (j <= 0)
                                frecverr("Lost connection");
                        amt -= j;
                        cp += j;
                } while (amt > 0);
                amt = BUFSIZ;
                if (i + amt > size)
                        amt = size - i;
                if (write(fd, buf, amt) != amt) {
                        err++;
                        break;
                }
        }
        (void)close(fd);
        if (err)
                frecverr("%s: write error", file);
        if (noresponse()) {             /* file sent had bad data in it */
                if (strchr(file, '/') == NULL)
                        (void)unlink(file);
                return(0);
        }
        ack();
        return(1);
}

static int
noresponse(void)
{
        char resp;

        if (read(STDOUT_FILENO, &resp, 1) != 1)
                frecverr("Lost connection");
        if (resp == '\0')
                return(0);
        return(1);
}

/*
 * Check to see if there is enough space on the disk for size bytes.
 * 1 == OK, 0 == Not OK.
 */
static int
chksize(int size)
{
        int64_t spacefree;
        struct statfs sfb;

        if (size <= 0)
                return (0);
        if (statfs(".", &sfb) < 0) {
                syslog(LOG_ERR, "%s: %m", "statfs(\".\")");
                return (1);
        }
        spacefree = sfb.f_bavail * (sfb.f_bsize / 512);
        size = (size + 511) / 512;
        if (minfree + size > spacefree)
                return(0);
        return(1);
}

static int
read_number(char *fn)
{
        char lin[80];
        FILE *fp;

        if ((fp = fopen(fn, "r")) == NULL)
                return (0);
        if (fgets(lin, sizeof(lin), fp) == NULL) {
                fclose(fp);
                return (0);
        }
        fclose(fp);
        return (atoi(lin));
}

/*
 * Remove all the files associated with the current job being transferred.
 */
static void
rcleanup(int signo)
{
        int save_errno = errno;

        if (tfname[0] && strchr(tfname, '/') == NULL)
                (void)unlink(tfname);
        if (dfname[0] && strchr(dfname, '/') == NULL) {
                do {
                        do
                                (void)unlink(dfname);
                        while (dfname[2]-- != 'A')
                                ;
                        dfname[2] = 'z';
                } while (dfname[0]-- != 'd');
        }
        dfname[0] = '\0';
        errno = save_errno;
}

static void
frecverr(const char *msg, ...)
{
        extern char fromb[];
        va_list ap;

        va_start(ap, msg);
        rcleanup(0);
        syslog(LOG_ERR, "%s", fromb);
        vsyslog(LOG_ERR, msg, ap);
        va_end(ap);
        putchar('\1');          /* return error code */
        exit(1);
}