usr.sbin/sendmail/rmail/rmail.c

/*
 * Copyright (c) 1988, 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. 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.
 */

#ifndef lint
static char copyright[] =
"@(#) Copyright (c) 1988, 1993\n\
        The Regents of the University of California.  All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)rmail.c     8.1 (Berkeley) 5/31/93";
#endif /* not lint */

/*
 * RMAIL -- UUCP mail server.
 *
 * This program reads the >From ... remote from ... lines that UUCP is so
 * fond of and turns them into something reasonable.  It then execs sendmail
 * with various options built from these lines.
 *
 * The expected syntax is:
 *
 *       <user> := [-a-z0-9]+
 *       <date> := ctime format
 *       <site> := [-a-z0-9!]+
 * <blank line> := "^\n$"
 *       <from> := "From" <space> <user> <space> <date>
 *                [<space> "remote from" <space> <site>]
 *    <forward> := ">" <from>
 *          msg := <from> <forward>* <blank-line> <body>
 *
 * The output of rmail(8) compresses the <forward> lines into a single
 * from path.
 *
 * The err(3) routine is included here deliberately to make this code
 * a bit more portable.
 */
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/wait.h>

#include <ctype.h>
#include <fcntl.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>

void err __P((int, const char *, ...));
void usage __P((void));

int
main(argc, argv)
        int argc;
        char *argv[];
{
        extern char *optarg;
        extern int errno, optind;
        FILE *fp;
        struct stat sb;
        size_t fplen, fptlen, len;
        off_t offset;
        int ch, debug, i, pdes[2], pid, status;
        char *addrp, *domain, *p, *t;
        char *from_path, *from_sys, *from_user;
        char *args[100], buf[2048], lbuf[2048];

        debug = 0;
        domain = "UUCP";                /* Default "domain". */
        while ((ch = getopt(argc, argv, "D:T")) != EOF)
                switch (ch) {
                case 'T':
                        debug = 1;
                        break;
                case 'D':
                        domain = optarg;
                        break;
                case '?':
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (argc < 1)
                usage();

        from_path = from_sys = from_user = NULL;
        for (offset = 0;;) {

                /* Get and nul-terminate the line. */
                if (fgets(lbuf, sizeof(lbuf), stdin) == NULL)
                        exit (EX_DATAERR);
                if ((p = strchr(lbuf, '\n')) == NULL)
                        err(EX_DATAERR, "line too long");
                *p = '\0';

                /* Parse lines until reach a non-"From" line. */
                if (!strncmp(lbuf, "From ", 5))
                        addrp = lbuf + 5;
                else if (!strncmp(lbuf, ">From ", 6))
                        addrp = lbuf + 6;
                else if (offset == 0)
                        err(EX_DATAERR,
                            "missing or empty From line: %s", lbuf);
                else {
                        *p = '\n';
                        break;
                }

                if (*addrp == '\0')
                        err(EX_DATAERR, "corrupted From line: %s", lbuf);

                /* Use the "remote from" if it exists. */
                for (p = addrp; (p = strchr(p + 1, 'r')) != NULL;)
                        if (!strncmp(p, "remote from ", 12)) {
                                for (t = p += 12; *t && !isspace(*t); ++t);
                                *t = '\0';
                                if (debug)
                                        (void)fprintf(stderr,
                                            "remote from: %s\n", p);
                                break;
                        }

                /* Else use the string up to the last bang. */
                if (p == NULL)
                        if (*addrp == '!')
                                err(EX_DATAERR,
                                    "bang starts address: %s", addrp);
                        else if ((t = strrchr(addrp, '!')) != NULL) {
                                *t = '\0';
                                p = addrp;
                                addrp = t + 1;
                                if (*addrp == '\0')
                                        err(EX_DATAERR,
                                            "corrupted From line: %s", lbuf);
                                if (debug)
                                        (void)fprintf(stderr, "bang: %s\n", p);
                        }

                /* 'p' now points to any system string from this line. */
                if (p != NULL) {
                        /* Nul terminate it as necessary. */
                        for (t = p; *t && !isspace(*t); ++t);
                        *t = '\0';

                        /* If the first system, copy to the from_sys string. */
                        if (from_sys == NULL) {
                                if ((from_sys = strdup(p)) == NULL)
                                        err(EX_TEMPFAIL, NULL);
                                if (debug)
                                        (void)fprintf(stderr,
                                            "from_sys: %s\n", from_sys);
                        }

                        /* Concatenate to the path string. */
                        len = t - p;
                        if (from_path == NULL) {
                                fplen = 0;
                                if ((from_path = malloc(fptlen = 256)) == NULL)
                                        err(EX_TEMPFAIL, NULL);
                        }
                        if (fplen + len + 2 > fptlen) {
                                fptlen += MAX(fplen + len + 2, 256);
                                if ((from_path =
                                    realloc(from_path, fptlen)) == NULL)
                                        err(EX_TEMPFAIL, NULL);
                        }
                        memmove(from_path + fplen, p, len);
                        fplen += len;
                        from_path[fplen++] = '!';
                        from_path[fplen] = '\0';
                }

                /* Save off from user's address; the last one wins. */
                for (p = addrp; *p && !isspace(*p); ++p);
                *p = '\0';
                if (from_user != NULL)
                        free(from_user);
                if ((from_user = strdup(addrp)) == NULL)
                        err(EX_TEMPFAIL, NULL);

                if (debug) {
                        if (from_path != NULL)
                                (void)fprintf(stderr,
                                    "from_path: %s\n", from_path);
                        (void)fprintf(stderr, "from_user: %s\n", from_user);
                }

                if (offset != -1)
                        offset = (off_t)ftell(stdin);
        }

        i = 0;
        args[i++] = _PATH_SENDMAIL;     /* Build sendmail's argument list. */
        args[i++] = "-oee";             /* No errors, just status. */
        args[i++] = "-odq";             /* Queue it, don't try to deliver. */
        args[i++] = "-oi";              /* Ignore '.' on a line by itself. */

        if (from_sys != NULL) {         /* Set sender's host name. */
                if (strchr(from_sys, '.') == NULL)
                        (void)snprintf(buf, sizeof(buf),
                            "-oMs%s.%s", from_sys, domain);
                else
                        (void)snprintf(buf, sizeof(buf), "-oMs%s", from_sys);
                if ((args[i++] = strdup(buf)) == NULL)
                         err(EX_TEMPFAIL, NULL);
        }
                                        /* Set protocol used. */
        (void)snprintf(buf, sizeof(buf), "-oMr%s", domain);
        if ((args[i++] = strdup(buf)) == NULL)
                err(EX_TEMPFAIL, NULL);

                                        /* Set name of ``from'' person. */
        (void)snprintf(buf, sizeof(buf), "-f%s%s",
            from_path ? from_path : "", from_user);
        if ((args[i++] = strdup(buf)) == NULL)
                err(EX_TEMPFAIL, NULL);

        /*
         * Don't copy arguments beginning with - as they will be
         * passed to sendmail and could be interpreted as flags.
         */
        do {
                if (*argv && **argv == '-')
                        err(EX_USAGE, "dash precedes argument: %s", *argv);
        } while ((args[i++] = *argv++) != NULL);

        if (debug) {
                (void)fprintf(stderr, "Sendmail arguments:\n");
                for (i = 0; args[i]; i++)
                        (void)fprintf(stderr, "\t%s\n", args[i]);
        }

        /*
         * If called with a regular file as standard input, seek to the right
         * position in the file and just exec sendmail.  Could probably skip
         * skip the stat, but it's not unreasonable to believe that a failed
         * seek will cause future reads to fail.
         */
        if (!fstat(STDIN_FILENO, &sb) && S_ISREG(sb.st_mode)) {
                if (lseek(STDIN_FILENO, offset, SEEK_SET) != offset)
                        err(EX_TEMPFAIL, "stdin seek");
                execv(_PATH_SENDMAIL, args);
                err(EX_OSERR, "%s", _PATH_SENDMAIL);
        }

        if (pipe(pdes) < 0)
                err(EX_OSERR, NULL);

        switch (pid = vfork()) {
        case -1:                                /* Err. */
                err(EX_OSERR, NULL);
        case 0:                                 /* Child. */
                if (pdes[0] != STDIN_FILENO) {
                        (void)dup2(pdes[0], STDIN_FILENO);
                        (void)close(pdes[0]);
                }
                (void)close(pdes[1]);
                execv(_PATH_SENDMAIL, args);
                _exit(127);
                /* NOTREACHED */
        }

        if ((fp = fdopen(pdes[1], "w")) == NULL)
                err(EX_OSERR, NULL);
        (void)close(pdes[0]);

        /* Copy the file down the pipe. */
        do {
                (void)fprintf(fp, "%s", lbuf);
        } while (fgets(lbuf, sizeof(lbuf), stdin) != NULL);

        if (ferror(stdin))
                err(EX_TEMPFAIL, "stdin: %s", strerror(errno));

        if (fclose(fp))
                err(EX_OSERR, NULL);

        if ((waitpid(pid, &status, 0)) == -1)
                err(EX_OSERR, "%s", _PATH_SENDMAIL);

        if (!WIFEXITED(status))
                err(EX_OSERR,
                    "%s: did not terminate normally", _PATH_SENDMAIL);

        if (WEXITSTATUS(status))
                err(status, "%s: terminated with %d (non-zero) status",
                    _PATH_SENDMAIL, WEXITSTATUS(status));
        exit(EX_OK);
}

void
usage()
{
        (void)fprintf(stderr, "usage: rmail [-T] [-D domain] user ...\n");
        exit(EX_USAGE);
}

#ifdef __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif

void
#ifdef __STDC__
err(int eval, const char *fmt, ...)
#else
err(eval, fmt, va_alist)
        int eval;
        const char *fmt;
        va_dcl
#endif
{
        va_list ap;
#if __STDC__
        va_start(ap, fmt);
#else
        va_start(ap);
#endif
        (void)fprintf(stderr, "rmail: ");
        (void)vfprintf(stderr, fmt, ap);
        va_end(ap);
        (void)fprintf(stderr, "\n");
        exit(eval);
}