usr.sbin/mailwrapper/mailwrapper.c

   1 /*      $OpenBSD: mailwrapper.c,v 1.16 2004/07/06 03:38:14 millert Exp $        */
   2 /*      $NetBSD: mailwrapper.c,v 1.9 2003/03/09 08:10:43 mjl Exp $      */
   3 /* $FreeBSD: src/usr.sbin/mailwrapper/mailwrapper.c,v 1.9 2003/07/06 12:44:11 charnier Exp $ */
   4 /* $DragonFly: src/usr.sbin/mailwrapper/mailwrapper.c,v 1.7 2005/07/04 11:36:30 corecode Exp $ */
   5
   6 /*
   7  * Copyright (c) 1998
   8  *      Perry E. Metzger.  All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgment:
  20  *      This product includes software developed for the NetBSD Project
  21  *      by Perry E. Metzger.
  22  * 4. The name of the author may not be used to endorse or promote products
  23  *    derived from this software without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  26  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  27  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  28  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  29  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  30  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  31  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  32  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  33  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  34  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  35  */
  36
  37 #include <err.h>
  38 #include <stdio.h>
  39 #include <string.h>
  40 #include <stdlib.h>
  41 #include <unistd.h>
  42 #include <libutil.h>
  43 #include <syslog.h>
  44 #include <stdarg.h>
  45
  46 #include "pathnames.h"
  47
  48 struct arglist {
  49         size_t argc, maxc;
  50         char **argv;
  51 };
  52
  53 static void initarg(struct arglist *);
  54 static void addarg(struct arglist *, char *, int);
  55
  56 static void
  57 initarg(struct arglist *al)
  58 {
  59         al->argc = 0;
  60         al->maxc = 10;
  61         if ((al->argv = malloc(al->maxc * sizeof(char *))) == NULL)
  62                 err(1, NULL);
  63 }
  64
  65 static void
  66 addarg(struct arglist *al, char *arg, int copy)
  67 {
  68         if (al->argc == al->maxc) {
  69                 al->maxc <<= 1;
  70                 al->argv = realloc(al->argv, al->maxc * sizeof(char *));
  71                 if (al->argv == NULL)
  72                         err(1, NULL);
  73         }
  74         if (copy) {
  75                 if ((al->argv[al->argc++] = strdup(arg)) == NULL)
  76                         err(1, NULL);
  77         } else
  78                 al->argv[al->argc++] = arg;
  79 }
  80
  81 int
  82 main(int argc, char **argv, char **envp)
  83 {
  84         FILE *config;
  85         char *line, *cp, *from, *to, *ap;
  86         const char *progname;
  87         size_t len, lineno = 0;
  88         int i;
  89         struct arglist al;
  90
  91         /* change progname to mailwrapper so we get sensible error messages */
  92         progname = getprogname();
  93         setprogname("mailwrapper");
  94
  95         if ((config = fopen(_PATH_MAILERCONF, "r")) == NULL) {
  96                 openlog("mailwrapper", LOG_PID, LOG_MAIL);
  97                 syslog(LOG_INFO, "can't open %s, using %s as default MTA",
  98                     _PATH_MAILERCONF, _PATH_DEFAULTMTA);
  99                 closelog();
 100                 execve(_PATH_DEFAULTMTA, argv, envp);
 101                 err(1, "cannot exec %s", _PATH_DEFAULTMTA);
 102                 /*NOTREACHED*/
 103         }
 104
 105         initarg(&al);
 106         addarg(&al, argv[0], 0);
 107
 108         for (;;) {
 109                 if ((line = fparseln(config, &len, &lineno, NULL, 0)) == NULL) {
 110                         if (feof(config))
 111                                 errx(1, "no mapping in %s", _PATH_MAILERCONF);
 112                         err(1, NULL);
 113                 }
 114
 115 #define WS      " \t\n"
 116                 cp = line;
 117
 118                 cp += strspn(cp, WS);
 119                 if (cp[0] == '\0') {
 120                         /* empty line */
 121                         free(line);
 122                         continue;
 123                 }
 124
 125                 if ((from = strsep(&cp, WS)) == NULL)
 126                         goto parse_error;
 127
 128                 cp += strspn(cp, WS);
 129
 130                 if ((to = strsep(&cp, WS)) == NULL)
 131                         goto parse_error;
 132
 133                 if (strcmp(from, progname) == 0) {
 134                         for (ap = strsep(&cp, WS); ap != NULL;
 135                             ap = strsep(&cp, WS))
 136                             if (*ap)
 137                                     addarg(&al, ap, 0);
 138                         break;
 139                 }
 140
 141                 free(line);
 142         }
 143
 144         fclose(config);
 145
 146         for (i = 1; i < argc; i++)
 147                 addarg(&al, argv[i], 0);
 148         addarg(&al, NULL, 0);
 149
 150         execve(to, al.argv, envp);
 151         err(1, "cannot exec %s", to);
 152         /*NOTREACHED*/
 153 parse_error:
 154         errx(1, "parse error in %s at line %lu",
 155             _PATH_MAILERCONF, (u_long)lineno);
 156         /*NOTREACHED*/
 157 }