usr/src/cmd/mailwrapper/mailwrapper.c

   1 /*      $OpenBSD: mailwrapper.c,v 1.18 2007/11/06 14:39:19 otto Exp $   */
   2 /*      $NetBSD: mailwrapper.c,v 1.9 2003/03/09 08:10:43 mjl Exp $      */
   3
   4 /*
   5  * Copyright (c) 1998
   6  *      Perry E. Metzger.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgment:
  18  *      This product includes software developed for the NetBSD Project
  19  *      by Perry E. Metzger.
  20  * 4. The name of the author may not be used to endorse or promote products
  21  *    derived from this software without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  25  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  26  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  27  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  28  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  29  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  30  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  31  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  32  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  33  */
  34
  35 #include <compat.h>
  36 #include <err.h>
  37 #include <stdio.h>
  38 #include <string.h>
  39 #include <unistd.h>
  40 #include <stdlib.h>
  41 #include <sysexits.h>
  42 #include <syslog.h>
  43 #include <limits.h>
  44
  45 #include "pathnames.h"
  46
  47 struct arglist {
  48         size_t argc, maxc;
  49         char **argv;
  50 };
  51
  52 int main(int, char *[], char *[]);
  53
  54 static void initarg(struct arglist *);
  55 static void addarg(struct arglist *, const char *);
  56
  57 static void
  58 initarg(struct arglist *al)
  59 {
  60         al->argc = 0;
  61         al->maxc = 10;
  62         if ((al->argv = calloc(al->maxc, sizeof (char *))) == NULL)
  63                 err(EX_TEMPFAIL, "calloc");
  64 }
  65
  66 static void
  67 addarg(struct arglist *al, const char *arg)
  68 {
  69
  70         if (al->argc == al->maxc) {
  71                 al->maxc <<= 1;
  72                 al->argv = reallocarray(al->argv, al->maxc, sizeof (char *));
  73                 if (al->argv == NULL)
  74                         err(EX_TEMPFAIL, "realloc");
  75         }
  76         if (arg == NULL)
  77                 al->argv[al->argc++] = NULL;
  78         else if ((al->argv[al->argc++] = strdup(arg)) == NULL)
  79                 err(EX_TEMPFAIL, "strdup");
  80 }
  81
  82 int
  83 main(int argc, char *argv[], char *envp[])
  84 {
  85         FILE *config;
  86         char *line, *cp, *from, *to, *ap;
  87         char progname[PATH_MAX+1];
  88         const char *name;
  89         size_t len, lineno = 0;
  90         int i;
  91         struct arglist al;
  92
  93         /* change __progname to mailwrapper so we get sensible error messages */
  94         name = getprogname();
  95         if (name) {
  96                 strncpy(progname, name, sizeof (progname));
  97         } else {
  98                 err(EX_OSERR, "cannot get program name");
  99         }
 100         setprogname("mailwrapper");
 101
 102         initarg(&al);
 103         addarg(&al, argv[0]);
 104
 105         if ((config = fopen(_PATH_MAILERCONF, "r")) == NULL) {
 106                 for (i = 1; i < argc; i++)
 107                         addarg(&al, argv[i]);
 108                 addarg(&al, NULL);
 109                 openlog(getprogname(), LOG_PID, LOG_MAIL);
 110                 syslog(LOG_INFO, "cannot open %s, using %s as default MTA",
 111                     _PATH_MAILERCONF, _PATH_DEFAULTMTA);
 112                 closelog();
 113                 execve(_PATH_DEFAULTMTA, al.argv, envp);
 114                 err(EX_OSERR, "cannot exec %s", _PATH_DEFAULTMTA);
 115                 /*NOTREACHED*/
 116         }
 117
 118         for (;;) {
 119                 if ((line = fparseln(config, &len, &lineno, NULL, 0)) == NULL) {
 120                         if (feof(config))
 121                                 errx(EX_CONFIG, "no mapping for %s in %s",
 122                                     progname, _PATH_MAILERCONF);
 123                         err(EX_CONFIG, "cannot parse line %lu",
 124                             (ulong_t)lineno);
 125                 }
 126
 127 #define WS      " \t\n"
 128                 cp = line;
 129
 130                 cp += strspn(cp, WS);
 131                 if (cp[0] == '\0') {
 132                         /* empty line */
 133                         free(line);
 134                         continue;
 135                 }
 136
 137                 if ((from = strsep(&cp, WS)) == NULL || cp == NULL)
 138                         goto parse_error;
 139
 140                 cp += strspn(cp, WS);
 141
 142                 if ((to = strsep(&cp, WS)) == NULL)
 143                         goto parse_error;
 144
 145                 if (strcmp(from, progname) == 0) {
 146                         for (ap = strsep(&cp, WS); ap != NULL;
 147                             ap = strsep(&cp, WS)) {
 148                                 if (*ap)
 149                                         addarg(&al, ap);
 150                         }
 151                         break;
 152                 }
 153
 154                 free(line);
 155         }
 156
 157         (void) fclose(config);
 158
 159         for (i = 1; i < argc; i++)
 160                 addarg(&al, argv[i]);
 161
 162         addarg(&al, NULL);
 163         execve(to, al.argv, envp);
 164         err(EX_OSERR, "cannot exec %s", to);
 165         /*NOTREACHED*/
 166 parse_error:
 167         errx(EX_CONFIG, "parse error in %s at line %lu",
 168             _PATH_MAILERCONF, (ulong_t)lineno);
 169         /*NOTREACHED*/
 170         return (0);
 171 }