usr.sbin/mailwrapper/mailwrapper.c

   1 /*      $NetBSD: mailwrapper.c,v 1.9 2003/03/09 08:10:43 mjl Exp $      */
   2
   3 /*
   4  * Copyright (c) 1998
   5  *      Perry E. Metzger.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgment:
  17  *      This product includes software developed for the NetBSD Project
  18  *      by Perry E. Metzger.
  19  * 4. The name of the author may not be used to endorse or promote products
  20  *    derived from this software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 #include <err.h>
  35 #include <stdio.h>
  36 #include <string.h>
  37 #include <stdlib.h>
  38 #include <unistd.h>
  39
  40 #define _PATH_MAILERCONF        "/etc/mailer.conf"
  41
  42 struct arglist {
  43         size_t argc, maxc;
  44         const char **argv;
  45 };
  46
  47 int main __P((int, char *[], char *[]));
  48
  49 static void initarg __P((struct arglist *));
  50 static void addarg __P((struct arglist *, const char *, int));
  51
  52 static void
  53 initarg(al)
  54         struct arglist *al;
  55 {
  56         al->argc = 0;
  57         al->maxc = 10;
  58         if ((al->argv = malloc(al->maxc * sizeof(char *))) == NULL)
  59                 /*
  60                  * This (using err("mailwrapper")) is intentional.
  61                  * Mailwrapper plays ugly games with argv[0] and thus it
  62                  * is often difficult for people to know that the error
  63                  * isn't from "mailq" or "sendmail" but from mailwrapper
  64                  * -- having mailwrapper add an indication that it was really
  65                  * mailwrapper running was a requested feature.
  66                  */
  67                 err(1, "mailwrapper");
  68 }
  69
  70 static void
  71 addarg(al, arg, copy)
  72         struct arglist *al;
  73         const char *arg;
  74         int copy;
  75 {
  76         if (al->argc == al->maxc) {
  77             al->maxc <<= 1;
  78             if ((al->argv = realloc(al->argv,
  79                 al->maxc * sizeof(char *))) == NULL)
  80                     err(1, "mailwrapper");
  81         }
  82         if (copy) {
  83                 if ((al->argv[al->argc++] = strdup(arg)) == NULL)
  84                         err(1, "mailwrapper:");
  85         } else
  86                 al->argv[al->argc++] = arg;
  87 }
  88
  89 int
  90 main(argc, argv, envp)
  91         int argc;
  92         char *argv[];
  93         char *envp[];
  94 {
  95         FILE *config;
  96         char *line, *cp, *from, *to, *ap;
  97         size_t len, lineno = 0;
  98         int i;
  99         struct arglist al;
 100
 101         initarg(&al);
 102         addarg(&al, argv[0], 0);
 103
 104         if ((config = fopen(_PATH_MAILERCONF, "r")) == NULL)
 105                 err(1, "mailwrapper: can't open %s", _PATH_MAILERCONF);
 106
 107         for (;;) {
 108                 if ((line = fparseln(config, &len, &lineno, NULL, 0)) == NULL) {
 109                         if (feof(config))
 110                                 errx(1, "mailwrapper: no mapping in %s",
 111                                     _PATH_MAILERCONF);
 112                         err(1, "mailwrapper");
 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, getprogname()) == 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         (void)fclose(config);
 145
 146         for (i = 1; i < argc; i++)
 147                 addarg(&al, argv[i], 0);
 148
 149         addarg(&al, NULL, 0);
 150         execve(to, __UNCONST(al.argv), envp);
 151         err(1, "mailwrapper: execing %s", to);
 152         /*NOTREACHED*/
 153 parse_error:
 154         errx(1, "mailwrapper: parse error in %s at line %lu",
 155             _PATH_MAILERCONF, (u_long)lineno);
 156         /*NOTREACHED*/
 157 }