xref: /freebsd/usr.sbin/mailwrapper/mailwrapper.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
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  * SPDX-License-Identifier: BSD-4-Clause
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 <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 #include <sys/param.h>
41 
42 #include <err.h>
43 #include <paths.h>
44 #include <stdio.h>
45 #include <string.h>
46 #include <unistd.h>
47 #include <stdlib.h>
48 #include <libutil.h>
49 #include <sysexits.h>
50 #include <syslog.h>
51 
52 #include "pathnames.h"
53 
54 struct arglist {
55 	size_t argc, maxc;
56 	char **argv;
57 };
58 
59 int main(int, char *[], char *[]);
60 
61 static void initarg(struct arglist *);
62 static void addarg(struct arglist *, const char *);
63 
64 static void
65 initarg(struct arglist *al)
66 {
67 	al->argc = 0;
68 	al->maxc = 10;
69 	if ((al->argv = calloc(al->maxc, sizeof(char *))) == NULL)
70 		err(EX_TEMPFAIL, "calloc");
71 }
72 
73 static void
74 addarg(struct arglist *al, const char *arg)
75 {
76 
77 	if (al->argc == al->maxc) {
78 		al->maxc <<= 1;
79 		al->argv = realloc(al->argv, al->maxc * sizeof(char *));
80 		if (al->argv == NULL)
81 			err(EX_TEMPFAIL, "realloc");
82 	}
83 	if (arg == NULL)
84 		al->argv[al->argc++] = NULL;
85 	else if ((al->argv[al->argc++] = strdup(arg)) == NULL)
86 		err(EX_TEMPFAIL, "strdup");
87 }
88 
89 int
90 main(int argc, char *argv[], char *envp[])
91 {
92 	FILE *config;
93 	char *line, *cp, *from, *to, *ap;
94 	const char *progname;
95 	char localmailerconf[MAXPATHLEN];
96 	const char *mailerconf;
97 	size_t len, lineno = 0;
98 	int i;
99 	struct arglist al;
100 
101 	/* change __progname to mailwrapper so we get sensible error messages */
102 	progname = getprogname();
103 	setprogname("mailwrapper");
104 
105 	initarg(&al);
106 	addarg(&al, argv[0]);
107 
108 	snprintf(localmailerconf, MAXPATHLEN, "%s/etc/mail/mailer.conf",
109 	    getlocalbase());
110 
111 	mailerconf = localmailerconf;
112 	if ((config = fopen(localmailerconf, "r")) == NULL)
113 		mailerconf = _PATH_MAILERCONF;
114 
115 	if (config == NULL && ((config = fopen(mailerconf, "r")) == NULL)) {
116 		addarg(&al, NULL);
117 		openlog(getprogname(), LOG_PID, LOG_MAIL);
118 		syslog(LOG_INFO, "cannot open %s, using %s as default MTA",
119 		    mailerconf, _PATH_DEFAULTMTA);
120 		closelog();
121 		execve(_PATH_DEFAULTMTA, al.argv, envp);
122 		err(EX_OSERR, "cannot exec %s", _PATH_DEFAULTMTA);
123 		/*NOTREACHED*/
124 	}
125 
126 	for (;;) {
127 		if ((line = fparseln(config, &len, &lineno, NULL, 0)) == NULL) {
128 			if (feof(config))
129 				errx(EX_CONFIG, "no mapping in %s", mailerconf);
130 			err(EX_CONFIG, "cannot parse line %lu", (u_long)lineno);
131 		}
132 
133 #define	WS	" \t\n"
134 		cp = line;
135 
136 		cp += strspn(cp, WS);
137 		if (cp[0] == '\0') {
138 			/* empty line */
139 			free(line);
140 			continue;
141 		}
142 
143 		if ((from = strsep(&cp, WS)) == NULL || cp == NULL)
144 			goto parse_error;
145 
146 		cp += strspn(cp, WS);
147 
148 		if ((to = strsep(&cp, WS)) == NULL)
149 			goto parse_error;
150 
151 		if (strcmp(from, progname) == 0) {
152 			for (ap = strsep(&cp, WS); ap != NULL;
153 			     ap = strsep(&cp, WS)) {
154 				if (*ap)
155 				    addarg(&al, ap);
156 			}
157 			break;
158 		}
159 
160 		free(line);
161 	}
162 
163 	(void)fclose(config);
164 
165 	for (i = 1; i < argc; i++)
166 		addarg(&al, argv[i]);
167 
168 	addarg(&al, NULL);
169 	execve(to, al.argv, envp);
170 	err(EX_OSERR, "cannot exec %s", to);
171 	/*NOTREACHED*/
172 parse_error:
173 	errx(EX_CONFIG, "parse error in %s at line %lu",
174 	    mailerconf, (u_long)lineno);
175 	/*NOTREACHED*/
176 }
177