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/param.h>
38
39#include <err.h>
40#include <paths.h>
41#include <stdio.h>
42#include <string.h>
43#include <unistd.h>
44#include <stdlib.h>
45#include <errno.h>
46#include <libutil.h>
47#include <sysexits.h>
48#include <syslog.h>
49
50#include "pathnames.h"
51
52struct arglist {
53	size_t argc, maxc;
54	char **argv;
55};
56
57int main(int, char *[], char *[]);
58
59static void initarg(struct arglist *);
60static void addarg(struct arglist *, const char *);
61
62static void
63initarg(struct arglist *al)
64{
65	al->argc = 0;
66	al->maxc = 10;
67	if ((al->argv = calloc(al->maxc, sizeof(char *))) == NULL)
68		err(EX_TEMPFAIL, "calloc");
69}
70
71static void
72addarg(struct arglist *al, const char *arg)
73{
74
75	if (al->argc == al->maxc) {
76		al->maxc <<= 1;
77		al->argv = realloc(al->argv, al->maxc * sizeof(char *));
78		if (al->argv == NULL)
79			err(EX_TEMPFAIL, "realloc");
80	}
81	if (arg == NULL)
82		al->argv[al->argc++] = NULL;
83	else if ((al->argv[al->argc++] = strdup(arg)) == NULL)
84		err(EX_TEMPFAIL, "strdup");
85}
86
87int
88main(int argc, char *argv[], char *envp[])
89{
90	FILE *config;
91	char *line, *cp, *from, *to, *ap;
92	const char *progname;
93	char localmailerconf[MAXPATHLEN];
94	const char *mailerconf;
95	size_t len, lineno = 0;
96	int i;
97	struct arglist al;
98
99	/* change __progname to mailwrapper so we get sensible error messages */
100	progname = getprogname();
101	setprogname("mailwrapper");
102
103	initarg(&al);
104	addarg(&al, argv[0]);
105
106	snprintf(localmailerconf, MAXPATHLEN, "%s/etc/mail/mailer.conf",
107	    getlocalbase());
108
109	mailerconf = localmailerconf;
110	if ((config = fopen(localmailerconf, "r")) == NULL)
111		mailerconf = _PATH_MAILERCONF;
112
113	if (config == NULL && ((config = fopen(mailerconf, "r")) == NULL)) {
114		int serrno = errno;
115		openlog(getprogname(), LOG_PID, LOG_MAIL);
116
117		if (serrno == ENOENT) {
118			addarg(&al, NULL);
119			syslog(LOG_INFO, "%s does not exist, using %s as default MTA",
120			    mailerconf, _PATH_DEFAULTMTA);
121			closelog();
122			execve(_PATH_DEFAULTMTA, al.argv, envp);
123			err(EX_OSERR, "cannot exec %s", _PATH_DEFAULTMTA);
124		} else {
125			syslog(LOG_INFO, "cannot open %s: %s",
126			    mailerconf, strerror(serrno));
127			closelog();
128			errno = serrno;
129			err(EX_OSERR, "cannot open %s", mailerconf);
130		}
131		/*NOTREACHED*/
132	}
133
134	for (;;) {
135		if ((line = fparseln(config, &len, &lineno, NULL, 0)) == NULL) {
136			if (feof(config))
137				errx(EX_CONFIG, "no mapping in %s", mailerconf);
138			err(EX_CONFIG, "cannot parse line %lu", (u_long)lineno);
139		}
140
141#define	WS	" \t\n"
142		cp = line;
143
144		cp += strspn(cp, WS);
145		if (cp[0] == '\0') {
146			/* empty line */
147			free(line);
148			continue;
149		}
150
151		if ((from = strsep(&cp, WS)) == NULL || cp == NULL)
152			goto parse_error;
153
154		cp += strspn(cp, WS);
155
156		if ((to = strsep(&cp, WS)) == NULL)
157			goto parse_error;
158
159		if (strcmp(from, progname) == 0) {
160			for (ap = strsep(&cp, WS); ap != NULL;
161			     ap = strsep(&cp, WS)) {
162				if (*ap)
163				    addarg(&al, ap);
164			}
165			break;
166		}
167
168		free(line);
169	}
170
171	(void)fclose(config);
172
173	for (i = 1; i < argc; i++)
174		addarg(&al, argv[i]);
175
176	addarg(&al, NULL);
177	execve(to, al.argv, envp);
178	err(EX_OSERR, "cannot exec %s", to);
179	/*NOTREACHED*/
180parse_error:
181	errx(EX_CONFIG, "parse error in %s at line %lu",
182	    mailerconf, (u_long)lineno);
183	/*NOTREACHED*/
184}
185