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: stable/11/usr.sbin/mailwrapper/mailwrapper.c 330449 2018-03-05 07:26:05Z eadler $");
39
40#include <sys/param.h>
41
42#include <err.h>
43#include <stdio.h>
44#include <string.h>
45#include <unistd.h>
46#include <stdlib.h>
47#include <libutil.h>
48#include <sysexits.h>
49#include <syslog.h>
50
51#include "pathnames.h"
52
53struct arglist {
54	size_t argc, maxc;
55	char **argv;
56};
57
58int main(int, char *[], char *[]);
59
60static void initarg(struct arglist *);
61static void addarg(struct arglist *, const char *);
62
63static void
64initarg(struct arglist *al)
65{
66	al->argc = 0;
67	al->maxc = 10;
68	if ((al->argv = calloc(al->maxc, sizeof(char *))) == NULL)
69		err(EX_TEMPFAIL, "calloc");
70}
71
72static void
73addarg(struct arglist *al, const char *arg)
74{
75
76	if (al->argc == al->maxc) {
77		al->maxc <<= 1;
78		al->argv = realloc(al->argv, al->maxc * sizeof(char *));
79		if (al->argv == NULL)
80			err(EX_TEMPFAIL, "realloc");
81	}
82	if (arg == NULL)
83		al->argv[al->argc++] = NULL;
84	else if ((al->argv[al->argc++] = strdup(arg)) == NULL)
85		err(EX_TEMPFAIL, "strdup");
86}
87
88int
89main(int argc, char *argv[], char *envp[])
90{
91	FILE *config;
92	char *line, *cp, *from, *to, *ap;
93	const char *progname;
94	char localmailerconf[MAXPATHLEN];
95	const char *mailerconf;
96	size_t len, lineno = 0;
97	int i;
98	struct arglist al;
99
100	/* change __progname to mailwrapper so we get sensible error messages */
101	progname = getprogname();
102	setprogname("mailwrapper");
103
104	initarg(&al);
105	addarg(&al, argv[0]);
106
107	snprintf(localmailerconf, MAXPATHLEN, "%s/etc/mail/mailer.conf",
108	    getenv("LOCALBASE") ? getenv("LOCALBASE") : "/usr/local");
109
110	mailerconf = localmailerconf;
111	if ((config = fopen(localmailerconf, "r")) == NULL)
112		mailerconf = _PATH_MAILERCONF;
113
114	if (config == NULL && ((config = fopen(mailerconf, "r")) == NULL)) {
115		addarg(&al, NULL);
116		openlog(getprogname(), LOG_PID, LOG_MAIL);
117		syslog(LOG_INFO, "cannot open %s, using %s as default MTA",
118		    mailerconf, _PATH_DEFAULTMTA);
119		closelog();
120		execve(_PATH_DEFAULTMTA, al.argv, envp);
121		err(EX_OSERR, "cannot exec %s", _PATH_DEFAULTMTA);
122		/*NOTREACHED*/
123	}
124
125	for (;;) {
126		if ((line = fparseln(config, &len, &lineno, NULL, 0)) == NULL) {
127			if (feof(config))
128				errx(EX_CONFIG, "no mapping in %s", mailerconf);
129			err(EX_CONFIG, "cannot parse line %lu", (u_long)lineno);
130		}
131
132#define	WS	" \t\n"
133		cp = line;
134
135		cp += strspn(cp, WS);
136		if (cp[0] == '\0') {
137			/* empty line */
138			free(line);
139			continue;
140		}
141
142		if ((from = strsep(&cp, WS)) == NULL || cp == NULL)
143			goto parse_error;
144
145		cp += strspn(cp, WS);
146
147		if ((to = strsep(&cp, WS)) == NULL)
148			goto parse_error;
149
150		if (strcmp(from, progname) == 0) {
151			for (ap = strsep(&cp, WS); ap != NULL;
152			     ap = strsep(&cp, WS)) {
153				if (*ap)
154				    addarg(&al, ap);
155			}
156			break;
157		}
158
159		free(line);
160	}
161
162	(void)fclose(config);
163
164	for (i = 1; i < argc; i++)
165		addarg(&al, argv[i]);
166
167	addarg(&al, NULL);
168	execve(to, al.argv, envp);
169	err(EX_OSERR, "cannot exec %s", to);
170	/*NOTREACHED*/
171parse_error:
172	errx(EX_CONFIG, "parse error in %s at line %lu",
173	    mailerconf, (u_long)lineno);
174	/*NOTREACHED*/
175}
176