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 <sys/cdefs.h>
36__FBSDID("$FreeBSD$");
37
38#include <err.h>
39#include <stdio.h>
40#include <string.h>
41#include <unistd.h>
42#include <stdlib.h>
43#include <libutil.h>
44#include <sysexits.h>
45#include <syslog.h>
46
47#include "pathnames.h"
48
49struct arglist {
50	size_t argc, maxc;
51	char **argv;
52};
53
54int main(int, char *[], char *[]);
55
56static void initarg(struct arglist *);
57static void addarg(struct arglist *, const char *);
58
59static void
60initarg(struct arglist *al)
61{
62	al->argc = 0;
63	al->maxc = 10;
64	if ((al->argv = calloc(al->maxc, sizeof(char *))) == NULL)
65		err(EX_TEMPFAIL, "calloc");
66}
67
68static void
69addarg(struct arglist *al, const char *arg)
70{
71
72	if (al->argc == al->maxc) {
73		al->maxc <<= 1;
74		al->argv = realloc(al->argv, al->maxc * sizeof(char *));
75		if (al->argv == NULL)
76			err(EX_TEMPFAIL, "realloc");
77	}
78	if (arg == NULL)
79		al->argv[al->argc++] = NULL;
80	else if ((al->argv[al->argc++] = strdup(arg)) == NULL)
81		err(EX_TEMPFAIL, "strdup");
82}
83
84int
85main(int argc, char *argv[], char *envp[])
86{
87	FILE *config;
88	char *line, *cp, *from, *to, *ap;
89	const char *progname;
90	size_t len, lineno = 0;
91	int i;
92	struct arglist al;
93
94	/* change __progname to mailwrapper so we get sensible error messages */
95	progname = getprogname();
96	setprogname("mailwrapper");
97
98	initarg(&al);
99	addarg(&al, argv[0]);
100
101	if ((config = fopen(_PATH_MAILERCONF, "r")) == NULL) {
102		addarg(&al, NULL);
103		openlog(getprogname(), LOG_PID, LOG_MAIL);
104		syslog(LOG_INFO, "cannot open %s, using %s as default MTA",
105		    _PATH_MAILERCONF, _PATH_DEFAULTMTA);
106		closelog();
107		execve(_PATH_DEFAULTMTA, al.argv, envp);
108		err(EX_OSERR, "cannot exec %s", _PATH_DEFAULTMTA);
109		/*NOTREACHED*/
110	}
111
112	for (;;) {
113		if ((line = fparseln(config, &len, &lineno, NULL, 0)) == NULL) {
114			if (feof(config))
115				errx(EX_CONFIG, "no mapping in %s", _PATH_MAILERCONF);
116			err(EX_CONFIG, "cannot parse line %lu", (u_long)lineno);
117		}
118
119#define	WS	" \t\n"
120		cp = line;
121
122		cp += strspn(cp, WS);
123		if (cp[0] == '\0') {
124			/* empty line */
125			free(line);
126			continue;
127		}
128
129		if ((from = strsep(&cp, WS)) == NULL || cp == NULL)
130			goto parse_error;
131
132		cp += strspn(cp, WS);
133
134		if ((to = strsep(&cp, WS)) == NULL)
135			goto parse_error;
136
137		if (strcmp(from, progname) == 0) {
138			for (ap = strsep(&cp, WS); ap != NULL;
139			     ap = strsep(&cp, WS)) {
140				if (*ap)
141				    addarg(&al, ap);
142			}
143			break;
144		}
145
146		free(line);
147	}
148
149	(void)fclose(config);
150
151	for (i = 1; i < argc; i++)
152		addarg(&al, argv[i]);
153
154	addarg(&al, NULL);
155	execve(to, al.argv, envp);
156	err(EX_OSERR, "cannot exec %s", to);
157	/*NOTREACHED*/
158parse_error:
159	errx(EX_CONFIG, "parse error in %s at line %lu",
160	    _PATH_MAILERCONF, (u_long)lineno);
161	/*NOTREACHED*/
162}
163