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: releng/11.0/usr.sbin/mailwrapper/mailwrapper.c 270675 2014-08-26 22:20:02Z bapt $");
37
38#include <sys/param.h>
39
40#include <err.h>
41#include <stdio.h>
42#include <string.h>
43#include <unistd.h>
44#include <stdlib.h>
45#include <libutil.h>
46#include <sysexits.h>
47#include <syslog.h>
48
49#include "pathnames.h"
50
51struct arglist {
52	size_t argc, maxc;
53	char **argv;
54};
55
56int main(int, char *[], char *[]);
57
58static void initarg(struct arglist *);
59static void addarg(struct arglist *, const char *);
60
61static void
62initarg(struct arglist *al)
63{
64	al->argc = 0;
65	al->maxc = 10;
66	if ((al->argv = calloc(al->maxc, sizeof(char *))) == NULL)
67		err(EX_TEMPFAIL, "calloc");
68}
69
70static void
71addarg(struct arglist *al, const char *arg)
72{
73
74	if (al->argc == al->maxc) {
75		al->maxc <<= 1;
76		al->argv = realloc(al->argv, al->maxc * sizeof(char *));
77		if (al->argv == NULL)
78			err(EX_TEMPFAIL, "realloc");
79	}
80	if (arg == NULL)
81		al->argv[al->argc++] = NULL;
82	else if ((al->argv[al->argc++] = strdup(arg)) == NULL)
83		err(EX_TEMPFAIL, "strdup");
84}
85
86int
87main(int argc, char *argv[], char *envp[])
88{
89	FILE *config;
90	char *line, *cp, *from, *to, *ap;
91	const char *progname;
92	char localmailerconf[MAXPATHLEN];
93	const char *mailerconf;
94	size_t len, lineno = 0;
95	int i;
96	struct arglist al;
97
98	/* change __progname to mailwrapper so we get sensible error messages */
99	progname = getprogname();
100	setprogname("mailwrapper");
101
102	initarg(&al);
103	addarg(&al, argv[0]);
104
105	snprintf(localmailerconf, MAXPATHLEN, "%s/etc/mail/mailer.conf",
106	    getenv("LOCALBASE") ? getenv("LOCALBASE") : "/usr/local");
107
108	mailerconf = localmailerconf;
109	if ((config = fopen(localmailerconf, "r")) == NULL)
110		mailerconf = _PATH_MAILERCONF;
111
112	if (config == NULL && ((config = fopen(mailerconf, "r")) == NULL)) {
113		addarg(&al, NULL);
114		openlog(getprogname(), LOG_PID, LOG_MAIL);
115		syslog(LOG_INFO, "cannot open %s, using %s as default MTA",
116		    mailerconf, _PATH_DEFAULTMTA);
117		closelog();
118		execve(_PATH_DEFAULTMTA, al.argv, envp);
119		err(EX_OSERR, "cannot exec %s", _PATH_DEFAULTMTA);
120		/*NOTREACHED*/
121	}
122
123	for (;;) {
124		if ((line = fparseln(config, &len, &lineno, NULL, 0)) == NULL) {
125			if (feof(config))
126				errx(EX_CONFIG, "no mapping in %s", mailerconf);
127			err(EX_CONFIG, "cannot parse line %lu", (u_long)lineno);
128		}
129
130#define	WS	" \t\n"
131		cp = line;
132
133		cp += strspn(cp, WS);
134		if (cp[0] == '\0') {
135			/* empty line */
136			free(line);
137			continue;
138		}
139
140		if ((from = strsep(&cp, WS)) == NULL || cp == NULL)
141			goto parse_error;
142
143		cp += strspn(cp, WS);
144
145		if ((to = strsep(&cp, WS)) == NULL)
146			goto parse_error;
147
148		if (strcmp(from, progname) == 0) {
149			for (ap = strsep(&cp, WS); ap != NULL;
150			     ap = strsep(&cp, WS)) {
151				if (*ap)
152				    addarg(&al, ap);
153			}
154			break;
155		}
156
157		free(line);
158	}
159
160	(void)fclose(config);
161
162	for (i = 1; i < argc; i++)
163		addarg(&al, argv[i]);
164
165	addarg(&al, NULL);
166	execve(to, al.argv, envp);
167	err(EX_OSERR, "cannot exec %s", to);
168	/*NOTREACHED*/
169parse_error:
170	errx(EX_CONFIG, "parse error in %s at line %lu",
171	    mailerconf, (u_long)lineno);
172	/*NOTREACHED*/
173}
174