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