xref: /netbsd/usr.sbin/mailwrapper/mailwrapper.c (revision c4a72b64)
1 /*	$NetBSD: mailwrapper.c,v 1.6 2002/11/30 03:10:57 lukem Exp $	*/
2 
3 /*
4  * Copyright (c) 1998
5  * 	Perry E. Metzger.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgment:
17  *	This product includes software developed for the NetBSD Project
18  *	by Perry E. Metzger.
19  * 4. The name of the author may not be used to endorse or promote products
20  *    derived from this software without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  */
33 
34 #include <err.h>
35 #include <stdio.h>
36 #include <string.h>
37 #include <stdlib.h>
38 #include <unistd.h>
39 
40 #define _PATH_MAILERCONF	"/etc/mailer.conf"
41 
42 struct arglist {
43 	size_t argc, maxc;
44 	char **argv;
45 };
46 
47 int main __P((int, char *[], char *[]));
48 
49 static void initarg __P((struct arglist *));
50 static void addarg __P((struct arglist *, const char *, int));
51 
52 static void
53 initarg(al)
54 	struct arglist *al;
55 {
56 	al->argc = 0;
57 	al->maxc = 10;
58 	if ((al->argv = malloc(al->maxc * sizeof(char *))) == NULL)
59 		err(1, "mailwrapper");
60 }
61 
62 static void
63 addarg(al, arg, copy)
64 	struct arglist *al;
65 	const char *arg;
66 	int copy;
67 {
68 	if (al->argc == al->maxc) {
69 	    al->maxc <<= 1;
70 	    if ((al->argv = realloc(al->argv,
71 		al->maxc * sizeof(char *))) == NULL)
72 		    err(1, "mailwrapper");
73 	}
74 	if (copy) {
75 		if ((al->argv[al->argc++] = strdup(arg)) == NULL)
76 			err(1, "mailwrapper:");
77 	} else
78 		al->argv[al->argc++] = (char *)arg;
79 }
80 
81 int
82 main(argc, argv, envp)
83 	int argc;
84 	char *argv[];
85 	char *envp[];
86 {
87 	FILE *config;
88 	char *line, *cp, *from, *to, *ap;
89 	size_t len, lineno = 0;
90 	struct arglist al;
91 
92 	initarg(&al);
93 	for (len = 0; len < argc; len++)
94 		addarg(&al, argv[len], 0);
95 
96 	if ((config = fopen(_PATH_MAILERCONF, "r")) == NULL)
97 		err(1, "mailwrapper: can't open %s", _PATH_MAILERCONF);
98 
99 	for (;;) {
100 		if ((line = fparseln(config, &len, &lineno, NULL, 0)) == NULL) {
101 			if (feof(config))
102 				errx(1, "mailwrapper: no mapping in %s",
103 				    _PATH_MAILERCONF);
104 			err(1, "mailwrapper");
105 		}
106 
107 #define	WS	" \t\n"
108 		cp = line;
109 
110 		cp += strspn(cp, WS);
111 		if (cp[0] == '\0') {
112 			/* empty line */
113 			free(line);
114 			continue;
115 		}
116 
117 		if ((from = strsep(&cp, WS)) == NULL)
118 			goto parse_error;
119 
120 		cp += strspn(cp, WS);
121 
122 		if ((to = strsep(&cp, WS)) == NULL)
123 			goto parse_error;
124 
125 		if (strcmp(from, getprogname()) == 0) {
126 			for (ap = strsep(&cp, WS); ap != NULL;
127 			    ap = strsep(&cp, WS))
128 			    if (*ap)
129 				    addarg(&al, ap, 0);
130 			break;
131 		}
132 
133 		free(line);
134 	}
135 
136 	(void)fclose(config);
137 
138 	addarg(&al, NULL, 0);
139 	execve(to, al.argv, envp);
140 	err(1, "mailwrapper: execing %s", to);
141 	/*NOTREACHED*/
142 parse_error:
143 	errx(1, "mailwrapper: parse error in %s at line %lu",
144 	    _PATH_MAILERCONF, (u_long)lineno);
145 	/*NOTREACHED*/
146 }
147