xref: /netbsd-src/usr.sbin/mailwrapper/mailwrapper.c (revision 421949a31fb0942d3d87278998c2d7d432d8b3cb)
1 /*	$NetBSD: mailwrapper.c,v 1.11 2018/01/23 21:06:25 sevan 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 	const char **argv;
45 };
46 
47 static void initarg(struct arglist *);
48 static void addarg(struct arglist *, const char *, int);
49 
50 static void
initarg(struct arglist * al)51 initarg(struct arglist *al)
52 {
53 	al->argc = 0;
54 	al->maxc = 10;
55 	if ((al->argv = malloc(al->maxc * sizeof(char *))) == NULL)
56 		/*
57 		 * This (using err("mailwrapper")) is intentional.
58 		 * Mailwrapper plays ugly games with argv[0] and thus it
59 		 * is often difficult for people to know that the error
60 		 * isn't from "mailq" or "sendmail" but from mailwrapper
61 		 * -- having mailwrapper add an indication that it was really
62 		 * mailwrapper running was a requested feature.
63 		 */
64 		err(1, "mailwrapper");
65 }
66 
67 static void
addarg(struct arglist * al,const char * arg,int copy)68 addarg(struct arglist *al, const char *arg, int copy)
69 {
70 	if (al->argc == al->maxc) {
71 	    al->maxc <<= 1;
72 	    if ((al->argv = realloc(al->argv,
73 		al->maxc * sizeof(char *))) == NULL)
74 		    err(1, "mailwrapper");
75 	}
76 	if (copy) {
77 		if ((al->argv[al->argc++] = strdup(arg)) == NULL)
78 			err(1, "mailwrapper:");
79 	} else
80 		al->argv[al->argc++] = arg;
81 }
82 
83 int
main(int argc,char * argv[],char * envp[])84 main(int argc, char *argv[], char *envp[])
85 {
86 	FILE *config;
87 	char *line, *cp, *from, *to, *ap;
88 	size_t len, lineno = 0;
89 	int i;
90 	struct arglist al;
91 
92 	initarg(&al);
93 	addarg(&al, argv[0], 0);
94 
95 	if ((config = fopen(_PATH_MAILERCONF, "r")) == NULL)
96 		err(1, "mailwrapper: can't open %s", _PATH_MAILERCONF);
97 
98 	for (;;) {
99 		if ((line = fparseln(config, &len, &lineno, NULL, 0)) == NULL) {
100 			if (feof(config))
101 				errx(1, "mailwrapper: no mapping in %s",
102 				    _PATH_MAILERCONF);
103 			err(1, "mailwrapper");
104 		}
105 
106 #define	WS	" \t\n"
107 		cp = line;
108 
109 		cp += strspn(cp, WS);
110 		if (cp[0] == '\0') {
111 			/* empty line */
112 			free(line);
113 			continue;
114 		}
115 
116 		if ((from = strsep(&cp, WS)) == NULL)
117 			goto parse_error;
118 
119 		cp += strspn(cp, WS);
120 
121 		if ((to = strsep(&cp, WS)) == NULL)
122 			goto parse_error;
123 
124 		if (strcmp(from, getprogname()) == 0) {
125 			for (ap = strsep(&cp, WS); ap != NULL;
126 			    ap = strsep(&cp, WS))
127 			    if (*ap)
128 				    addarg(&al, ap, 0);
129 			break;
130 		}
131 
132 		free(line);
133 	}
134 
135 	(void)fclose(config);
136 
137 	for (i = 1; i < argc; i++)
138 		addarg(&al, argv[i], 0);
139 
140 	addarg(&al, NULL, 0);
141 	execve(to, __UNCONST(al.argv), envp);
142 	err(1, "mailwrapper: execing %s", to);
143 	/*NOTREACHED*/
144 parse_error:
145 	errx(1, "mailwrapper: parse error in %s at line %lu",
146 	    _PATH_MAILERCONF, (u_long)lineno);
147 	/*NOTREACHED*/
148 }
149