xref: /netbsd-src/usr.bin/from/from.c (revision 3b01aba77a7a698587faaae455bbfe740923c1f5)
1 /*	$NetBSD: from.c,v 1.13 2001/07/01 00:09:46 mjl Exp $	*/
2 
3 /*
4  * Copyright (c) 1980, 1988, 1993
5  *	The Regents of the University of California.  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 acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/cdefs.h>
37 #ifndef lint
38 __COPYRIGHT("@(#) Copyright (c) 1980, 1988, 1993\n\
39 	The Regents of the University of California.  All rights reserved.\n");
40 #endif /* not lint */
41 
42 #ifndef lint
43 #if 0
44 static char sccsid[] = "@(#)from.c	8.1 (Berkeley) 6/6/93";
45 #endif
46 __RCSID("$NetBSD: from.c,v 1.13 2001/07/01 00:09:46 mjl Exp $");
47 #endif /* not lint */
48 
49 #include <sys/types.h>
50 #include <ctype.h>
51 #include <err.h>
52 #include <paths.h>
53 #include <pwd.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <unistd.h>
58 
59 int	main (int, char **);
60 int	match (const char *, const char *);
61 
62 int
63 main(int argc, char **argv)
64 {
65 	struct passwd *pwd;
66 	int ch, newline;
67 	char *file, *sender, *p;
68 #if MAXPATHLEN > BUFSIZ
69 	char buf[MAXPATHLEN];
70 #else
71 	char buf[BUFSIZ];
72 #endif
73 
74 	file = sender = NULL;
75 	while ((ch = getopt(argc, argv, "f:s:")) != -1)
76 		switch((char)ch) {
77 		case 'f':
78 			file = optarg;
79 			break;
80 		case 's':
81 			sender = optarg;
82 			for (p = sender; *p; ++p)
83 				if (isupper((unsigned char)*p))
84 					*p = tolower(*p);
85 			break;
86 		default:
87 			fprintf(stderr, "usage: from [-f file] [-s sender] [user]\n");
88 			exit(1);
89 		}
90 	argv += optind;
91 
92 	/*
93 	 * We find the mailbox by:
94 	 *	1 -f flag
95 	 *	2 user
96 	 *	2 MAIL environment variable
97 	 *	3 _PATH_MAILDIR/file
98 	 */
99 	if (!file) {
100 		if (!(file = *argv)) {
101 			if (!(file = getenv("MAIL"))) {
102 				if (!(pwd = getpwuid(getuid())))
103 					errx(1, "no password file entry for you");
104 				if ((file = getenv("USER")) != NULL) {
105 					(void)snprintf(buf, sizeof(buf),
106 					    "%s/%s", _PATH_MAILDIR, file);
107 					file = buf;
108 				} else
109 					(void)snprintf(file = buf, sizeof(buf),
110 					    "%s/%s",
111 					    _PATH_MAILDIR, pwd->pw_name);
112 			}
113 		} else {
114 			(void)snprintf(buf, sizeof(buf), "%s/%s",
115 				_PATH_MAILDIR, file);
116 			file = buf;
117 		}
118 	}
119 	if (!freopen(file, "r", stdin))
120 		err(1, "can't read %s", file);
121 
122 	for (newline = 1; fgets(buf, sizeof(buf), stdin);) {
123 		if (*buf == '\n') {
124 			newline = 1;
125 			continue;
126 		}
127 		if (newline && !strncmp(buf, "From ", 5) &&
128 		    (!sender || match(buf + 5, sender)))
129 			printf("%s", buf);
130 		newline = 0;
131 	}
132 	exit(0);
133 }
134 
135 int
136 match(const char *line, const char *sender)
137 {
138 	char ch, pch, first;
139 	const char *p, *t;
140 
141 	for (first = *sender++;;) {
142 		if (isspace((unsigned char)(ch = *line)))
143 			return(0);
144 		++line;
145 		if (isupper((unsigned char)ch))
146 			ch = tolower(ch);
147 		if (ch != first)
148 			continue;
149 		for (p = sender, t = line;;) {
150 			if (!(pch = *p++))
151 				return(1);
152 			if (isupper((unsigned char)(ch = *t++)))
153 				ch = tolower(ch);
154 			if (ch != pch)
155 				break;
156 		}
157 	}
158 	/* NOTREACHED */
159 }
160