xref: /netbsd-src/usr.bin/from/from.c (revision d9158b13b5dfe46201430699a3f7a235ecf28df3)
1 /*
2  * Copyright (c) 1980, 1988 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #ifndef lint
35 char copyright[] =
36 "@(#) Copyright (c) 1980, 1988 The Regents of the University of California.\n\
37  All rights reserved.\n";
38 #endif /* not lint */
39 
40 #ifndef lint
41 /*static char sccsid[] = "from: @(#)from.c	5.7 (Berkeley) 3/1/91";*/
42 static char rcsid[] = "$Id: from.c,v 1.3 1994/01/25 08:44:44 deraadt Exp $";
43 #endif /* not lint */
44 
45 #include <sys/types.h>
46 #include <ctype.h>
47 #include <pwd.h>
48 #include <stdio.h>
49 #include <stdlib.h>
50 #include <unistd.h>
51 #include <paths.h>
52 
53 main(argc, argv)
54 	int argc;
55 	char **argv;
56 {
57 	extern char *optarg;
58 	extern int optind;
59 	struct passwd *pwd;
60 	int ch, newline;
61 	char *file, *sender, *p;
62 #if MAXPATHLEN > BUFSIZ
63 	char buf[MAXPATHLEN];
64 #else
65 	char buf[BUFSIZ];
66 #endif
67 
68 	file = sender = NULL;
69 	while ((ch = getopt(argc, argv, "f:s:")) != EOF)
70 		switch((char)ch) {
71 		case 'f':
72 			file = optarg;
73 			break;
74 		case 's':
75 			sender = optarg;
76 			for (p = sender; *p; ++p)
77 				if (isupper(*p))
78 					*p = tolower(*p);
79 			break;
80 		case '?':
81 		default:
82 			fprintf(stderr, "usage: from [-f file] [-s sender] [user]\n");
83 			exit(1);
84 		}
85 	argv += optind;
86 
87 	/*
88 	 * We find the mailbox by:
89 	 *	1 -f flag
90 	 *	2 user
91 	 *	2 MAIL environment variable
92 	 *	3 _PATH_MAILDIR/file
93 	 */
94 	if (!file) {
95 		if (!(file = *argv)) {
96 			if (!(file = getenv("MAIL"))) {
97 				if (!(pwd = getpwuid(getuid()))) {
98 					(void)fprintf(stderr,
99 				"from: no password file entry for you.\n");
100 					exit(1);
101 				}
102 				(void)sprintf(file = buf, "%s/%s",
103 					      _PATH_MAILDIR, pwd->pw_name);
104 			}
105 		}
106 		else
107 			(void)sprintf(file = buf, "%s/%s", _PATH_MAILDIR, file);
108 	}
109 	if (!freopen(file, "r", stdin)) {
110 		(void)fprintf(stderr, "from: can't read %s.\n", file);
111 		exit(1);
112 	}
113 	for (newline = 1; fgets(buf, sizeof(buf), stdin);) {
114 		if (*buf == '\n') {
115 			newline = 1;
116 			continue;
117 		}
118 		if (newline && !strncmp(buf, "From ", 5) &&
119 		    (!sender || match(buf + 5, sender)))
120 			printf("%s", buf);
121 		newline = 0;
122 	}
123 	exit(0);
124 }
125 
126 match(line, sender)
127 	register char *line, *sender;
128 {
129 	register char ch, pch, first, *p, *t;
130 
131 	for (first = *sender++;;) {
132 		if (isspace(ch = *line))
133 			return(0);
134 		++line;
135 		if (isupper(ch))
136 			ch = tolower(ch);
137 		if (ch != first)
138 			continue;
139 		for (p = sender, t = line;;) {
140 			if (!(pch = *p++))
141 				return(1);
142 			if (isupper(ch = *t++))
143 				ch = tolower(ch);
144 			if (ch != pch)
145 				break;
146 		}
147 	}
148 	/* NOTREACHED */
149 }
150