from.c revision 1590 
1/*
2 * Copyright (c) 1980, 1988, 1993
3 *	The Regents of the University of California.  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
35static char copyright[] =
36"@(#) Copyright (c) 1980, 1988, 1993\n\
37	The Regents of the University of California.  All rights reserved.\n";
38#endif /* not lint */
39
40#ifndef lint
41static char sccsid[] = "@(#)from.c	8.1 (Berkeley) 6/6/93";
42#endif /* not lint */
43
44#include <sys/types.h>
45#include <ctype.h>
46#include <pwd.h>
47#include <stdio.h>
48#include <paths.h>
49
50main(argc, argv)
51	int argc;
52	char **argv;
53{
54	extern char *optarg;
55	extern int optind;
56	struct passwd *pwd;
57	int ch, newline;
58	char *file, *sender, *p;
59#if MAXPATHLEN > BUFSIZ
60	char buf[MAXPATHLEN];
61#else
62	char buf[BUFSIZ];
63#endif
64
65	file = sender = NULL;
66	while ((ch = getopt(argc, argv, "f:s:")) != EOF)
67		switch((char)ch) {
68		case 'f':
69			file = optarg;
70			break;
71		case 's':
72			sender = optarg;
73			for (p = sender; *p; ++p)
74				if (isupper(*p))
75					*p = tolower(*p);
76			break;
77		case '?':
78		default:
79			fprintf(stderr, "usage: from [-f file] [-s sender] [user]\n");
80			exit(1);
81		}
82	argv += optind;
83
84	if (!file) {
85		if (!(file = *argv)) {
86			if (!(pwd = getpwuid(getuid()))) {
87				fprintf(stderr,
88				    "from: no password file entry for you.\n");
89				exit(1);
90			}
91			file = pwd->pw_name;
92		}
93		(void)sprintf(buf, "%s/%s", _PATH_MAILDIR, file);
94		file = buf;
95	}
96	if (!freopen(file, "r", stdin)) {
97		fprintf(stderr, "from: can't read %s.\n", file);
98		exit(1);
99	}
100	for (newline = 1; fgets(buf, sizeof(buf), stdin);) {
101		if (*buf == '\n') {
102			newline = 1;
103			continue;
104		}
105		if (newline && !strncmp(buf, "From ", 5) &&
106		    (!sender || match(buf + 5, sender)))
107			printf("%s", buf);
108		newline = 0;
109	}
110	exit(0);
111}
112
113match(line, sender)
114	register char *line, *sender;
115{
116	register char ch, pch, first, *p, *t;
117
118	for (first = *sender++;;) {
119		if (isspace(ch = *line))
120			return(0);
121		++line;
122		if (isupper(ch))
123			ch = tolower(ch);
124		if (ch != first)
125			continue;
126		for (p = sender, t = line;;) {
127			if (!(pch = *p++))
128				return(1);
129			if (isupper(ch = *t++))
130				ch = tolower(ch);
131			if (ch != pch)
132				break;
133		}
134	}
135	/* NOTREACHED */
136}
137