xref: /freebsd/usr.bin/from/from.c (revision 98d04b7c6888c429582660d613d7142b6aea6967)
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
35 static 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
41 static 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 <string.h>
49 #include <paths.h>
50 
51 main(argc, argv)
52 	int argc;
53 	char **argv;
54 {
55 	extern char *optarg;
56 	extern int optind;
57 	struct passwd *pwd;
58 	int ch, newline;
59 	char *file, *sender, *p;
60 #if MAXPATHLEN > BUFSIZ
61 	char buf[MAXPATHLEN];
62 #else
63 	char buf[BUFSIZ];
64 #endif
65 
66 	file = sender = NULL;
67 	while ((ch = getopt(argc, argv, "f:s:?")) != EOF)
68 		switch((char)ch) {
69 		case 'f':
70 			file = optarg;
71 			break;
72 		case 's':
73 			sender = optarg;
74 			for (p = sender; *p; ++p)
75 				if (isupper(*p))
76 					*p = tolower(*p);
77 			break;
78 		case '?':
79 		default:
80 			fprintf(stderr, "usage: from [-f file] [-s sender] [user]\n");
81 			exit(1);
82 		}
83 	argv += optind;
84 
85 	if (!file) {
86 		if (!(file = *argv)) {
87 			if (!(pwd = getpwuid(getuid()))) {
88 				fprintf(stderr,
89 				    "from: no password file entry for you.\n");
90 				exit(1);
91 			}
92 			file = pwd->pw_name;
93 		}
94 		(void)sprintf(buf, "%s/%s", _PATH_MAILDIR, file);
95 		file = buf;
96 	}
97 
98 	/* read from stdin */
99 	if (strcmp(file, "-") == 0) {
100 	}
101 	else if (!freopen(file, "r", stdin)) {
102 		fprintf(stderr, "from: can't read %s.\n", file);
103 		exit(1);
104 	}
105 	for (newline = 1; fgets(buf, sizeof(buf), stdin);) {
106 		if (*buf == '\n') {
107 			newline = 1;
108 			continue;
109 		}
110 		if (newline && !strncmp(buf, "From ", 5) &&
111 		    (!sender || match(buf + 5, sender)))
112 			printf("%s", buf);
113 		newline = 0;
114 	}
115 	exit(0);
116 }
117 
118 match(line, sender)
119 	register char *line, *sender;
120 {
121 	register char ch, pch, first, *p, *t;
122 
123 	for (first = *sender++;;) {
124 		if (isspace(ch = *line))
125 			return(0);
126 		++line;
127 		if (isupper(ch))
128 			ch = tolower(ch);
129 		if (ch != first)
130 			continue;
131 		for (p = sender, t = line;;) {
132 			if (!(pch = *p++))
133 				return(1);
134 			if (isupper(ch = *t++))
135 				ch = tolower(ch);
136 			if (ch != pch)
137 				break;
138 		}
139 	}
140 	/* NOTREACHED */
141 }
142