xref: /freebsd/usr.bin/from/from.c (revision 587392a5a04955b85c3beac4cff26ca568359f54)
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  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #ifndef lint
31 static const char copyright[] =
32 "@(#) Copyright (c) 1980, 1988, 1993\n\
33 	The Regents of the University of California.  All rights reserved.\n";
34 #endif /* not lint */
35 
36 #ifndef lint
37 #if 0
38 static char sccsid[] = "@(#)from.c	8.1 (Berkeley) 6/6/93";
39 #endif
40 #endif /* not lint */
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
43 
44 #include <sys/types.h>
45 #include <ctype.h>
46 #include <err.h>
47 #include <pwd.h>
48 #include <stdio.h>
49 #include <stdlib.h>
50 #include <paths.h>
51 #include <string.h>
52 #include <unistd.h>
53 
54 int match(const char *, const char *);
55 static void usage(void);
56 
57 int
58 main(int argc, char **argv)
59 {
60 	FILE *mbox;
61 	struct passwd *pwd;
62 	int ch, count, newline;
63 	const char *file;
64 	char *sender, *p;
65 #if MAXPATHLEN > BUFSIZ
66 	char buf[MAXPATHLEN];
67 #else
68 	char buf[BUFSIZ];
69 #endif
70 
71 	file = sender = NULL;
72 	count = -1;
73 	while ((ch = getopt(argc, argv, "cf:s:")) != -1)
74 		switch (ch) {
75 		case 'c':
76 			count = 0;
77 			break;
78 		case 'f':
79 			file = optarg;
80 			break;
81 		case 's':
82 			sender = optarg;
83 			for (p = sender; *p; ++p)
84 				if (isupper(*p))
85 					*p = tolower(*p);
86 			break;
87 		case '?':
88 		default:
89 			usage();
90 		}
91 	argc -= optind;
92 	argv += optind;
93 
94 	if (file == NULL) {
95 		if (argc) {
96 			(void)snprintf(buf, sizeof(buf), "%s/%s", _PATH_MAILDIR, *argv);
97 			file  = buf;
98 		} else {
99 			if (!(file = getenv("MAIL"))) {
100 				if (!(pwd = getpwuid(getuid())))
101 					errx(1, "no password file entry for you");
102 				file = pwd->pw_name;
103 				(void)snprintf(buf, sizeof(buf),
104 				    "%s/%s", _PATH_MAILDIR, file);
105 				file = buf;
106 			}
107 		}
108 	}
109 
110 	/* read from stdin */
111 	if (strcmp(file, "-") == 0) {
112 		mbox = stdin;
113 	}
114 	else if ((mbox = fopen(file, "r")) == NULL) {
115 		errx(1, "can't read %s", file);
116 	}
117 	for (newline = 1; fgets(buf, sizeof(buf), mbox);) {
118 		if (*buf == '\n') {
119 			newline = 1;
120 			continue;
121 		}
122 		if (newline && !strncmp(buf, "From ", 5) &&
123 		    (!sender || match(buf + 5, sender))) {
124 			if (count != -1)
125 				count++;
126 			else
127 				printf("%s", buf);
128 		}
129 		newline = 0;
130 	}
131 	if (count != -1)
132 		printf("There %s %d message%s in your incoming mailbox.\n",
133 		    count == 1 ? "is" : "are", count, count == 1 ? "" : "s");
134 	fclose(mbox);
135 	exit(0);
136 }
137 
138 static void
139 usage(void)
140 {
141 	fprintf(stderr, "usage: from [-c] [-f file] [-s sender] [user]\n");
142 	exit(1);
143 }
144 
145 int
146 match(const char *line, const char *sender)
147 {
148 	char ch, pch, first;
149 	const char *p, *t;
150 
151 	for (first = *sender++;;) {
152 		if (isspace(ch = *line))
153 			return(0);
154 		++line;
155 		if (isupper(ch))
156 			ch = tolower(ch);
157 		if (ch != first)
158 			continue;
159 		for (p = sender, t = line;;) {
160 			if (!(pch = *p++))
161 				return(1);
162 			if (isupper(ch = *t++))
163 				ch = tolower(ch);
164 			if (ch != pch)
165 				break;
166 		}
167 	}
168 	/* NOTREACHED */
169 }
170