xref: /freebsd/usr.bin/from/from.c (revision 2008043f386721d58158e37e0d7e50df8095942d)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
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. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #ifndef lint
33 static const char copyright[] =
34 "@(#) Copyright (c) 1980, 1988, 1993\n\
35 	The Regents of the University of California.  All rights reserved.\n";
36 #endif /* not lint */
37 
38 #ifndef lint
39 #if 0
40 static char sccsid[] = "@(#)from.c	8.1 (Berkeley) 6/6/93";
41 #endif
42 #endif /* not lint */
43 #include <sys/cdefs.h>
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 static int match(const char *, const char *);
55 static void usage(void) __dead2;
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 				*p = tolower(*p);
85 			break;
86 		case '?':
87 		default:
88 			usage();
89 		}
90 	argc -= optind;
91 	argv += optind;
92 
93 	if (file == NULL) {
94 		if (argc) {
95 			(void)snprintf(buf, sizeof(buf), "%s/%s", _PATH_MAILDIR, *argv);
96 			file  = buf;
97 		} else {
98 			if (!(file = getenv("MAIL"))) {
99 				if (!(pwd = getpwuid(getuid())))
100 					errx(1, "no password file entry for you");
101 				file = pwd->pw_name;
102 				(void)snprintf(buf, sizeof(buf),
103 				    "%s/%s", _PATH_MAILDIR, file);
104 				file = buf;
105 			}
106 		}
107 	}
108 
109 	/* read from stdin */
110 	if (strcmp(file, "-") == 0) {
111 		mbox = stdin;
112 	}
113 	else if ((mbox = fopen(file, "r")) == NULL) {
114 		errx(1, "can't read %s", file);
115 	}
116 	for (newline = 1; fgets(buf, sizeof(buf), mbox);) {
117 		if (*buf == '\n') {
118 			newline = 1;
119 			continue;
120 		}
121 		if (newline && !strncmp(buf, "From ", 5) &&
122 		    (!sender || match(buf + 5, sender))) {
123 			if (count != -1)
124 				count++;
125 			else
126 				printf("%s", buf);
127 		}
128 		newline = 0;
129 	}
130 	if (count != -1)
131 		printf("There %s %d message%s in your incoming mailbox.\n",
132 		    count == 1 ? "is" : "are", count, count == 1 ? "" : "s");
133 	fclose(mbox);
134 	exit(0);
135 }
136 
137 static void
138 usage(void)
139 {
140 	fprintf(stderr, "usage: from [-c] [-f file] [-s sender] [user]\n");
141 	exit(1);
142 }
143 
144 static int
145 match(const char *line, const char *sender)
146 {
147 	char ch, pch, first;
148 	const char *p, *t;
149 
150 	for (first = *sender++;;) {
151 		if (isspace(ch = *line))
152 			return(0);
153 		++line;
154 		ch = tolower(ch);
155 		if (ch != first)
156 			continue;
157 		for (p = sender, t = line;;) {
158 			if (!(pch = *p++))
159 				return(1);
160 			ch = tolower(*t);
161 			t++;
162 			if (ch != pch)
163 				break;
164 		}
165 	}
166 	/* NOTREACHED */
167 }
168