xref: /freebsd/usr.bin/from/from.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
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 __FBSDID("$FreeBSD$");
45 
46 #include <sys/types.h>
47 #include <ctype.h>
48 #include <err.h>
49 #include <pwd.h>
50 #include <stdio.h>
51 #include <stdlib.h>
52 #include <paths.h>
53 #include <string.h>
54 #include <unistd.h>
55 
56 static int match(const char *, const char *);
57 static void usage(void);
58 
59 int
60 main(int argc, char **argv)
61 {
62 	FILE *mbox;
63 	struct passwd *pwd;
64 	int ch, count, newline;
65 	const char *file;
66 	char *sender, *p;
67 #if MAXPATHLEN > BUFSIZ
68 	char buf[MAXPATHLEN];
69 #else
70 	char buf[BUFSIZ];
71 #endif
72 
73 	file = sender = NULL;
74 	count = -1;
75 	while ((ch = getopt(argc, argv, "cf:s:")) != -1)
76 		switch (ch) {
77 		case 'c':
78 			count = 0;
79 			break;
80 		case 'f':
81 			file = optarg;
82 			break;
83 		case 's':
84 			sender = optarg;
85 			for (p = sender; *p; ++p)
86 				*p = tolower(*p);
87 			break;
88 		case '?':
89 		default:
90 			usage();
91 		}
92 	argc -= optind;
93 	argv += optind;
94 
95 	if (file == NULL) {
96 		if (argc) {
97 			(void)snprintf(buf, sizeof(buf), "%s/%s", _PATH_MAILDIR, *argv);
98 			file  = buf;
99 		} else {
100 			if (!(file = getenv("MAIL"))) {
101 				if (!(pwd = getpwuid(getuid())))
102 					errx(1, "no password file entry for you");
103 				file = pwd->pw_name;
104 				(void)snprintf(buf, sizeof(buf),
105 				    "%s/%s", _PATH_MAILDIR, file);
106 				file = buf;
107 			}
108 		}
109 	}
110 
111 	/* read from stdin */
112 	if (strcmp(file, "-") == 0) {
113 		mbox = stdin;
114 	}
115 	else if ((mbox = fopen(file, "r")) == NULL) {
116 		errx(1, "can't read %s", file);
117 	}
118 	for (newline = 1; fgets(buf, sizeof(buf), mbox);) {
119 		if (*buf == '\n') {
120 			newline = 1;
121 			continue;
122 		}
123 		if (newline && !strncmp(buf, "From ", 5) &&
124 		    (!sender || match(buf + 5, sender))) {
125 			if (count != -1)
126 				count++;
127 			else
128 				printf("%s", buf);
129 		}
130 		newline = 0;
131 	}
132 	if (count != -1)
133 		printf("There %s %d message%s in your incoming mailbox.\n",
134 		    count == 1 ? "is" : "are", count, count == 1 ? "" : "s");
135 	fclose(mbox);
136 	exit(0);
137 }
138 
139 static void
140 usage(void)
141 {
142 	fprintf(stderr, "usage: from [-c] [-f file] [-s sender] [user]\n");
143 	exit(1);
144 }
145 
146 static int
147 match(const char *line, const char *sender)
148 {
149 	char ch, pch, first;
150 	const char *p, *t;
151 
152 	for (first = *sender++;;) {
153 		if (isspace(ch = *line))
154 			return(0);
155 		++line;
156 		ch = tolower(ch);
157 		if (ch != first)
158 			continue;
159 		for (p = sender, t = line;;) {
160 			if (!(pch = *p++))
161 				return(1);
162 			ch = tolower(*t);
163 			t++;
164 			if (ch != pch)
165 				break;
166 		}
167 	}
168 	/* NOTREACHED */
169 }
170