xref: /freebsd/usr.bin/from/from.c (revision 5b31cc94b10d4bb7109c6b27940a0fc76a44a331)
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 #endif /* not lint */
40 #include <sys/cdefs.h>
41 #include <sys/types.h>
42 #include <ctype.h>
43 #include <err.h>
44 #include <pwd.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <paths.h>
48 #include <string.h>
49 #include <unistd.h>
50 
51 static int match(const char *, const char *);
52 static void usage(void) __dead2;
53 
54 int
55 main(int argc, char **argv)
56 {
57 	FILE *mbox;
58 	struct passwd *pwd;
59 	int ch, count, newline;
60 	const char *file;
61 	char *sender, *p;
62 #if MAXPATHLEN > BUFSIZ
63 	char buf[MAXPATHLEN];
64 #else
65 	char buf[BUFSIZ];
66 #endif
67 
68 	file = sender = NULL;
69 	count = -1;
70 	while ((ch = getopt(argc, argv, "cf:s:")) != -1)
71 		switch (ch) {
72 		case 'c':
73 			count = 0;
74 			break;
75 		case 'f':
76 			file = optarg;
77 			break;
78 		case 's':
79 			sender = optarg;
80 			for (p = sender; *p; ++p)
81 				*p = tolower(*p);
82 			break;
83 		case '?':
84 		default:
85 			usage();
86 		}
87 	argc -= optind;
88 	argv += optind;
89 
90 	if (file == NULL) {
91 		if (argc) {
92 			(void)snprintf(buf, sizeof(buf), "%s/%s", _PATH_MAILDIR, *argv);
93 			file  = buf;
94 		} else {
95 			if (!(file = getenv("MAIL"))) {
96 				if (!(pwd = getpwuid(getuid())))
97 					errx(1, "no password file entry for you");
98 				file = pwd->pw_name;
99 				(void)snprintf(buf, sizeof(buf),
100 				    "%s/%s", _PATH_MAILDIR, file);
101 				file = buf;
102 			}
103 		}
104 	}
105 
106 	/* read from stdin */
107 	if (strcmp(file, "-") == 0) {
108 		mbox = stdin;
109 	}
110 	else if ((mbox = fopen(file, "r")) == NULL) {
111 		errx(1, "can't read %s", file);
112 	}
113 	for (newline = 1; fgets(buf, sizeof(buf), mbox);) {
114 		if (*buf == '\n') {
115 			newline = 1;
116 			continue;
117 		}
118 		if (newline && !strncmp(buf, "From ", 5) &&
119 		    (!sender || match(buf + 5, sender))) {
120 			if (count != -1)
121 				count++;
122 			else
123 				printf("%s", buf);
124 		}
125 		newline = 0;
126 	}
127 	if (count != -1)
128 		printf("There %s %d message%s in your incoming mailbox.\n",
129 		    count == 1 ? "is" : "are", count, count == 1 ? "" : "s");
130 	fclose(mbox);
131 	exit(0);
132 }
133 
134 static void
135 usage(void)
136 {
137 	fprintf(stderr, "usage: from [-c] [-f file] [-s sender] [user]\n");
138 	exit(1);
139 }
140 
141 static int
142 match(const char *line, const char *sender)
143 {
144 	char ch, pch, first;
145 	const char *p, *t;
146 
147 	for (first = *sender++;;) {
148 		if (isspace(ch = *line))
149 			return(0);
150 		++line;
151 		ch = tolower(ch);
152 		if (ch != first)
153 			continue;
154 		for (p = sender, t = line;;) {
155 			if (!(pch = *p++))
156 				return(1);
157 			ch = tolower(*t);
158 			t++;
159 			if (ch != pch)
160 				break;
161 		}
162 	}
163 	/* NOTREACHED */
164 }
165