1 /* $OpenBSD: from.c,v 1.28 2021/07/12 15:09:19 beck Exp $ */
2 /* $NetBSD: from.c,v 1.6 1995/09/01 01:39:10 jtc Exp $ */
3
4 /*
5 * Copyright (c) 1980, 1988, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #include <sys/types.h>
34 #include <ctype.h>
35 #include <pwd.h>
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <unistd.h>
39 #include <paths.h>
40 #include <string.h>
41 #include <err.h>
42 #include <errno.h>
43
44 int match(char *, char *);
45 char *mail_spool(char *file, const char *user);
46
47 int
main(int argc,char * argv[])48 main(int argc, char *argv[])
49 {
50 int ch, newline, fflag = 0;
51 char *file, *line, *sender, *p;
52 size_t linesize = 0;
53 ssize_t linelen;
54 FILE *fp;
55
56 file = line = sender = NULL;
57 while ((ch = getopt(argc, argv, "f:s:")) != -1) {
58 switch(ch) {
59 case 'f':
60 fflag = 1;
61 file = optarg;
62 break;
63 case 's':
64 sender = optarg;
65 for (p = sender; *p; ++p)
66 if (isupper((unsigned char)*p))
67 *p = tolower((unsigned char)*p);
68 break;
69 default:
70 fprintf(stderr,
71 "usage: from [-f file] [-s sender] [user]\n");
72 exit(EXIT_FAILURE);
73 }
74 }
75 argv += optind;
76
77 if (pledge("stdio unveil rpath getpw", NULL) == -1)
78 err(1, "pledge");
79
80 file = mail_spool(file, *argv);
81
82 if (unveil(file, "r") == -1)
83 err(1, "unveil %s", file);
84 if (pledge("stdio rpath", NULL) == -1)
85 err(1, "pledge");
86
87 if ((fp = fopen(file, "r")) == NULL) {
88 if (!fflag && errno == ENOENT)
89 exit(EXIT_SUCCESS);
90 err(1, "%s", file);
91 }
92
93 if (pledge("stdio", NULL) == -1)
94 err(1, "pledge");
95
96 for (newline = 1; (linelen = getline(&line, &linesize, fp)) != -1;) {
97 if (*line == '\n') {
98 newline = 1;
99 continue;
100 }
101 if (newline && !strncmp(line, "From ", 5) &&
102 (!sender || match(line + 5, sender)))
103 printf("%s", line);
104 newline = 0;
105 }
106 free(line);
107 if (ferror(fp))
108 err(EXIT_FAILURE, "getline");
109 fclose(fp);
110 exit(EXIT_SUCCESS);
111 }
112
113 char *
mail_spool(char * file,const char * user)114 mail_spool(char *file, const char *user)
115 {
116 struct passwd *pwd;
117
118 /*
119 * We find the mailbox by:
120 * 1 -f flag
121 * 2 _PATH_MAILDIR/user (from argv)
122 * 2 MAIL environment variable
123 * 3 _PATH_MAILDIR/user (from environment or passwd db)
124 */
125 if (file == NULL) {
126 if (user == NULL) {
127 if ((file = getenv("MAIL")) == NULL) {
128 if ((user = getenv("LOGNAME")) == NULL &&
129 (user = getenv("USER")) == NULL) {
130 if (!(pwd = getpwuid(getuid())))
131 errx(1, "no password file "
132 "entry for you");
133 user = pwd->pw_name;
134 }
135 }
136 }
137 if (file == NULL) {
138 if (asprintf(&file, "%s/%s", _PATH_MAILDIR, user) == -1)
139 err(1, NULL);
140 }
141 }
142 return(file);
143 }
144
145 int
match(char * line,char * sender)146 match(char *line, char *sender)
147 {
148 char ch, pch, first, *p, *t;
149
150 for (first = *sender++;;) {
151 if (isspace((unsigned char)(ch = *line)))
152 return(0);
153 ++line;
154 if (isupper((unsigned char)ch))
155 ch = tolower((unsigned char)ch);
156 if (ch != first)
157 continue;
158 for (p = sender, t = line;;) {
159 if (!(pch = *p++))
160 return(1);
161 if (isupper((unsigned char)(ch = *t++)))
162 ch = tolower((unsigned char)ch);
163 if (ch != pch)
164 break;
165 }
166 }
167 /* NOTREACHED */
168 }
169