1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2000 Dan Papasian. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30
31 __FBSDID("$FreeBSD$");
32
33 #include <sys/param.h>
34 #include <sys/stat.h>
35 #include <err.h>
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <string.h>
39 #include <unistd.h>
40
41 static void usage(void);
42 static int print_matches(char *, char *);
43
44 static int silent;
45 static int allpaths;
46
47 int
main(int argc,char ** argv)48 main(int argc, char **argv)
49 {
50 char *p, *path;
51 ssize_t pathlen;
52 int opt, status;
53
54 status = EXIT_SUCCESS;
55
56 while ((opt = getopt(argc, argv, "as")) != -1) {
57 switch (opt) {
58 case 'a':
59 allpaths = 1;
60 break;
61 case 's':
62 silent = 1;
63 break;
64 default:
65 usage();
66 break;
67 }
68 }
69
70 argv += optind;
71 argc -= optind;
72
73 if (argc == 0)
74 usage();
75
76 if ((p = getenv("PATH")) == NULL)
77 exit(EXIT_FAILURE);
78 pathlen = strlen(p) + 1;
79 path = malloc(pathlen);
80 if (path == NULL)
81 err(EXIT_FAILURE, NULL);
82
83 while (argc > 0) {
84 memcpy(path, p, pathlen);
85
86 if (strlen(*argv) >= FILENAME_MAX ||
87 print_matches(path, *argv) == -1)
88 status = EXIT_FAILURE;
89
90 argv++;
91 argc--;
92 }
93
94 exit(status);
95 }
96
97 static void
usage(void)98 usage(void)
99 {
100
101 (void)fprintf(stderr, "usage: which [-as] program ...\n");
102 exit(EXIT_FAILURE);
103 }
104
105 static int
is_there(char * candidate)106 is_there(char *candidate)
107 {
108 struct stat fin;
109
110 /* XXX work around access(2) false positives for superuser */
111 if (access(candidate, X_OK) == 0 &&
112 stat(candidate, &fin) == 0 &&
113 S_ISREG(fin.st_mode) &&
114 (getuid() != 0 ||
115 (fin.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) != 0)) {
116 if (!silent)
117 printf("%s\n", candidate);
118 return (1);
119 }
120 return (0);
121 }
122
123 static int
print_matches(char * path,char * filename)124 print_matches(char *path, char *filename)
125 {
126 char candidate[PATH_MAX];
127 const char *d;
128 int found;
129
130 if (strchr(filename, '/') != NULL)
131 return (is_there(filename) ? 0 : -1);
132 found = 0;
133 while ((d = strsep(&path, ":")) != NULL) {
134 if (*d == '\0')
135 d = ".";
136 if (snprintf(candidate, sizeof(candidate), "%s/%s", d,
137 filename) >= (int)sizeof(candidate))
138 continue;
139 if (is_there(candidate)) {
140 found = 1;
141 if (!allpaths)
142 break;
143 }
144 }
145 return (found ? 0 : -1);
146 }
147
148