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
30 #include <sys/param.h>
31 #include <sys/stat.h>
32 #include <err.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <string.h>
36 #include <unistd.h>
37
38 static void usage(void);
39 static int print_matches(char *, char *);
40
41 static int silent;
42 static int allpaths;
43
44 int
main(int argc,char ** argv)45 main(int argc, char **argv)
46 {
47 char *p, *path;
48 size_t pathlen;
49 int opt, status;
50
51 status = EXIT_SUCCESS;
52
53 while ((opt = getopt(argc, argv, "as")) != -1) {
54 switch (opt) {
55 case 'a':
56 allpaths = 1;
57 break;
58 case 's':
59 silent = 1;
60 break;
61 default:
62 usage();
63 break;
64 }
65 }
66
67 argv += optind;
68 argc -= optind;
69
70 if (argc == 0)
71 usage();
72
73 if ((p = getenv("PATH")) == NULL)
74 exit(EXIT_FAILURE);
75 pathlen = strlen(p) + 1;
76 path = malloc(pathlen);
77 if (path == NULL)
78 err(EXIT_FAILURE, NULL);
79
80 while (argc > 0) {
81 memcpy(path, p, pathlen);
82
83 if (strlen(*argv) >= FILENAME_MAX ||
84 print_matches(path, *argv) == -1)
85 status = EXIT_FAILURE;
86
87 argv++;
88 argc--;
89 }
90
91 exit(status);
92 }
93
94 static void
usage(void)95 usage(void)
96 {
97
98 (void)fprintf(stderr, "usage: which [-as] program ...\n");
99 exit(EXIT_FAILURE);
100 }
101
102 static int
is_there(char * candidate)103 is_there(char *candidate)
104 {
105 struct stat fin;
106
107 /* XXX work around access(2) false positives for superuser */
108 if (access(candidate, X_OK) == 0 &&
109 stat(candidate, &fin) == 0 &&
110 S_ISREG(fin.st_mode) &&
111 (getuid() != 0 ||
112 (fin.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) != 0)) {
113 if (!silent)
114 printf("%s\n", candidate);
115 return (1);
116 }
117 return (0);
118 }
119
120 static int
print_matches(char * path,char * filename)121 print_matches(char *path, char *filename)
122 {
123 char candidate[PATH_MAX];
124 const char *d;
125 int found;
126
127 if (strchr(filename, '/') != NULL)
128 return (is_there(filename) ? 0 : -1);
129 found = 0;
130 while ((d = strsep(&path, ":")) != NULL) {
131 if (*d == '\0')
132 d = ".";
133 if (snprintf(candidate, sizeof(candidate), "%s/%s", d,
134 filename) >= (int)sizeof(candidate))
135 continue;
136 if (is_there(candidate)) {
137 found = 1;
138 if (!allpaths)
139 break;
140 }
141 }
142 return (found ? 0 : -1);
143 }
144
145