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