summaryrefslogtreecommitdiff
path: root/usr.bin/which/which.c
blob: 419b32fe35c65197b9c130cf19fb4415b6bac8d3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
/*	$OpenBSD: which.c,v 1.19 2014/05/20 01:25:23 guenther Exp $	*/

/*
 * Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/param.h>
#include <sys/stat.h>
#include <sys/sysctl.h>

#include <err.h>
#include <errno.h>
#include <locale.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define PROG_WHICH	1
#define PROG_WHEREIS	2

extern char *__progname;

int findprog(char *, char *, int, int);
__dead void usage(void);

/*
 * which(1) -- find an executable(s) in the user's path
 * whereis(1) -- find an executable(s) in the default user path
 *
 * Return values:
 *	0 - all executables found
 *	1 - some found, some not
 *	2 - none found
 */

int
main(int argc, char *argv[])
{
	char *path;
	size_t n;
	int ch, allmatches = 0, notfound = 0, progmode = PROG_WHICH;

	(void)setlocale(LC_ALL, "");

	while ((ch = getopt(argc, argv, "a")) != -1)
		switch (ch) {
		case 'a':
			allmatches = 1;
			break;
		default:
			usage();
		}
	argc -= optind;
	argv += optind;

	if (argc == 0)
		usage();

	if (strcmp(__progname, "whereis") == 0) {
		progmode = PROG_WHEREIS;
		path = _PATH_STDPATH;
	} else {
		if ((path = getenv("PATH")) == NULL)
			err(1, "can't get $PATH from environment");
	}

	/* To make access(2) do what we want */
	if (setgid(getegid()))
		err(1, "Can't set gid to %u", getegid());
	if (setuid(geteuid()))
		err(1, "Can't set uid to %u", geteuid());

	for (n = 0; n < argc; n++)
		if (findprog(argv[n], path, progmode, allmatches) == 0)
			notfound++;

	exit((notfound == 0) ? 0 : ((notfound == argc) ? 2 : 1));
}

int
findprog(char *prog, char *path, int progmode, int allmatches)
{
	char *p, filename[MAXPATHLEN];
	int proglen, plen, rval = 0;
	struct stat sbuf;
	char *pathcpy;

	/* Special case if prog contains '/' */
	if (strchr(prog, '/')) {
		if ((stat(prog, &sbuf) == 0) && S_ISREG(sbuf.st_mode) &&
		    access(prog, X_OK) == 0) {
			(void)puts(prog);
			return (1);
		} else {
			warnx("%s: Command not found.", prog);
			return (0);
		}
	}

	if ((path = strdup(path)) == NULL)
		err(1, "strdup");
	pathcpy = path;

	proglen = strlen(prog);
	while ((p = strsep(&pathcpy, ":")) != NULL) {
		if (*p == '\0')
			p = ".";

		plen = strlen(p);
		while (p[plen-1] == '/')
			p[--plen] = '\0';	/* strip trailing '/' */

		if (plen + 1 + proglen >= sizeof(filename)) {
			warnc(ENAMETOOLONG, "%s/%s", p, prog);
			free(path);
			return (0);
		}

		snprintf(filename, sizeof(filename), "%s/%s", p, prog);
		if ((stat(filename, &sbuf) == 0) && S_ISREG(sbuf.st_mode) &&
		    access(filename, X_OK) == 0) {
			(void)puts(filename);
			rval = 1;
			if (!allmatches) {
				free(path);
				return (rval);
			}
		}
	}
	(void)free(path);

	/* whereis(1) is silent on failure. */
	if (!rval && progmode != PROG_WHEREIS)
		warnx("%s: Command not found.", prog);
	return (rval);
}

__dead void
usage(void)
{
	(void)fprintf(stderr, "usage: %s [-a] name ...\n", __progname);
	exit(1);
}