summaryrefslogtreecommitdiffhomepage
path: root/coreutils/chmod.c
blob: 1bd0bd5c2920db4f302039c61236086d45579f15 (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
158
159
160
/* vi: set sw=4 ts=4: */
/*
 * Mini chmod implementation for busybox
 *
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 *
 * Reworked by (C) 2002 Vladimir Oleynik <dzo@simtreas.ru>
 *  to correctly parse '-rwxgoa'
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

/* BB_AUDIT SUSv3 compliant */
/* BB_AUDIT GNU defects - unsupported long options. */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/chmod.html */

#include "libbb.h"

/* This is a NOEXEC applet. Be very careful! */


#define OPT_RECURSE (option_mask32 & 1)
#define OPT_VERBOSE (USE_DESKTOP(option_mask32 & 2) SKIP_DESKTOP(0))
#define OPT_CHANGED (USE_DESKTOP(option_mask32 & 4) SKIP_DESKTOP(0))
#define OPT_QUIET   (USE_DESKTOP(option_mask32 & 8) SKIP_DESKTOP(0))
#define OPT_STR     "R" USE_DESKTOP("vcf")

/* coreutils:
 * chmod never changes the permissions of symbolic links; the chmod
 * system call cannot change their permissions. This is not a problem
 * since the permissions of symbolic links are never used.
 * However, for each symbolic link listed on the command line, chmod changes
 * the permissions of the pointed-to file. In contrast, chmod ignores
 * symbolic links encountered during recursive directory traversals.
 */

static int fileAction(const char *fileName, struct stat *statbuf, void* param, int depth)
{
	mode_t newmode;

	/* match coreutils behavior */
	if (depth == 0) {
		/* statbuf holds lstat result, but we need stat (follow link) */
		if (stat(fileName, statbuf))
			goto err;
	} else { /* depth > 0: skip links */
		if (S_ISLNK(statbuf->st_mode))
			return TRUE;
	}
	newmode = statbuf->st_mode;

	if (!bb_parse_mode((char *)param, &newmode))
		bb_error_msg_and_die("invalid mode: %s", (char *)param);

	if (chmod(fileName, newmode) == 0) {
		if (OPT_VERBOSE
		 || (OPT_CHANGED && statbuf->st_mode != newmode)
		) {
			printf("mode of '%s' changed to %04o (%s)\n", fileName,
				newmode & 07777, bb_mode_string(newmode)+1);
		}
		return TRUE;
	}
 err:
	if (!OPT_QUIET)
		bb_simple_perror_msg(fileName);
	return FALSE;
}

int chmod_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int chmod_main(int argc ATTRIBUTE_UNUSED, char **argv)
{
	int retval = EXIT_SUCCESS;
	char *arg, **argp;
	char *smode;

	/* Convert first encountered -r into ar, -w into aw etc
	 * so that getopt would not eat it */
	argp = argv;
	while ((arg = *++argp)) {
		/* Mode spec must be the first arg (sans -R etc) */
		/* (protect against mishandling e.g. "chmod 644 -r") */
		if (arg[0] != '-') {
			arg = NULL;
			break;
		}
		/* An option. Not a -- or valid option? */
		if (arg[1] && !strchr("-"OPT_STR, arg[1])) {
			arg[0] = 'a';
			break;
		}
	}

	/* Parse options */
	opt_complementary = "-2";
	getopt32(argv, ("-"OPT_STR) + 1); /* Reuse string */
	argv += optind;

	/* Restore option-like mode if needed */
	if (arg) arg[0] = '-';

	/* Ok, ready to do the deed now */
	smode = *argv++;
	do {
		if (!recursive_action(*argv,
			OPT_RECURSE,    // recurse
			fileAction,     // file action
			fileAction,     // dir action
			smode,          // user data
			0)              // depth
		) {
			retval = EXIT_FAILURE;
		}
	} while (*++argv);

	return retval;
}

/*
Security: chmod is too important and too subtle.
This is a test script (busybox chmod versus coreutils).
Run it in empty directory.

#!/bin/sh
t1="/tmp/busybox chmod"
t2="/usr/bin/chmod"
create() {
    rm -rf $1; mkdir $1
    (
    cd $1 || exit 1
    mkdir dir
    >up
    >file
    >dir/file
    ln -s dir linkdir
    ln -s file linkfile
    ln -s ../up dir/up
    )
}
tst() {
    (cd test1; $t1 $1)
    (cd test2; $t2 $1)
    (cd test1; ls -lR) >out1
    (cd test2; ls -lR) >out2
    echo "chmod $1" >out.diff
    if ! diff -u out1 out2 >>out.diff; then exit 1; fi
    rm out.diff
}
echo "If script produced 'out.diff' file, then at least one testcase failed"
create test1; create test2
tst "a+w file"
tst "a-w dir"
tst "a+w linkfile"
tst "a-w linkdir"
tst "-R a+w file"
tst "-R a-w dir"
tst "-R a+w linkfile"
tst "-R a-w linkdir"
tst "a-r,a+x linkfile"
*/