1/* vi: set sw=4 ts=4: */
2/*
3 * Mini chmod implementation for busybox
4 *
5 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
6 *
7 * Reworked by (C) 2002 Vladimir Oleynik <dzo@simtreas.ru>
8 *  to correctly parse '-rwxgoa'
9 *
10 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
11 */
12
13/* BB_AUDIT SUSv3 compliant */
14/* BB_AUDIT GNU defects - unsupported long options. */
15/* http://www.opengroup.org/onlinepubs/007904975/utilities/chmod.html */
16
17#include "libbb.h"
18
19/* This is a NOEXEC applet. Be very careful! */
20
21
22#define OPT_RECURSE (option_mask32 & 1)
23#define OPT_VERBOSE (USE_DESKTOP(option_mask32 & 2) SKIP_DESKTOP(0))
24#define OPT_CHANGED (USE_DESKTOP(option_mask32 & 4) SKIP_DESKTOP(0))
25#define OPT_QUIET   (USE_DESKTOP(option_mask32 & 8) SKIP_DESKTOP(0))
26#define OPT_STR     "R" USE_DESKTOP("vcf")
27
28/* coreutils:
29 * chmod never changes the permissions of symbolic links; the chmod
30 * system call cannot change their permissions. This is not a problem
31 * since the permissions of symbolic links are never used.
32 * However, for each symbolic link listed on the command line, chmod changes
33 * the permissions of the pointed-to file. In contrast, chmod ignores
34 * symbolic links encountered during recursive directory traversals.
35 */
36
37static int fileAction(const char *fileName, struct stat *statbuf, void* param, int depth)
38{
39	mode_t newmode;
40
41	/* match coreutils behavior */
42	if (depth == 0) {
43		/* statbuf holds lstat result, but we need stat (follow link) */
44		if (stat(fileName, statbuf))
45			goto err;
46	} else { /* depth > 0: skip links */
47		if (S_ISLNK(statbuf->st_mode))
48			return TRUE;
49	}
50	newmode = statbuf->st_mode;
51
52	if (!bb_parse_mode((char *)param, &newmode))
53		bb_error_msg_and_die("invalid mode: %s", (char *)param);
54
55	if (chmod(fileName, newmode) == 0) {
56		if (OPT_VERBOSE
57		 || (OPT_CHANGED && statbuf->st_mode != newmode)
58		) {
59			printf("mode of '%s' changed to %04o (%s)\n", fileName,
60				newmode & 07777, bb_mode_string(newmode)+1);
61		}
62		return TRUE;
63	}
64 err:
65	if (!OPT_QUIET)
66		bb_perror_msg("%s", fileName);
67	return FALSE;
68}
69
70int chmod_main(int argc, char **argv);
71int chmod_main(int argc, char **argv)
72{
73	int retval = EXIT_SUCCESS;
74	char *arg, **argp;
75	char *smode;
76
77	/* Convert first encountered -r into ar, -w into aw etc
78	 * so that getopt would not eat it */
79	argp = argv;
80	while ((arg = *++argp)) {
81		/* Mode spec must be the first arg (sans -R etc) */
82		/* (protect against mishandling e.g. "chmod 644 -r") */
83		if (arg[0] != '-') {
84			arg = NULL;
85			break;
86		}
87		/* An option. Not a -- or valid option? */
88		if (arg[1] && !strchr("-"OPT_STR, arg[1])) {
89			arg[0] = 'a';
90			break;
91		}
92	}
93
94	/* Parse options */
95	opt_complementary = "-2";
96	getopt32(argv, ("-"OPT_STR) + 1); /* Reuse string */
97	argv += optind;
98
99	/* Restore option-like mode if needed */
100	if (arg) arg[0] = '-';
101
102	/* Ok, ready to do the deed now */
103	smode = *argv++;
104	do {
105		if (!recursive_action(*argv,
106			OPT_RECURSE,    // recurse
107			fileAction,     // file action
108			fileAction,     // dir action
109			smode,          // user data
110			0)              // depth
111		) {
112			retval = EXIT_FAILURE;
113		}
114	} while (*++argv);
115
116	return retval;
117}
118
119/*
120Security: chmod is too important and too subtle.
121This is a test script (busybox chmod versus coreutils).
122Run it in empty directory.
123
124#!/bin/sh
125t1="/tmp/busybox chmod"
126t2="/usr/bin/chmod"
127create() {
128    rm -rf $1; mkdir $1
129    (
130    cd $1 || exit 1
131    mkdir dir
132    >up
133    >file
134    >dir/file
135    ln -s dir linkdir
136    ln -s file linkfile
137    ln -s ../up dir/up
138    )
139}
140tst() {
141    (cd test1; $t1 $1)
142    (cd test2; $t2 $1)
143    (cd test1; ls -lR) >out1
144    (cd test2; ls -lR) >out2
145    echo "chmod $1" >out.diff
146    if ! diff -u out1 out2 >>out.diff; then exit 1; fi
147    rm out.diff
148}
149echo "If script produced 'out.diff' file, then at least one testcase failed"
150create test1; create test2
151tst "a+w file"
152tst "a-w dir"
153tst "a+w linkfile"
154tst "a-w linkdir"
155tst "-R a+w file"
156tst "-R a-w dir"
157tst "-R a+w linkfile"
158tst "-R a-w linkdir"
159tst "a-r,a+x linkfile"
160*/
161