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 source tree.
11 */
12 //config:config CHMOD
13 //config: bool "chmod (5.5 kb)"
14 //config: default y
15 //config: help
16 //config: chmod is used to change the access permission of files.
17
18 //applet:IF_CHMOD(APPLET_NOEXEC(chmod, chmod, BB_DIR_BIN, BB_SUID_DROP, chmod))
19
20 //kbuild:lib-$(CONFIG_CHMOD) += chmod.o
21
22 /* BB_AUDIT SUSv3 compliant */
23 /* BB_AUDIT GNU defects - unsupported long options. */
24 /* http://www.opengroup.org/onlinepubs/007904975/utilities/chmod.html */
25
26 //usage:#define chmod_trivial_usage
27 //usage: "[-R"IF_DESKTOP("cvf")"] MODE[,MODE]... FILE..."
28 //usage:#define chmod_full_usage "\n\n"
29 //usage: "MODE is octal number (bit pattern sstrwxrwxrwx) or [ugoa]{+|-|=}[rwxXst]"
30 //usage: "\n"
31 //next 4 options are the same for chmod/chown/chgrp:
32 //usage: "\n -R Recurse"
33 //usage: IF_DESKTOP(
34 //usage: "\n -c List changed files"
35 //usage: "\n -v Verbose"
36 //usage: "\n -f Hide errors"
37 //usage: )
38 //usage:
39 //usage:#define chmod_example_usage
40 //usage: "$ ls -l /tmp/foo\n"
41 //usage: "-rw-rw-r-- 1 root root 0 Apr 12 18:25 /tmp/foo\n"
42 //usage: "$ chmod u+x /tmp/foo\n"
43 //usage: "$ ls -l /tmp/foo\n"
44 //usage: "-rwxrw-r-- 1 root root 0 Apr 12 18:25 /tmp/foo*\n"
45 //usage: "$ chmod 444 /tmp/foo\n"
46 //usage: "$ ls -l /tmp/foo\n"
47 //usage: "-r--r--r-- 1 root root 0 Apr 12 18:25 /tmp/foo\n"
48
49 #include "libbb.h"
50
51 /* This is a NOEXEC applet. Be very careful! */
52
53
54 #define OPT_RECURSE (option_mask32 & 1)
55 #define OPT_VERBOSE (IF_DESKTOP(option_mask32 & 2) IF_NOT_DESKTOP(0))
56 #define OPT_CHANGED (IF_DESKTOP(option_mask32 & 4) IF_NOT_DESKTOP(0))
57 #define OPT_QUIET (IF_DESKTOP(option_mask32 & 8) IF_NOT_DESKTOP(0))
58 #define OPT_STR "R" IF_DESKTOP("vcf")
59
60 /* coreutils:
61 * chmod never changes the permissions of symbolic links; the chmod
62 * system call cannot change their permissions. This is not a problem
63 * since the permissions of symbolic links are never used.
64 * However, for each symbolic link listed on the command line, chmod changes
65 * the permissions of the pointed-to file. In contrast, chmod ignores
66 * symbolic links encountered during recursive directory traversals.
67 */
68
fileAction(struct recursive_state * state,const char * fileName,struct stat * statbuf)69 static int FAST_FUNC fileAction(struct recursive_state *state,
70 const char *fileName,
71 struct stat *statbuf)
72 {
73 mode_t newmode;
74
75 /* match coreutils behavior */
76 if (state->depth == 0) {
77 /* statbuf holds lstat result, but we need stat (follow link) */
78 if (stat(fileName, statbuf))
79 goto err;
80 } else { /* depth > 0: skip links */
81 if (S_ISLNK(statbuf->st_mode))
82 return TRUE;
83 }
84
85 newmode = bb_parse_mode((char *)state->userData, statbuf->st_mode);
86 if (newmode == (mode_t)-1)
87 bb_error_msg_and_die("invalid mode '%s'", (char *)state->userData);
88
89 if (chmod(fileName, newmode) == 0) {
90 if (OPT_VERBOSE
91 || (OPT_CHANGED
92 && (statbuf->st_mode & 07777) != (newmode & 07777))
93 ) {
94 char modestr[12];
95 printf("mode of '%s' changed to %04o (%s)\n", fileName,
96 newmode & 07777, bb_mode_string(modestr, newmode)+1);
97 }
98 return TRUE;
99 }
100 err:
101 if (!OPT_QUIET)
102 bb_simple_perror_msg(fileName);
103 return FALSE;
104 }
105
106 int chmod_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
chmod_main(int argc UNUSED_PARAM,char ** argv)107 int chmod_main(int argc UNUSED_PARAM, char **argv)
108 {
109 int retval = EXIT_SUCCESS;
110 char *arg, **argp;
111 char *smode;
112
113 /* Convert first encountered -r into ar, -w into aw etc
114 * so that getopt would not eat it */
115 argp = argv;
116 while ((arg = *++argp)) {
117 /* Mode spec must be the first arg (sans -R etc) */
118 /* (protect against mishandling e.g. "chmod 644 -r") */
119 if (arg[0] != '-') {
120 arg = NULL;
121 break;
122 }
123 /* An option. Not a -- or valid option? */
124 if (arg[1] && !strchr("-"OPT_STR, arg[1])) {
125 arg[0] = 'a';
126 break;
127 }
128 }
129
130 /* Parse options */
131 getopt32(argv, "^" OPT_STR "\0" "-2");
132 argv += optind;
133
134 /* Restore option-like mode if needed */
135 if (arg) arg[0] = '-';
136
137 /* Ok, ready to do the deed now */
138 smode = *argv++;
139 do {
140 if (!recursive_action(*argv,
141 OPT_RECURSE, // recurse
142 fileAction, // file action
143 fileAction, // dir action
144 smode) // user data
145 ) {
146 retval = EXIT_FAILURE;
147 }
148 } while (*++argv);
149
150 return retval;
151 }
152
153 /*
154 Security: chmod is too important and too subtle.
155 This is a test script (busybox chmod versus coreutils).
156 Run it in empty directory.
157
158 #!/bin/sh
159 t1="/tmp/busybox chmod"
160 t2="/usr/bin/chmod"
161 create() {
162 rm -rf $1; mkdir $1
163 (
164 cd $1 || exit 1
165 mkdir dir
166 >up
167 >file
168 >dir/file
169 ln -s dir linkdir
170 ln -s file linkfile
171 ln -s ../up dir/up
172 )
173 }
174 tst() {
175 (cd test1; $t1 $1)
176 (cd test2; $t2 $1)
177 (cd test1; ls -lR) >out1
178 (cd test2; ls -lR) >out2
179 echo "chmod $1" >out.diff
180 if ! diff -u out1 out2 >>out.diff; then exit 1; fi
181 rm out.diff
182 }
183 echo "If script produced 'out.diff' file, then at least one testcase failed"
184 create test1; create test2
185 tst "a+w file"
186 tst "a-w dir"
187 tst "a+w linkfile"
188 tst "a-w linkdir"
189 tst "-R a+w file"
190 tst "-R a-w dir"
191 tst "-R a+w linkfile"
192 tst "-R a-w linkdir"
193 tst "a-r,a+x linkfile"
194 */
195