coreutils/chmod.c

   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
  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;
 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 */