busybox/coreutils/chmod.c

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/* 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.
*/
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/* BB_AUDIT SUSv3 compliant */
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/* BB_AUDIT GNU defects - unsupported long options. */
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/* http://www.opengroup.org/onlinepubs/007904975/utilities/chmod.html */
#include "busybox.h"
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#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")
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/* 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);
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if (chmod(fileName, newmode) == 0) {
if (OPT_VERBOSE
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|| (OPT_CHANGED && statbuf->st_mode != newmode)
) {
printf("mode of '%s' changed to %04o (%s)\n", fileName,
newmode & 07777, bb_mode_string(newmode)+1);
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}
return TRUE;
}
err:
if (!OPT_QUIET)
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bb_perror_msg("%s", fileName);
return FALSE;
}
int chmod_main(int argc, char **argv);
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int chmod_main(int argc, char **argv)
{
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int retval = EXIT_SUCCESS;
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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;
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break;
}
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/* An option. Not a -- or valid option? */
if (arg[1] && !strchr("-"OPT_STR, arg[1])) {
arg[0] = 'a';
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break;
}
}
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/* Parse options */
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opt_complementary = "-2";
getopt32(argc, argv, ("-"OPT_STR) + 1); /* Reuse string */
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argv += optind;
/* Restore option-like mode if needed */
if (arg) arg[0] = '-';
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/* Ok, ready to do the deed now */
smode = *argv++;
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do {
if (!recursive_action(*argv,
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OPT_RECURSE, // recurse
FALSE, // follow links: coreutils doesn't
FALSE, // depth first
fileAction, // file action
fileAction, // dir action
smode, // user data
0) // depth
) {
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retval = EXIT_FAILURE;
}
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} 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 dir. Probably requires bash.
#!/bin/sh
function 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
)
}
function 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
mv out.diff out1.diff
}
t1="/tmp/busybox chmod"
t2="/usr/bin/chmod"
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"
*/