source: MondoRescue/branches/stable/mindi-busybox/coreutils/chmod.c@ 1770

/* 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_perror_msg("%s", fileName);
    return FALSE;
}

int chmod_main(int argc, char **argv);
int chmod_main(int argc, 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"
*/