source: MondoRescue/branches/2.2.5/mindi-busybox/e2fsprogs/chattr.c@ 1765

/* vi: set sw=4 ts=4: */
/*
 * chattr.c     - Change file attributes on an ext2 file system
 *
 * Copyright (C) 1993, 1994  Remy Card <card@masi.ibp.fr>
 *                           Laboratoire MASI, Institut Blaise Pascal
 *                           Universite Pierre et Marie Curie (Paris VI)
 *
 * This file can be redistributed under the terms of the GNU General
 * Public License
 */

/*
 * History:
 * 93/10/30 - Creation
 * 93/11/13 - Replace stat() calls by lstat() to avoid loops
 * 94/02/27 - Integrated in Ted's distribution
 * 98/12/29 - Ignore symlinks when working recursively (G M Sipe)
 * 98/12/29 - Display version info only when -V specified (G M Sipe)
 */

#include "libbb.h"
#include "e2fs_lib.h"

#define OPT_ADD 1
#define OPT_REM 2
#define OPT_SET 4
#define OPT_SET_VER 8

struct globals {
    unsigned long version;
    unsigned long af;
    unsigned long rf;
    smallint flags;
    smallint recursive;
};

static unsigned long get_flag(char c)
{
    /* Two separate vectors take less space than vector of structs */
    static const char flags_letter[] ALIGN1 = "ASDacdijsutT";
    static const unsigned long flags_val[] = {
        /* A */ EXT2_NOATIME_FL,
        /* S */ EXT2_SYNC_FL,
        /* D */ EXT2_DIRSYNC_FL,
        /* a */ EXT2_APPEND_FL,
        /* c */ EXT2_COMPR_FL,
        /* d */ EXT2_NODUMP_FL,
        /* i */ EXT2_IMMUTABLE_FL,
        /* j */ EXT3_JOURNAL_DATA_FL,
        /* s */ EXT2_SECRM_FL,
        /* u */ EXT2_UNRM_FL,
        /* t */ EXT2_NOTAIL_FL,
        /* T */ EXT2_TOPDIR_FL,
    };
    const char *fp;

    for (fp = flags_letter; *fp; fp++)
        if (*fp == c)
            return flags_val[fp - flags_letter];
    bb_show_usage();
}

static int decode_arg(const char *arg, struct globals *gp)
{
    unsigned long *fl;
    char opt = *arg++;

    fl = &gp->af;
    if (opt == '-') {
        gp->flags |= OPT_REM;
        fl = &gp->rf;
    } else if (opt == '+') {
        gp->flags |= OPT_ADD;
    } else if (opt == '=') {
        gp->flags |= OPT_SET;
    } else
        return 0;

    while (*arg)
        *fl |= get_flag(*arg++);

    return 1;
}

static void change_attributes(const char *name, struct globals *gp);

static int chattr_dir_proc(const char *dir_name, struct dirent *de, void *gp)
{
    char *path = concat_subpath_file(dir_name, de->d_name);
    /* path is NULL if de->d_name is "." or "..", else... */
    if (path) {
        change_attributes(path, gp);
        free(path);
    }
    return 0;
}

static void change_attributes(const char *name, struct globals *gp)
{
    unsigned long fsflags;
    struct stat st;

    if (lstat(name, &st) != 0) {
        bb_perror_msg("stat %s", name);
        return;
    }
    if (S_ISLNK(st.st_mode) && gp->recursive)
        return;

    /* Don't try to open device files, fifos etc.  We probably
     * ought to display an error if the file was explicitly given
     * on the command line (whether or not recursive was
     * requested).  */
    if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode) && !S_ISDIR(st.st_mode))
        return;

    if (gp->flags & OPT_SET_VER)
        if (fsetversion(name, gp->version) != 0)
            bb_perror_msg("setting version on %s", name);

    if (gp->flags & OPT_SET) {
        fsflags = gp->af;
    } else {
        if (fgetflags(name, &fsflags) != 0) {
            bb_perror_msg("reading flags on %s", name);
            goto skip_setflags;
        }
        /*if (gp->flags & OPT_REM) - not needed, rf is zero otherwise */
            fsflags &= ~gp->rf;
        /*if (gp->flags & OPT_ADD) - not needed, af is zero otherwise */
            fsflags |= gp->af;
        /* What is this? And why it's not done for SET case? */
        if (!S_ISDIR(st.st_mode))
            fsflags &= ~EXT2_DIRSYNC_FL;
    }
    if (fsetflags(name, fsflags) != 0)
        bb_perror_msg("setting flags on %s", name);

 skip_setflags:
    if (gp->recursive && S_ISDIR(st.st_mode))
        iterate_on_dir(name, chattr_dir_proc, gp);
}

int chattr_main(int argc, char **argv);
int chattr_main(int argc, char **argv)
{
    struct globals g;
    char *arg;

    memset(&g, 0, sizeof(g));

    /* parse the args */
    while ((arg = *++argv)) {
        /* take care of -R and -v <version> */
        if (arg[0] == '-'
         && (arg[1] == 'R' || arg[1] == 'v')
         && !arg[2]
        ) {
            if (arg[1] == 'R') {
                g.recursive = 1;
                continue;
            }
            /* arg[1] == 'v' */
            if (!*++argv)
                bb_show_usage();
            g.version = xatoul(*argv);
            g.flags |= OPT_SET_VER;
            continue;
        }

        if (!decode_arg(arg, &g))
            break;
    }

    /* run sanity checks on all the arguments given us */
    if (!*argv)
        bb_show_usage();
    if ((g.flags & OPT_SET) && (g.flags & (OPT_ADD|OPT_REM)))
        bb_error_msg_and_die("= is incompatible with - and +");
    if (g.rf & g.af)
        bb_error_msg_and_die("can't set and unset a flag");
    if (!g.flags)
        bb_error_msg_and_die("must use '-v', =, - or +");

    /* now run chattr on all the files passed to us */
    do change_attributes(*argv, &g); while (*++argv);

    return EXIT_SUCCESS;
}