source: MondoRescue/trunk/mindi-busybox/coreutils/ln.c@ 956

/* vi: set sw=4 ts=4: */
/*
 * Mini ln implementation for busybox
 *
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */

/* BB_AUDIT SUSv3 compliant */
/* BB_AUDIT GNU options missing: -d, -F, -i, and -v. */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/ln.html */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include "busybox.h"

#define LN_SYMLINK          1
#define LN_FORCE            2
#define LN_NODEREFERENCE    4
#define LN_BACKUP           8
#define LN_SUFFIX           16

int ln_main(int argc, char **argv)
{
    int status = EXIT_SUCCESS;
    int flag;
    char *last;
    char *src_name;
    char *src;
    char *suffix = "~";
    struct stat statbuf;
    int (*link_func)(const char *, const char *);

    flag = bb_getopt_ulflags(argc, argv, "sfnbS:", &suffix);

    if (argc == optind) {
        bb_show_usage();
    }

    last = argv[argc - 1];
    argv += optind;

    if (argc == optind + 1) {
        *--argv = last;
        last = bb_get_last_path_component(bb_xstrdup(last));
    }

    do {
        src_name = NULL;
        src = last;

        if (is_directory(src,
                         (flag & LN_NODEREFERENCE) ^ LN_NODEREFERENCE,
                         NULL)) {
            src_name = bb_xstrdup(*argv);
            src = concat_path_file(src, bb_get_last_path_component(src_name));
            free(src_name);
            src_name = src;
        }
        if (!(flag & LN_SYMLINK) && stat(*argv, &statbuf)) {
            bb_perror_msg("%s", *argv);
            status = EXIT_FAILURE;
            free(src_name);
            continue;
        }

        if (flag & LN_BACKUP) {
                char *backup;
                backup = bb_xasprintf("%s%s", src, suffix);
                if (rename(src, backup) < 0 && errno != ENOENT) {
                        bb_perror_msg("%s", src);
                        status = EXIT_FAILURE;
                        free(backup);
                        continue;
                }
                free(backup);
                /*
                 * When the source and dest are both hard links to the same
                 * inode, a rename may succeed even though nothing happened.
                 * Therefore, always unlink().
                 */
                unlink(src);
        } else if (flag & LN_FORCE) {
            unlink(src);
        }

        link_func = link;
        if (flag & LN_SYMLINK) {
            link_func = symlink;
        }

        if (link_func(*argv, src) != 0) {
            bb_perror_msg("%s", src);
            status = EXIT_FAILURE;
        }

        free(src_name);

    } while ((++argv)[1]);

    return status;
}