source: MondoRescue/branches/2.2.5/mindi-busybox/coreutils/ln.c@ 1765

/* vi: set sw=4 ts=4: */
/*
 * Mini ln implementation for busybox
 *
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

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

#include "libbb.h"

/* This is a NOEXEC applet. Be very careful! */


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

    flag = getopt32(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(xstrdup(last));
    }

    do {
        src_name = NULL;
        src = last;

        if (is_directory(src,
                        (flag & LN_NODEREFERENCE) ^ LN_NODEREFERENCE,
                        NULL)
        ) {
            src_name = 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)) {
            // coreutils: "ln dangling_symlink new_hardlink" works
            if (lstat(*argv, &statbuf) || !S_ISLNK(statbuf.st_mode)) {
                bb_perror_msg("%s", *argv);
                status = EXIT_FAILURE;
                free(src_name);
                continue;
            }
        }

        if (flag & LN_BACKUP) {
            char *backup;
            backup = 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;
}