hush/coreutils/ln.c

/*
 * Mini ln implementation for busybox
 *
 *
 * Copyright (C) 1999 by Lineo, inc.
 * Written by Erik Andersen <andersen@lineo.com>, <andersee@debian.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
 *
 */

#include "internal.h"
#define BB_DECLARE_EXTERN
#define bb_need_name_too_long
#define bb_need_not_a_directory
#include "messages.c"

#include <stdio.h>
#include <dirent.h>
#include <errno.h>
#include <sys/param.h>		/* for PATH_MAX */

static const char ln_usage[] =
    "ln [OPTION] TARGET... LINK_NAME|DIRECTORY\n\n"
    "Create a link named LINK_NAME or DIRECTORY to the specified TARGET\n\n"
    "Options:\n"
    "\t-s\tmake symbolic links instead of hard links\n"
    "\t-f\tremove existing destination files\n"
    "\t-n\tno dereference symlinks - treat like normal file\n";

static int symlinkFlag = FALSE;
static int removeoldFlag = FALSE;
static int followLinks = TRUE;

extern int ln_main(int argc, char **argv)
{
    char *linkName;
    int linkIntoDirFlag;

    if (argc < 3) {
	usage (ln_usage);
    }
    argc--;
    argv++;

    /* Parse any options */
    while (**argv == '-') {
	while (*++(*argv))
	    switch (**argv) {
	    case 's':
		symlinkFlag = TRUE;
		break;
	    case 'f':
		removeoldFlag = TRUE;
		break;
	    case 'n':
		followLinks = FALSE;
		break;
	    default:
		usage (ln_usage);
	    }
	argc--;
	argv++;
    }

    linkName = argv[argc - 1];

    if (strlen(linkName) > PATH_MAX) {
	fprintf(stderr, name_too_long, "ln");
	exit FALSE;
    }

    linkIntoDirFlag = isDirectory(linkName, TRUE);

    if ((argc > 3) && !linkIntoDirFlag) {
	fprintf(stderr, not_a_directory, "ln", linkName);
	exit FALSE;
    }

    while (argc-- >= 2) {
	char srcName[PATH_MAX + 1];
	int nChars, status;

	if (strlen(*argv) > PATH_MAX) {
	    fprintf(stderr, name_too_long, "ln");
	    exit FALSE;
	}

	if (followLinks == FALSE) {
	    strcpy(srcName, *argv);
	} else {
	    /* Warning!  This can silently truncate if > PATH_MAX, but
	    I don't think that there can be one > PATH_MAX anyway. */
	    nChars = readlink(*argv, srcName, PATH_MAX);
	    srcName[nChars] = '\0';
	}

	if (removeoldFlag == TRUE) {
	    status = ( unlink(linkName) && errno != ENOENT );
	    if (status != 0) {
		perror(linkName);
		exit FALSE;
	    }
	}

	if (symlinkFlag == TRUE)
	    status = symlink(*argv, linkName);
	else
	    status = link(*argv, linkName);
	if (status != 0) {
	    perror(linkName);
	    exit FALSE;
	}
    }
    exit TRUE;
}