busybox/libbb/deb_extract.c

/* vi: set sw=4 ts=4: */
/*
 * Copyright (C) tons of folks.  Tracking down who wrote what
 * isn't something I'm going to worry about...  If you wrote something
 * here, please feel free to acknowledge your work.
 *
 * 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
 *
 * Based in part on code from sash, Copyright (c) 1999 by David I. Bell 
 * Permission has been granted to redistribute this code under the GPL.
 *
 */

#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include "libbb.h"

/*
 * The contents of argument depend on the value of function.
 * It is either a dir name or a control file or field name(see dpkg_deb.c)
 */
extern char *deb_extract(const char *package_filename, const int function, const char *argument, const char *argument2)
{

	FILE *deb_file, *uncompressed_file;
	ar_headers_t *headers = NULL;
	char *ared_file = NULL;
	char *output_buffer = NULL;
	int gunzip_pid;

	switch (function) {
		case (extract_info):
		case (extract_control):
		case (extract_field):
			ared_file = xstrdup("control.tar.gz");
			break;
		default:
			ared_file = xstrdup("data.tar.gz");
			break;
	}

	/* open the debian package to be worked on */
	deb_file = wfopen(package_filename, "r");

	headers = (ar_headers_t *) xmalloc(sizeof(ar_headers_t));	
	
	/* get a linked list of all ar entries */
	if ((headers = get_ar_headers(deb_file)) == NULL) {
		error_msg("Couldnt get ar headers\n");
		return(NULL);
	}

	/* seek to the start of the .tar.gz file within the ar file*/
	if (seek_ared_file(deb_file, headers, ared_file) == EXIT_FAILURE) {
		error_msg("Couldnt seek to ar file");
	}

	/* open a stream of decompressed data */
	uncompressed_file = fdopen(gz_open(deb_file, &gunzip_pid), "r");

	if (function & extract_fsys_tarfile) {
		copy_file_chunk(uncompressed_file, stdout, -1);
	} else {
		FILE *output;

		if (function & extract_contents_to_file) {
			output = wfopen(argument, "w");
		} else {
			output = stdout;
		}

		output_buffer = untar(uncompressed_file, output, function, argument, argument2);
		if (output != stdout) {
			fclose(output);
		}
	}
	gz_close(gunzip_pid);
	fclose(deb_file);
	fclose(uncompressed_file);
	free(ared_file);

	return(output_buffer);
}