hush/archival/libunarchive/check_trailer_gzip.c
2002-09-25 02:47:48 +00:00

63 lines
1.9 KiB
C

/* vi: set sw=4 ts=4: */
/*
* busybox gunzip trailing header handler
* Copyright Glenn McGrath 2002
*
* 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 <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include "config.h"
#include "busybox.h"
#include "unarchive.h"
extern unsigned int gunzip_crc;
extern unsigned int gunzip_bytes_out;
extern unsigned char *gunzip_in_buffer;
extern unsigned char gunzip_in_buffer_count;
extern void check_trailer_gzip(int src_fd)
{
unsigned int stored_crc = 0;
unsigned char count;
/* top up the input buffer with the rest of the trailer */
xread_all(src_fd, &gunzip_in_buffer[gunzip_in_buffer_count], 8 - gunzip_in_buffer_count);
for (count = 0; count != 4; count++) {
stored_crc |= (gunzip_in_buffer[count] << (count * 8));
}
/* Validate decompression - crc */
if (stored_crc != (gunzip_crc ^ 0xffffffffL)) {
error_msg("invalid compressed data--crc error");
}
/* Validate decompression - size */
if (gunzip_bytes_out !=
(gunzip_in_buffer[4] | (gunzip_in_buffer[5] << 8) |
(gunzip_in_buffer[6] << 16) | (gunzip_in_buffer[7] << 24))) {
error_msg("invalid compressed data--length error");
}
}