63 lines
		
	
	
		
			1.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			63 lines
		
	
	
		
			1.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* vi: set sw=4 ts=4: */
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/*
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 *  busybox gunzip trailing header handler
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 *  Copyright Glenn McGrath 2002
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 *
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 *  This program is free software; you can redistribute it and/or modify
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 *  it under the terms of the GNU General Public License as published by
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 *  the Free Software Foundation; either version 2 of the License, or
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 *  (at your option) any later version.
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 *
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 *  This program is distributed in the hope that it will be useful,
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 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
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 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 *  GNU General Public License for more details.
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 *
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 *  You should have received a copy of the GNU General Public License
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 *  along with this program; if not, write to the Free Software
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 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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 */
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include "config.h"
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#include "busybox.h"
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#include "unarchive.h"
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extern unsigned int gunzip_crc;
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extern unsigned int gunzip_bytes_out;
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extern unsigned char *gunzip_in_buffer;
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extern unsigned char gunzip_in_buffer_count;
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extern void check_trailer_gzip(int src_fd)
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{
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	unsigned int stored_crc = 0;
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	unsigned char count;
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	/* top up the input buffer with the rest of the trailer */
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	xread_all(src_fd, &gunzip_in_buffer[gunzip_in_buffer_count], 8 - gunzip_in_buffer_count);
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	for (count = 0; count != 4; count++) {
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		stored_crc |= (gunzip_in_buffer[count] << (count * 8));
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	}
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	/* Validate decompression - crc */
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	if (stored_crc != (gunzip_crc ^ 0xffffffffL)) {
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		error_msg("invalid compressed data--crc error");
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	}
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	/* Validate decompression - size */
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	if (gunzip_bytes_out != 
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		(gunzip_in_buffer[4] | (gunzip_in_buffer[5] << 8) |
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		(gunzip_in_buffer[6] << 16) | (gunzip_in_buffer[7] << 24))) {
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		error_msg("invalid compressed data--length error");
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	}
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}
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