react-native-update/ios/RCTPushy/BSDiff/bzip/bspatch.c

/*-
 * Copyright 2003-2005 Colin Percival
 * Copyright 2012 Matthew Endsley
 * All rights reserved
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted providing that the following conditions 
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "bspatch.h"
#include <bzlib.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <err.h>
#include <unistd.h>
#include <fcntl.h>

static int64_t offtin(uint8_t *buf)
{
	int64_t y;

	y=buf[7]&0x7F;
	y=y*256;y+=buf[6];
	y=y*256;y+=buf[5];
	y=y*256;y+=buf[4];
	y=y*256;y+=buf[3];
	y=y*256;y+=buf[2];
	y=y*256;y+=buf[1];
	y=y*256;y+=buf[0];

	if(buf[7]&0x80) y=-y;

	return y;
}

int bspatch(const uint8_t* old, int64_t oldsize, uint8_t* new, int64_t newsize, struct bspatch_stream* stream)
{
	uint8_t buf[8];
	int64_t oldpos,newpos;
	int64_t ctrl[3];
	int64_t i;

	oldpos=0;newpos=0;
	while(newpos<newsize) {
		/* Read control data */
		for(i=0;i<=2;i++) {
			if (stream->read(stream, buf, 8))
				return -1;
			ctrl[i]=offtin(buf);
		};

		/* Sanity-check */
		if(newpos+ctrl[0]>newsize)
			return -1;

		/* Read diff string */
		if (stream->read(stream, new + newpos, ctrl[0]))
			return -1;

		/* Add old data to diff string */
		for(i=0;i<ctrl[0];i++)
			if((oldpos+i>=0) && (oldpos+i<oldsize))
				new[newpos+i]+=old[oldpos+i];

		/* Adjust pointers */
		newpos+=ctrl[0];
		oldpos+=ctrl[0];

		/* Sanity-check */
		if(newpos+ctrl[1]>newsize)
			return -1;

		/* Read extra string */
		if (stream->read(stream, new + newpos, ctrl[1]))
			return -1;

		/* Adjust pointers */
		newpos+=ctrl[1];
		oldpos+=ctrl[2];
	};

	return 0;
}

static int bz2_read(const struct bspatch_stream* stream, void* buffer, int length)
{
    int n;
    int bz2err;
    BZFILE* bz2;
    
    bz2 = (BZFILE*)stream->opaque;
    n = BZ2_bzRead(&bz2err, bz2, buffer, length);
    if (n != length)
        return -1;
    
    return 0;
}

int beginPatch(const char* oldfile, const char* newfile, const char* patchfile)
{
    FILE * f;
    int fd;
    int bz2err;
    uint8_t header[32];
    uint8_t *old, *new;
    int64_t oldsize, newsize;
    BZFILE* bz2;
    struct bspatch_stream stream;
    
    //    if(argc!=4) errx(1,"usage: %s oldfile newfile patchfile\n",argv[0]);
    
    /* Open patch file */
    if ((f = fopen(patchfile, "r")) == NULL) {
        //        err(1, "fopen(%s)", patchfile);
        return -1;
    }
    
    /* Read header */
    if (fread(header, 1, 32, f) != 32) {
        if (feof(f)) {
            //            errx(1, "Corrupt patch\n");
        }
        //        err(1, "fread(%s)", patchfile);
        return -1;
    }
    
    /* Check for appropriate magic */
    if (memcmp(header, "ENDSLEY/BSDIFF43", 16) != 0) {
        //        errx(1, "Corrupt patch\n");
        return -1;
    }
    
    /* Read lengths from header */
    newsize=offtin(header+16);
    if(newsize<0) {
        //        errx(1,"Corrupt patch\n");
        return -1;
    }
    
    /* Close patch file and re-open it via libbzip2 at the right places */
    if(((fd=open(oldfile,O_RDONLY,0))<0) ||
       ((oldsize=lseek(fd,0,SEEK_END))==-1) ||
       ((old=malloc(oldsize+1))==NULL) ||
       (lseek(fd,0,SEEK_SET)!=0) ||
       (read(fd,old,oldsize)!=oldsize) ||
       (close(fd)==-1)) err(1,"%s",oldfile);
    if((new=malloc(newsize+1))==NULL) err(1,NULL);
    
    if (NULL == (bz2 = BZ2_bzReadOpen(&bz2err, f, 0, 1, NULL, 0))) {
        //        errx(1, "BZ2_bzReadOpen, bz2err=%d", bz2err);
        return -1;
    }
    
    stream.read = bz2_read;
    stream.opaque = bz2;
    if (bspatch(old, oldsize, new, newsize, &stream)) {
        //        errx(1, "bspatch");
        return -1;
    }
    
    /* Clean up the bzip2 reads */
    BZ2_bzReadClose(&bz2err, bz2);
    fclose(f);
    
    /* Write the new file */
    if(((fd=open(newfile,O_CREAT|O_TRUNC|O_WRONLY,0666))<0) ||
       (write(fd,new,newsize)!=newsize) || (close(fd)==-1)) {
        err(1,"%s",newfile);
        return -1;
    }
    free(new);
    free(old);
    return 0;
}