tools/applypatch/imgpatch.c - platform/build - Git at Google

 /*
  * Copyright (C) 2009 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 // See imgdiff.c in this directory for a description of the patch file
 // format.

 #include <stdio.h>
 #include <sys/stat.h>
 #include <errno.h>
 #include <unistd.h>
 #include <string.h>

 #include "zlib.h"
 #include "mincrypt/sha.h"
 #include "applypatch.h"
 #include "imgdiff.h"

 int Read4(unsigned char* p) {
   return (int)(((unsigned int)p[3] << 24) |
                ((unsigned int)p[2] << 16) |
                ((unsigned int)p[1] << 8) |
                (unsigned int)p[0]);
 }

 long long Read8(unsigned char* p) {
   return (long long)(((unsigned long long)p[7] << 56) |
                      ((unsigned long long)p[6] << 48) |
                      ((unsigned long long)p[5] << 40) |
                      ((unsigned long long)p[4] << 32) |
                      ((unsigned long long)p[3] << 24) |
                      ((unsigned long long)p[2] << 16) |
                      ((unsigned long long)p[1] << 8) |
                      (unsigned long long)p[0]);
 }

 /*
  * Apply the patch given in 'patch_filename' to the source data given
  * by (old_data, old_size).  Write the patched output to the 'output'
  * file, and update the SHA context with the output data as well.
  * Return 0 on success.
  */
 int ApplyImagePatch(const unsigned char* old_data, ssize_t old_size,
                     const char* patch_filename,
                     FILE* output, SHA_CTX* ctx) {
   FILE* f;
   if ((f = fopen(patch_filename, "rb")) == NULL) {
     fprintf(stderr, "failed to open patch file\n");
     return -1;
   }

   unsigned char header[12];
   if (fread(header, 1, 12, f) != 12) {
     fprintf(stderr, "failed to read patch file header\n");
     return -1;
   }

   if (memcmp(header, "IMGDIFF1", 8) != 0) {
     fprintf(stderr, "corrupt patch file header (magic number)\n");
     return -1;
   }

   int num_chunks = Read4(header+8);

   int i;
   for (i = 0; i < num_chunks; ++i) {
     // each chunk's header record starts with 28 bytes (4 + 8*3).
     unsigned char chunk[28];
     if (fread(chunk, 1, 28, f) != 28) {
       fprintf(stderr, "failed to read chunk %d record\n", i);
       return -1;
     }

     int type = Read4(chunk);
     size_t src_start = Read8(chunk+4);
     size_t src_len = Read8(chunk+12);
     size_t patch_offset = Read8(chunk+20);

     if (type == CHUNK_NORMAL) {
       fprintf(stderr, "CHUNK %d:  normal   patch offset %d\n", i, patch_offset);

       ApplyBSDiffPatch(old_data + src_start, src_len,
                        patch_filename, patch_offset,
                        output, ctx);
     } else if (type == CHUNK_GZIP) {
       fprintf(stderr, "CHUNK %d:  gzip     patch offset %d\n", i, patch_offset);

       // gzip chunks have an additional 40 + gzip_header_len + 8 bytes
       // in their chunk header.
       unsigned char* gzip = malloc(40);
       if (fread(gzip, 1, 40, f) != 40) {
         fprintf(stderr, "failed to read chunk %d initial gzip data\n", i);
         return -1;
       }
       size_t gzip_header_len = Read4(gzip+36);
       gzip = realloc(gzip, 40 + gzip_header_len + 8);
       if (fread(gzip+40, 1, gzip_header_len+8, f) != gzip_header_len+8) {
         fprintf(stderr, "failed to read chunk %d remaining gzip data\n", i);
         return -1;
       }

       size_t expanded_len = Read8(gzip);
       size_t target_len = Read8(gzip);
       int gz_level = Read4(gzip+16);
       int gz_method = Read4(gzip+20);
       int gz_windowBits = Read4(gzip+24);
       int gz_memLevel = Read4(gzip+28);
       int gz_strategy = Read4(gzip+32);

       // Decompress the source data; the chunk header tells us exactly
       // how big we expect it to be when decompressed.

       unsigned char* expanded_source = malloc(expanded_len);
       if (expanded_source == NULL) {
         fprintf(stderr, "failed to allocate %d bytes for expanded_source\n",
                 expanded_len);
         return -1;
       }

       z_stream strm;
       strm.zalloc = Z_NULL;
       strm.zfree = Z_NULL;
       strm.opaque = Z_NULL;
       strm.avail_in = src_len - (gzip_header_len + 8);
       strm.next_in = (unsigned char*)(old_data + src_start + gzip_header_len);
       strm.avail_out = expanded_len;
       strm.next_out = expanded_source;

       int ret;
       ret = inflateInit2(&strm, -15);
       if (ret != Z_OK) {
         fprintf(stderr, "failed to init source inflation: %d\n", ret);
         return -1;
       }

       // Because we've provided enough room to accommodate the output
       // data, we expect one call to inflate() to suffice.
       ret = inflate(&strm, Z_SYNC_FLUSH);
       if (ret != Z_STREAM_END) {
         fprintf(stderr, "source inflation returned %d\n", ret);
         return -1;
       }
       // We should have filled the output buffer exactly.
       if (strm.avail_out != 0) {
         fprintf(stderr, "source inflation short by %d bytes\n", strm.avail_out);
         return -1;
       }
       inflateEnd(&strm);

       // Next, apply the bsdiff patch (in memory) to the uncompressed
       // data.
       unsigned char* uncompressed_target_data;
       ssize_t uncompressed_target_size;
       if (ApplyBSDiffPatchMem(expanded_source, expanded_len,
                               patch_filename, patch_offset,
                               &uncompressed_target_data,
                               &uncompressed_target_size) != 0) {
         return -1;
       }

       // Now compress the target data and append it to the output.

       // start with the gzip header.
       fwrite(gzip+40, 1, gzip_header_len, output);
       SHA_update(ctx, gzip+40, gzip_header_len);

       // we're done with the expanded_source data buffer, so we'll
       // reuse that memory to receive the output of deflate.
       unsigned char* temp_data = expanded_source;
       ssize_t temp_size = expanded_len;
       if (temp_size < 32768) {
         // ... unless the buffer is too small, in which case we'll
         // allocate a fresh one.
         free(temp_data);
         temp_data = malloc(32768);
         temp_size = 32768;
       }

       // now the deflate stream
       strm.zalloc = Z_NULL;
       strm.zfree = Z_NULL;
       strm.opaque = Z_NULL;
       strm.avail_in = uncompressed_target_size;
       strm.next_in = uncompressed_target_data;
       ret = deflateInit2(&strm, gz_level, gz_method, gz_windowBits,
                          gz_memLevel, gz_strategy);
       do {
         strm.avail_out = temp_size;
         strm.next_out = temp_data;
         ret = deflate(&strm, Z_FINISH);
         size_t have = temp_size - strm.avail_out;

         if (fwrite(temp_data, 1, have, output) != have) {
           fprintf(stderr, "failed to write %d compressed bytes to output\n",
                   have);
           return -1;
         }
         SHA_update(ctx, temp_data, have);
       } while (ret != Z_STREAM_END);
       deflateEnd(&strm);

       // lastly, the gzip footer.
       fwrite(gzip+40+gzip_header_len, 1, 8, output);
       SHA_update(ctx, gzip+40+gzip_header_len, 8);

       free(temp_data);
       free(uncompressed_target_data);
       free(gzip);
     } else {
       fprintf(stderr, "patch chunk %d is unknown type %d\n", i, type);
       return -1;
     }
   }

   return 0;
 }
	/*
	* Copyright (C) 2009 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	// See imgdiff.c in this directory for a description of the patch file
	// format.

	#include <stdio.h>
	#include <sys/stat.h>
	#include <errno.h>
	#include <unistd.h>
	#include <string.h>

	#include "zlib.h"
	#include "mincrypt/sha.h"
	#include "applypatch.h"
	#include "imgdiff.h"

	int Read4(unsigned char* p) {
	return (int)(((unsigned int)p[3] << 24) \|
	((unsigned int)p[2] << 16) \|
	((unsigned int)p[1] << 8) \|
	(unsigned int)p[0]);
	}

	long long Read8(unsigned char* p) {
	return (long long)(((unsigned long long)p[7] << 56) \|
	((unsigned long long)p[6] << 48) \|
	((unsigned long long)p[5] << 40) \|
	((unsigned long long)p[4] << 32) \|
	((unsigned long long)p[3] << 24) \|
	((unsigned long long)p[2] << 16) \|
	((unsigned long long)p[1] << 8) \|
	(unsigned long long)p[0]);
	}

	/*
	* Apply the patch given in 'patch_filename' to the source data given
	* by (old_data, old_size). Write the patched output to the 'output'
	* file, and update the SHA context with the output data as well.
	* Return 0 on success.
	*/
	int ApplyImagePatch(const unsigned char* old_data, ssize_t old_size,
	const char* patch_filename,
	FILE* output, SHA_CTX* ctx) {
	FILE* f;
	if ((f = fopen(patch_filename, "rb")) == NULL) {
	fprintf(stderr, "failed to open patch file\n");
	return -1;
	}

	unsigned char header[12];
	if (fread(header, 1, 12, f) != 12) {
	fprintf(stderr, "failed to read patch file header\n");
	return -1;
	}

	if (memcmp(header, "IMGDIFF1", 8) != 0) {
	fprintf(stderr, "corrupt patch file header (magic number)\n");
	return -1;
	}

	int num_chunks = Read4(header+8);

	int i;
	for (i = 0; i < num_chunks; ++i) {
	// each chunk's header record starts with 28 bytes (4 + 8*3).
	unsigned char chunk[28];
	if (fread(chunk, 1, 28, f) != 28) {
	fprintf(stderr, "failed to read chunk %d record\n", i);
	return -1;
	}

	int type = Read4(chunk);
	size_t src_start = Read8(chunk+4);
	size_t src_len = Read8(chunk+12);
	size_t patch_offset = Read8(chunk+20);

	if (type == CHUNK_NORMAL) {
	fprintf(stderr, "CHUNK %d: normal patch offset %d\n", i, patch_offset);

	ApplyBSDiffPatch(old_data + src_start, src_len,
	patch_filename, patch_offset,
	output, ctx);
	} else if (type == CHUNK_GZIP) {
	fprintf(stderr, "CHUNK %d: gzip patch offset %d\n", i, patch_offset);

	// gzip chunks have an additional 40 + gzip_header_len + 8 bytes
	// in their chunk header.
	unsigned char* gzip = malloc(40);
	if (fread(gzip, 1, 40, f) != 40) {
	fprintf(stderr, "failed to read chunk %d initial gzip data\n", i);
	return -1;
	}
	size_t gzip_header_len = Read4(gzip+36);
	gzip = realloc(gzip, 40 + gzip_header_len + 8);
	if (fread(gzip+40, 1, gzip_header_len+8, f) != gzip_header_len+8) {
	fprintf(stderr, "failed to read chunk %d remaining gzip data\n", i);
	return -1;
	}

	size_t expanded_len = Read8(gzip);
	size_t target_len = Read8(gzip);
	int gz_level = Read4(gzip+16);
	int gz_method = Read4(gzip+20);
	int gz_windowBits = Read4(gzip+24);
	int gz_memLevel = Read4(gzip+28);
	int gz_strategy = Read4(gzip+32);

	// Decompress the source data; the chunk header tells us exactly
	// how big we expect it to be when decompressed.

	unsigned char* expanded_source = malloc(expanded_len);
	if (expanded_source == NULL) {
	fprintf(stderr, "failed to allocate %d bytes for expanded_source\n",
	expanded_len);
	return -1;
	}

	z_stream strm;
	strm.zalloc = Z_NULL;
	strm.zfree = Z_NULL;
	strm.opaque = Z_NULL;
	strm.avail_in = src_len - (gzip_header_len + 8);
	strm.next_in = (unsigned char*)(old_data + src_start + gzip_header_len);
	strm.avail_out = expanded_len;
	strm.next_out = expanded_source;

	int ret;
	ret = inflateInit2(&strm, -15);
	if (ret != Z_OK) {
	fprintf(stderr, "failed to init source inflation: %d\n", ret);
	return -1;
	}

	// Because we've provided enough room to accommodate the output
	// data, we expect one call to inflate() to suffice.
	ret = inflate(&strm, Z_SYNC_FLUSH);
	if (ret != Z_STREAM_END) {
	fprintf(stderr, "source inflation returned %d\n", ret);
	return -1;
	}
	// We should have filled the output buffer exactly.
	if (strm.avail_out != 0) {
	fprintf(stderr, "source inflation short by %d bytes\n", strm.avail_out);
	return -1;
	}
	inflateEnd(&strm);

	// Next, apply the bsdiff patch (in memory) to the uncompressed
	// data.
	unsigned char* uncompressed_target_data;
	ssize_t uncompressed_target_size;
	if (ApplyBSDiffPatchMem(expanded_source, expanded_len,
	patch_filename, patch_offset,
	&uncompressed_target_data,
	&uncompressed_target_size) != 0) {
	return -1;
	}

	// Now compress the target data and append it to the output.

	// start with the gzip header.
	fwrite(gzip+40, 1, gzip_header_len, output);
	SHA_update(ctx, gzip+40, gzip_header_len);

	// we're done with the expanded_source data buffer, so we'll
	// reuse that memory to receive the output of deflate.
	unsigned char* temp_data = expanded_source;
	ssize_t temp_size = expanded_len;
	if (temp_size < 32768) {
	// ... unless the buffer is too small, in which case we'll
	// allocate a fresh one.
	free(temp_data);
	temp_data = malloc(32768);
	temp_size = 32768;
	}

	// now the deflate stream
	strm.zalloc = Z_NULL;
	strm.zfree = Z_NULL;
	strm.opaque = Z_NULL;
	strm.avail_in = uncompressed_target_size;
	strm.next_in = uncompressed_target_data;
	ret = deflateInit2(&strm, gz_level, gz_method, gz_windowBits,
	gz_memLevel, gz_strategy);
	do {
	strm.avail_out = temp_size;
	strm.next_out = temp_data;
	ret = deflate(&strm, Z_FINISH);
	size_t have = temp_size - strm.avail_out;

	if (fwrite(temp_data, 1, have, output) != have) {
	fprintf(stderr, "failed to write %d compressed bytes to output\n",
	have);
	return -1;
	}
	SHA_update(ctx, temp_data, have);
	} while (ret != Z_STREAM_END);
	deflateEnd(&strm);

	// lastly, the gzip footer.
	fwrite(gzip+40+gzip_header_len, 1, 8, output);
	SHA_update(ctx, gzip+40+gzip_header_len, 8);

	free(temp_data);
	free(uncompressed_target_data);
	free(gzip);
	} else {
	fprintf(stderr, "patch chunk %d is unknown type %d\n", i, type);
	return -1;
	}
	}

	return 0;
	}