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-rw-r--r--applypatch/imgpatch.cpp234
1 files changed, 234 insertions, 0 deletions
diff --git a/applypatch/imgpatch.cpp b/applypatch/imgpatch.cpp
new file mode 100644
index 000000000..26888f8ee
--- /dev/null
+++ b/applypatch/imgpatch.cpp
@@ -0,0 +1,234 @@
+/*
+ * 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/cdefs.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <malloc.h>
+#include <unistd.h>
+#include <string.h>
+
+#include "zlib.h"
+#include "mincrypt/sha.h"
+#include "applypatch.h"
+#include "imgdiff.h"
+#include "utils.h"
+
+/*
+ * 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 __unused,
+ const Value* patch,
+ SinkFn sink, void* token, SHA_CTX* ctx,
+ const Value* bonus_data) {
+ ssize_t pos = 12;
+ char* header = patch->data;
+ if (patch->size < 12) {
+ printf("patch too short to contain header\n");
+ return -1;
+ }
+
+ // IMGDIFF2 uses CHUNK_NORMAL, CHUNK_DEFLATE, and CHUNK_RAW.
+ // (IMGDIFF1, which is no longer supported, used CHUNK_NORMAL and
+ // CHUNK_GZIP.)
+ if (memcmp(header, "IMGDIFF2", 8) != 0) {
+ printf("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 4 bytes.
+ if (pos + 4 > patch->size) {
+ printf("failed to read chunk %d record\n", i);
+ return -1;
+ }
+ int type = Read4(patch->data + pos);
+ pos += 4;
+
+ if (type == CHUNK_NORMAL) {
+ char* normal_header = patch->data + pos;
+ pos += 24;
+ if (pos > patch->size) {
+ printf("failed to read chunk %d normal header data\n", i);
+ return -1;
+ }
+
+ size_t src_start = Read8(normal_header);
+ size_t src_len = Read8(normal_header+8);
+ size_t patch_offset = Read8(normal_header+16);
+
+ ApplyBSDiffPatch(old_data + src_start, src_len,
+ patch, patch_offset, sink, token, ctx);
+ } else if (type == CHUNK_RAW) {
+ char* raw_header = patch->data + pos;
+ pos += 4;
+ if (pos > patch->size) {
+ printf("failed to read chunk %d raw header data\n", i);
+ return -1;
+ }
+
+ ssize_t data_len = Read4(raw_header);
+
+ if (pos + data_len > patch->size) {
+ printf("failed to read chunk %d raw data\n", i);
+ return -1;
+ }
+ if (ctx) SHA_update(ctx, patch->data + pos, data_len);
+ if (sink((unsigned char*)patch->data + pos,
+ data_len, token) != data_len) {
+ printf("failed to write chunk %d raw data\n", i);
+ return -1;
+ }
+ pos += data_len;
+ } else if (type == CHUNK_DEFLATE) {
+ // deflate chunks have an additional 60 bytes in their chunk header.
+ char* deflate_header = patch->data + pos;
+ pos += 60;
+ if (pos > patch->size) {
+ printf("failed to read chunk %d deflate header data\n", i);
+ return -1;
+ }
+
+ size_t src_start = Read8(deflate_header);
+ size_t src_len = Read8(deflate_header+8);
+ size_t patch_offset = Read8(deflate_header+16);
+ size_t expanded_len = Read8(deflate_header+24);
+ size_t target_len = Read8(deflate_header+32);
+ int level = Read4(deflate_header+40);
+ int method = Read4(deflate_header+44);
+ int windowBits = Read4(deflate_header+48);
+ int memLevel = Read4(deflate_header+52);
+ int strategy = Read4(deflate_header+56);
+
+ // Decompress the source data; the chunk header tells us exactly
+ // how big we expect it to be when decompressed.
+
+ // Note: expanded_len will include the bonus data size if
+ // the patch was constructed with bonus data. The
+ // deflation will come up 'bonus_size' bytes short; these
+ // must be appended from the bonus_data value.
+ size_t bonus_size = (i == 1 && bonus_data != NULL) ? bonus_data->size : 0;
+
+ unsigned char* expanded_source = reinterpret_cast<unsigned char*>(malloc(expanded_len));
+ if (expanded_source == NULL) {
+ printf("failed to allocate %zu 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;
+ strm.next_in = (unsigned char*)(old_data + src_start);
+ strm.avail_out = expanded_len;
+ strm.next_out = expanded_source;
+
+ int ret;
+ ret = inflateInit2(&strm, -15);
+ if (ret != Z_OK) {
+ printf("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) {
+ printf("source inflation returned %d\n", ret);
+ return -1;
+ }
+ // We should have filled the output buffer exactly, except
+ // for the bonus_size.
+ if (strm.avail_out != bonus_size) {
+ printf("source inflation short by %zu bytes\n", strm.avail_out-bonus_size);
+ return -1;
+ }
+ inflateEnd(&strm);
+
+ if (bonus_size) {
+ memcpy(expanded_source + (expanded_len - bonus_size),
+ bonus_data->data, bonus_size);
+ }
+
+ // 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, patch_offset,
+ &uncompressed_target_data,
+ &uncompressed_target_size) != 0) {
+ return -1;
+ }
+
+ // Now compress the target data and append it to the output.
+
+ // 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 = reinterpret_cast<unsigned char*>(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, level, method, windowBits, memLevel, strategy);
+ do {
+ strm.avail_out = temp_size;
+ strm.next_out = temp_data;
+ ret = deflate(&strm, Z_FINISH);
+ ssize_t have = temp_size - strm.avail_out;
+
+ if (sink(temp_data, have, token) != have) {
+ printf("failed to write %ld compressed bytes to output\n",
+ (long)have);
+ return -1;
+ }
+ if (ctx) SHA_update(ctx, temp_data, have);
+ } while (ret != Z_STREAM_END);
+ deflateEnd(&strm);
+
+ free(temp_data);
+ free(uncompressed_target_data);
+ } else {
+ printf("patch chunk %d is unknown type %d\n", i, type);
+ return -1;
+ }
+ }
+
+ return 0;
+}
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