relocate applypatch; add type system and new functions to edify
- Move applypatch to this package (from build).
- Add a rudimentary type system to edify: instead of just returning a
char*, functions now return a Value*, which is a struct that can
carry different types of value (currently just STRING and BLOB).
Convert all functions to this new scheme.
- Change the one-argument form of package_extract_file to return a
Value of the new BLOB type.
- Add read_file() to load a local file and return a blob, and
sha1_check() to test a blob (or string) against a set of possible
sha1s. read_file() uses the file-loading code from applypatch so it
can read MTD partitions as well.
This is the start of better integration between applypatch and the
rest of edify.
b/2361316 - VZW Issue PP628: Continuous reset to Droid logo:
framework-res.apk update failed (CR LIBtt59130)
Change-Id: Ibd038074749a4d515de1f115c498c6c589ee91e5
diff --git a/applypatch/imgdiff.c b/applypatch/imgdiff.c
new file mode 100644
index 0000000..6b9ebee
--- /dev/null
+++ b/applypatch/imgdiff.c
@@ -0,0 +1,1010 @@
+/*
+ * 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.
+ */
+
+/*
+ * This program constructs binary patches for images -- such as boot.img
+ * and recovery.img -- that consist primarily of large chunks of gzipped
+ * data interspersed with uncompressed data. Doing a naive bsdiff of
+ * these files is not useful because small changes in the data lead to
+ * large changes in the compressed bitstream; bsdiff patches of gzipped
+ * data are typically as large as the data itself.
+ *
+ * To patch these usefully, we break the source and target images up into
+ * chunks of two types: "normal" and "gzip". Normal chunks are simply
+ * patched using a plain bsdiff. Gzip chunks are first expanded, then a
+ * bsdiff is applied to the uncompressed data, then the patched data is
+ * gzipped using the same encoder parameters. Patched chunks are
+ * concatenated together to create the output file; the output image
+ * should be *exactly* the same series of bytes as the target image used
+ * originally to generate the patch.
+ *
+ * To work well with this tool, the gzipped sections of the target
+ * image must have been generated using the same deflate encoder that
+ * is available in applypatch, namely, the one in the zlib library.
+ * In practice this means that images should be compressed using the
+ * "minigzip" tool included in the zlib distribution, not the GNU gzip
+ * program.
+ *
+ * An "imgdiff" patch consists of a header describing the chunk structure
+ * of the file and any encoding parameters needed for the gzipped
+ * chunks, followed by N bsdiff patches, one per chunk.
+ *
+ * For a diff to be generated, the source and target images must have the
+ * same "chunk" structure: that is, the same number of gzipped and normal
+ * chunks in the same order. Android boot and recovery images currently
+ * consist of five chunks: a small normal header, a gzipped kernel, a
+ * small normal section, a gzipped ramdisk, and finally a small normal
+ * footer.
+ *
+ * Caveats: we locate gzipped sections within the source and target
+ * images by searching for the byte sequence 1f8b0800: 1f8b is the gzip
+ * magic number; 08 specifies the "deflate" encoding [the only encoding
+ * supported by the gzip standard]; and 00 is the flags byte. We do not
+ * currently support any extra header fields (which would be indicated by
+ * a nonzero flags byte). We also don't handle the case when that byte
+ * sequence appears spuriously in the file. (Note that it would have to
+ * occur spuriously within a normal chunk to be a problem.)
+ *
+ *
+ * The imgdiff patch header looks like this:
+ *
+ * "IMGDIFF1" (8) [magic number and version]
+ * chunk count (4)
+ * for each chunk:
+ * chunk type (4) [CHUNK_{NORMAL, GZIP, DEFLATE, RAW}]
+ * if chunk type == CHUNK_NORMAL:
+ * source start (8)
+ * source len (8)
+ * bsdiff patch offset (8) [from start of patch file]
+ * if chunk type == CHUNK_GZIP: (version 1 only)
+ * source start (8)
+ * source len (8)
+ * bsdiff patch offset (8) [from start of patch file]
+ * source expanded len (8) [size of uncompressed source]
+ * target expected len (8) [size of uncompressed target]
+ * gzip level (4)
+ * method (4)
+ * windowBits (4)
+ * memLevel (4)
+ * strategy (4)
+ * gzip header len (4)
+ * gzip header (gzip header len)
+ * gzip footer (8)
+ * if chunk type == CHUNK_DEFLATE: (version 2 only)
+ * source start (8)
+ * source len (8)
+ * bsdiff patch offset (8) [from start of patch file]
+ * source expanded len (8) [size of uncompressed source]
+ * target expected len (8) [size of uncompressed target]
+ * gzip level (4)
+ * method (4)
+ * windowBits (4)
+ * memLevel (4)
+ * strategy (4)
+ * if chunk type == RAW: (version 2 only)
+ * target len (4)
+ * data (target len)
+ *
+ * All integers are little-endian. "source start" and "source len"
+ * specify the section of the input image that comprises this chunk,
+ * including the gzip header and footer for gzip chunks. "source
+ * expanded len" is the size of the uncompressed source data. "target
+ * expected len" is the size of the uncompressed data after applying
+ * the bsdiff patch. The next five parameters specify the zlib
+ * parameters to be used when compressing the patched data, and the
+ * next three specify the header and footer to be wrapped around the
+ * compressed data to create the output chunk (so that header contents
+ * like the timestamp are recreated exactly).
+ *
+ * After the header there are 'chunk count' bsdiff patches; the offset
+ * of each from the beginning of the file is specified in the header.
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <sys/types.h>
+
+#include "zlib.h"
+#include "imgdiff.h"
+#include "utils.h"
+
+typedef struct {
+ int type; // CHUNK_NORMAL, CHUNK_DEFLATE
+ size_t start; // offset of chunk in original image file
+
+ size_t len;
+ unsigned char* data; // data to be patched (uncompressed, for deflate chunks)
+
+ size_t source_start;
+ size_t source_len;
+
+ off_t* I; // used by bsdiff
+
+ // --- for CHUNK_DEFLATE chunks only: ---
+
+ // original (compressed) deflate data
+ size_t deflate_len;
+ unsigned char* deflate_data;
+
+ char* filename; // used for zip entries
+
+ // deflate encoder parameters
+ int level, method, windowBits, memLevel, strategy;
+
+ size_t source_uncompressed_len;
+} ImageChunk;
+
+typedef struct {
+ int data_offset;
+ int deflate_len;
+ int uncomp_len;
+ char* filename;
+} ZipFileEntry;
+
+static int fileentry_compare(const void* a, const void* b) {
+ int ao = ((ZipFileEntry*)a)->data_offset;
+ int bo = ((ZipFileEntry*)b)->data_offset;
+ if (ao < bo) {
+ return -1;
+ } else if (ao > bo) {
+ return 1;
+ } else {
+ return 0;
+ }
+}
+
+// from bsdiff.c
+int bsdiff(u_char* old, off_t oldsize, off_t** IP, u_char* new, off_t newsize,
+ const char* patch_filename);
+
+unsigned char* ReadZip(const char* filename,
+ int* num_chunks, ImageChunk** chunks,
+ int include_pseudo_chunk) {
+ struct stat st;
+ if (stat(filename, &st) != 0) {
+ printf("failed to stat \"%s\": %s\n", filename, strerror(errno));
+ return NULL;
+ }
+
+ unsigned char* img = malloc(st.st_size);
+ FILE* f = fopen(filename, "rb");
+ if (fread(img, 1, st.st_size, f) != st.st_size) {
+ printf("failed to read \"%s\" %s\n", filename, strerror(errno));
+ fclose(f);
+ return NULL;
+ }
+ fclose(f);
+
+ // look for the end-of-central-directory record.
+
+ int i;
+ for (i = st.st_size-20; i >= 0 && i > st.st_size - 65600; --i) {
+ if (img[i] == 0x50 && img[i+1] == 0x4b &&
+ img[i+2] == 0x05 && img[i+3] == 0x06) {
+ break;
+ }
+ }
+ // double-check: this archive consists of a single "disk"
+ if (!(img[i+4] == 0 && img[i+5] == 0 && img[i+6] == 0 && img[i+7] == 0)) {
+ printf("can't process multi-disk archive\n");
+ return NULL;
+ }
+
+ int cdcount = Read2(img+i+8);
+ int cdoffset = Read4(img+i+16);
+
+ ZipFileEntry* temp_entries = malloc(cdcount * sizeof(ZipFileEntry));
+ int entrycount = 0;
+
+ unsigned char* cd = img+cdoffset;
+ for (i = 0; i < cdcount; ++i) {
+ if (!(cd[0] == 0x50 && cd[1] == 0x4b && cd[2] == 0x01 && cd[3] == 0x02)) {
+ printf("bad central directory entry %d\n", i);
+ return NULL;
+ }
+
+ int clen = Read4(cd+20); // compressed len
+ int ulen = Read4(cd+24); // uncompressed len
+ int nlen = Read2(cd+28); // filename len
+ int xlen = Read2(cd+30); // extra field len
+ int mlen = Read2(cd+32); // file comment len
+ int hoffset = Read4(cd+42); // local header offset
+
+ char* filename = malloc(nlen+1);
+ memcpy(filename, cd+46, nlen);
+ filename[nlen] = '\0';
+
+ int method = Read2(cd+10);
+
+ cd += 46 + nlen + xlen + mlen;
+
+ if (method != 8) { // 8 == deflate
+ free(filename);
+ continue;
+ }
+
+ unsigned char* lh = img + hoffset;
+
+ if (!(lh[0] == 0x50 && lh[1] == 0x4b && lh[2] == 0x03 && lh[3] == 0x04)) {
+ printf("bad local file header entry %d\n", i);
+ return NULL;
+ }
+
+ if (Read2(lh+26) != nlen || memcmp(lh+30, filename, nlen) != 0) {
+ printf("central dir filename doesn't match local header\n");
+ return NULL;
+ }
+
+ xlen = Read2(lh+28); // extra field len; might be different from CD entry?
+
+ temp_entries[entrycount].data_offset = hoffset+30+nlen+xlen;
+ temp_entries[entrycount].deflate_len = clen;
+ temp_entries[entrycount].uncomp_len = ulen;
+ temp_entries[entrycount].filename = filename;
+ ++entrycount;
+ }
+
+ qsort(temp_entries, entrycount, sizeof(ZipFileEntry), fileentry_compare);
+
+#if 0
+ printf("found %d deflated entries\n", entrycount);
+ for (i = 0; i < entrycount; ++i) {
+ printf("off %10d len %10d unlen %10d %p %s\n",
+ temp_entries[i].data_offset,
+ temp_entries[i].deflate_len,
+ temp_entries[i].uncomp_len,
+ temp_entries[i].filename,
+ temp_entries[i].filename);
+ }
+#endif
+
+ *num_chunks = 0;
+ *chunks = malloc((entrycount*2+2) * sizeof(ImageChunk));
+ ImageChunk* curr = *chunks;
+
+ if (include_pseudo_chunk) {
+ curr->type = CHUNK_NORMAL;
+ curr->start = 0;
+ curr->len = st.st_size;
+ curr->data = img;
+ curr->filename = NULL;
+ curr->I = NULL;
+ ++curr;
+ ++*num_chunks;
+ }
+
+ int pos = 0;
+ int nextentry = 0;
+
+ while (pos < st.st_size) {
+ if (nextentry < entrycount && pos == temp_entries[nextentry].data_offset) {
+ curr->type = CHUNK_DEFLATE;
+ curr->start = pos;
+ curr->deflate_len = temp_entries[nextentry].deflate_len;
+ curr->deflate_data = img + pos;
+ curr->filename = temp_entries[nextentry].filename;
+ curr->I = NULL;
+
+ curr->len = temp_entries[nextentry].uncomp_len;
+ curr->data = malloc(curr->len);
+
+ z_stream strm;
+ strm.zalloc = Z_NULL;
+ strm.zfree = Z_NULL;
+ strm.opaque = Z_NULL;
+ strm.avail_in = curr->deflate_len;
+ strm.next_in = curr->deflate_data;
+
+ // -15 means we are decoding a 'raw' deflate stream; zlib will
+ // not expect zlib headers.
+ int ret = inflateInit2(&strm, -15);
+
+ strm.avail_out = curr->len;
+ strm.next_out = curr->data;
+ ret = inflate(&strm, Z_NO_FLUSH);
+ if (ret != Z_STREAM_END) {
+ printf("failed to inflate \"%s\"; %d\n", curr->filename, ret);
+ return NULL;
+ }
+
+ inflateEnd(&strm);
+
+ pos += curr->deflate_len;
+ ++nextentry;
+ ++*num_chunks;
+ ++curr;
+ continue;
+ }
+
+ // use a normal chunk to take all the data up to the start of the
+ // next deflate section.
+
+ curr->type = CHUNK_NORMAL;
+ curr->start = pos;
+ if (nextentry < entrycount) {
+ curr->len = temp_entries[nextentry].data_offset - pos;
+ } else {
+ curr->len = st.st_size - pos;
+ }
+ curr->data = img + pos;
+ curr->filename = NULL;
+ curr->I = NULL;
+ pos += curr->len;
+
+ ++*num_chunks;
+ ++curr;
+ }
+
+ free(temp_entries);
+ return img;
+}
+
+/*
+ * Read the given file and break it up into chunks, putting the number
+ * of chunks and their info in *num_chunks and **chunks,
+ * respectively. Returns a malloc'd block of memory containing the
+ * contents of the file; various pointers in the output chunk array
+ * will point into this block of memory. The caller should free the
+ * return value when done with all the chunks. Returns NULL on
+ * failure.
+ */
+unsigned char* ReadImage(const char* filename,
+ int* num_chunks, ImageChunk** chunks) {
+ struct stat st;
+ if (stat(filename, &st) != 0) {
+ printf("failed to stat \"%s\": %s\n", filename, strerror(errno));
+ return NULL;
+ }
+
+ unsigned char* img = malloc(st.st_size + 4);
+ FILE* f = fopen(filename, "rb");
+ if (fread(img, 1, st.st_size, f) != st.st_size) {
+ printf("failed to read \"%s\" %s\n", filename, strerror(errno));
+ fclose(f);
+ return NULL;
+ }
+ fclose(f);
+
+ // append 4 zero bytes to the data so we can always search for the
+ // four-byte string 1f8b0800 starting at any point in the actual
+ // file data, without special-casing the end of the data.
+ memset(img+st.st_size, 0, 4);
+
+ size_t pos = 0;
+
+ *num_chunks = 0;
+ *chunks = NULL;
+
+ while (pos < st.st_size) {
+ unsigned char* p = img+pos;
+
+ if (st.st_size - pos >= 4 &&
+ p[0] == 0x1f && p[1] == 0x8b &&
+ p[2] == 0x08 && // deflate compression
+ p[3] == 0x00) { // no header flags
+ // 'pos' is the offset of the start of a gzip chunk.
+
+ *num_chunks += 3;
+ *chunks = realloc(*chunks, *num_chunks * sizeof(ImageChunk));
+ ImageChunk* curr = *chunks + (*num_chunks-3);
+
+ // create a normal chunk for the header.
+ curr->start = pos;
+ curr->type = CHUNK_NORMAL;
+ curr->len = GZIP_HEADER_LEN;
+ curr->data = p;
+ curr->I = NULL;
+
+ pos += curr->len;
+ p += curr->len;
+ ++curr;
+
+ curr->type = CHUNK_DEFLATE;
+ curr->filename = NULL;
+ curr->I = NULL;
+
+ // We must decompress this chunk in order to discover where it
+ // ends, and so we can put the uncompressed data and its length
+ // into curr->data and curr->len.
+
+ size_t allocated = 32768;
+ curr->len = 0;
+ curr->data = malloc(allocated);
+ curr->start = pos;
+ curr->deflate_data = p;
+
+ z_stream strm;
+ strm.zalloc = Z_NULL;
+ strm.zfree = Z_NULL;
+ strm.opaque = Z_NULL;
+ strm.avail_in = st.st_size - pos;
+ strm.next_in = p;
+
+ // -15 means we are decoding a 'raw' deflate stream; zlib will
+ // not expect zlib headers.
+ int ret = inflateInit2(&strm, -15);
+
+ do {
+ strm.avail_out = allocated - curr->len;
+ strm.next_out = curr->data + curr->len;
+ ret = inflate(&strm, Z_NO_FLUSH);
+ curr->len = allocated - strm.avail_out;
+ if (strm.avail_out == 0) {
+ allocated *= 2;
+ curr->data = realloc(curr->data, allocated);
+ }
+ } while (ret != Z_STREAM_END);
+
+ curr->deflate_len = st.st_size - strm.avail_in - pos;
+ inflateEnd(&strm);
+ pos += curr->deflate_len;
+ p += curr->deflate_len;
+ ++curr;
+
+ // create a normal chunk for the footer
+
+ curr->type = CHUNK_NORMAL;
+ curr->start = pos;
+ curr->len = GZIP_FOOTER_LEN;
+ curr->data = img+pos;
+ curr->I = NULL;
+
+ pos += curr->len;
+ p += curr->len;
+ ++curr;
+
+ // The footer (that we just skipped over) contains the size of
+ // the uncompressed data. Double-check to make sure that it
+ // matches the size of the data we got when we actually did
+ // the decompression.
+ size_t footer_size = Read4(p-4);
+ if (footer_size != curr[-2].len) {
+ printf("Error: footer size %d != decompressed size %d\n",
+ footer_size, curr[-2].len);
+ free(img);
+ return NULL;
+ }
+ } else {
+ // Reallocate the list for every chunk; we expect the number of
+ // chunks to be small (5 for typical boot and recovery images).
+ ++*num_chunks;
+ *chunks = realloc(*chunks, *num_chunks * sizeof(ImageChunk));
+ ImageChunk* curr = *chunks + (*num_chunks-1);
+ curr->start = pos;
+ curr->I = NULL;
+
+ // 'pos' is not the offset of the start of a gzip chunk, so scan
+ // forward until we find a gzip header.
+ curr->type = CHUNK_NORMAL;
+ curr->data = p;
+
+ for (curr->len = 0; curr->len < (st.st_size - pos); ++curr->len) {
+ if (p[curr->len] == 0x1f &&
+ p[curr->len+1] == 0x8b &&
+ p[curr->len+2] == 0x08 &&
+ p[curr->len+3] == 0x00) {
+ break;
+ }
+ }
+ pos += curr->len;
+ }
+ }
+
+ return img;
+}
+
+#define BUFFER_SIZE 32768
+
+/*
+ * Takes the uncompressed data stored in the chunk, compresses it
+ * using the zlib parameters stored in the chunk, and checks that it
+ * matches exactly the compressed data we started with (also stored in
+ * the chunk). Return 0 on success.
+ */
+int TryReconstruction(ImageChunk* chunk, unsigned char* out) {
+ size_t p = 0;
+
+#if 0
+ printf("trying %d %d %d %d %d\n",
+ chunk->level, chunk->method, chunk->windowBits,
+ chunk->memLevel, chunk->strategy);
+#endif
+
+ z_stream strm;
+ strm.zalloc = Z_NULL;
+ strm.zfree = Z_NULL;
+ strm.opaque = Z_NULL;
+ strm.avail_in = chunk->len;
+ strm.next_in = chunk->data;
+ int ret;
+ ret = deflateInit2(&strm, chunk->level, chunk->method, chunk->windowBits,
+ chunk->memLevel, chunk->strategy);
+ do {
+ strm.avail_out = BUFFER_SIZE;
+ strm.next_out = out;
+ ret = deflate(&strm, Z_FINISH);
+ size_t have = BUFFER_SIZE - strm.avail_out;
+
+ if (memcmp(out, chunk->deflate_data+p, have) != 0) {
+ // mismatch; data isn't the same.
+ deflateEnd(&strm);
+ return -1;
+ }
+ p += have;
+ } while (ret != Z_STREAM_END);
+ deflateEnd(&strm);
+ if (p != chunk->deflate_len) {
+ // mismatch; ran out of data before we should have.
+ return -1;
+ }
+ return 0;
+}
+
+/*
+ * Verify that we can reproduce exactly the same compressed data that
+ * we started with. Sets the level, method, windowBits, memLevel, and
+ * strategy fields in the chunk to the encoding parameters needed to
+ * produce the right output. Returns 0 on success.
+ */
+int ReconstructDeflateChunk(ImageChunk* chunk) {
+ if (chunk->type != CHUNK_DEFLATE) {
+ printf("attempt to reconstruct non-deflate chunk\n");
+ return -1;
+ }
+
+ size_t p = 0;
+ unsigned char* out = malloc(BUFFER_SIZE);
+
+ // We only check two combinations of encoder parameters: level 6
+ // (the default) and level 9 (the maximum).
+ for (chunk->level = 6; chunk->level <= 9; chunk->level += 3) {
+ chunk->windowBits = -15; // 32kb window; negative to indicate a raw stream.
+ chunk->memLevel = 8; // the default value.
+ chunk->method = Z_DEFLATED;
+ chunk->strategy = Z_DEFAULT_STRATEGY;
+
+ if (TryReconstruction(chunk, out) == 0) {
+ free(out);
+ return 0;
+ }
+ }
+
+ free(out);
+ return -1;
+}
+
+/*
+ * Given source and target chunks, compute a bsdiff patch between them
+ * by running bsdiff in a subprocess. Return the patch data, placing
+ * its length in *size. Return NULL on failure. We expect the bsdiff
+ * program to be in the path.
+ */
+unsigned char* MakePatch(ImageChunk* src, ImageChunk* tgt, size_t* size) {
+ if (tgt->type == CHUNK_NORMAL) {
+ if (tgt->len <= 160) {
+ tgt->type = CHUNK_RAW;
+ *size = tgt->len;
+ return tgt->data;
+ }
+ }
+
+ char ptemp[] = "/tmp/imgdiff-patch-XXXXXX";
+ mkstemp(ptemp);
+
+ int r = bsdiff(src->data, src->len, &(src->I), tgt->data, tgt->len, ptemp);
+ if (r != 0) {
+ printf("bsdiff() failed: %d\n", r);
+ return NULL;
+ }
+
+ struct stat st;
+ if (stat(ptemp, &st) != 0) {
+ printf("failed to stat patch file %s: %s\n",
+ ptemp, strerror(errno));
+ return NULL;
+ }
+
+ unsigned char* data = malloc(st.st_size);
+
+ if (tgt->type == CHUNK_NORMAL && tgt->len <= st.st_size) {
+ unlink(ptemp);
+
+ tgt->type = CHUNK_RAW;
+ *size = tgt->len;
+ return tgt->data;
+ }
+
+ *size = st.st_size;
+
+ FILE* f = fopen(ptemp, "rb");
+ if (f == NULL) {
+ printf("failed to open patch %s: %s\n", ptemp, strerror(errno));
+ return NULL;
+ }
+ if (fread(data, 1, st.st_size, f) != st.st_size) {
+ printf("failed to read patch %s: %s\n", ptemp, strerror(errno));
+ return NULL;
+ }
+ fclose(f);
+
+ unlink(ptemp);
+
+ tgt->source_start = src->start;
+ switch (tgt->type) {
+ case CHUNK_NORMAL:
+ tgt->source_len = src->len;
+ break;
+ case CHUNK_DEFLATE:
+ tgt->source_len = src->deflate_len;
+ tgt->source_uncompressed_len = src->len;
+ break;
+ }
+
+ return data;
+}
+
+/*
+ * Cause a gzip chunk to be treated as a normal chunk (ie, as a blob
+ * of uninterpreted data). The resulting patch will likely be about
+ * as big as the target file, but it lets us handle the case of images
+ * where some gzip chunks are reconstructible but others aren't (by
+ * treating the ones that aren't as normal chunks).
+ */
+void ChangeDeflateChunkToNormal(ImageChunk* ch) {
+ if (ch->type != CHUNK_DEFLATE) return;
+ ch->type = CHUNK_NORMAL;
+ free(ch->data);
+ ch->data = ch->deflate_data;
+ ch->len = ch->deflate_len;
+}
+
+/*
+ * Return true if the data in the chunk is identical (including the
+ * compressed representation, for gzip chunks).
+ */
+int AreChunksEqual(ImageChunk* a, ImageChunk* b) {
+ if (a->type != b->type) return 0;
+
+ switch (a->type) {
+ case CHUNK_NORMAL:
+ return a->len == b->len && memcmp(a->data, b->data, a->len) == 0;
+
+ case CHUNK_DEFLATE:
+ return a->deflate_len == b->deflate_len &&
+ memcmp(a->deflate_data, b->deflate_data, a->deflate_len) == 0;
+
+ default:
+ printf("unknown chunk type %d\n", a->type);
+ return 0;
+ }
+}
+
+/*
+ * Look for runs of adjacent normal chunks and compress them down into
+ * a single chunk. (Such runs can be produced when deflate chunks are
+ * changed to normal chunks.)
+ */
+void MergeAdjacentNormalChunks(ImageChunk* chunks, int* num_chunks) {
+ int out = 0;
+ int in_start = 0, in_end;
+ while (in_start < *num_chunks) {
+ if (chunks[in_start].type != CHUNK_NORMAL) {
+ in_end = in_start+1;
+ } else {
+ // in_start is a normal chunk. Look for a run of normal chunks
+ // that constitute a solid block of data (ie, each chunk begins
+ // where the previous one ended).
+ for (in_end = in_start+1;
+ in_end < *num_chunks && chunks[in_end].type == CHUNK_NORMAL &&
+ (chunks[in_end].start ==
+ chunks[in_end-1].start + chunks[in_end-1].len &&
+ chunks[in_end].data ==
+ chunks[in_end-1].data + chunks[in_end-1].len);
+ ++in_end);
+ }
+
+ if (in_end == in_start+1) {
+#if 0
+ printf("chunk %d is now %d\n", in_start, out);
+#endif
+ if (out != in_start) {
+ memcpy(chunks+out, chunks+in_start, sizeof(ImageChunk));
+ }
+ } else {
+#if 0
+ printf("collapse normal chunks %d-%d into %d\n", in_start, in_end-1, out);
+#endif
+
+ // Merge chunks [in_start, in_end-1] into one chunk. Since the
+ // data member of each chunk is just a pointer into an in-memory
+ // copy of the file, this can be done without recopying (the
+ // output chunk has the first chunk's start location and data
+ // pointer, and length equal to the sum of the input chunk
+ // lengths).
+ chunks[out].type = CHUNK_NORMAL;
+ chunks[out].start = chunks[in_start].start;
+ chunks[out].data = chunks[in_start].data;
+ chunks[out].len = chunks[in_end-1].len +
+ (chunks[in_end-1].start - chunks[in_start].start);
+ }
+
+ ++out;
+ in_start = in_end;
+ }
+ *num_chunks = out;
+}
+
+ImageChunk* FindChunkByName(const char* name,
+ ImageChunk* chunks, int num_chunks) {
+ int i;
+ for (i = 0; i < num_chunks; ++i) {
+ if (chunks[i].type == CHUNK_DEFLATE && chunks[i].filename &&
+ strcmp(name, chunks[i].filename) == 0) {
+ return chunks+i;
+ }
+ }
+ return NULL;
+}
+
+void DumpChunks(ImageChunk* chunks, int num_chunks) {
+ int i;
+ for (i = 0; i < num_chunks; ++i) {
+ printf("chunk %d: type %d start %d len %d\n",
+ i, chunks[i].type, chunks[i].start, chunks[i].len);
+ }
+}
+
+int main(int argc, char** argv) {
+ if (argc != 4 && argc != 5) {
+ usage:
+ printf("usage: %s [-z] <src-img> <tgt-img> <patch-file>\n",
+ argv[0]);
+ return 2;
+ }
+
+ int zip_mode = 0;
+
+ if (strcmp(argv[1], "-z") == 0) {
+ zip_mode = 1;
+ --argc;
+ ++argv;
+ }
+
+
+ int num_src_chunks;
+ ImageChunk* src_chunks;
+ int num_tgt_chunks;
+ ImageChunk* tgt_chunks;
+ int i;
+
+ if (zip_mode) {
+ if (ReadZip(argv[1], &num_src_chunks, &src_chunks, 1) == NULL) {
+ printf("failed to break apart source zip file\n");
+ return 1;
+ }
+ if (ReadZip(argv[2], &num_tgt_chunks, &tgt_chunks, 0) == NULL) {
+ printf("failed to break apart target zip file\n");
+ return 1;
+ }
+ } else {
+ if (ReadImage(argv[1], &num_src_chunks, &src_chunks) == NULL) {
+ printf("failed to break apart source image\n");
+ return 1;
+ }
+ if (ReadImage(argv[2], &num_tgt_chunks, &tgt_chunks) == NULL) {
+ printf("failed to break apart target image\n");
+ return 1;
+ }
+
+ // Verify that the source and target images have the same chunk
+ // structure (ie, the same sequence of deflate and normal chunks).
+
+ if (!zip_mode) {
+ // Merge the gzip header and footer in with any adjacent
+ // normal chunks.
+ MergeAdjacentNormalChunks(tgt_chunks, &num_tgt_chunks);
+ MergeAdjacentNormalChunks(src_chunks, &num_src_chunks);
+ }
+
+ if (num_src_chunks != num_tgt_chunks) {
+ printf("source and target don't have same number of chunks!\n");
+ printf("source chunks:\n");
+ DumpChunks(src_chunks, num_src_chunks);
+ printf("target chunks:\n");
+ DumpChunks(tgt_chunks, num_tgt_chunks);
+ return 1;
+ }
+ for (i = 0; i < num_src_chunks; ++i) {
+ if (src_chunks[i].type != tgt_chunks[i].type) {
+ printf("source and target don't have same chunk "
+ "structure! (chunk %d)\n", i);
+ printf("source chunks:\n");
+ DumpChunks(src_chunks, num_src_chunks);
+ printf("target chunks:\n");
+ DumpChunks(tgt_chunks, num_tgt_chunks);
+ return 1;
+ }
+ }
+ }
+
+ for (i = 0; i < num_tgt_chunks; ++i) {
+ if (tgt_chunks[i].type == CHUNK_DEFLATE) {
+ // Confirm that given the uncompressed chunk data in the target, we
+ // can recompress it and get exactly the same bits as are in the
+ // input target image. If this fails, treat the chunk as a normal
+ // non-deflated chunk.
+ if (ReconstructDeflateChunk(tgt_chunks+i) < 0) {
+ printf("failed to reconstruct target deflate chunk %d [%s]; "
+ "treating as normal\n", i, tgt_chunks[i].filename);
+ ChangeDeflateChunkToNormal(tgt_chunks+i);
+ if (zip_mode) {
+ ImageChunk* src = FindChunkByName(tgt_chunks[i].filename, src_chunks, num_src_chunks);
+ if (src) {
+ ChangeDeflateChunkToNormal(src);
+ }
+ } else {
+ ChangeDeflateChunkToNormal(src_chunks+i);
+ }
+ continue;
+ }
+
+ // If two deflate chunks are identical (eg, the kernel has not
+ // changed between two builds), treat them as normal chunks.
+ // This makes applypatch much faster -- it can apply a trivial
+ // patch to the compressed data, rather than uncompressing and
+ // recompressing to apply the trivial patch to the uncompressed
+ // data.
+ ImageChunk* src;
+ if (zip_mode) {
+ src = FindChunkByName(tgt_chunks[i].filename, src_chunks, num_src_chunks);
+ } else {
+ src = src_chunks+i;
+ }
+
+ if (src == NULL || AreChunksEqual(tgt_chunks+i, src)) {
+ ChangeDeflateChunkToNormal(tgt_chunks+i);
+ if (src) {
+ ChangeDeflateChunkToNormal(src);
+ }
+ }
+ }
+ }
+
+ // Merging neighboring normal chunks.
+ if (zip_mode) {
+ // For zips, we only need to do this to the target: deflated
+ // chunks are matched via filename, and normal chunks are patched
+ // using the entire source file as the source.
+ MergeAdjacentNormalChunks(tgt_chunks, &num_tgt_chunks);
+ } else {
+ // For images, we need to maintain the parallel structure of the
+ // chunk lists, so do the merging in both the source and target
+ // lists.
+ MergeAdjacentNormalChunks(tgt_chunks, &num_tgt_chunks);
+ MergeAdjacentNormalChunks(src_chunks, &num_src_chunks);
+ if (num_src_chunks != num_tgt_chunks) {
+ // This shouldn't happen.
+ printf("merging normal chunks went awry\n");
+ return 1;
+ }
+ }
+
+ // Compute bsdiff patches for each chunk's data (the uncompressed
+ // data, in the case of deflate chunks).
+
+ printf("Construct patches for %d chunks...\n", num_tgt_chunks);
+ unsigned char** patch_data = malloc(num_tgt_chunks * sizeof(unsigned char*));
+ size_t* patch_size = malloc(num_tgt_chunks * sizeof(size_t));
+ for (i = 0; i < num_tgt_chunks; ++i) {
+ if (zip_mode) {
+ ImageChunk* src;
+ if (tgt_chunks[i].type == CHUNK_DEFLATE &&
+ (src = FindChunkByName(tgt_chunks[i].filename, src_chunks,
+ num_src_chunks))) {
+ patch_data[i] = MakePatch(src, tgt_chunks+i, patch_size+i);
+ } else {
+ patch_data[i] = MakePatch(src_chunks, tgt_chunks+i, patch_size+i);
+ }
+ } else {
+ patch_data[i] = MakePatch(src_chunks+i, tgt_chunks+i, patch_size+i);
+ }
+ printf("patch %3d is %d bytes (of %d)\n",
+ i, patch_size[i], tgt_chunks[i].source_len);
+ }
+
+ // Figure out how big the imgdiff file header is going to be, so
+ // that we can correctly compute the offset of each bsdiff patch
+ // within the file.
+
+ size_t total_header_size = 12;
+ for (i = 0; i < num_tgt_chunks; ++i) {
+ total_header_size += 4;
+ switch (tgt_chunks[i].type) {
+ case CHUNK_NORMAL:
+ total_header_size += 8*3;
+ break;
+ case CHUNK_DEFLATE:
+ total_header_size += 8*5 + 4*5;
+ break;
+ case CHUNK_RAW:
+ total_header_size += 4 + patch_size[i];
+ break;
+ }
+ }
+
+ size_t offset = total_header_size;
+
+ FILE* f = fopen(argv[3], "wb");
+
+ // Write out the headers.
+
+ fwrite("IMGDIFF2", 1, 8, f);
+ Write4(num_tgt_chunks, f);
+ for (i = 0; i < num_tgt_chunks; ++i) {
+ Write4(tgt_chunks[i].type, f);
+
+ switch (tgt_chunks[i].type) {
+ case CHUNK_NORMAL:
+ printf("chunk %3d: normal (%10d, %10d) %10d\n", i,
+ tgt_chunks[i].start, tgt_chunks[i].len, patch_size[i]);
+ Write8(tgt_chunks[i].source_start, f);
+ Write8(tgt_chunks[i].source_len, f);
+ Write8(offset, f);
+ offset += patch_size[i];
+ break;
+
+ case CHUNK_DEFLATE:
+ printf("chunk %3d: deflate (%10d, %10d) %10d %s\n", i,
+ tgt_chunks[i].start, tgt_chunks[i].deflate_len, patch_size[i],
+ tgt_chunks[i].filename);
+ Write8(tgt_chunks[i].source_start, f);
+ Write8(tgt_chunks[i].source_len, f);
+ Write8(offset, f);
+ Write8(tgt_chunks[i].source_uncompressed_len, f);
+ Write8(tgt_chunks[i].len, f);
+ Write4(tgt_chunks[i].level, f);
+ Write4(tgt_chunks[i].method, f);
+ Write4(tgt_chunks[i].windowBits, f);
+ Write4(tgt_chunks[i].memLevel, f);
+ Write4(tgt_chunks[i].strategy, f);
+ offset += patch_size[i];
+ break;
+
+ case CHUNK_RAW:
+ printf("chunk %3d: raw (%10d, %10d)\n", i,
+ tgt_chunks[i].start, tgt_chunks[i].len);
+ Write4(patch_size[i], f);
+ fwrite(patch_data[i], 1, patch_size[i], f);
+ break;
+ }
+ }
+
+ // Append each chunk's bsdiff patch, in order.
+
+ for (i = 0; i < num_tgt_chunks; ++i) {
+ if (tgt_chunks[i].type != CHUNK_RAW) {
+ fwrite(patch_data[i], 1, patch_size[i], f);
+ }
+ }
+
+ fclose(f);
+
+ return 0;
+}