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new image diffing tool and support for image patches in applypatch

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Images (like boot and recovery) consist of large sections of gzipped
data interspersed with other data.  To do effective binary patching of
these files, we need to apply patches to the gzipped parts in
'uncompressed space', that is, we decompress, apply a patch, then
recompress to obtain the desired output.

This change defines a new format with these patches, which is
basically a description of how the source and target files are to be
divided up into chunks and a bsdiff patch for each chunk.  We add a
new host executable, "imgdiff", for generating these patches from
source and target images, and add support in applypatch for
recognizing this format and applying it on the device.
This commit is contained in:
Doug Zongker
2009-05-27 18:24:03 -07:00
parent 8b70e8c657
commit 02d444b07e
7 changed files with 890 additions and 28 deletions
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64
tools/applypatch/bsdiff.c
View File

@@ -29,6 +29,7 @@
#include <bzlib.h>
#include "mincrypt/sha.h"
#include "applypatch.h"
void ShowBSDiffLicense() {
puts("The bsdiff library used herein is:\n"
@@ -80,10 +81,34 @@ static off_t offtin(u_char *buf)
return y;
}
int ApplyBSDiffPatch(const unsigned char* old_data, ssize_t old_size,
const char* patch_filename,
const char* patch_filename, ssize_t patch_offset,
FILE* output, SHA_CTX* ctx) {
unsigned char* new_data;
ssize_t new_size;
if (ApplyBSDiffPatchMem(old_data, old_size, patch_filename, patch_offset,
&new_data, &new_size) != 0) {
return -1;
}
if (fwrite(new_data, 1, new_size, output) < new_size) {
fprintf(stderr, "short write of output: %d (%s)\n", errno, strerror(errno));
return 1;
}
if (ctx) {
SHA_update(ctx, new_data, new_size);
}
free(new_data);
return 0;
}
int ApplyBSDiffPatchMem(const unsigned char* old_data, ssize_t old_size,
const char* patch_filename, ssize_t patch_offset,
unsigned char** new_data, ssize_t* new_size) {
FILE* f;
if ((f = fopen(patch_filename, "rb")) == NULL) {
fprintf(stderr, "failed to open patch file\n");
@@ -102,6 +127,8 @@ int ApplyBSDiffPatch(const unsigned char* old_data, ssize_t old_size,
// from oldfile to x bytes from the diff block; copy y bytes from the
// extra block; seek forwards in oldfile by z bytes".
fseek(f, patch_offset, SEEK_SET);
unsigned char header[32];
if (fread(header, 1, 32, f) < 32) {
fprintf(stderr, "failed to read patch file header\n");
@@ -109,17 +136,16 @@ int ApplyBSDiffPatch(const unsigned char* old_data, ssize_t old_size,
}
if (memcmp(header, "BSDIFF40", 8) != 0) {
fprintf(stderr, "corrupt patch file header (magic number)\n");
fprintf(stderr, "corrupt bsdiff patch file header (magic number)\n");
return 1;
}
ssize_t ctrl_len, data_len;
ssize_t new_size;
ctrl_len = offtin(header+8);
data_len = offtin(header+16);
new_size = offtin(header+24);
*new_size = offtin(header+24);
if (ctrl_len < 0 || data_len < 0 || new_size < 0) {
if (ctrl_len < 0 || data_len < 0 || *new_size < 0) {
fprintf(stderr, "corrupt patch file header (data lengths)\n");
return 1;
}
@@ -135,7 +161,7 @@ int ApplyBSDiffPatch(const unsigned char* old_data, ssize_t old_size,
fprintf(stderr, "failed to open patch file\n"); \
return 1; \
} \
if (fseeko(f, offset, SEEK_SET)) { \
if (fseeko(f, offset+patch_offset, SEEK_SET)) { \
fprintf(stderr, "failed to seek in patch file\n"); \
return 1; \
} \
@@ -150,9 +176,10 @@ int ApplyBSDiffPatch(const unsigned char* old_data, ssize_t old_size,
#undef OPEN_AT
unsigned char* new_data = malloc(new_size);
if (new_data == NULL) {
fprintf(stderr, "failed to allocate memory for output file\n");
*new_data = malloc(*new_size);
if (*new_data == NULL) {
fprintf(stderr, "failed to allocate %d bytes of memory for output file\n",
(int)*new_size);
return 1;
}
@@ -161,7 +188,7 @@ int ApplyBSDiffPatch(const unsigned char* old_data, ssize_t old_size,
off_t len_read;
int i;
unsigned char buf[8];
while (newpos < new_size) {
while (newpos < *new_size) {
// Read control data
for (i = 0; i < 3; ++i) {
len_read = BZ2_bzRead(&bzerr, cpfbz2, buf, 8);
@@ -173,13 +200,13 @@ int ApplyBSDiffPatch(const unsigned char* old_data, ssize_t old_size,
}
// Sanity check
if (newpos + ctrl[0] > new_size) {
if (newpos + ctrl[0] > *new_size) {
fprintf(stderr, "corrupt patch (new file overrun)\n");
return 1;
}
// Read diff string
len_read = BZ2_bzRead(&bzerr, dpfbz2, new_data + newpos, ctrl[0]);
len_read = BZ2_bzRead(&bzerr, dpfbz2, *new_data + newpos, ctrl[0]);
if (len_read < ctrl[0] || !(bzerr == BZ_OK || bzerr == BZ_STREAM_END)) {
fprintf(stderr, "corrupt patch (read diff)\n");
return 1;
@@ -188,7 +215,7 @@ int ApplyBSDiffPatch(const unsigned char* old_data, ssize_t old_size,
// Add old data to diff string
for (i = 0; i < ctrl[0]; ++i) {
if ((oldpos+i >= 0) && (oldpos+i < old_size)) {
new_data[newpos+i] += old_data[oldpos+i];
(*new_data)[newpos+i] += old_data[oldpos+i];
}
}
@@ -197,13 +224,13 @@ int ApplyBSDiffPatch(const unsigned char* old_data, ssize_t old_size,
oldpos += ctrl[0];
// Sanity check
if (newpos + ctrl[1] > new_size) {
if (newpos + ctrl[1] > *new_size) {
fprintf(stderr, "corrupt patch (new file overrun)\n");
return 1;
}
// Read extra string
len_read = BZ2_bzRead(&bzerr, epfbz2, new_data + newpos, ctrl[1]);
len_read = BZ2_bzRead(&bzerr, epfbz2, *new_data + newpos, ctrl[1]);
if (len_read < ctrl[1] || !(bzerr == BZ_OK || bzerr == BZ_STREAM_END)) {
fprintf(stderr, "corrupt patch (read extra)\n");
return 1;
@@ -221,12 +248,5 @@ int ApplyBSDiffPatch(const unsigned char* old_data, ssize_t old_size,
fclose(dpf);
fclose(epf);
if (fwrite(new_data, 1, new_size, output) < new_size) {
fprintf(stderr, "short write of output: %d (%s)\n", errno, strerror(errno));
return 1;
}
SHA_update(ctx, new_data, new_size);
free(new_data);
return 0;
}