int main(int argc, char** argv) {
if (argc < 2) {
usage:
printf(
"usage: %s [-b <bonus-file>] <src-file> <tgt-file> <tgt-sha1> <tgt-size> "
"[<src-sha1>:<patch> ...]\n"
" or %s -c <file> [<sha1> ...]\n"
" or %s -s <bytes>\n"
" or %s -l\n"
"\n"
"Filenames may be of the form\n"
" MTD:<partition>:<len_1>:<sha1_1>:<len_2>:<sha1_2>:...\n"
"to specify reading from or writing to an MTD partition.\n\n",
argv[0], argv[0], argv[0], argv[0]);
return 2;
}
int result;
if (strncmp(argv[1], "-l", 3) == 0) {
result = ShowLicenses();
} else if (strncmp(argv[1], "-c", 3) == 0) {
result = CheckMode(argc, argv);
} else if (strncmp(argv[1], "-s", 3) == 0) {
result = SpaceMode(argc, argv);
} else if (strncmp(argv[1], "-t", 3) == 0) {
result = TeeUpdateMode(argc, argv);
} else {
result = PatchMode(argc, argv);
}
if (result == 2) {
goto usage;
}
return result;
}
int applypatch(int argc, char** argv) {
if (argc < 2) {
return 2;
}
if (strncmp(argv[1], "-l", 3) == 0) {
return ShowLicenses();
}
if (strncmp(argv[1], "-c", 3) == 0) {
return CheckMode(argc, argv);
}
if (strncmp(argv[1], "-s", 3) == 0) {
if (argc != 3) {
return 2;
}
size_t bytes = strtol(argv[2], NULL, 10);
if (MakeFreeSpaceOnCache(bytes) < 0) {
printf("unable to make %ld bytes available on /cache\n", (long)bytes);
return 1;
} else {
return 0;
}
}
uint8_t target_sha1[SHA_DIGEST_SIZE];
const char* source_filename = argv[1];
const char* target_filename = argv[2];
if (target_filename[0] == '-' &&
target_filename[1] == '\0') {
target_filename = source_filename;
}
if (ParseSha1(argv[3], target_sha1) != 0) {
fprintf(stderr, "failed to parse tgt-sha1 \"%s\"\n", argv[3]);
return 1;
}
unsigned long target_size = strtoul(argv[4], NULL, 0);
int num_patches;
Patch* patches;
if (ParseShaArgs(argc-5, argv+5, &patches, &num_patches) < 0) { return 1; }
FileContents copy_file;
FileContents source_file;
const char* source_patch_filename = NULL;
const char* copy_patch_filename = NULL;
int made_copy = 0;
// We try to load the target file into the source_file object.
if (LoadFileContents(target_filename, &source_file) == 0) {
if (memcmp(source_file.sha1, target_sha1, SHA_DIGEST_SIZE) == 0) {
// The early-exit case: the patch was already applied, this file
// has the desired hash, nothing for us to do.
fprintf(stderr, "\"%s\" is already target; no patch needed\n",
target_filename);
return 0;
}
}
if (source_file.data == NULL ||
(target_filename != source_filename &&
strcmp(target_filename, source_filename) != 0)) {
// Need to load the source file: either we failed to load the
// target file, or we did but it's different from the source file.
free(source_file.data);
LoadFileContents(source_filename, &source_file);
}
if (source_file.data != NULL) {
const Patch* to_use =
FindMatchingPatch(source_file.sha1, patches, num_patches);
if (to_use != NULL) {
source_patch_filename = to_use->patch_filename;
}
}
if (source_patch_filename == NULL) {
free(source_file.data);
fprintf(stderr, "source file is bad; trying copy\n");
if (LoadFileContents(CACHE_TEMP_SOURCE, ©_file) < 0) {
// fail.
fprintf(stderr, "failed to read copy file\n");
return 1;
}
const Patch* to_use =
FindMatchingPatch(copy_file.sha1, patches, num_patches);
if (to_use != NULL) {
copy_patch_filename = to_use->patch_filename;
}
if (copy_patch_filename == NULL) {
// fail.
fprintf(stderr, "copy file doesn't match source SHA-1s either\n");
return 1;
}
}
// Is there enough room in the target filesystem to hold the patched
// file?
if (strncmp(target_filename, "MTD:", 4) == 0) {
// If the target is an MTD partition, we're actually going to
// write the output to /tmp and then copy it to the partition.
// statfs() always returns 0 blocks free for /tmp, so instead
// we'll just assume that /tmp has enough space to hold the file.
// We still write the original source to cache, in case the MTD
// write is interrupted.
if (MakeFreeSpaceOnCache(source_file.size) < 0) {
fprintf(stderr, "not enough free space on /cache\n");
return 1;
}
if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) {
fprintf(stderr, "failed to back up source file\n");
return 1;
}
made_copy = 1;
} else {
// assume that target_filename (eg "/system/app/Foo.apk") is located
// on the same filesystem as its top-level directory ("/system").
// We need something that exists for calling statfs().
char* target_fs = strdup(target_filename);
char* slash = strchr(target_fs+1, '/');
if (slash != NULL) {
*slash = '\0';
}
size_t free_space = FreeSpaceForFile(target_fs);
int enough_space =
free_space > (target_size * 3 / 2); // 50% margin of error
printf("target %ld bytes; free space %ld bytes; enough %d\n",
(long)target_size, (long)free_space, enough_space);
if (!enough_space && source_patch_filename != NULL) {
// Using the original source, but not enough free space. First
// copy the source file to cache, then delete it from the original
// location.
if (strncmp(source_filename, "MTD:", 4) == 0) {
// It's impossible to free space on the target filesystem by
// deleting the source if the source is an MTD partition. If
// we're ever in a state where we need to do this, fail.
fprintf(stderr, "not enough free space for target but source is MTD\n");
return 1;
}
if (MakeFreeSpaceOnCache(source_file.size) < 0) {
fprintf(stderr, "not enough free space on /cache\n");
return 1;
}
if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) {
fprintf(stderr, "failed to back up source file\n");
return 1;
}
made_copy = 1;
unlink(source_filename);
size_t free_space = FreeSpaceForFile(target_fs);
printf("(now %ld bytes free for target)\n", (long)free_space);
}
}
FileContents* source_to_use;
const char* patch_filename;
if (source_patch_filename != NULL) {
source_to_use = &source_file;
patch_filename = source_patch_filename;
} else {
source_to_use = ©_file;
patch_filename = copy_patch_filename;
}
char* outname = NULL;
FILE* output = NULL;
MemorySinkInfo msi;
SinkFn sink = NULL;
void* token = NULL;
if (strncmp(target_filename, "MTD:", 4) == 0) {
// We store the decoded output in memory.
msi.buffer = malloc(target_size);
if (msi.buffer == NULL) {
fprintf(stderr, "failed to alloc %ld bytes for output\n",
(long)target_size);
return 1;
}
msi.pos = 0;
msi.size = target_size;
sink = MemorySink;
token = &msi;
} else {
// We write the decoded output to "<tgt-file>.patch".
outname = (char*)malloc(strlen(target_filename) + 10);
strcpy(outname, target_filename);
strcat(outname, ".patch");
output = fopen(outname, "wb");
if (output == NULL) {
fprintf(stderr, "failed to open output file %s: %s\n",
outname, strerror(errno));
return 1;
}
sink = FileSink;
token = output;
}
#define MAX_HEADER_LENGTH 8
unsigned char header[MAX_HEADER_LENGTH];
FILE* patchf = fopen(patch_filename, "rb");
if (patchf == NULL) {
fprintf(stderr, "failed to open patch file %s: %s\n",
patch_filename, strerror(errno));
return 1;
}
int header_bytes_read = fread(header, 1, MAX_HEADER_LENGTH, patchf);
fclose(patchf);
SHA_CTX ctx;
SHA_init(&ctx);
if (header_bytes_read >= 4 &&
header[0] == 0xd6 && header[1] == 0xc3 &&
header[2] == 0xc4 && header[3] == 0) {
// xdelta3 patches begin "VCD" (with the high bits set) followed
// by a zero byte (the version number).
fprintf(stderr, "error: xdelta3 patches no longer supported\n");
return 1;
} else if (header_bytes_read >= 8 &&
memcmp(header, "BSDIFF40", 8) == 0) {
int result = ApplyBSDiffPatch(source_to_use->data, source_to_use->size,
patch_filename, 0, sink, token, &ctx);
if (result != 0) {
fprintf(stderr, "ApplyBSDiffPatch failed\n");
return result;
}
} else if (header_bytes_read >= 8 &&
memcmp(header, "IMGDIFF", 7) == 0 &&
(header[7] == '1' || header[7] == '2')) {
int result = ApplyImagePatch(source_to_use->data, source_to_use->size,
patch_filename, sink, token, &ctx);
if (result != 0) {
fprintf(stderr, "ApplyImagePatch failed\n");
return result;
}
} else {
fprintf(stderr, "Unknown patch file format\n");
return 1;
}
if (output != NULL) {
fflush(output);
fsync(fileno(output));
fclose(output);
}
const uint8_t* current_target_sha1 = SHA_final(&ctx);
if (memcmp(current_target_sha1, target_sha1, SHA_DIGEST_SIZE) != 0) {
fprintf(stderr, "patch did not produce expected sha1\n");
return 1;
}
if (output == NULL) {
// Copy the temp file to the MTD partition.
if (WriteToMTDPartition(msi.buffer, msi.pos, target_filename) != 0) {
fprintf(stderr, "write of patched data to %s failed\n", target_filename);
return 1;
}
free(msi.buffer);
} else {
// Give the .patch file the same owner, group, and mode of the
// original source file.
if (chmod(outname, source_to_use->st.st_mode) != 0) {
fprintf(stderr, "chmod of \"%s\" failed: %s\n", outname, strerror(errno));
return 1;
}
if (chown(outname, source_to_use->st.st_uid,
source_to_use->st.st_gid) != 0) {
fprintf(stderr, "chown of \"%s\" failed: %s\n", outname, strerror(errno));
return 1;
}
// Finally, rename the .patch file to replace the target file.
if (rename(outname, target_filename) != 0) {
fprintf(stderr, "rename of .patch to \"%s\" failed: %s\n",
target_filename, strerror(errno));
return 1;
}
}
// If this run of applypatch created the copy, and we're here, we
// can delete it.
if (made_copy) unlink(CACHE_TEMP_SOURCE);
// Success!
return 0;
}