StrixOS/build
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

add support for reading MTD partitions to applypatch

Browse Source 
Allow an MTD partition so serve as a source "file" in applypatch,
using a magically-formatted 'filename' that specifies the partition
name, size of data to read, and expected hash.  Build incremental OTAs
that update the recovery image via a patch.
This commit is contained in:
Doug Zongker
2009-05-29 11:41:21 -07:00
parent bfeb193659
commit f6a8bada5f
4 changed files with 272 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files

216
tools/applypatch/applypatch.c
View File

@@ -25,12 +25,22 @@
#include "mincrypt/sha.h"
#include "applypatch.h"
#include "mtdutils/mtdutils.h"
int LoadMTDContents(const char* filename, FileContents* file);
int ParseSha1(const char* str, uint8_t* digest);
// Read a file into memory; store it and its associated metadata in
// *file. Return 0 on success.
int LoadFileContents(const char* filename, FileContents* file) {
file->data = NULL;
// A special 'filename' beginning with "MTD:" means to load the
// contents of an MTD partition.
if (strncmp(filename, "MTD:", 4) == 0) {
return LoadMTDContents(filename, file);
}
if (stat(filename, &file->st) != 0) {
fprintf(stderr, "failed to stat \"%s\": %s\n", filename, strerror(errno));
return -1;
@@ -61,6 +71,178 @@ int LoadFileContents(const char* filename, FileContents* file) {
return 0;
}
static size_t* size_array;
// comparison function for qsort()ing an int array of indexes into
// size_array[].
static int compare_size_indices(const void* a, const void* b) {
int aa = *(int*)a;
int bb = *(int*)b;
if (size_array[aa] < size_array[bb]) {
return -1;
} else if (size_array[aa] > size_array[bb]) {
return 1;
} else {
return 0;
}
}
// Load the contents of an MTD partition into the provided
// FileContents. filename should be a string of the form
// "MTD:<partition_name>:<size_1>:<sha1_1>:<size_2>:<sha1_2>:...".
// The smallest size_n bytes for which that prefix of the mtd contents
// has the corresponding sha1 hash will be loaded. It is acceptable
// for a size value to be repeated with different sha1s. Will return
// 0 on success.
//
// This complexity is needed because if an OTA installation is
// interrupted, the partition might contain either the source or the
// target data, which might be of different lengths. We need to know
// the length in order to read from MTD (there is no "end-of-file"
// marker), so the caller must specify the possible lengths and the
// hash of the data, and we'll do the load expecting to find one of
// those hashes.
int LoadMTDContents(const char* filename, FileContents* file) {
char* copy = strdup(filename);
const char* magic = strtok(copy, ":");
if (strcmp(magic, "MTD") != 0) {
fprintf(stderr, "LoadMTDContents called with bad filename (%s)\n",
filename);
return -1;
}
const char* partition = strtok(NULL, ":");
int i;
int colons = 0;
for (i = 0; filename[i] != '\0'; ++i) {
if (filename[i] == ':') {
++colons;
}
}
if (colons < 3 || colons%2 == 0) {
fprintf(stderr, "LoadMTDContents called with bad filename (%s)\n",
filename);
}
int pairs = (colons-1)/2; // # of (size,sha1) pairs in filename
int* index = malloc(pairs * sizeof(int));
size_t* size = malloc(pairs * sizeof(size_t));
char** sha1sum = malloc(pairs * sizeof(char*));
for (i = 0; i < pairs; ++i) {
const char* size_str = strtok(NULL, ":");
size[i] = strtol(size_str, NULL, 10);
if (size[i] == 0) {
fprintf(stderr, "LoadMTDContents called with bad size (%s)\n", filename);
return -1;
}
sha1sum[i] = strtok(NULL, ":");
index[i] = i;
}
// sort the index[] array so it indexs the pairs in order of
// increasing size.
size_array = size;
qsort(index, pairs, sizeof(int), compare_size_indices);
static int partitions_scanned = 0;
if (!partitions_scanned) {
mtd_scan_partitions();
partitions_scanned = 1;
}
const MtdPartition* mtd = mtd_find_partition_by_name(partition);
if (mtd == NULL) {
fprintf(stderr, "mtd partition \"%s\" not found (loading %s)\n",
partition, filename);
return -1;
}
MtdReadContext* ctx = mtd_read_partition(mtd);
if (ctx == NULL) {
fprintf(stderr, "failed to initialize read of mtd partition \"%s\"\n",
partition);
return -1;
}
SHA_CTX sha_ctx;
SHA_init(&sha_ctx);
uint8_t parsed_sha[SHA_DIGEST_SIZE];
// allocate enough memory to hold the largest size.
file->data = malloc(size[index[pairs-1]]);
char* p = (char*)file->data;
file->size = 0; // # bytes read so far
for (i = 0; i < pairs; ++i) {
// Read enough additional bytes to get us up to the next size
// (again, we're trying the possibilities in order of increasing
// size).
size_t next = size[index[i]] - file->size;
size_t read = 0;
if (next > 0) {
read = mtd_read_data(ctx, p, next);
if (next != read) {
fprintf(stderr, "short read (%d bytes of %d) for partition \"%s\"\n",
read, next, partition);
free(file->data);
file->data = NULL;
return -1;
}
SHA_update(&sha_ctx, p, read);
file->size += read;
}
// Duplicate the SHA context and finalize the duplicate so we can
// check it against this pair's expected hash.
SHA_CTX temp_ctx;
memcpy(&temp_ctx, &sha_ctx, sizeof(SHA_CTX));
const uint8_t* sha_so_far = SHA_final(&temp_ctx);
if (ParseSha1(sha1sum[index[i]], parsed_sha) != 0) {
fprintf(stderr, "failed to parse sha1 %s in %s\n",
sha1sum[index[i]], filename);
free(file->data);
file->data = NULL;
return -1;
}
if (memcmp(sha_so_far, parsed_sha, SHA_DIGEST_SIZE) == 0) {
// we have a match. stop reading the partition; we'll return
// the data we've read so far.
printf("mtd read matched size %d sha %s\n",
size[index[i]], sha1sum[index[i]]);
break;
}
p += read;
}
mtd_read_close(ctx);
if (i == pairs) {
// Ran off the end of the list of (size,sha1) pairs without
// finding a match.
fprintf(stderr, "contents of MTD partition \"%s\" didn't match %s\n",
partition, filename);
free(file->data);
file->data = NULL;
return -1;
}
const uint8_t* sha_final = SHA_final(&sha_ctx);
for (i = 0; i < SHA_DIGEST_SIZE; ++i) {
file->sha1[i] = sha_final[i];
}
free(copy);
free(index);
free(size);
free(sha1sum);
return 0;
}
// Save the contents of the given FileContents object under the given
// filename. Return 0 on success.
int SaveFileContents(const char* filename, FileContents file) {
@@ -178,8 +360,13 @@ int CheckMode(int argc, char** argv) {
FileContents file;
file.data = NULL;
// It's okay to specify no sha1s; the check will pass if the
// LoadFileContents is successful. (Useful for reading MTD
// partitions, where the filename encodes the sha1s; no need to
// check them twice.)
if (LoadFileContents(argv[2], &file) != 0 ||
FindMatchingPatch(file.sha1, patches, num_patches) == NULL) {
(num_patches > 0 &&
FindMatchingPatch(file.sha1, patches, num_patches) == NULL)) {
fprintf(stderr, "file \"%s\" doesn't have any of expected "
"sha1 sums; checking cache\n", argv[2]);
@@ -241,14 +428,24 @@ size_t FreeSpaceForFile(const char* filename) {
//
// - otherwise, or if any error is encountered, exits with non-zero
// status.
//
// <src-file> (or <file> in check mode) may refer to an MTD partition
// to read the source data. See the comments for the
// LoadMTDContents() function above for the format of such a filename.
int main(int argc, char** argv) {
if (argc < 2) {
usage:
fprintf(stderr, "usage: %s <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",
fprintf(stderr,
"usage: %s <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"
"<src-file> or <file> may be of the form\n"
" MTD:<partition>:<len_1>:<sha1_1>:<len_2>:<sha1_2>:...\n"
"to specify reading from an MTD partition.\n\n",
argv[0], argv[0], argv[0], argv[0]);
return 1;
}
@@ -370,6 +567,15 @@ int main(int argc, char** argv) {
// 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;