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Diffstat (limited to 'applypatch/applypatch.cpp')
| -rw-r--r-- | applypatch/applypatch.cpp | 1025 |
1 files changed, 1025 insertions, 0 deletions
diff --git a/applypatch/applypatch.cpp b/applypatch/applypatch.cpp new file mode 100644 index 000000000..96bd88e88 --- /dev/null +++ b/applypatch/applypatch.cpp @@ -0,0 +1,1025 @@ +/* + * Copyright (C) 2008 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. + */ + +#include <errno.h> +#include <fcntl.h> +#include <libgen.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/stat.h> +#include <sys/statfs.h> +#include <sys/types.h> +#include <unistd.h> + +#include "mincrypt/sha.h" +#include "applypatch.h" +#include "mtdutils/mtdutils.h" +#include "edify/expr.h" + +static int LoadPartitionContents(const char* filename, FileContents* file); +static ssize_t FileSink(const unsigned char* data, ssize_t len, void* token); +static int GenerateTarget(FileContents* source_file, + const Value* source_patch_value, + FileContents* copy_file, + const Value* copy_patch_value, + const char* source_filename, + const char* target_filename, + const uint8_t target_sha1[SHA_DIGEST_SIZE], + size_t target_size, + const Value* bonus_data); + +static int mtd_partitions_scanned = 0; + +// Read a file into memory; store the file contents and associated +// metadata in *file. +// +// Return 0 on success. +int LoadFileContents(const char* filename, FileContents* file) { + file->data = NULL; + + // A special 'filename' beginning with "MTD:" or "EMMC:" means to + // load the contents of a partition. + if (strncmp(filename, "MTD:", 4) == 0 || + strncmp(filename, "EMMC:", 5) == 0) { + return LoadPartitionContents(filename, file); + } + + if (stat(filename, &file->st) != 0) { + printf("failed to stat \"%s\": %s\n", filename, strerror(errno)); + return -1; + } + + file->size = file->st.st_size; + file->data = reinterpret_cast<unsigned char*>(malloc(file->size)); + + FILE* f = fopen(filename, "rb"); + if (f == NULL) { + printf("failed to open \"%s\": %s\n", filename, strerror(errno)); + free(file->data); + file->data = NULL; + return -1; + } + + size_t bytes_read = fread(file->data, 1, file->size, f); + if (bytes_read != static_cast<size_t>(file->size)) { + printf("short read of \"%s\" (%zu bytes of %zd)\n", filename, bytes_read, file->size); + free(file->data); + file->data = NULL; + return -1; + } + fclose(f); + + SHA_hash(file->data, file->size, file->sha1); + 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) { + const int aa = *reinterpret_cast<const int*>(a); + const int bb = *reinterpret_cast<const 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 or EMMC partition into the provided +// FileContents. filename should be a string of the form +// "MTD:<partition_name>:<size_1>:<sha1_1>:<size_2>:<sha1_2>:..." (or +// "EMMC:<partition_device>:..."). The smallest size_n bytes for +// which that prefix of the partition 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 a partition (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. +enum PartitionType { MTD, EMMC }; + +static int LoadPartitionContents(const char* filename, FileContents* file) { + char* copy = strdup(filename); + const char* magic = strtok(copy, ":"); + + enum PartitionType type; + + if (strcmp(magic, "MTD") == 0) { + type = MTD; + } else if (strcmp(magic, "EMMC") == 0) { + type = EMMC; + } else { + printf("LoadPartitionContents 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) { + printf("LoadPartitionContents called with bad filename (%s)\n", + filename); + } + + int pairs = (colons-1)/2; // # of (size,sha1) pairs in filename + int* index = reinterpret_cast<int*>(malloc(pairs * sizeof(int))); + size_t* size = reinterpret_cast<size_t*>(malloc(pairs * sizeof(size_t))); + char** sha1sum = reinterpret_cast<char**>(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) { + printf("LoadPartitionContents called with bad size (%s)\n", filename); + return -1; + } + sha1sum[i] = strtok(NULL, ":"); + index[i] = i; + } + + // sort the index[] array so it indexes the pairs in order of + // increasing size. + size_array = size; + qsort(index, pairs, sizeof(int), compare_size_indices); + + MtdReadContext* ctx = NULL; + FILE* dev = NULL; + + switch (type) { + case MTD: { + if (!mtd_partitions_scanned) { + mtd_scan_partitions(); + mtd_partitions_scanned = 1; + } + + const MtdPartition* mtd = mtd_find_partition_by_name(partition); + if (mtd == NULL) { + printf("mtd partition \"%s\" not found (loading %s)\n", + partition, filename); + return -1; + } + + ctx = mtd_read_partition(mtd); + if (ctx == NULL) { + printf("failed to initialize read of mtd partition \"%s\"\n", + partition); + return -1; + } + break; + } + + case EMMC: + dev = fopen(partition, "rb"); + if (dev == NULL) { + printf("failed to open emmc partition \"%s\": %s\n", + partition, strerror(errno)); + 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 = reinterpret_cast<unsigned char*>(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) { + switch (type) { + case MTD: + read = mtd_read_data(ctx, p, next); + break; + + case EMMC: + read = fread(p, 1, next, dev); + break; + } + if (next != read) { + printf("short read (%zu bytes of %zu) 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) { + printf("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("partition read matched size %zu sha %s\n", + size[index[i]], sha1sum[index[i]]); + break; + } + + p += read; + } + + switch (type) { + case MTD: + mtd_read_close(ctx); + break; + + case EMMC: + fclose(dev); + break; + } + + + if (i == pairs) { + // Ran off the end of the list of (size,sha1) pairs without + // finding a match. + printf("contents of 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 (size_t i = 0; i < SHA_DIGEST_SIZE; ++i) { + file->sha1[i] = sha_final[i]; + } + + // Fake some stat() info. + file->st.st_mode = 0644; + file->st.st_uid = 0; + file->st.st_gid = 0; + + 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, const FileContents* file) { + int fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_SYNC, S_IRUSR | S_IWUSR); + if (fd < 0) { + printf("failed to open \"%s\" for write: %s\n", filename, strerror(errno)); + return -1; + } + + ssize_t bytes_written = FileSink(file->data, file->size, &fd); + if (bytes_written != file->size) { + printf("short write of \"%s\" (%zd bytes of %zd) (%s)\n", + filename, bytes_written, file->size, strerror(errno)); + close(fd); + return -1; + } + if (fsync(fd) != 0) { + printf("fsync of \"%s\" failed: %s\n", filename, strerror(errno)); + return -1; + } + if (close(fd) != 0) { + printf("close of \"%s\" failed: %s\n", filename, strerror(errno)); + return -1; + } + + if (chmod(filename, file->st.st_mode) != 0) { + printf("chmod of \"%s\" failed: %s\n", filename, strerror(errno)); + return -1; + } + if (chown(filename, file->st.st_uid, file->st.st_gid) != 0) { + printf("chown of \"%s\" failed: %s\n", filename, strerror(errno)); + return -1; + } + + return 0; +} + +// Write a memory buffer to 'target' partition, a string of the form +// "MTD:<partition>[:...]" or "EMMC:<partition_device>:". Return 0 on +// success. +int WriteToPartition(unsigned char* data, size_t len, const char* target) { + char* copy = strdup(target); + const char* magic = strtok(copy, ":"); + + enum PartitionType type; + if (strcmp(magic, "MTD") == 0) { + type = MTD; + } else if (strcmp(magic, "EMMC") == 0) { + type = EMMC; + } else { + printf("WriteToPartition called with bad target (%s)\n", target); + return -1; + } + const char* partition = strtok(NULL, ":"); + + if (partition == NULL) { + printf("bad partition target name \"%s\"\n", target); + return -1; + } + + switch (type) { + case MTD: { + if (!mtd_partitions_scanned) { + mtd_scan_partitions(); + mtd_partitions_scanned = 1; + } + + const MtdPartition* mtd = mtd_find_partition_by_name(partition); + if (mtd == NULL) { + printf("mtd partition \"%s\" not found for writing\n", partition); + return -1; + } + + MtdWriteContext* ctx = mtd_write_partition(mtd); + if (ctx == NULL) { + printf("failed to init mtd partition \"%s\" for writing\n", partition); + return -1; + } + + size_t written = mtd_write_data(ctx, reinterpret_cast<char*>(data), len); + if (written != len) { + printf("only wrote %zu of %zu bytes to MTD %s\n", written, len, partition); + mtd_write_close(ctx); + return -1; + } + + if (mtd_erase_blocks(ctx, -1) < 0) { + printf("error finishing mtd write of %s\n", partition); + mtd_write_close(ctx); + return -1; + } + + if (mtd_write_close(ctx)) { + printf("error closing mtd write of %s\n", partition); + return -1; + } + break; + } + + case EMMC: { + size_t start = 0; + bool success = false; + int fd = open(partition, O_RDWR | O_SYNC); + if (fd < 0) { + printf("failed to open %s: %s\n", partition, strerror(errno)); + return -1; + } + + for (int attempt = 0; attempt < 2; ++attempt) { + if (TEMP_FAILURE_RETRY(lseek(fd, start, SEEK_SET)) == -1) { + printf("failed seek on %s: %s\n", partition, strerror(errno)); + return -1; + } + while (start < len) { + size_t to_write = len - start; + if (to_write > 1<<20) to_write = 1<<20; + + ssize_t written = TEMP_FAILURE_RETRY(write(fd, data+start, to_write)); + if (written == -1) { + printf("failed write writing to %s: %s\n", partition, strerror(errno)); + return -1; + } + start += written; + } + if (fsync(fd) != 0) { + printf("failed to sync to %s (%s)\n", partition, strerror(errno)); + return -1; + } + if (close(fd) != 0) { + printf("failed to close %s (%s)\n", partition, strerror(errno)); + return -1; + } + fd = open(partition, O_RDONLY); + if (fd < 0) { + printf("failed to reopen %s for verify (%s)\n", partition, strerror(errno)); + return -1; + } + + // Drop caches so our subsequent verification read + // won't just be reading the cache. + sync(); + int dc = open("/proc/sys/vm/drop_caches", O_WRONLY); + if (TEMP_FAILURE_RETRY(write(dc, "3\n", 2)) == -1) { + printf("write to /proc/sys/vm/drop_caches failed: %s\n", strerror(errno)); + } else { + printf(" caches dropped\n"); + } + close(dc); + sleep(1); + + // verify + if (TEMP_FAILURE_RETRY(lseek(fd, 0, SEEK_SET)) == -1) { + printf("failed to seek back to beginning of %s: %s\n", + partition, strerror(errno)); + return -1; + } + unsigned char buffer[4096]; + start = len; + for (size_t p = 0; p < len; p += sizeof(buffer)) { + size_t to_read = len - p; + if (to_read > sizeof(buffer)) { + to_read = sizeof(buffer); + } + + size_t so_far = 0; + while (so_far < to_read) { + ssize_t read_count = + TEMP_FAILURE_RETRY(read(fd, buffer+so_far, to_read-so_far)); + if (read_count == -1) { + printf("verify read error %s at %zu: %s\n", + partition, p, strerror(errno)); + return -1; + } + if (static_cast<size_t>(read_count) < to_read) { + printf("short verify read %s at %zu: %zd %zu %s\n", + partition, p, read_count, to_read, strerror(errno)); + } + so_far += read_count; + } + + if (memcmp(buffer, data+p, to_read) != 0) { + printf("verification failed starting at %zu\n", p); + start = p; + break; + } + } + + if (start == len) { + printf("verification read succeeded (attempt %d)\n", attempt+1); + success = true; + break; + } + } + + if (!success) { + printf("failed to verify after all attempts\n"); + return -1; + } + + if (close(fd) != 0) { + printf("error closing %s (%s)\n", partition, strerror(errno)); + return -1; + } + sync(); + break; + } + } + + free(copy); + return 0; +} + + +// Take a string 'str' of 40 hex digits and parse it into the 20 +// byte array 'digest'. 'str' may contain only the digest or be of +// the form "<digest>:<anything>". Return 0 on success, -1 on any +// error. +int ParseSha1(const char* str, uint8_t* digest) { + const char* ps = str; + uint8_t* pd = digest; + for (int i = 0; i < SHA_DIGEST_SIZE * 2; ++i, ++ps) { + int digit; + if (*ps >= '0' && *ps <= '9') { + digit = *ps - '0'; + } else if (*ps >= 'a' && *ps <= 'f') { + digit = *ps - 'a' + 10; + } else if (*ps >= 'A' && *ps <= 'F') { + digit = *ps - 'A' + 10; + } else { + return -1; + } + if (i % 2 == 0) { + *pd = digit << 4; + } else { + *pd |= digit; + ++pd; + } + } + if (*ps != '\0') return -1; + return 0; +} + +// Search an array of sha1 strings for one matching the given sha1. +// Return the index of the match on success, or -1 if no match is +// found. +int FindMatchingPatch(uint8_t* sha1, char* const * const patch_sha1_str, + int num_patches) { + uint8_t patch_sha1[SHA_DIGEST_SIZE]; + for (int i = 0; i < num_patches; ++i) { + if (ParseSha1(patch_sha1_str[i], patch_sha1) == 0 && + memcmp(patch_sha1, sha1, SHA_DIGEST_SIZE) == 0) { + return i; + } + } + return -1; +} + +// Returns 0 if the contents of the file (argv[2]) or the cached file +// match any of the sha1's on the command line (argv[3:]). Returns +// nonzero otherwise. +int applypatch_check(const char* filename, int num_patches, + char** const patch_sha1_str) { + FileContents file; + file.data = NULL; + + // It's okay to specify no sha1s; the check will pass if the + // LoadFileContents is successful. (Useful for reading + // partitions, where the filename encodes the sha1s; no need to + // check them twice.) + if (LoadFileContents(filename, &file) != 0 || + (num_patches > 0 && + FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0)) { + printf("file \"%s\" doesn't have any of expected " + "sha1 sums; checking cache\n", filename); + + free(file.data); + file.data = NULL; + + // If the source file is missing or corrupted, it might be because + // we were killed in the middle of patching it. A copy of it + // should have been made in CACHE_TEMP_SOURCE. If that file + // exists and matches the sha1 we're looking for, the check still + // passes. + + if (LoadFileContents(CACHE_TEMP_SOURCE, &file) != 0) { + printf("failed to load cache file\n"); + return 1; + } + + if (FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0) { + printf("cache bits don't match any sha1 for \"%s\"\n", filename); + free(file.data); + return 1; + } + } + + free(file.data); + return 0; +} + +int ShowLicenses() { + ShowBSDiffLicense(); + return 0; +} + +ssize_t FileSink(const unsigned char* data, ssize_t len, void* token) { + int fd = *reinterpret_cast<int *>(token); + ssize_t done = 0; + ssize_t wrote; + while (done < len) { + wrote = TEMP_FAILURE_RETRY(write(fd, data+done, len-done)); + if (wrote == -1) { + printf("error writing %zd bytes: %s\n", (len-done), strerror(errno)); + return done; + } + done += wrote; + } + return done; +} + +typedef struct { + unsigned char* buffer; + ssize_t size; + ssize_t pos; +} MemorySinkInfo; + +ssize_t MemorySink(const unsigned char* data, ssize_t len, void* token) { + MemorySinkInfo* msi = reinterpret_cast<MemorySinkInfo*>(token); + if (msi->size - msi->pos < len) { + return -1; + } + memcpy(msi->buffer + msi->pos, data, len); + msi->pos += len; + return len; +} + +// Return the amount of free space (in bytes) on the filesystem +// containing filename. filename must exist. Return -1 on error. +size_t FreeSpaceForFile(const char* filename) { + struct statfs sf; + if (statfs(filename, &sf) != 0) { + printf("failed to statfs %s: %s\n", filename, strerror(errno)); + return -1; + } + return sf.f_bsize * sf.f_bavail; +} + +int CacheSizeCheck(size_t bytes) { + if (MakeFreeSpaceOnCache(bytes) < 0) { + printf("unable to make %ld bytes available on /cache\n", (long)bytes); + return 1; + } else { + return 0; + } +} + +static void print_short_sha1(const uint8_t sha1[SHA_DIGEST_SIZE]) { + const char* hex = "0123456789abcdef"; + for (size_t i = 0; i < 4; ++i) { + putchar(hex[(sha1[i]>>4) & 0xf]); + putchar(hex[sha1[i] & 0xf]); + } +} + +// This function applies binary patches to files in a way that is safe +// (the original file is not touched until we have the desired +// replacement for it) and idempotent (it's okay to run this program +// multiple times). +// +// - if the sha1 hash of <target_filename> is <target_sha1_string>, +// does nothing and exits successfully. +// +// - otherwise, if the sha1 hash of <source_filename> is one of the +// entries in <patch_sha1_str>, the corresponding patch from +// <patch_data> (which must be a VAL_BLOB) is applied to produce a +// new file (the type of patch is automatically detected from the +// blob daat). If that new file has sha1 hash <target_sha1_str>, +// moves it to replace <target_filename>, and exits successfully. +// Note that if <source_filename> and <target_filename> are not the +// same, <source_filename> is NOT deleted on success. +// <target_filename> may be the string "-" to mean "the same as +// source_filename". +// +// - otherwise, or if any error is encountered, exits with non-zero +// status. +// +// <source_filename> may refer to a partition to read the source data. +// See the comments for the LoadPartition Contents() function above +// for the format of such a filename. + +int applypatch(const char* source_filename, + const char* target_filename, + const char* target_sha1_str, + size_t target_size, + int num_patches, + char** const patch_sha1_str, + Value** patch_data, + Value* bonus_data) { + printf("patch %s: ", source_filename); + + if (target_filename[0] == '-' && target_filename[1] == '\0') { + target_filename = source_filename; + } + + uint8_t target_sha1[SHA_DIGEST_SIZE]; + if (ParseSha1(target_sha1_str, target_sha1) != 0) { + printf("failed to parse tgt-sha1 \"%s\"\n", target_sha1_str); + return 1; + } + + FileContents copy_file; + FileContents source_file; + copy_file.data = NULL; + source_file.data = NULL; + const Value* source_patch_value = NULL; + const Value* copy_patch_value = NULL; + + // 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. + printf("already "); + print_short_sha1(target_sha1); + putchar('\n'); + free(source_file.data); + 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); + source_file.data = NULL; + LoadFileContents(source_filename, &source_file); + } + + if (source_file.data != NULL) { + int to_use = FindMatchingPatch(source_file.sha1, patch_sha1_str, num_patches); + if (to_use >= 0) { + source_patch_value = patch_data[to_use]; + } + } + + if (source_patch_value == NULL) { + free(source_file.data); + source_file.data = NULL; + printf("source file is bad; trying copy\n"); + + if (LoadFileContents(CACHE_TEMP_SOURCE, ©_file) < 0) { + // fail. + printf("failed to read copy file\n"); + return 1; + } + + int to_use = FindMatchingPatch(copy_file.sha1, patch_sha1_str, num_patches); + if (to_use >= 0) { + copy_patch_value = patch_data[to_use]; + } + + if (copy_patch_value == NULL) { + // fail. + printf("copy file doesn't match source SHA-1s either\n"); + free(copy_file.data); + return 1; + } + } + + int result = GenerateTarget(&source_file, source_patch_value, + ©_file, copy_patch_value, + source_filename, target_filename, + target_sha1, target_size, bonus_data); + free(source_file.data); + free(copy_file.data); + + return result; +} + +static int GenerateTarget(FileContents* source_file, + const Value* source_patch_value, + FileContents* copy_file, + const Value* copy_patch_value, + const char* source_filename, + const char* target_filename, + const uint8_t target_sha1[SHA_DIGEST_SIZE], + size_t target_size, + const Value* bonus_data) { + int retry = 1; + SHA_CTX ctx; + int output; + MemorySinkInfo msi; + FileContents* source_to_use; + char* outname; + int made_copy = 0; + + // 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[strlen(target_filename)+1]; + char* slash = strchr(target_filename+1, '/'); + if (slash != NULL) { + int count = slash - target_filename; + strncpy(target_fs, target_filename, count); + target_fs[count] = '\0'; + } else { + strcpy(target_fs, target_filename); + } + + do { + // Is there enough room in the target filesystem to hold the patched + // file? + + if (strncmp(target_filename, "MTD:", 4) == 0 || + strncmp(target_filename, "EMMC:", 5) == 0) { + // If the target is a 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 partition write is interrupted. + if (MakeFreeSpaceOnCache(source_file->size) < 0) { + printf("not enough free space on /cache\n"); + return 1; + } + if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) { + printf("failed to back up source file\n"); + return 1; + } + made_copy = 1; + retry = 0; + } else { + int enough_space = 0; + if (retry > 0) { + size_t free_space = FreeSpaceForFile(target_fs); + enough_space = + (free_space > (256 << 10)) && // 256k (two-block) minimum + (free_space > (target_size * 3 / 2)); // 50% margin of error + if (!enough_space) { + printf("target %zu bytes; free space %zu bytes; retry %d; enough %d\n", + target_size, free_space, retry, enough_space); + } + } + + if (!enough_space) { + retry = 0; + } + + if (!enough_space && source_patch_value != 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 || + strncmp(source_filename, "EMMC:", 5) == 0) { + // It's impossible to free space on the target filesystem by + // deleting the source if the source is a partition. If + // we're ever in a state where we need to do this, fail. + printf("not enough free space for target but source is partition\n"); + return 1; + } + + if (MakeFreeSpaceOnCache(source_file->size) < 0) { + printf("not enough free space on /cache\n"); + return 1; + } + + if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) { + printf("failed to back up source file\n"); + return 1; + } + made_copy = 1; + unlink(source_filename); + + size_t free_space = FreeSpaceForFile(target_fs); + printf("(now %zu bytes free for target) ", free_space); + } + } + + const Value* patch; + if (source_patch_value != NULL) { + source_to_use = source_file; + patch = source_patch_value; + } else { + source_to_use = copy_file; + patch = copy_patch_value; + } + + if (patch->type != VAL_BLOB) { + printf("patch is not a blob\n"); + return 1; + } + + SinkFn sink = NULL; + void* token = NULL; + output = -1; + outname = NULL; + if (strncmp(target_filename, "MTD:", 4) == 0 || + strncmp(target_filename, "EMMC:", 5) == 0) { + // We store the decoded output in memory. + msi.buffer = reinterpret_cast<unsigned char*>(malloc(target_size)); + if (msi.buffer == NULL) { + printf("failed to alloc %zu bytes for output\n", 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 = reinterpret_cast<char*>(malloc(strlen(target_filename) + 10)); + strcpy(outname, target_filename); + strcat(outname, ".patch"); + + output = open(outname, O_WRONLY | O_CREAT | O_TRUNC | O_SYNC, S_IRUSR | S_IWUSR); + if (output < 0) { + printf("failed to open output file %s: %s\n", + outname, strerror(errno)); + return 1; + } + sink = FileSink; + token = &output; + } + + char* header = patch->data; + ssize_t header_bytes_read = patch->size; + + SHA_init(&ctx); + + int result; + + if (header_bytes_read >= 8 && + memcmp(header, "BSDIFF40", 8) == 0) { + result = ApplyBSDiffPatch(source_to_use->data, source_to_use->size, + patch, 0, sink, token, &ctx); + } else if (header_bytes_read >= 8 && + memcmp(header, "IMGDIFF2", 8) == 0) { + result = ApplyImagePatch(source_to_use->data, source_to_use->size, + patch, sink, token, &ctx, bonus_data); + } else { + printf("Unknown patch file format\n"); + return 1; + } + + if (output >= 0) { + if (fsync(output) != 0) { + printf("failed to fsync file \"%s\" (%s)\n", outname, strerror(errno)); + result = 1; + } + if (close(output) != 0) { + printf("failed to close file \"%s\" (%s)\n", outname, strerror(errno)); + result = 1; + } + } + + if (result != 0) { + if (retry == 0) { + printf("applying patch failed\n"); + return result != 0; + } else { + printf("applying patch failed; retrying\n"); + } + if (outname != NULL) { + unlink(outname); + } + } else { + // succeeded; no need to retry + break; + } + } while (retry-- > 0); + + const uint8_t* current_target_sha1 = SHA_final(&ctx); + if (memcmp(current_target_sha1, target_sha1, SHA_DIGEST_SIZE) != 0) { + printf("patch did not produce expected sha1\n"); + return 1; + } else { + printf("now "); + print_short_sha1(target_sha1); + putchar('\n'); + } + + if (output < 0) { + // Copy the temp file to the partition. + if (WriteToPartition(msi.buffer, msi.pos, target_filename) != 0) { + printf("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) { + printf("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) { + printf("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) { + printf("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; +} |