From 155771bafa347a1bcba982c6d846240975ea91ef Mon Sep 17 00:00:00 2001 From: Tao Bao Date: Tue, 5 Jun 2018 11:26:01 -0700 Subject: applypatch: Clean up the function comments. Also two minor changes (other than renaming some parameters): - Added constness to the first parameter of FindMatchingPatch(); - Declared WriteToPartition() as static. Bug: 110106408 Test: mmma -j bootable/recovery Change-Id: I388958c944a23ce4a38a757ce2249f6a89dd4f03 --- applypatch/applypatch.cpp | 163 ++++++++++------------------- applypatch/include/applypatch/applypatch.h | 58 ++++++++-- 2 files changed, 105 insertions(+), 116 deletions(-) (limited to 'applypatch') diff --git a/applypatch/applypatch.cpp b/applypatch/applypatch.cpp index 14137de96..ce7702636 100644 --- a/applypatch/applypatch.cpp +++ b/applypatch/applypatch.cpp @@ -49,8 +49,6 @@ static int GenerateTarget(const FileContents& source_file, const std::unique_ptr const std::string& target_filename, const uint8_t target_sha1[SHA_DIGEST_LENGTH], const Value* bonus_data); -// 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) { // A special 'filename' beginning with "EMMC:" means to load the contents of a partition. if (strncmp(filename, "EMMC:", 5) == 0) { @@ -80,20 +78,16 @@ int LoadFileContents(const char* filename, FileContents* file) { return 0; } -// Load the contents of an EMMC partition into the provided -// FileContents. filename should be a string of the form -// "EMMC::...". 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. +// Loads the contents of an EMMC partition into the provided FileContents. filename should be a +// string of the form "EMMC::...". 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. Returns 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. +// 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. static int LoadPartitionContents(const std::string& filename, FileContents* file) { std::vector pieces = android::base::Split(filename, ":"); if (pieces.size() < 4 || pieces.size() % 2 != 0 || pieces[0] != "EMMC") { @@ -184,8 +178,6 @@ static int LoadPartitionContents(const std::string& filename, FileContents* file 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) { unique_fd fd(ota_open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_SYNC, S_IRUSR | S_IWUSR)); if (fd == -1) { @@ -211,11 +203,10 @@ int SaveFileContents(const char* filename, const FileContents* file) { return 0; } -// Write a memory buffer to 'target' partition, a string of the form -// "EMMC:[:...]". The target name -// might contain multiple colons, but WriteToPartition() only uses the first -// two and ignores the rest. Return 0 on success. -int WriteToPartition(const unsigned char* data, size_t len, const std::string& target) { +// Writes a memory buffer to 'target' partition, a string of the form +// "EMMC:[:...]". The target name might contain multiple colons, but +// WriteToPartition() only uses the first two and ignores the rest. Returns 0 on success. +static int WriteToPartition(const unsigned char* data, size_t len, const std::string& target) { std::vector pieces = android::base::Split(target, ":"); if (pieces.size() < 2 || pieces[0] != "EMMC") { printf("WriteToPartition called with bad target (%s)\n", target.c_str()); @@ -343,42 +334,37 @@ int WriteToPartition(const unsigned char* data, size_t len, const std::string& t 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 ":". 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_LENGTH * 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; - } + const char* ps = str; + uint8_t* pd = digest; + for (int i = 0; i < SHA_DIGEST_LENGTH * 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 (*ps != '\0') return -1; - return 0; + 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. -static int FindMatchingPatch(uint8_t* sha1, const std::vector& patch_sha1_str) { - for (size_t i = 0; i < patch_sha1_str.size(); ++i) { +// Searches a vector of SHA-1 strings for one matching the given SHA-1. Returns the index of the +// match on success, or -1 if no match is found. +static int FindMatchingPatch(const uint8_t* sha1, const std::vector& patch_sha1s) { + for (size_t i = 0; i < patch_sha1s.size(); ++i) { uint8_t patch_sha1[SHA_DIGEST_LENGTH]; - if (ParseSha1(patch_sha1_str[i].c_str(), patch_sha1) == 0 && + if (ParseSha1(patch_sha1s[i].c_str(), patch_sha1) == 0 && memcmp(patch_sha1, sha1, SHA_DIGEST_LENGTH) == 0) { return i; } @@ -386,29 +372,24 @@ static int FindMatchingPatch(uint8_t* sha1, const std::vector& patc 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, const std::vector& patch_sha1_str) { +int applypatch_check(const char* filename, const std::vector& patch_sha1s) { + // It's okay to specify no SHA-1s; the check will pass if the LoadFileContents is successful. + // (Useful for reading partitions, where the filename encodes the SHA-1s; no need to check them + // twice.) FileContents file; - - // 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 || - (!patch_sha1_str.empty() && FindMatchingPatch(file.sha1, patch_sha1_str) < 0)) { + (!patch_sha1s.empty() && FindMatchingPatch(file.sha1, patch_sha1s) < 0)) { printf("file \"%s\" doesn't have any of expected sha1 sums; checking cache\n", filename); // 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. + // of patching it. A copy should have been made in cache_temp_source. If that file exists and + // matches the SHA-1 we're looking for, the check still passes. if (LoadFileContents(Paths::Get().cache_temp_source().c_str(), &file) != 0) { printf("failed to load cache file\n"); return 1; } - if (FindMatchingPatch(file.sha1, patch_sha1_str) < 0) { + if (FindMatchingPatch(file.sha1, patch_sha1s) < 0) { printf("cache bits don't match any sha1 for \"%s\"\n", filename); return 1; } @@ -417,8 +398,8 @@ int applypatch_check(const char* filename, const std::vector& patch } int ShowLicenses() { - ShowBSDiffLicense(); - return 0; + ShowBSDiffLicense(); + return 0; } static size_t FileSink(const unsigned char* data, size_t len, int fd) { @@ -434,8 +415,6 @@ static size_t FileSink(const unsigned char* data, size_t len, int fd) { return done; } -// Return the amount of free space (in bytes) on the filesystem -// containing filename. filename must exist. Return -1 on error. size_t FreeSpaceForFile(const std::string& filename) { struct statfs sf; if (statfs(filename.c_str(), &sf) != 0) { @@ -446,37 +425,16 @@ size_t FreeSpaceForFile(const std::string& filename) { } int CacheSizeCheck(size_t bytes) { - if (MakeFreeSpaceOnCache(bytes) < 0) { - printf("unable to make %zu bytes available on /cache\n", bytes); - return 1; - } - return 0; + if (MakeFreeSpaceOnCache(bytes) < 0) { + printf("unable to make %zu bytes available on /cache\n", bytes); + return 1; + } + return 0; } -// This function applies binary patches to EMMC target 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 SHA-1 hash of is , does nothing and exits -// successfully. -// -// - Otherwise, if the SHA-1 hash of is one of the entries in , -// the corresponding patch from (which must be a VAL_BLOB) is applied to produce a -// new file (the type of patch is automatically detected from the blob data). If that new file -// has SHA-1 hash , moves it to replace , and exits -// successfully. Note that if and are not the same, -// is NOT deleted on success. may be the string "-" to mean -// "the same as ". -// -// - Otherwise, or if any error is encountered, exits with non-zero status. -// -// must refer to an EMMC partition to read the source data. See the comments for -// the LoadPartitionContents() function above for the format of such a filename. has -// become obsolete since we have dropped the support for patching non-EMMC targets (EMMC targets -// have the size embedded in the filename). int applypatch(const char* source_filename, const char* target_filename, const char* target_sha1_str, size_t /* target_size */, - const std::vector& patch_sha1_str, + const std::vector& patch_sha1s, const std::vector>& patch_data, const Value* bonus_data) { printf("patch %s: ", source_filename); @@ -515,7 +473,7 @@ int applypatch(const char* source_filename, const char* target_filename, } if (!source_file.data.empty()) { - int to_use = FindMatchingPatch(source_file.sha1, patch_sha1_str); + int to_use = FindMatchingPatch(source_file.sha1, patch_sha1s); if (to_use != -1) { return GenerateTarget(source_file, patch_data[to_use], target_filename, target_sha1, bonus_data); @@ -530,7 +488,7 @@ int applypatch(const char* source_filename, const char* target_filename, return 1; } - int to_use = FindMatchingPatch(copy_file.sha1, patch_sha1_str); + int to_use = FindMatchingPatch(copy_file.sha1, patch_sha1s); if (to_use == -1) { printf("copy file doesn't match source SHA-1s either\n"); return 1; @@ -539,13 +497,6 @@ int applypatch(const char* source_filename, const char* target_filename, return GenerateTarget(copy_file, patch_data[to_use], target_filename, target_sha1, bonus_data); } -/* - * This function flashes a given image to the target partition. It verifies - * the target cheksum first, and will return if target has the desired hash. - * It checks the checksum of the given source image before flashing, and - * verifies the target partition afterwards. The function is idempotent. - * Returns zero on success. - */ int applypatch_flash(const char* source_filename, const char* target_filename, const char* target_sha1_str, size_t target_size) { printf("flash %s: ", target_filename); diff --git a/applypatch/include/applypatch/applypatch.h b/applypatch/include/applypatch/applypatch.h index 77125f9de..ef133f290 100644 --- a/applypatch/include/applypatch/applypatch.h +++ b/applypatch/include/applypatch/applypatch.h @@ -39,23 +39,61 @@ using SinkFn = std::function; // applypatch.cpp int ShowLicenses(); + +// Returns the amount of free space (in bytes) on the filesystem containing filename, or -1 on +// error. filename must exist. size_t FreeSpaceForFile(const std::string& filename); + +// Checks whether /cache partition has at least 'bytes'-byte free space. Returns 0 on having +// sufficient space. int CacheSizeCheck(size_t bytes); + +// Parses a given string of 40 hex digits into 20-byte array 'digest'. 'str' may contain only the +// digest or be of the form ":". Returns 0 on success, or -1 on any error. int ParseSha1(const char* str, uint8_t* digest); -int applypatch(const char* source_filename, - const char* target_filename, - const char* target_sha1_str, - size_t target_size, - const std::vector& patch_sha1_str, - const std::vector>& patch_data, - const Value* bonus_data); -int applypatch_check(const char* filename, - const std::vector& patch_sha1_str); +// Applies binary patches to eMMC target 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 SHA-1 hash of 'target_filename' is 'target_sha1_string', does nothing and returns +// successfully. +// +// - Otherwise, if the SHA-1 hash of 'source_filename' is one of the entries in 'patch_sha1s', 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 data). If that new file has +// SHA-1 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' must refer to an eMMC partition to read the source data. See the comments for +// the LoadPartitionContents() function for the format of such a filename. 'target_size' has become +// obsolete since we have dropped the support for patching non-eMMC targets (eMMC targets have the +// size embedded in the filename). +int applypatch(const char* source_filename, const char* target_filename, + const char* target_sha1_str, size_t target_size, + const std::vector& patch_sha1s, + const std::vector>& patch_data, const Value* bonus_data); + +// Returns 0 if the contents of the file or the cached file match any of the given SHA-1's. Returns +// nonzero otherwise. +int applypatch_check(const char* filename, const std::vector& patch_sha1s); + +// Flashes a given image to the target partition. It verifies the target cheksum first, and will +// return if target already has the desired hash. Otherwise it checks the checksum of the given +// source image before flashing, and verifies the target partition afterwards. The function is +// idempotent. Returns zero on success. int applypatch_flash(const char* source_filename, const char* target_filename, const char* target_sha1_str, size_t target_size); +// Reads a file into memory; stores the file contents and associated metadata in *file. Returns 0 +// on success, or -1 on error. int LoadFileContents(const char* filename, FileContents* file); + +// Saves the given FileContents object to the given filename. Returns 0 on success, or -1 on error. int SaveFileContents(const char* filename, const FileContents* file); // bspatch.cpp @@ -79,9 +117,9 @@ int ApplyImagePatch(const unsigned char* old_data, size_t old_size, const Value& // freecache.cpp int MakeFreeSpaceOnCache(size_t bytes_needed); + // Removes the files in |dirname| until we have at least |bytes_needed| bytes of free space on // the partition. The size of the free space is returned by calling |space_checker|. bool RemoveFilesInDirectory(size_t bytes_needed, const std::string& dirname, const std::function& space_checker); - #endif -- cgit v1.2.3