| #include "idmap.h" |
| |
| #include <UniquePtr.h> |
| #include <androidfw/AssetManager.h> |
| #include <androidfw/ResourceTypes.h> |
| #include <androidfw/ZipFileRO.h> |
| #include <utils/String8.h> |
| |
| #include <fcntl.h> |
| #include <sys/file.h> |
| #include <sys/stat.h> |
| |
| using namespace android; |
| |
| namespace { |
| int get_zip_entry_crc(const char *zip_path, const char *entry_name, uint32_t *crc) |
| { |
| UniquePtr<ZipFileRO> zip(ZipFileRO::open(zip_path)); |
| if (zip.get() == NULL) { |
| return -1; |
| } |
| ZipEntryRO entry = zip->findEntryByName(entry_name); |
| if (entry == NULL) { |
| return -1; |
| } |
| if (!zip->getEntryInfo(entry, NULL, NULL, NULL, NULL, NULL, reinterpret_cast<long*>(crc))) { |
| return -1; |
| } |
| zip->releaseEntry(entry); |
| return 0; |
| } |
| |
| int open_idmap(const char *path) |
| { |
| int fd = TEMP_FAILURE_RETRY(open(path, O_WRONLY | O_CREAT | O_TRUNC, 0644)); |
| if (fd == -1) { |
| ALOGD("error: open %s: %s\n", path, strerror(errno)); |
| goto fail; |
| } |
| if (fchmod(fd, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH) < 0) { |
| ALOGD("error: fchmod %s: %s\n", path, strerror(errno)); |
| goto fail; |
| } |
| if (TEMP_FAILURE_RETRY(flock(fd, LOCK_EX | LOCK_NB)) != 0) { |
| ALOGD("error: flock %s: %s\n", path, strerror(errno)); |
| goto fail; |
| } |
| |
| return fd; |
| fail: |
| if (fd != -1) { |
| close(fd); |
| unlink(path); |
| } |
| return -1; |
| } |
| |
| int write_idmap(int fd, const uint32_t *data, size_t size) |
| { |
| if (lseek(fd, SEEK_SET, 0) < 0) { |
| return -1; |
| } |
| size_t bytesLeft = size; |
| while (bytesLeft > 0) { |
| ssize_t w = TEMP_FAILURE_RETRY(write(fd, data + size - bytesLeft, bytesLeft)); |
| if (w < 0) { |
| fprintf(stderr, "error: write: %s\n", strerror(errno)); |
| return -1; |
| } |
| bytesLeft -= static_cast<size_t>(w); |
| } |
| return 0; |
| } |
| |
| bool is_idmap_stale_fd(const char *target_apk_path, const char *overlay_apk_path, int idmap_fd) |
| { |
| static const size_t N = ResTable::IDMAP_HEADER_SIZE_BYTES; |
| struct stat st; |
| if (fstat(idmap_fd, &st) == -1) { |
| return true; |
| } |
| if (st.st_size < static_cast<off_t>(N)) { |
| // file is empty or corrupt |
| return true; |
| } |
| |
| char buf[N]; |
| size_t bytesLeft = N; |
| if (lseek(idmap_fd, SEEK_SET, 0) < 0) { |
| return true; |
| } |
| for (;;) { |
| ssize_t r = TEMP_FAILURE_RETRY(read(idmap_fd, buf + N - bytesLeft, bytesLeft)); |
| if (r < 0) { |
| return true; |
| } |
| bytesLeft -= static_cast<size_t>(r); |
| if (bytesLeft == 0) { |
| break; |
| } |
| if (r == 0) { |
| // "shouldn't happen" |
| return true; |
| } |
| } |
| |
| uint32_t cached_target_crc, cached_overlay_crc; |
| String8 cached_target_path, cached_overlay_path; |
| if (!ResTable::getIdmapInfo(buf, N, NULL, &cached_target_crc, &cached_overlay_crc, |
| &cached_target_path, &cached_overlay_path)) { |
| return true; |
| } |
| |
| if (cached_target_path != target_apk_path) { |
| return true; |
| } |
| if (cached_overlay_path != overlay_apk_path) { |
| return true; |
| } |
| |
| uint32_t actual_target_crc, actual_overlay_crc; |
| if (get_zip_entry_crc(target_apk_path, AssetManager::RESOURCES_FILENAME, |
| &actual_target_crc) == -1) { |
| return true; |
| } |
| if (get_zip_entry_crc(overlay_apk_path, AssetManager::RESOURCES_FILENAME, |
| &actual_overlay_crc) == -1) { |
| return true; |
| } |
| |
| return cached_target_crc != actual_target_crc || cached_overlay_crc != actual_overlay_crc; |
| } |
| |
| bool is_idmap_stale_path(const char *target_apk_path, const char *overlay_apk_path, |
| const char *idmap_path) |
| { |
| struct stat st; |
| if (stat(idmap_path, &st) == -1) { |
| // non-existing idmap is always stale; on other errors, abort idmap generation |
| return errno == ENOENT; |
| } |
| |
| int idmap_fd = TEMP_FAILURE_RETRY(open(idmap_path, O_RDONLY)); |
| if (idmap_fd == -1) { |
| return false; |
| } |
| bool is_stale = is_idmap_stale_fd(target_apk_path, overlay_apk_path, idmap_fd); |
| close(idmap_fd); |
| return is_stale; |
| } |
| |
| int create_idmap(const char *target_apk_path, const char *overlay_apk_path, |
| uint32_t **data, size_t *size) |
| { |
| uint32_t target_crc, overlay_crc; |
| if (get_zip_entry_crc(target_apk_path, AssetManager::RESOURCES_FILENAME, |
| &target_crc) == -1) { |
| return -1; |
| } |
| if (get_zip_entry_crc(overlay_apk_path, AssetManager::RESOURCES_FILENAME, |
| &overlay_crc) == -1) { |
| return -1; |
| } |
| |
| AssetManager am; |
| bool b = am.createIdmap(target_apk_path, overlay_apk_path, target_crc, overlay_crc, |
| data, size); |
| return b ? 0 : -1; |
| } |
| |
| int create_and_write_idmap(const char *target_apk_path, const char *overlay_apk_path, |
| int fd, bool check_if_stale) |
| { |
| if (check_if_stale) { |
| if (!is_idmap_stale_fd(target_apk_path, overlay_apk_path, fd)) { |
| // already up to date -- nothing to do |
| return 0; |
| } |
| } |
| |
| uint32_t *data = NULL; |
| size_t size; |
| |
| if (create_idmap(target_apk_path, overlay_apk_path, &data, &size) == -1) { |
| return -1; |
| } |
| |
| if (write_idmap(fd, data, size) == -1) { |
| free(data); |
| return -1; |
| } |
| |
| free(data); |
| return 0; |
| } |
| } |
| |
| int idmap_create_path(const char *target_apk_path, const char *overlay_apk_path, |
| const char *idmap_path) |
| { |
| if (!is_idmap_stale_path(target_apk_path, overlay_apk_path, idmap_path)) { |
| // already up to date -- nothing to do |
| return EXIT_SUCCESS; |
| } |
| |
| int fd = open_idmap(idmap_path); |
| if (fd == -1) { |
| return EXIT_FAILURE; |
| } |
| |
| int r = create_and_write_idmap(target_apk_path, overlay_apk_path, fd, false); |
| close(fd); |
| if (r != 0) { |
| unlink(idmap_path); |
| } |
| return r == 0 ? EXIT_SUCCESS : EXIT_FAILURE; |
| } |
| |
| int idmap_create_fd(const char *target_apk_path, const char *overlay_apk_path, int fd) |
| { |
| return create_and_write_idmap(target_apk_path, overlay_apk_path, fd, true) == 0 ? |
| EXIT_SUCCESS : EXIT_FAILURE; |
| } |