am 340aa8cb: Merge "New command line tool \'idmap\'" (99188064) · Commits · e / os / android_frameworks_native

cmds/idmap/Android.mk

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		# Copyright (C) 2012 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.

		LOCAL_PATH:= $(call my-dir)
		include $(CLEAR_VARS)

		LOCAL_SRC_FILES := idmap.cpp create.cpp scan.cpp inspect.cpp

		LOCAL_SHARED_LIBRARIES := liblog libutils libandroidfw

		LOCAL_MODULE := idmap

		LOCAL_C_INCLUDES := external/zlib

		LOCAL_MODULE_TAGS := optional

		include $(BUILD_EXECUTABLE)

cmds/idmap/create.cpp

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		#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/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, (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 -= 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 < N) {
		// file is empty or corrupt
		return true;
		}

		char buf[N];
		ssize_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 -= 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, &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;
		}

cmds/idmap/idmap.cpp

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		#include "idmap.h"

		#include <private/android_filesystem_config.h> // for AID_SYSTEM

		#include <stdlib.h>
		#include <string.h>

		namespace {
		const char *usage = "NAME\n\
		idmap - create or display idmap files\n\
		\n\
		SYNOPSIS \n\
		idmap --help \n\
		idmap --fd target overlay fd \n\
		idmap --path target overlay idmap \n\
		idmap --scan dir-to-scan target-to-look-for target dir-to-hold-idmaps \n\
		idmap --inspect idmap \n\
		\n\
		DESCRIPTION \n\
		Idmap files play an integral part in the runtime resource overlay framework. An idmap \n\
		file contains a mapping of resource identifiers between overlay package and its target \n\
		package; this mapping is used during resource lookup. Idmap files also act as control \n\
		files by their existence: if not present, the corresponding overlay package is ignored \n\
		when the resource context is created. \n\
		\n\
		Idmap files are stored in /data/resource-cache. For each pair (target package, overlay \n\
		package), there exists exactly one idmap file, or none if the overlay should not be used. \n\
		\n\
		NOMENCLATURE \n\
		target: the original, non-overlay, package. Each target package may be associated with \n\
		any number of overlay packages. \n\
		\n\
		overlay: an overlay package. Each overlay package is associated with exactly one target \n\
		package, specified in the overlay's manifest using the <overlay target=\"...\"/> \n\
		tag. \n\
		\n\
		OPTIONS \n\
		--help: display this help \n\
		\n\
		--fd: create idmap for target package 'target' (path to apk) and overlay package 'overlay' \n\
		(path to apk); write results to file descriptor 'fd' (integer). This invocation \n\
		version is intended to be used by a parent process with higher privileges to call \n\
		idmap in a controlled way: the parent will open a suitable file descriptor, fork, \n\
		drop its privileges and exec. This tool will continue execution without the extra \n\
		privileges, but still have write access to a file it could not have opened on its \n\
		own. \n\
		\n\
		--path: create idmap for target package 'target' (path to apk) and overlay package \n\
		'overlay' (path to apk); write results to 'idmap' (path). \n\
		\n\
		--scan: non-recursively search directory 'dir-to-scan' (path) for overlay packages with \n\
		target package 'target-to-look-for' (package name) present at 'target' (path to \n\
		apk). For each overlay package found, create an idmap file in 'dir-to-hold-idmaps' \n\
		(path). \n\
		\n\
		--inspect: decode the binary format of 'idmap' (path) and display the contents in a \n\
		debug-friendly format. \n\
		\n\
		EXAMPLES \n\
		Create an idmap file: \n\
		\n\
		$ adb shell idmap --path /system/app/target.apk \\ \n\
		/vendor/overlay/overlay.apk \\ \n\
		/data/resource-cache/vendor@overlay@overlay.apk@idmap \n\
		\n\
		Display an idmap file: \n\
		\n\
		$ adb shell idmap --inspect /data/resource-cache/vendor@overlay@overlay.apk@idmap \n\
		SECTION ENTRY VALUE OFFSET COMMENT \n\
		IDMAP HEADER magic 0x706d6469 0x0 \n\
		base crc 0x484aa77f 0x1 \n\
		overlay crc 0x03c66fa5 0x2 \n\
		base path .......... 0x03-0x42 /system/app/target.apk \n\
		overlay path .......... 0x43-0x82 /vendor/overlay/overlay.apk \n\
		DATA HEADER types count 0x00000003 0x83 \n\
		padding 0x00000000 0x84 \n\
		type offset 0x00000004 0x85 absolute offset 0x87, xml \n\
		type offset 0x00000007 0x86 absolute offset 0x8a, string \n\
		DATA BLOCK entry count 0x00000001 0x87 \n\
		entry offset 0x00000000 0x88 \n\
		entry 0x7f020000 0x89 xml/integer \n\
		DATA BLOCK entry count 0x00000002 0x8a \n\
		entry offset 0x00000000 0x8b \n\
		entry 0x7f030000 0x8c string/str \n\
		entry 0x7f030001 0x8d string/str2 \n\
		\n\
		In this example, the overlay package provides three alternative resource values:\n\
		xml/integer, string/str and string/str2.\n\
		\n\
		NOTES \n\
		This tool and its expected invocation from installd is modelled on dexopt.";

		bool verify_directory_readable(const char *path)
		{
		return access(path, R_OK \| X_OK) == 0;
		}

		bool verify_directory_writable(const char *path)
		{
		return access(path, W_OK) == 0;
		}

		bool verify_file_readable(const char *path)
		{
		return access(path, R_OK) == 0;
		}

		bool verify_root_or_system()
		{
		uid_t uid = getuid();
		gid_t gid = getgid();

		return (uid == 0 && gid == 0) \|\| (uid == AID_SYSTEM && gid == AID_SYSTEM);
		}

		int maybe_create_fd(const char target_apk_path, const char overlay_apk_path,
		const char *idmap_str)
		{
		// anyone (not just root or system) may do --fd -- the file has
		// already been opened by someone else on our behalf

		char *endptr;
		int idmap_fd = strtol(idmap_str, &endptr, 10);
		if (*endptr != '\0') {
		fprintf(stderr, "error: failed to parse file descriptor argument %s\n", idmap_str);
		return -1;
		}

		if (!verify_file_readable(target_apk_path)) {
		ALOGD("error: failed to read apk %s: %s\n", target_apk_path, strerror(errno));
		return -1;
		}

		if (!verify_file_readable(overlay_apk_path)) {
		ALOGD("error: failed to read apk %s: %s\n", overlay_apk_path, strerror(errno));
		return -1;
		}

		return idmap_create_fd(target_apk_path, overlay_apk_path, idmap_fd);
		}

		int maybe_create_path(const char target_apk_path, const char overlay_apk_path,
		const char *idmap_path)
		{
		if (!verify_root_or_system()) {
		fprintf(stderr, "error: permission denied: not user root or user system\n");
		return -1;
		}

		if (!verify_file_readable(target_apk_path)) {
		ALOGD("error: failed to read apk %s: %s\n", target_apk_path, strerror(errno));
		return -1;
		}

		if (!verify_file_readable(overlay_apk_path)) {
		ALOGD("error: failed to read apk %s: %s\n", overlay_apk_path, strerror(errno));
		return -1;
		}

		return idmap_create_path(target_apk_path, overlay_apk_path, idmap_path);
		}

		int maybe_scan(const char overlay_dir, const char target_package_name,
		const char target_apk_path, const char idmap_dir)
		{
		if (!verify_root_or_system()) {
		fprintf(stderr, "error: permission denied: not user root or user system\n");
		return -1;
		}

		if (!verify_directory_readable(overlay_dir)) {
		ALOGD("error: no read access to %s: %s\n", overlay_dir, strerror(errno));
		return -1;
		}

		if (!verify_file_readable(target_apk_path)) {
		ALOGD("error: failed to read apk %s: %s\n", target_apk_path, strerror(errno));
		return -1;
		}

		if (!verify_directory_writable(idmap_dir)) {
		ALOGD("error: no write access to %s: %s\n", idmap_dir, strerror(errno));
		return -1;
		}

		return idmap_scan(overlay_dir, target_package_name, target_apk_path, idmap_dir);
		}

		int maybe_inspect(const char *idmap_path)
		{
		// anyone (not just root or system) may do --inspect
		if (!verify_file_readable(idmap_path)) {
		ALOGD("error: failed to read idmap %s: %s\n", idmap_path, strerror(errno));
		return -1;
		}
		return idmap_inspect(idmap_path);
		}
		}

		int main(int argc, char **argv)
		{
		#if 0
		{
		char buf[1024];
		buf[0] = '\0';
		for (int i = 0; i < argc; ++i) {
		strncat(buf, argv[i], sizeof(buf) - 1);
		strncat(buf, " ", sizeof(buf) - 1);
		}
		ALOGD("%s:%d: uid=%d gid=%d argv=%s\n", __FILE__, __LINE__, getuid(), getgid(), buf);
		}
		#endif

		if (argc == 2 && !strcmp(argv[1], "--help")) {
		printf("%s\n", usage);
		return 0;
		}

		if (argc == 5 && !strcmp(argv[1], "--fd")) {
		return maybe_create_fd(argv[2], argv[3], argv[4]);
		}

		if (argc == 5 && !strcmp(argv[1], "--path")) {
		return maybe_create_path(argv[2], argv[3], argv[4]);
		}

		if (argc == 6 && !strcmp(argv[1], "--scan")) {
		return maybe_scan(argv[2], argv[3], argv[4], argv[5]);
		}

		if (argc == 3 && !strcmp(argv[1], "--inspect")) {
		return maybe_inspect(argv[2]);
		}

		fprintf(stderr, "Usage: don't use this (cf dexopt usage).\n");
		return EXIT_FAILURE;
		}

cmds/idmap/idmap.h

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		#ifndef _IDMAP_H_
		#define _IDMAP_H_

		#define LOG_TAG "idmap"

		#include <utils/Log.h>

		#include <errno.h>
		#include <stdio.h>

		#ifndef TEMP_FAILURE_RETRY
		// Used to retry syscalls that can return EINTR.
		#define TEMP_FAILURE_RETRY(exp) ({ \
		typeof (exp) _rc; \
		do { \
		_rc = (exp); \
		} while (_rc == -1 && errno == EINTR); \
		_rc; })
		#endif

		int idmap_create_path(const char target_apk_path, const char overlay_apk_path,
		const char *idmap_path);

		int idmap_create_fd(const char target_apk_path, const char overlay_apk_path, int fd);

		// Regarding target_package_name: the idmap_scan implementation should
		// be able to extract this from the manifest in target_apk_path,
		// simplifying the external API.
		int idmap_scan(const char overlay_dir, const char target_package_name,
		const char target_apk_path, const char idmap_dir);

		int idmap_inspect(const char *idmap_path);

		#endif // _IDMAP_H_

cmds/idmap/inspect.cpp

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