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#include "idmap.h"
#include <memory>
#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)
{
std::unique_ptr<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, 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)) != 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, 0, SEEK_SET) < 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, 0, SEEK_SET) < 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;
}
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