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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <string>
#include "Mappable.h"
#include "mozilla/IntegerPrintfMacros.h"
#include "mozilla/UniquePtr.h"
#ifdef ANDROID
# include "mozilla/Ashmem.h"
#endif
#include <sys/stat.h>
#include <errno.h>
#include "ElfLoader.h"
#include "XZStream.h"
#include "Logging.h"
using mozilla::MakeUnique;
using mozilla::UniquePtr;
class CacheValidator {
public:
CacheValidator(const char* aCachedLibPath, Zip* aZip, Zip::Stream* aStream)
: mCachedLibPath(aCachedLibPath) {
static const char kChecksumSuffix[] = ".crc";
mCachedChecksumPath =
MakeUnique<char[]>(strlen(aCachedLibPath) + sizeof(kChecksumSuffix));
sprintf(mCachedChecksumPath.get(), "%s%s", aCachedLibPath, kChecksumSuffix);
DEBUG_LOG("mCachedChecksumPath: %s", mCachedChecksumPath.get());
mChecksum = aStream->GetCRC32();
DEBUG_LOG("mChecksum: %x", mChecksum);
}
// Returns whether the cache is valid and up-to-date.
bool IsValid() const {
// Validate based on checksum.
RefPtr<Mappable> checksumMap =
MappableFile::Create(mCachedChecksumPath.get());
if (!checksumMap) {
// Force caching if checksum is missing in cache.
return false;
}
DEBUG_LOG("Comparing %x with %s", mChecksum, mCachedChecksumPath.get());
MappedPtr checksumBuf = checksumMap->mmap(nullptr, checksumMap->GetLength(),
PROT_READ, MAP_PRIVATE, 0);
if (checksumBuf == MAP_FAILED) {
WARN("Couldn't map %s to validate checksum", mCachedChecksumPath.get());
return false;
}
if (memcmp(checksumBuf, &mChecksum, sizeof(mChecksum))) {
return false;
}
return !access(mCachedLibPath.c_str(), R_OK);
}
// Caches the APK-provided checksum used in future cache validations.
void CacheChecksum() const {
AutoCloseFD fd(open(mCachedChecksumPath.get(),
O_TRUNC | O_RDWR | O_CREAT | O_NOATIME,
S_IRUSR | S_IWUSR));
if (fd == -1) {
WARN("Couldn't open %s to update checksum", mCachedChecksumPath.get());
return;
}
DEBUG_LOG("Updating checksum %s", mCachedChecksumPath.get());
const size_t size = sizeof(mChecksum);
size_t written = 0;
while (written < size) {
ssize_t ret =
write(fd, reinterpret_cast<const uint8_t*>(&mChecksum) + written,
size - written);
if (ret >= 0) {
written += ret;
} else if (errno != EINTR) {
WARN("Writing checksum %s failed with errno %d",
mCachedChecksumPath.get(), errno);
break;
}
}
}
private:
const std::string mCachedLibPath;
UniquePtr<char[]> mCachedChecksumPath;
uint32_t mChecksum;
};
Mappable* MappableFile::Create(const char* path) {
int fd = open(path, O_RDONLY);
if (fd != -1) return new MappableFile(fd);
return nullptr;
}
MemoryRange MappableFile::mmap(const void* addr, size_t length, int prot,
int flags, off_t offset) {
MOZ_ASSERT(fd != -1);
MOZ_ASSERT(!(flags & MAP_SHARED));
flags |= MAP_PRIVATE;
return MemoryRange::mmap(const_cast<void*>(addr), length, prot, flags, fd,
offset);
}
void MappableFile::finalize() {
/* Close file ; equivalent to close(fd.forget()) */
fd = -1;
}
size_t MappableFile::GetLength() const {
struct stat st;
return fstat(fd, &st) ? 0 : st.st_size;
}
Mappable* MappableExtractFile::Create(const char* name, Zip* zip,
Zip::Stream* stream) {
MOZ_ASSERT(zip && stream);
const char* cachePath = getenv("MOZ_LINKER_CACHE");
if (!cachePath || !*cachePath) {
WARN(
"MOZ_LINKER_EXTRACT is set, but not MOZ_LINKER_CACHE; "
"not extracting");
return nullptr;
}
// Ensure that the cache dir is private.
chmod(cachePath, 0770);
UniquePtr<char[]> path =
MakeUnique<char[]>(strlen(cachePath) + strlen(name) + 2);
sprintf(path.get(), "%s/%s", cachePath, name);
CacheValidator validator(path.get(), zip, stream);
if (validator.IsValid()) {
DEBUG_LOG("Reusing %s", static_cast<char*>(path.get()));
return MappableFile::Create(path.get());
}
DEBUG_LOG("Extracting to %s", static_cast<char*>(path.get()));
AutoCloseFD fd;
fd = open(path.get(), O_TRUNC | O_RDWR | O_CREAT | O_NOATIME,
S_IRUSR | S_IWUSR);
if (fd == -1) {
ERROR("Couldn't open %s to decompress library", path.get());
return nullptr;
}
AutoUnlinkFile file(path.release());
if (stream->GetType() == Zip::Stream::DEFLATE) {
if (ftruncate(fd, stream->GetUncompressedSize()) == -1) {
ERROR("Couldn't ftruncate %s to decompress library", file.get());
return nullptr;
}
/* Map the temporary file for use as inflate buffer */
MappedPtr buffer(MemoryRange::mmap(nullptr, stream->GetUncompressedSize(),
PROT_WRITE, MAP_SHARED, fd, 0));
if (buffer == MAP_FAILED) {
ERROR("Couldn't map %s to decompress library", file.get());
return nullptr;
}
z_stream zStream = stream->GetZStream(buffer);
/* Decompress */
if (inflateInit2(&zStream, -MAX_WBITS) != Z_OK) {
ERROR("inflateInit failed: %s", zStream.msg);
return nullptr;
}
if (inflate(&zStream, Z_FINISH) != Z_STREAM_END) {
ERROR("inflate failed: %s", zStream.msg);
return nullptr;
}
if (inflateEnd(&zStream) != Z_OK) {
ERROR("inflateEnd failed: %s", zStream.msg);
return nullptr;
}
if (zStream.total_out != stream->GetUncompressedSize()) {
ERROR("File not fully uncompressed! %ld / %d", zStream.total_out,
static_cast<unsigned int>(stream->GetUncompressedSize()));
return nullptr;
}
} else if (XZStream::IsXZ(stream->GetBuffer(), stream->GetSize())) {
XZStream xzStream(stream->GetBuffer(), stream->GetSize());
if (!xzStream.Init()) {
ERROR("Couldn't initialize XZ decoder");
return nullptr;
}
DEBUG_LOG("XZStream created, compressed=%" PRIuPTR
", uncompressed=%" PRIuPTR,
xzStream.Size(), xzStream.UncompressedSize());
if (ftruncate(fd, xzStream.UncompressedSize()) == -1) {
ERROR("Couldn't ftruncate %s to decompress library", file.get());
return nullptr;
}
MappedPtr buffer(MemoryRange::mmap(nullptr, xzStream.UncompressedSize(),
PROT_WRITE, MAP_SHARED, fd, 0));
if (buffer == MAP_FAILED) {
ERROR("Couldn't map %s to decompress library", file.get());
return nullptr;
}
const size_t written = xzStream.Decode(buffer, buffer.GetLength());
DEBUG_LOG("XZStream decoded %" PRIuPTR, written);
if (written != buffer.GetLength()) {
ERROR("Error decoding XZ file %s", file.get());
return nullptr;
}
} else {
return nullptr;
}
validator.CacheChecksum();
return new MappableExtractFile(fd.forget(), file.release());
}
/**
* _MappableBuffer is a buffer which content can be mapped at different
* locations in the virtual address space.
* On Linux, uses a (deleted) temporary file on a tmpfs for sharable content.
* On Android, uses ashmem.
*/
class _MappableBuffer : public MappedPtr {
public:
/**
* Returns a _MappableBuffer instance with the given name and the given
* length.
*/
static _MappableBuffer* Create(const char* name, size_t length) {
AutoCloseFD fd;
const char* ident;
#ifdef ANDROID
/* On Android, initialize an ashmem region with the given length */
fd = mozilla::android::ashmem_create(name, length);
ident = name;
#else
/* On Linux, use /dev/shm as base directory for temporary files, assuming
* it's on tmpfs */
/* TODO: check that /dev/shm is tmpfs */
char path[256];
sprintf(path, "/dev/shm/%s.XXXXXX", name);
fd = mkstemp(path);
if (fd == -1) return nullptr;
unlink(path);
ftruncate(fd, length);
ident = path;
#endif
void* buf =
::mmap(nullptr, length, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (buf != MAP_FAILED) {
DEBUG_LOG("Decompression buffer of size 0x%" PRIxPTR
" in "
#ifdef ANDROID
"ashmem "
#endif
"\"%s\", mapped @%p",
length, ident, buf);
return new _MappableBuffer(fd.forget(), buf, length);
}
return nullptr;
}
void* mmap(const void* addr, size_t length, int prot, int flags,
off_t offset) {
MOZ_ASSERT(fd != -1);
#ifdef ANDROID
/* Mapping ashmem MAP_PRIVATE is like mapping anonymous memory, even when
* there is content in the ashmem */
if (flags & MAP_PRIVATE) {
flags &= ~MAP_PRIVATE;
flags |= MAP_SHARED;
}
#endif
return ::mmap(const_cast<void*>(addr), length, prot, flags, fd, offset);
}
private:
_MappableBuffer(int fd, void* buf, size_t length)
: MappedPtr(buf, length), fd(fd) {}
/* File descriptor for the temporary file or ashmem */
AutoCloseFD fd;
};
Mappable* MappableDeflate::Create(const char* name, Zip* zip,
Zip::Stream* stream) {
MOZ_ASSERT(stream->GetType() == Zip::Stream::DEFLATE);
_MappableBuffer* buf =
_MappableBuffer::Create(name, stream->GetUncompressedSize());
if (buf) return new MappableDeflate(buf, zip, stream);
return nullptr;
}
MappableDeflate::MappableDeflate(_MappableBuffer* buf, Zip* zip,
Zip::Stream* stream)
: zip(zip), buffer(buf), zStream(stream->GetZStream(*buf)) {}
MappableDeflate::~MappableDeflate() {}
MemoryRange MappableDeflate::mmap(const void* addr, size_t length, int prot,
int flags, off_t offset) {
MOZ_ASSERT(buffer);
MOZ_ASSERT(!(flags & MAP_SHARED));
flags |= MAP_PRIVATE;
/* The deflate stream is uncompressed up to the required offset + length, if
* it hasn't previously been uncompressed */
ssize_t missing = offset + length + zStream.avail_out - buffer->GetLength();
if (missing > 0) {
uInt avail_out = zStream.avail_out;
zStream.avail_out = missing;
if ((*buffer == zStream.next_out) &&
(inflateInit2(&zStream, -MAX_WBITS) != Z_OK)) {
ERROR("inflateInit failed: %s", zStream.msg);
return MemoryRange(MAP_FAILED, 0);
}
int ret = inflate(&zStream, Z_SYNC_FLUSH);
if (ret < 0) {
ERROR("inflate failed: %s", zStream.msg);
return MemoryRange(MAP_FAILED, 0);
}
if (ret == Z_NEED_DICT) {
ERROR("zstream requires a dictionary. %s", zStream.msg);
return MemoryRange(MAP_FAILED, 0);
}
zStream.avail_out = avail_out - missing + zStream.avail_out;
if (ret == Z_STREAM_END) {
if (inflateEnd(&zStream) != Z_OK) {
ERROR("inflateEnd failed: %s", zStream.msg);
return MemoryRange(MAP_FAILED, 0);
}
if (zStream.total_out != buffer->GetLength()) {
ERROR("File not fully uncompressed! %ld / %d", zStream.total_out,
static_cast<unsigned int>(buffer->GetLength()));
return MemoryRange(MAP_FAILED, 0);
}
}
}
#if defined(ANDROID) && defined(__arm__)
if (prot & PROT_EXEC) {
/* We just extracted data that may be executed in the future.
* We thus need to ensure Instruction and Data cache coherency. */
DEBUG_LOG("cacheflush(%p, %p)", *buffer + offset,
*buffer + (offset + length));
cacheflush(reinterpret_cast<uintptr_t>(*buffer + offset),
reinterpret_cast<uintptr_t>(*buffer + (offset + length)), 0);
}
#endif
return MemoryRange(buffer->mmap(addr, length, prot, flags, offset), length);
}
void MappableDeflate::finalize() {
/* Free zlib internal buffers */
inflateEnd(&zStream);
/* Free decompression buffer */
buffer = nullptr;
/* Remove reference to Zip archive */
zip = nullptr;
}
size_t MappableDeflate::GetLength() const { return buffer->GetLength(); }