gecko-dev/mozglue/linker/Mappable.cpp

299 lines
9.2 KiB
C++

/* 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 "Mappable.h"
#ifdef ANDROID
#include <linux/ashmem.h>
#endif
#include "ElfLoader.h"
#include "Logging.h"
#ifndef PAGE_SIZE
#define PAGE_SIZE 4096
#endif
#ifndef PAGE_MASK
#define PAGE_MASK (~ (PAGE_SIZE - 1))
#endif
MappableFile *MappableFile::Create(const char *path)
{
int fd = open(path, O_RDONLY);
if (fd != -1)
return new MappableFile(fd);
return NULL;
}
void *
MappableFile::mmap(const void *addr, size_t length, int prot, int flags,
off_t offset)
{
// ASSERT(fd != -1)
// ASSERT(! flags & MAP_SHARED)
flags |= MAP_PRIVATE;
void *mapped = ::mmap(const_cast<void *>(addr), length, prot, flags,
fd, offset);
if (mapped == MAP_FAILED)
return mapped;
/* Fill the remainder of the last page with zeroes when the requested
* protection has write bits. */
if ((mapped != MAP_FAILED) && (prot & PROT_WRITE) &&
(length & (PAGE_SIZE - 1))) {
memset(reinterpret_cast<char *>(mapped) + length, 0,
PAGE_SIZE - (length & ~(PAGE_MASK)));
}
return mapped;
}
void
MappableFile::finalize()
{
/* Close file ; equivalent to close(fd.forget()) */
fd = -1;
}
MappableExtractFile *
MappableExtractFile::Create(const char *name, Zip::Stream *stream)
{
const char *cachePath = getenv("MOZ_LINKER_CACHE");
if (!cachePath || !*cachePath) {
log("Warning: MOZ_LINKER_EXTRACT is set, but not MOZ_LINKER_CACHE; "
"not extracting");
return NULL;
}
AutoDeleteArray<char> path = new char[strlen(cachePath) + strlen(name) + 2];
sprintf(path, "%s/%s", cachePath, name);
debug("Extracting to %s", (char *)path);
AutoCloseFD fd = open(path, O_TRUNC | O_RDWR | O_CREAT | O_NOATIME,
S_IRUSR | S_IWUSR);
if (fd == -1) {
log("Couldn't open %s to decompress library", path.get());
return NULL;
}
AutoUnlinkFile file = path.forget();
if (ftruncate(fd, stream->GetUncompressedSize()) == -1) {
log("Couldn't ftruncate %s to decompress library", file.get());
return NULL;
}
/* Map the temporary file for use as inflate buffer */
MappedPtr buffer(::mmap(NULL, stream->GetUncompressedSize(), PROT_WRITE,
MAP_SHARED, fd, 0), stream->GetUncompressedSize());
if (buffer == MAP_FAILED) {
log("Couldn't map %s to decompress library", file.get());
return NULL;
}
z_stream zStream = stream->GetZStream(buffer);
/* Decompress */
if (inflateInit2(&zStream, -MAX_WBITS) != Z_OK) {
log("inflateInit failed: %s", zStream.msg);
return NULL;
}
if (inflate(&zStream, Z_FINISH) != Z_STREAM_END) {
log("inflate failed: %s", zStream.msg);
return NULL;
}
if (inflateEnd(&zStream) != Z_OK) {
log("inflateEnd failed: %s", zStream.msg);
return NULL;
}
if (zStream.total_out != stream->GetUncompressedSize()) {
log("File not fully uncompressed! %ld / %d", zStream.total_out,
static_cast<unsigned int>(stream->GetUncompressedSize()));
return NULL;
}
return new MappableExtractFile(fd.forget(), file.forget());
}
MappableExtractFile::~MappableExtractFile()
{
/* When destroying from a forked process, we don't want the file to be
* removed, as the main process is still using the file. Although it
* doesn't really matter, it helps e.g. valgrind that the file is there.
* The string still needs to be delete[]d, though */
if (pid != getpid())
delete [] path.forget();
}
/**
* _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;
#ifdef ANDROID
/* On Android, initialize an ashmem region with the given length */
fd = open("/" ASHMEM_NAME_DEF, O_RDWR, 0600);
if (fd == -1)
return NULL;
char str[ASHMEM_NAME_LEN];
strlcpy(str, name, sizeof(str));
ioctl(fd, ASHMEM_SET_NAME, str);
if (ioctl(fd, ASHMEM_SET_SIZE, length))
return NULL;
/* The Gecko crash reporter is confused by adjacent memory mappings of
* the same file. On Android, subsequent mappings are growing in memory
* address, and chances are we're going to map from the same file
* descriptor right away. Allocate one page more than requested so that
* there is a gap between this mapping and the subsequent one. */
void *buf = ::mmap(NULL, length + PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (buf != MAP_FAILED) {
/* Actually create the gap with anonymous memory */
::mmap(reinterpret_cast<char *>(buf) + ((length + PAGE_SIZE) & PAGE_MASK),
PAGE_SIZE, PROT_NONE, MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
-1, 0);
debug("Decompression buffer of size %d in ashmem \"%s\", mapped @%p",
length, str, buf);
return new _MappableBuffer(fd.forget(), buf, length);
}
#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 NULL;
unlink(path);
ftruncate(fd, length);
void *buf = ::mmap(NULL, length, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (buf != MAP_FAILED) {
debug("Decompression buffer of size %ld in \"%s\", mapped @%p",
length, path, buf);
return new _MappableBuffer(fd.forget(), buf, length);
}
#endif
return NULL;
}
void *mmap(const void *addr, size_t length, int prot, int flags, off_t offset)
{
// 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);
}
#ifdef ANDROID
~_MappableBuffer() {
/* Free the additional page we allocated. See _MappableBuffer::Create */
munmap(this + ((GetLength() + PAGE_SIZE) & ~(PAGE_SIZE - 1)), PAGE_SIZE);
}
#endif
private:
_MappableBuffer(int fd, void *buf, size_t length)
: MappedPtr(buf, length), fd(fd) { }
/* File descriptor for the temporary file or ashmem */
AutoCloseFD fd;
};
MappableDeflate *
MappableDeflate::Create(const char *name, Zip *zip, Zip::Stream *stream)
{
// ASSERT(stream->GetType() == Zip::Stream::DEFLATE)
_MappableBuffer *buf = _MappableBuffer::Create(name, stream->GetUncompressedSize());
if (buf)
return new MappableDeflate(buf, zip, stream);
return NULL;
}
MappableDeflate::MappableDeflate(_MappableBuffer *buf, Zip *zip,
Zip::Stream *stream)
: zip(zip), buffer(buf), zStream(stream->GetZStream(*buf)) { }
MappableDeflate::~MappableDeflate() { }
void *
MappableDeflate::mmap(const void *addr, size_t length, int prot, int flags, off_t offset)
{
// ASSERT(buffer)
// 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)) {
log("inflateInit failed: %s", zStream.msg);
return MAP_FAILED;
}
int ret = inflate(&zStream, Z_SYNC_FLUSH);
if (ret < 0) {
log("inflate failed: %s", zStream.msg);
return MAP_FAILED;
}
if (ret == Z_NEED_DICT) {
log("zstream requires a dictionary. %s", zStream.msg);
return MAP_FAILED;
}
zStream.avail_out = avail_out - missing + zStream.avail_out;
if (ret == Z_STREAM_END) {
if (inflateEnd(&zStream) != Z_OK) {
log("inflateEnd failed: %s", zStream.msg);
return MAP_FAILED;
}
if (zStream.total_out != buffer->GetLength()) {
log("File not fully uncompressed! %ld / %d", zStream.total_out,
static_cast<unsigned int>(buffer->GetLength()));
return MAP_FAILED;
}
}
}
#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("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 buffer->mmap(addr, length, prot, flags, offset);
}
void
MappableDeflate::finalize()
{
/* Free decompression buffer */
buffer = NULL;
/* Remove reference to Zip archive */
zip = NULL;
}