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// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/memory/shared_memory_handle.h"
#include <mach/mach_vm.h>
#include <stddef.h>
#include <sys/mman.h>
#include <unistd.h>
#include "base/mac/mac_util.h"
#include "base/mac/mach_logging.h"
#include "base/posix/eintr_wrapper.h"
namespace base {
SharedMemoryHandle::SharedMemoryHandle()
: type_(MACH), memory_object_(MACH_PORT_NULL) {}
SharedMemoryHandle::SharedMemoryHandle(
const base::FileDescriptor& file_descriptor)
: type_(POSIX), file_descriptor_(file_descriptor) {}
SharedMemoryHandle::SharedMemoryHandle(mach_vm_size_t size) {
type_ = MACH;
mach_port_t named_right;
kern_return_t kr = mach_make_memory_entry_64(
mach_task_self(),
&size,
0, // Address.
MAP_MEM_NAMED_CREATE | VM_PROT_READ | VM_PROT_WRITE,
&named_right,
MACH_PORT_NULL); // Parent handle.
if (kr != KERN_SUCCESS) {
memory_object_ = MACH_PORT_NULL;
return;
}
memory_object_ = named_right;
size_ = size;
pid_ = GetCurrentProcId();
ownership_passes_to_ipc_ = false;
}
SharedMemoryHandle::SharedMemoryHandle(mach_port_t memory_object,
mach_vm_size_t size,
base::ProcessId pid)
: type_(MACH),
memory_object_(memory_object),
size_(size),
pid_(pid),
ownership_passes_to_ipc_(false) {}
SharedMemoryHandle::SharedMemoryHandle(const SharedMemoryHandle& handle) {
CopyRelevantData(handle);
}
SharedMemoryHandle& SharedMemoryHandle::operator=(
const SharedMemoryHandle& handle) {
if (this == &handle)
return *this;
type_ = handle.type_;
CopyRelevantData(handle);
return *this;
}
SharedMemoryHandle SharedMemoryHandle::Duplicate() const {
switch (type_) {
case POSIX: {
if (!IsValid())
return SharedMemoryHandle();
int duped_fd = HANDLE_EINTR(dup(file_descriptor_.fd));
if (duped_fd < 0)
return SharedMemoryHandle();
return SharedMemoryHandle(FileDescriptor(duped_fd, true));
}
case MACH: {
if (!IsValid())
return SharedMemoryHandle(MACH_PORT_NULL, 0, 0);
// Increment the ref count.
kern_return_t kr = mach_port_mod_refs(mach_task_self(), memory_object_,
MACH_PORT_RIGHT_SEND, 1);
DCHECK_EQ(kr, KERN_SUCCESS);
SharedMemoryHandle handle(*this);
handle.SetOwnershipPassesToIPC(true);
return handle;
}
}
}
bool SharedMemoryHandle::operator==(const SharedMemoryHandle& handle) const {
if (!IsValid() && !handle.IsValid())
return true;
if (type_ != handle.type_)
return false;
switch (type_) {
case POSIX:
return file_descriptor_.fd == handle.file_descriptor_.fd;
case MACH:
return memory_object_ == handle.memory_object_ && size_ == handle.size_ &&
pid_ == handle.pid_;
}
}
bool SharedMemoryHandle::operator!=(const SharedMemoryHandle& handle) const {
return !(*this == handle);
}
bool SharedMemoryHandle::IsValid() const {
switch (type_) {
case POSIX:
return file_descriptor_.fd >= 0;
case MACH:
return memory_object_ != MACH_PORT_NULL;
}
}
mach_port_t SharedMemoryHandle::GetMemoryObject() const {
DCHECK_EQ(type_, MACH);
return memory_object_;
}
bool SharedMemoryHandle::GetSize(size_t* size) const {
if (!IsValid()) {
*size = 0;
return true;
}
switch (type_) {
case SharedMemoryHandle::POSIX:
struct stat st;
if (fstat(file_descriptor_.fd, &st) != 0)
return false;
if (st.st_size < 0)
return false;
*size = st.st_size;
return true;
case SharedMemoryHandle::MACH:
*size = size_;
return true;
}
}
bool SharedMemoryHandle::MapAt(off_t offset,
size_t bytes,
void** memory,
bool read_only) {
DCHECK(IsValid());
switch (type_) {
case SharedMemoryHandle::POSIX:
*memory = mmap(nullptr, bytes, PROT_READ | (read_only ? 0 : PROT_WRITE),
MAP_SHARED, file_descriptor_.fd, offset);
return *memory != MAP_FAILED;
case SharedMemoryHandle::MACH:
DCHECK_EQ(pid_, GetCurrentProcId());
kern_return_t kr = mach_vm_map(
mach_task_self(),
reinterpret_cast<mach_vm_address_t*>(memory), // Output parameter
bytes,
0, // Alignment mask
VM_FLAGS_ANYWHERE,
memory_object_,
offset,
FALSE, // Copy
VM_PROT_READ | (read_only ? 0 : VM_PROT_WRITE), // Current protection
VM_PROT_WRITE | VM_PROT_READ | VM_PROT_IS_MASK, // Maximum protection
VM_INHERIT_NONE);
return kr == KERN_SUCCESS;
}
}
void SharedMemoryHandle::Close() const {
if (!IsValid())
return;
switch (type_) {
case POSIX:
if (IGNORE_EINTR(close(file_descriptor_.fd)) < 0)
DPLOG(ERROR) << "Error closing fd";
break;
case MACH:
kern_return_t kr = mach_port_deallocate(mach_task_self(), memory_object_);
if (kr != KERN_SUCCESS)
MACH_DLOG(ERROR, kr) << "Error deallocating mach port";
break;
}
}
void SharedMemoryHandle::SetOwnershipPassesToIPC(bool ownership_passes) {
DCHECK_EQ(type_, MACH);
ownership_passes_to_ipc_ = ownership_passes;
}
bool SharedMemoryHandle::OwnershipPassesToIPC() const {
DCHECK_EQ(type_, MACH);
return ownership_passes_to_ipc_;
}
void SharedMemoryHandle::CopyRelevantData(const SharedMemoryHandle& handle) {
type_ = handle.type_;
switch (type_) {
case POSIX:
file_descriptor_ = handle.file_descriptor_;
break;
case MACH:
memory_object_ = handle.memory_object_;
size_ = handle.size_;
pid_ = handle.pid_;
ownership_passes_to_ipc_ = handle.ownership_passes_to_ipc_;
break;
}
}
} // namespace base
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