ladybird/AK/SharedBuffer.cpp
Nico Weber 3f45e9ab1e Lagom: Add LibGemini, LibGfx
They are dependencies of LibWeb and might be useful for
running test-web on GitHub actions one day.
2020-07-23 23:02:28 +02:00

218 lines
5.8 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#if defined(__serenity__) || defined(__linux__)
# include <AK/SharedBuffer.h>
# include <AK/kmalloc.h>
# include <Kernel/API/Syscall.h>
# include <stdio.h>
# if defined(__serenity__)
# include <serenity.h>
# elif defined(__linux__)
# include <AK/String.h>
# include <fcntl.h>
# include <sys/mman.h>
static String shbuf_shm_name(int shbuf_id)
{
return String::format("/serenity-shm:%d", shbuf_id);
}
# endif
namespace AK {
RefPtr<SharedBuffer> SharedBuffer::create_with_size(int size)
{
# if defined(__serenity__)
void* data;
int shbuf_id = shbuf_create(size, &data);
if (shbuf_id < 0) {
perror("shbuf_create");
return nullptr;
}
# elif defined(__linux__)
// Not atomic, so don't create shared buffers from many threads too hard under lagom.
static unsigned g_shm_id = 0;
int shbuf_id = (getpid() << 8) | (g_shm_id++);
int fd = shm_open(shbuf_shm_name(shbuf_id).characters(), O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
if (fd < 0) {
perror("shm_open");
return nullptr;
}
if (ftruncate(fd, size) < 0) {
perror("ftruncate");
return nullptr;
}
void* data = mmap(nullptr, size + sizeof(size_t), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (data == MAP_FAILED) {
perror("mmap");
return nullptr;
}
size_t* size_data = reinterpret_cast<size_t*>(data);
*size_data = size;
data = reinterpret_cast<u8*>(data) + sizeof(size_t);
if (close(fd) < 0) {
perror("close");
return nullptr;
}
# endif
return adopt(*new SharedBuffer(shbuf_id, size, data));
}
bool SharedBuffer::share_with(pid_t peer)
{
# if defined(__serenity__)
int ret = shbuf_allow_pid(shbuf_id(), peer);
if (ret < 0) {
perror("shbuf_allow_pid");
return false;
}
# else
(void)peer;
# endif
return true;
}
bool SharedBuffer::share_globally()
{
# if defined(__serenity__)
int ret = shbuf_allow_all(shbuf_id());
if (ret < 0) {
perror("shbuf_allow_all");
return false;
}
# endif
return true;
}
RefPtr<SharedBuffer> SharedBuffer::create_from_shbuf_id(int shbuf_id)
{
# if defined(__serenity__)
size_t size = 0;
void* data = shbuf_get(shbuf_id, &size);
if (data == (void*)-1)
return nullptr;
# elif defined(__linux__)
int fd = shm_open(shbuf_shm_name(shbuf_id).characters(), O_RDWR, S_IRUSR | S_IWUSR);
if (fd < 0) {
perror("shm_open");
return nullptr;
}
void* data = mmap(nullptr, sizeof(size_t), PROT_READ, MAP_SHARED, fd, 0);
if (data == MAP_FAILED) {
perror("mmap");
return nullptr;
}
size_t* size_data = reinterpret_cast<size_t*>(data);
size_t size = *size_data;
if (munmap(data, sizeof(size_t)) < 0) {
perror("munmap");
return nullptr;
}
data = mmap(nullptr, size + sizeof(size_t), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (data == MAP_FAILED) {
perror("mmap");
return nullptr;
}
data = reinterpret_cast<u8*>(data) + sizeof(size_t);
if (close(fd) < 0) {
perror("close");
return nullptr;
}
# endif
return adopt(*new SharedBuffer(shbuf_id, size, data));
}
SharedBuffer::SharedBuffer(int shbuf_id, int size, void* data)
: m_shbuf_id(shbuf_id)
, m_size(size)
, m_data(data)
{
}
SharedBuffer::~SharedBuffer()
{
if (m_shbuf_id >= 0) {
# if defined(__serenity__)
int rc = shbuf_release(m_shbuf_id);
if (rc < 0) {
perror("shbuf_release");
}
# elif defined(__linux__)
if (munmap(reinterpret_cast<u8*>(m_data) - sizeof(size_t), m_size + sizeof(size_t)) < 0)
perror("munmap");
if (shm_unlink(shbuf_shm_name(m_shbuf_id).characters()) < 0)
perror("unlink");
# endif
}
}
void SharedBuffer::seal()
{
# if defined(__serenity__)
int rc = shbuf_seal(m_shbuf_id);
if (rc < 0) {
perror("shbuf_seal");
ASSERT_NOT_REACHED();
}
# endif
}
void SharedBuffer::set_volatile()
{
# if defined(__serenity__)
u32 rc = syscall(SC_shbuf_set_volatile, m_shbuf_id, true);
ASSERT(rc == 0);
# endif
}
bool SharedBuffer::set_nonvolatile()
{
# if defined(__serenity__)
u32 rc = syscall(SC_shbuf_set_volatile, m_shbuf_id, false);
if (rc == 0)
return true;
ASSERT(rc == 1);
# endif
return false;
}
}
#endif