RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-26 21:47:46 +00:00
Code Issues Activity Actions

SharedBuffer: Split the creation and share steps

Browse source 
This allows us to seal a buffer *before* anyone else has access to it
(well, ok, the creating process still does, but you can't win them all).

It also means that a SharedBuffer can be shared with multiple clients:
all you need is to have access to it to share it on again.
This commit is contained in:
Robin Burchell 2019-07-18 09:52:22 +02:00 • committed by Andreas Kling
parent f60d7e5d1f
commit b907608e46
12 changed files with 58 additions and 22 deletions
Download patch file Download diff file Expand all files Collapse all files

14
Libraries/LibC/SharedBuffer.cpp
View file

@ -3,10 +3,10 @@
#include <stdio.h>
#include <unistd.h>
RefPtr<SharedBuffer> SharedBuffer::create(pid_t peer, int size)
RefPtr<SharedBuffer> SharedBuffer::create_with_size(int size)
{
void* data;
int shared_buffer_id = create_shared_buffer(peer, size, &data);
int shared_buffer_id = create_shared_buffer(size, &data);
if (shared_buffer_id < 0) {
perror("create_shared_buffer");
return nullptr;
@ -14,6 +14,16 @@ RefPtr<SharedBuffer> SharedBuffer::create(pid_t peer, int size)
return adopt(*new SharedBuffer(shared_buffer_id, size, data));
}
bool SharedBuffer::share_with(pid_t peer)
{
int ret = share_buffer_with(shared_buffer_id(), peer);
if (ret < 0) {
perror("share_buffer_with");
return false;
}
return true;
}
RefPtr<SharedBuffer> SharedBuffer::create_from_shared_buffer_id(int shared_buffer_id)
{
void* data = get_shared_buffer(shared_buffer_id);

3
Libraries/LibC/SharedBuffer.h
View file

@ -5,10 +5,11 @@
class SharedBuffer : public RefCounted<SharedBuffer> {
public:
static RefPtr<SharedBuffer> create(pid_t peer, int);
static RefPtr<SharedBuffer> create_with_size(int);
static RefPtr<SharedBuffer> create_from_shared_buffer_id(int);
~SharedBuffer();
bool share_with(pid_t);
int shared_buffer_id() const { return m_shared_buffer_id; }
void seal();
int size() const { return m_size; }

10
Libraries/LibC/unistd.cpp
View file

@ -423,9 +423,15 @@ int read_tsc(unsigned* lsw, unsigned* msw)
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int create_shared_buffer(pid_t peer_pid, int size, void** buffer)
int create_shared_buffer(int size, void** buffer)
{
int rc = syscall(SC_create_shared_buffer, peer_pid, size, buffer);
int rc = syscall(SC_create_shared_buffer, size, buffer);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int share_buffer_with(int shared_buffer_id, pid_t peer_pid)
{
int rc = syscall(SC_share_buffer_with, shared_buffer_id, peer_pid);
__RETURN_WITH_ERRNO(rc, rc, -1);
}

3
Libraries/LibC/unistd.h
View file

@ -21,7 +21,8 @@ int gettid();
int donate(int tid);
int create_thread(int (*)(void*), void*);
void exit_thread(int);
int create_shared_buffer(pid_t peer_pid, int, void** buffer);
int create_shared_buffer(int, void** buffer);
int share_buffer_with(int, pid_t peer_pid);
void* get_shared_buffer(int shared_buffer_id);
int release_shared_buffer(int shared_buffer_id);
int seal_shared_buffer(int shared_buffer_id);