RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-14 09:24:57 +00:00
Code Issues Activity Actions

LibC: Implement pthread_cancel

Browse source
This commit is contained in:
Tim Schumacher 2022-06-12 14:48:28 +02:00 • committed by Brian Gianforcaro
parent 1269ce0c35
commit 899fd74f8e
5 changed files with 71 additions and 4 deletions
Download patch file Download diff file Expand all files Collapse all files

46
Userland/Libraries/LibC/pthread.cpp
View file

@ -12,6 +12,7 @@
#include <AK/StdLibExtras.h>
#include <Kernel/API/Syscall.h>
#include <LibSystem/syscall.h>
#include <bits/pthread_cancel.h>
#include <bits/pthread_integration.h>
#include <errno.h>
#include <limits.h>
@ -51,6 +52,8 @@ struct CleanupHandler {
static thread_local SinglyLinkedList<CleanupHandler> cleanup_handlers;
static __thread bool pending_cancellation = false;
extern "C" {
[[noreturn]] static void exit_thread(void* code, void* stack_location, size_t stack_size)
@ -154,6 +157,21 @@ void pthread_exit(void* value_ptr)
pthread_exit_without_cleanup_handlers(value_ptr);
}
void __pthread_maybe_cancel()
{
// Check if we have cancellations enabled.
if (s_thread_cancel_state != PTHREAD_CANCEL_ENABLE)
return;
// Check if a cancellation request is pending.
if (!pending_cancellation)
return;
// Exit the thread via `pthread_exit`. This handles passing the
// return value and calling the cleanup handlers for us.
pthread_exit(PTHREAD_CANCELED);
}
// https://pubs.opengroup.org/onlinepubs/009695399/functions/pthread_cleanup_push.html
void pthread_cleanup_push(void (*routine)(void*), void* arg)
{
@ -481,11 +499,35 @@ int pthread_setschedparam([[maybe_unused]] pthread_t thread, [[maybe_unused]] in
return 0;
}
static void pthread_cancel_signal_handler(int signal)
{
// SIGCANCEL is a custom signal that is beyond the usual range of signal numbers.
// Let's make sure we know about it in case we still end up in here, but the signal
// number is being mangled.
VERIFY(signal == SIGCANCEL);
// Note: We don't handle PTHREAD_CANCEL_ASYNCHRONOUS any different from PTHREAD_CANCEL_DEFERRED,
// since ASYNCHRONOUS just means that the thread can be cancelled at any time (instead of just
// at the next cancellation point) and it seems to be generally discouraged to use it at all.
pending_cancellation = true;
}
// https://pubs.opengroup.org/onlinepubs/009695399/functions/pthread_cancel.html
// NOTE: libgcc expects this function to exist in libpthread, even if it is not implemented.
int pthread_cancel(pthread_t)
int pthread_cancel(pthread_t thread)
{
TODO();
// Set up our signal handler, which listens on SIGCANCEL and flips the cancellation indicator.
// Note that signal handlers are shared across the whole process, so we can just set that up at any time.
static bool set_up_cancel_handler = false;
if (!set_up_cancel_handler) {
struct sigaction act = {};
act.sa_handler = pthread_cancel_signal_handler;
sigaction(SIGCANCEL, &act, nullptr);
set_up_cancel_handler = true;
}
return pthread_kill(thread, SIGCANCEL);
}
int pthread_setname_np(pthread_t thread, char const* name)