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#include "pthread_impl.h"
void __cancel()
{
pthread_t self = __pthread_self();
self->cp_sp = 0;
self->canceldisable = 1;
self->cancelasync = 0;
pthread_exit(PTHREAD_CANCELED);
}
long __syscall_cp_asm(volatile void *, long, long, long, long, long, long, long);
long (__syscall_cp)(long nr, long u, long v, long w, long x, long y, long z)
{
pthread_t self;
uintptr_t old_sp, old_ip;
long r;
if (!libc.lock || (self = __pthread_self())->canceldisable)
return __syscall(nr, u, v, w, x, y, z);
old_sp = self->cp_sp;
old_ip = self->cp_ip;
self->cp_sp = 0;
self->cp_ip = 0;
r = __syscall_cp_asm(&self->cp_sp, nr, u, v, w, x, y, z);
self->cp_ip = old_ip;
self->cp_sp = old_sp;
if (r == -EINTR && self->cancel) __cancel();
return r;
}
static void cancel_handler(int sig, siginfo_t *si, void *ctx)
{
pthread_t self = __pthread_self();
ucontext_t *uc = ctx;
uintptr_t sp = ((uintptr_t *)&uc->uc_mcontext)[CANCEL_REG_SP];
uintptr_t ip = ((uintptr_t *)&uc->uc_mcontext)[CANCEL_REG_IP];
if (!self->cancel || self->canceldisable) return;
sigaddset(&uc->uc_sigmask, SIGCANCEL);
if (self->cancelasync || sp == self->cp_sp && ip <= self->cp_ip) {
self->canceldisable = 1;
pthread_sigmask(SIG_SETMASK, &uc->uc_sigmask, 0);
__cancel();
}
if (self->cp_sp)
__syscall(SYS_tgkill, self->pid, self->tid, SIGCANCEL);
}
static void testcancel()
{
pthread_t self = __pthread_self();
if (self->cancel && !self->canceldisable)
__cancel();
}
static void init_cancellation()
{
struct sigaction sa = {
.sa_flags = SA_SIGINFO | SA_RESTART,
.sa_sigaction = cancel_handler
};
sigfillset(&sa.sa_mask);
__libc_sigaction(SIGCANCEL, &sa, 0);
libc.testcancel = testcancel;
}
int pthread_cancel(pthread_t t)
{
static int init;
if (!init) {
init_cancellation();
init = 1;
}
a_store(&t->cancel, 1);
return pthread_kill(t, SIGCANCEL);
}
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