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#define _GNU_SOURCE
#include <string.h>
#include "pthread_impl.h"
#include "syscall.h"
hidden long __cancel(), __syscall_cp_asm(), __syscall_cp_c();
long __cancel()
{
pthread_t self = __pthread_self();
if (self->canceldisable == PTHREAD_CANCEL_ENABLE || self->cancelasync)
pthread_exit(PTHREAD_CANCELED);
self->canceldisable = PTHREAD_CANCEL_DISABLE;
return -ECANCELED;
}
long __syscall_cp_asm(volatile void *, syscall_arg_t,
syscall_arg_t, syscall_arg_t, syscall_arg_t,
syscall_arg_t, syscall_arg_t, syscall_arg_t);
long __syscall_cp_c(syscall_arg_t nr,
syscall_arg_t u, syscall_arg_t v, syscall_arg_t w,
syscall_arg_t x, syscall_arg_t y, syscall_arg_t z)
{
pthread_t self;
long r;
int st;
if ((st=(self=__pthread_self())->canceldisable)
&& (st==PTHREAD_CANCEL_DISABLE || nr==SYS_close))
return __syscall(nr, u, v, w, x, y, z);
r = __syscall_cp_asm(&self->cancel, nr, u, v, w, x, y, z);
if (r==-EINTR && nr!=SYS_close && self->cancel &&
self->canceldisable != PTHREAD_CANCEL_DISABLE)
r = __cancel();
return r;
}
static void _sigaddset(sigset_t *set, int sig)
{
unsigned s = sig-1;
set->__bits[s/8/sizeof *set->__bits] |= 1UL<<(s&8*sizeof *set->__bits-1);
}
extern hidden const char __cp_begin[1], __cp_end[1], __cp_cancel[1];
static void cancel_handler(int sig, siginfo_t *si, void *ctx)
{
pthread_t self = __pthread_self();
ucontext_t *uc = ctx;
uintptr_t pc = uc->uc_mcontext.MC_PC;
a_barrier();
if (!self->cancel || self->canceldisable == PTHREAD_CANCEL_DISABLE) return;
_sigaddset(&uc->uc_sigmask, SIGCANCEL);
if (self->cancelasync) {
pthread_sigmask(SIG_SETMASK, &uc->uc_sigmask, 0);
__cancel();
}
if (pc >= (uintptr_t)__cp_begin && pc < (uintptr_t)__cp_end) {
uc->uc_mcontext.MC_PC = (uintptr_t)__cp_cancel;
#ifdef CANCEL_GOT
uc->uc_mcontext.MC_GOT = CANCEL_GOT;
#endif
return;
}
__syscall(SYS_tkill, self->tid, SIGCANCEL);
}
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_ONSTACK,
.sa_sigaction = cancel_handler
};
memset(&sa.sa_mask, -1, _NSIG/8);
__libc_sigaction(SIGCANCEL, &sa, 0);
}
int pthread_cancel(pthread_t t)
{
static int init;
if (!init) {
init_cancellation();
init = 1;
}
a_store(&t->cancel, 1);
if (t == pthread_self()) {
if (t->canceldisable == PTHREAD_CANCEL_ENABLE && t->cancelasync)
pthread_exit(PTHREAD_CANCELED);
return 0;
}
return pthread_kill(t, SIGCANCEL);
}
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