void
__pthread_exit (void *value)
{
THREAD_SETMEM (THREAD_SELF, result, value);
__do_cancel ();
}
/* The next two functions are similar to pthread_setcanceltype() but
more specialized for the use in the cancelable functions like write().
They do not need to check parameters etc. */
int
attribute_hidden
__pthread_enable_asynccancel (void)
{
struct pthread *self = THREAD_SELF;
int oldval = THREAD_GETMEM (self, cancelhandling);
while (1)
{
int newval = oldval | CANCELTYPE_BITMASK;
if (newval == oldval)
break;
int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
oldval);
if (__builtin_expect (curval == oldval, 1))
{
if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval))
{
THREAD_SETMEM (self, result, PTHREAD_CANCELED);
__do_cancel ();
}
break;
}
/* Prepare the next round. */
oldval = curval;
}
return oldval;
}
void
attribute_protected
__pthread_exit (void* value)
{
THREAD_SETMEM (THREAD_SELF, result, value);
__do_cancel ();
}
/* For asynchronous cancellation we use a signal. This is the handler. */
static void
sigcancel_handler (int sig, siginfo_t *si, void *ctx)
{
#ifdef __ASSUME_CORRECT_SI_PID
/* Determine the process ID. It might be negative if the thread is
in the middle of a fork() call. */
pid_t pid = THREAD_GETMEM (THREAD_SELF, pid);
if (__builtin_expect (pid < 0, 0))
pid = -pid;
#endif
/* Safety check. It would be possible to call this function for
other signals and send a signal from another process. This is not
correct and might even be a security problem. Try to catch as
many incorrect invocations as possible. */
if (sig != SIGCANCEL
#ifdef __ASSUME_CORRECT_SI_PID
/* Kernels before 2.5.75 stored the thread ID and not the process
ID in si_pid so we skip this test. */
|| si->si_pid != pid
#endif
|| si->si_code != SI_TKILL)
return;
struct pthread *self = THREAD_SELF;
int oldval = THREAD_GETMEM (self, cancelhandling);
while (1)
{
/* We are canceled now. When canceled by another thread this flag
is already set but if the signal is directly send (internally or
from another process) is has to be done here. */
int newval = oldval | CANCELING_BITMASK | CANCELED_BITMASK;
if (oldval == newval || (oldval & EXITING_BITMASK) != 0)
/* Already canceled or exiting. */
break;
int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
oldval);
if (curval == oldval)
{
/* Set the return value. */
THREAD_SETMEM (self, result, PTHREAD_CANCELED);
/* Make sure asynchronous cancellation is still enabled. */
if ((newval & CANCELTYPE_BITMASK) != 0)
/* Run the registered destructors and terminate the thread. */
__do_cancel ();
break;
}
oldval = curval;
}
}
int
attribute_hidden
__pthread_enable_asynccancel (void)
{
struct pthread *self = THREAD_SELF;
int oldval;
if (is_recording()) {
pthread_log_record (0, PTHREAD_CANCELHANDLING_ENTER, (u_long) &self->cancelhandling, 1);
oldval = THREAD_GETMEM (self, cancelhandling);
pthread_log_record (oldval, PTHREAD_CANCELHANDLING_EXIT, (u_long) &self->cancelhandling, 0);
} else if (is_replaying()) {
pthread_log_replay (PTHREAD_CANCELHANDLING_ENTER, (u_long) &self->cancelhandling);
oldval = pthread_log_replay (PTHREAD_CANCELHANDLING_EXIT, (u_long) &self->cancelhandling);
} else {
oldval = THREAD_GETMEM (self, cancelhandling);
}
while (1)
{
int newval = oldval | CANCELTYPE_BITMASK;
if (newval == oldval)
break;
int curval;
if (is_recording()) {
pthread_log_record (0, PTHREAD_CANCELHANDLING_ENTER, (u_long) &self->cancelhandling, 1);
curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval, oldval);
pthread_log_record (curval, PTHREAD_CANCELHANDLING_EXIT, (u_long) &self->cancelhandling, 0);
} else if (is_replaying()) {
pthread_log_replay (PTHREAD_CANCELHANDLING_ENTER, (u_long) &self->cancelhandling);
curval = pthread_log_replay (PTHREAD_CANCELHANDLING_EXIT, (u_long) &self->cancelhandling);
} else {
curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval, oldval);
}
if (__builtin_expect (curval == oldval, 1))
{
if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval))
{
THREAD_SETMEM (self, result, PTHREAD_CANCELED);
__do_cancel ();
}
break;
}
/* Prepare the next round. */
oldval = curval;
}
return oldval;
}
int
__pthread_setcanceltype (int type, int *oldtype)
{
if (type < PTHREAD_CANCEL_DEFERRED || type > PTHREAD_CANCEL_ASYNCHRONOUS)
return EINVAL;
#ifndef SIGCANCEL
if (type == PTHREAD_CANCEL_ASYNCHRONOUS)
return ENOTSUP;
#endif
volatile struct pthread *self = THREAD_SELF;
int oldval = THREAD_GETMEM (self, cancelhandling);
while (1)
{
int newval = (type == PTHREAD_CANCEL_ASYNCHRONOUS
? oldval | CANCELTYPE_BITMASK
: oldval & ~CANCELTYPE_BITMASK);
/* Store the old value. */
if (oldtype != NULL)
*oldtype = ((oldval & CANCELTYPE_BITMASK)
? PTHREAD_CANCEL_ASYNCHRONOUS : PTHREAD_CANCEL_DEFERRED);
/* Avoid doing unnecessary work. The atomic operation can
potentially be expensive if the memory has to be locked and
remote cache lines have to be invalidated. */
if (oldval == newval)
break;
/* Update the cancel handling word. This has to be done
atomically since other bits could be modified as well. */
int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
oldval);
if (__glibc_likely (curval == oldval))
{
if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval))
{
THREAD_SETMEM (self, result, PTHREAD_CANCELED);
__do_cancel ();
}
break;
}
/* Prepare for the next round. */
oldval = curval;
}
return 0;
}
int
attribute_protected
__pthread_setcancelstate (
int state,
int *oldstate)
{
volatile struct pthread *self;
if (state < PTHREAD_CANCEL_ENABLE || state > PTHREAD_CANCEL_DISABLE)
return EINVAL;
self = THREAD_SELF;
int oldval = THREAD_GETMEM (self, cancelhandling);
while (1)
{
int newval = (state == PTHREAD_CANCEL_DISABLE
? oldval | CANCELSTATE_BITMASK
: oldval & ~CANCELSTATE_BITMASK);
/* Store the old value. */
if (oldstate != NULL)
*oldstate = ((oldval & CANCELSTATE_BITMASK)
? PTHREAD_CANCEL_DISABLE : PTHREAD_CANCEL_ENABLE);
/* Avoid doing unnecessary work. The atomic operation can
potentially be expensive if the memory has to be locked and
remote cache lines have to be invalidated. */
if (oldval == newval)
break;
/* Update the cancel handling word. This has to be done
atomically since other bits could be modified as well. */
int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
oldval);
if (__builtin_expect (curval == oldval, 1))
{
if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval))
__do_cancel ();
break;
}
/* Prepare for the next round. */
oldval = curval;
}
return 0;
}
/* The next two functions are similar to pthread_setcanceltype() but
more specialized for the use in the cancelable functions like write().
They do not need to check parameters etc. */
int
attribute_hidden
__libc_enable_asynccancel (void)
{
struct pthread *self = THREAD_SELF;
int oldval = THREAD_GETMEM (self, cancelhandling);
while (1)
{
int newval = oldval | CANCELTYPE_BITMASK;
if (__builtin_expect ((oldval & CANCELED_BITMASK) != 0, 0))
{
/* If we are already exiting or if PTHREAD_CANCEL_DISABLED,
stop right here. */
if ((oldval & (EXITING_BITMASK | CANCELSTATE_BITMASK)) != 0)
break;
int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
newval, oldval);
if (__builtin_expect (curval != oldval, 0))
{
/* Somebody else modified the word, try again. */
oldval = curval;
continue;
}
THREAD_SETMEM (self, result, PTHREAD_CANCELED);
__do_cancel ();
/* NOTREACHED */
}
int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
oldval);
if (__builtin_expect (curval == oldval, 1))
break;
/* Prepare the next round. */
oldval = curval;
}
return oldval;
}
/* For asynchronous cancellation we use a signal. This is the handler. */
static void
sigcancel_handler (int sig, siginfo_t *si, void *ctx)
{
/* Safety check. It would be possible to call this function for
other signals and send a signal from another process. This is not
correct and might even be a security problem. Try to catch as
many incorrect invocations as possible. */
if (sig != SIGCANCEL
|| si->si_pid != __getpid()
|| si->si_code != SI_TKILL)
return;
struct pthread *self = THREAD_SELF;
int oldval = THREAD_GETMEM (self, cancelhandling);
while (1)
{
/* We are canceled now. When canceled by another thread this flag
is already set but if the signal is directly send (internally or
from another process) is has to be done here. */
int newval = oldval | CANCELING_BITMASK | CANCELED_BITMASK;
if (oldval == newval || (oldval & EXITING_BITMASK) != 0)
/* Already canceled or exiting. */
break;
int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
oldval);
if (curval == oldval)
{
/* Set the return value. */
THREAD_SETMEM (self, result, PTHREAD_CANCELED);
/* Make sure asynchronous cancellation is still enabled. */
if ((newval & CANCELTYPE_BITMASK) != 0)
/* Run the registered destructors and terminate the thread. */
__do_cancel ();
break;
}
oldval = curval;
}
}
