-/* Copyright (C) 2002, 2003 Free Software Foundation, Inc.
+/* Copyright (C) 2002-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library; if not, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
#include <sched.h>
#include <setjmp.h>
#include <atomic.h>
#include <ldsodefs.h>
#include <tls.h>
+#include <stdint.h>
+#include "kernel-features.h"
-#define CLONE_SIGNAL (CLONE_SIGHAND | CLONE_THREAD)
+
+#define CLONE_SIGNAL (CLONE_SIGHAND | CLONE_THREAD)
/* Unless otherwise specified, the thread "register" is going to be
initialized with a pointer to the TCB. */
#ifndef TLS_MULTIPLE_THREADS_IN_TCB
-/* Variable set to a nonzero value if more than one thread runs or ran. */
-int __pthread_multiple_threads attribute_hidden;
/* Pointer to the corresponding variable in libc. */
int *__libc_multiple_threads_ptr attribute_hidden;
#endif
static int
-create_thread (struct pthread *pd, STACK_VARIABLES_PARMS)
+do_clone (struct pthread *pd, const struct pthread_attr *attr,
+ int clone_flags, int (*fct) (void *), STACK_VARIABLES_PARMS,
+ int stopped)
{
#ifdef PREPARE_CREATE
PREPARE_CREATE;
#endif
-#ifdef TLS_TCB_AT_TP
- assert (pd->tcb != NULL);
-#endif
-
- if (__builtin_expect (THREAD_GETMEM (THREAD_SELF, report_events), 0))
+ if (__glibc_unlikely (stopped != 0))
+ /* We make sure the thread does not run far by forcing it to get a
+ lock. We lock it here too so that the new thread cannot continue
+ until we tell it to. */
+ lll_lock (pd->lock, LLL_PRIVATE);
+
+ /* One more thread. We cannot have the thread do this itself, since it
+ might exist but not have been scheduled yet by the time we've returned
+ and need to check the value to behave correctly. We must do it before
+ creating the thread, in case it does get scheduled first and then
+ might mistakenly think it was the only thread. In the failure case,
+ we momentarily store a false value; this doesn't matter because there
+ is no kosher thing a signal handler interrupting us right here can do
+ that cares whether the thread count is correct. */
+ atomic_increment (&__nptl_nthreads);
+
+ int rc = ARCH_CLONE (fct, STACK_VARIABLES_ARGS, clone_flags,
+ pd, &pd->tid, TLS_VALUE, &pd->tid);
+
+ if (__glibc_unlikely (rc == -1))
{
- /* The parent thread is supposed to report events. Check whether
- the TD_CREATE event is needed, too. */
- const int _idx = __td_eventword (TD_CREATE);
- const uint32_t _mask = __td_eventmask (TD_CREATE);
+ atomic_decrement (&__nptl_nthreads); /* Oops, we lied for a second. */
- if ((_mask & (__nptl_threads_events.event_bits[_idx]
- | pd->eventbuf.eventmask.event_bits[_idx])) != 0)
- {
- /* We have to report the new thread. Make sure the thread
- does not run far by forcing it to get a lock. We lock it
- here too so that the new thread cannot continue until we
- tell it to. */
- lll_lock (pd->lock);
-
- /* Create the thread. */
- if (ARCH_CLONE (start_thread_debug, STACK_VARIABLES_ARGS,
- CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGNAL |
- CLONE_SETTLS | CLONE_PARENT_SETTID |
- CLONE_CHILD_CLEARTID | CLONE_DETACHED | 0,
- pd, &pd->tid, TLS_VALUE, &pd->tid) == -1)
- /* Failed. */
- return errno;
-
-#ifdef TLS_MULTIPLE_THREADS_IN_TCB
- /* We now have for sure more than one thread. */
- pd->multiple_threads = 1;
-#else
- __pthread_multiple_threads = *__libc_multiple_threads_ptr = 1;
-#endif
+ /* Perhaps a thread wants to change the IDs and if waiting
+ for this stillborn thread. */
+ if (__builtin_expect (atomic_exchange_acq (&pd->setxid_futex, 0)
+ == -2, 0))
+ lll_futex_wake (&pd->setxid_futex, 1, LLL_PRIVATE);
- /* Now fill in the information about the new thread in
- the newly created thread's data structure. We cannot let
- the new thread do this since we don't know whether it was
- already scheduled when we send the event. */
- pd->eventbuf.eventnum = TD_CREATE;
- pd->eventbuf.eventdata = pd;
+ /* Free the resources. */
+ __deallocate_stack (pd);
- /* Enqueue the descriptor. */
- do
- pd->nextevent = __nptl_last_event;
- while (atomic_compare_and_exchange_acq (&__nptl_last_event, pd,
- pd->nextevent) != 0);
+ /* We have to translate error codes. */
+ return errno == ENOMEM ? EAGAIN : errno;
+ }
- /* Now call the function which signals the event. */
- __nptl_create_event ();
+ /* Now we have the possibility to set scheduling parameters etc. */
+ if (__glibc_unlikely (stopped != 0))
+ {
+ INTERNAL_SYSCALL_DECL (err);
+ int res = 0;
- /* And finally restart the new thread. */
- lll_unlock (pd->lock);
+ /* Set the affinity mask if necessary. */
+ if (attr->cpuset != NULL)
+ {
+ res = INTERNAL_SYSCALL (sched_setaffinity, err, 3, pd->tid,
+ attr->cpusetsize, attr->cpuset);
+
+ if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (res, err)))
+ {
+ /* The operation failed. We have to kill the thread. First
+ send it the cancellation signal. */
+ INTERNAL_SYSCALL_DECL (err2);
+ err_out:
+ (void) INTERNAL_SYSCALL (tgkill, err2, 3,
+ THREAD_GETMEM (THREAD_SELF, pid),
+ pd->tid, SIGCANCEL);
+
+ /* We do not free the stack here because the canceled thread
+ itself will do this. */
+
+ return (INTERNAL_SYSCALL_ERROR_P (res, err)
+ ? INTERNAL_SYSCALL_ERRNO (res, err)
+ : 0);
+ }
+ }
- return 0;
+ /* Set the scheduling parameters. */
+ if ((attr->flags & ATTR_FLAG_NOTINHERITSCHED) != 0)
+ {
+ res = INTERNAL_SYSCALL (sched_setscheduler, err, 3, pd->tid,
+ pd->schedpolicy, &pd->schedparam);
+
+ if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (res, err)))
+ goto err_out;
}
}
-#ifdef NEED_DL_SYSINFO
- assert (THREAD_GETMEM (THREAD_SELF, sysinfo) == pd->sysinfo);
+ /* We now have for sure more than one thread. The main thread might
+ not yet have the flag set. No need to set the global variable
+ again if this is what we use. */
+ THREAD_SETMEM (THREAD_SELF, header.multiple_threads, 1);
+
+ return 0;
+}
+
+
+static int
+create_thread (struct pthread *pd, const struct pthread_attr *attr,
+ STACK_VARIABLES_PARMS)
+{
+#ifdef TLS_TCB_AT_TP
+ assert (pd->header.tcb != NULL);
#endif
/* We rely heavily on various flags the CLONE function understands:
sys_exit() in the location pointed to by the seventh parameter
to CLONE.
- CLONE_DETACHED
- No signal is generated if the thread exists and it is
- automatically reaped.
-
The termination signal is chosen to be zero which means no signal
is sent. */
- if (ARCH_CLONE (start_thread, STACK_VARIABLES_ARGS,
- CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGNAL |
- CLONE_SETTLS | CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID |
- CLONE_DETACHED | 0, pd, &pd->tid, TLS_VALUE, &pd->tid) == -1)
- /* Failed. */
- return errno;
-
-#ifdef TLS_MULTIPLE_THREADS_IN_TCB
- /* We now have for sure more than one thread. */
- THREAD_SETMEM (THREAD_SELF, multiple_threads, 1);
+ int clone_flags = (CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGNAL
+ | CLONE_SETTLS | CLONE_PARENT_SETTID
+ | CLONE_CHILD_CLEARTID | CLONE_SYSVSEM
+ | 0);
+
+ if (__glibc_unlikely (THREAD_GETMEM (THREAD_SELF, report_events)))
+ {
+ /* The parent thread is supposed to report events. Check whether
+ the TD_CREATE event is needed, too. */
+ const int _idx = __td_eventword (TD_CREATE);
+ const uint32_t _mask = __td_eventmask (TD_CREATE);
+
+ if ((_mask & (__nptl_threads_events.event_bits[_idx]
+ | pd->eventbuf.eventmask.event_bits[_idx])) != 0)
+ {
+ /* We always must have the thread start stopped. */
+ pd->stopped_start = true;
+
+ /* Create the thread. We always create the thread stopped
+ so that it does not get far before we tell the debugger. */
+ int res = do_clone (pd, attr, clone_flags, start_thread,
+ STACK_VARIABLES_ARGS, 1);
+ if (res == 0)
+ {
+ /* Now fill in the information about the new thread in
+ the newly created thread's data structure. We cannot let
+ the new thread do this since we don't know whether it was
+ already scheduled when we send the event. */
+ pd->eventbuf.eventnum = TD_CREATE;
+ pd->eventbuf.eventdata = pd;
+
+ /* Enqueue the descriptor. */
+ do
+ pd->nextevent = __nptl_last_event;
+ while (atomic_compare_and_exchange_bool_acq (&__nptl_last_event,
+ pd, pd->nextevent)
+ != 0);
+
+ /* Now call the function which signals the event. */
+ __nptl_create_event ();
+
+ /* And finally restart the new thread. */
+ lll_unlock (pd->lock, LLL_PRIVATE);
+ }
+
+ return res;
+ }
+ }
+
+#ifdef NEED_DL_SYSINFO
+ assert (THREAD_SELF_SYSINFO == THREAD_SYSINFO (pd));
#endif
- return 0;
+ /* Determine whether the newly created threads has to be started
+ stopped since we have to set the scheduling parameters or set the
+ affinity. */
+ bool stopped = false;
+ if (attr != NULL && (attr->cpuset != NULL
+ || (attr->flags & ATTR_FLAG_NOTINHERITSCHED) != 0))
+ stopped = true;
+ pd->stopped_start = stopped;
+ pd->parent_cancelhandling = THREAD_GETMEM (THREAD_SELF, cancelhandling);
+
+ /* Actually create the thread. */
+ int res = do_clone (pd, attr, clone_flags, start_thread,
+ STACK_VARIABLES_ARGS, stopped);
+
+ if (res == 0 && stopped)
+ /* And finally restart the new thread. */
+ lll_unlock (pd->lock, LLL_PRIVATE);
+
+ return res;
}
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