/* Thread creation. Copyright (C) 2000, 2002, 2005, 2007 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with the GNU C Library; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include #include #include #include #include #include #ifdef HAVE_USELOCALE # include #endif /* The total number of pthreads currently active. This is defined here since it would be really stupid to have a threads-using program that doesn't call `pthread_create'. */ __atomic_t __pthread_total; /* The entry-point for new threads. */ static void entry_point (void *(*start_routine)(void *), void *arg) { #ifdef HAVE_USELOCALE /* A fresh thread needs to be bound to the global locale. */ uselocale (LC_GLOBAL_LOCALE); #endif __pthread_startup (); pthread_exit (start_routine (arg)); } /* Create a thread with attributes given by ATTR, executing START_ROUTINE with argument ARG. */ int pthread_create (pthread_t *thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg) { int err; struct __pthread *pthread; err = __pthread_create_internal (&pthread, attr, start_routine, arg); if (! err) *thread = pthread->thread; return err; } /* Internal version of pthread_create. See comment in pt-internal.h. */ int __pthread_create_internal (struct __pthread **thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg) { int err; struct __pthread *pthread; const struct __pthread_attr *setup; sigset_t sigset; /* Allocate a new thread structure. */ err = __pthread_alloc (&pthread); if (err) goto failed; /* Use the default attributes if ATTR is NULL. */ setup = attr ? attr : &__pthread_default_attr; /* Initialize the thread state. */ pthread->state = (setup->detachstate == PTHREAD_CREATE_DETACHED ? PTHREAD_DETACHED : PTHREAD_JOINABLE); /* If the user supplied a stack, it is not our responsibility to setup a stack guard. */ if (setup->stackaddr) pthread->guardsize = 0; else pthread->guardsize = (setup->guardsize <= setup->stacksize ? setup->guardsize : setup->stacksize); /* Find a stack. There are several scenarios: if a detached thread kills itself, it has no way to deallocate its stack, thus it leaves PTHREAD->stack set to true. We try to reuse it here, however, if the user supplied a stack, we cannot use the old one. Right now, we simply deallocate it. */ if (pthread->stack) { if (setup->stackaddr != __pthread_default_attr.stackaddr) { __pthread_stack_dealloc (pthread->stackaddr, pthread->stacksize); pthread->stackaddr = setup->stackaddr; pthread->stacksize = setup->stacksize; } } else { err = __pthread_stack_alloc (&pthread->stackaddr, setup->stacksize); if (err) goto failed_stack_alloc; pthread->stacksize = setup->stacksize; pthread->stack = 1; } /* Allocate the kernel thread and other required resources. */ err = __pthread_thread_alloc (pthread); if (err) goto failed_thread_alloc; /* And initialize the rest of the machine context. This may include additional machine- and system-specific initializations that prove convenient. */ err = __pthread_setup (pthread, entry_point, start_routine, arg); if (err) goto failed_setup; /* Initialize the system-specific signal state for the new thread. */ err = __pthread_sigstate_init (pthread); if (err) goto failed_sigstate; /* Set the new thread's signal mask and set the pending signals to empty. POSIX says: "The signal mask shall be inherited from the creating thread. The set of signals pending for the new thread shall be empty." If the currnet thread is not a pthread then we just inherit the process' sigmask. */ if (__pthread_num_threads == 1) err = sigprocmask (0, 0, &sigset); else err = __pthread_sigstate (_pthread_self (), 0, 0, &sigset, 0); assert_perror (err); err = __pthread_sigstate (pthread, SIG_SETMASK, &sigset, 0, 1); assert_perror (err); /* Increase the total number of threads. We do this before actually starting the new thread, since the new thread might immediately call `pthread_exit' which decreases the number of threads and calls `exit' if the number of threads reaches zero. Increasing the number of threads from within the new thread isn't an option since this thread might return and call `pthread_exit' before the new thread runs. */ __atomic_inc (&__pthread_total); /* Store a pointer to this thread in the thread ID lookup table. We could use __thread_setid, however, we only lock for reading as no other thread should be using this entry (we also assume that the store is atomic). */ pthread_rwlock_rdlock (&__pthread_threads_lock); __pthread_threads[pthread->thread - 1] = pthread; pthread_rwlock_unlock (&__pthread_threads_lock); /* At this point it is possible to guess our pthread ID. We have to make sure that all functions taking a pthread_t argument can handle the fact that this thread isn't really running yet. */ /* Schedule the new thread. */ err = __pthread_thread_start (pthread); if (err) goto failed_starting; /* At this point the new thread is up and running. */ *thread = pthread; return 0; failed_starting: __pthread_setid (pthread->thread, NULL); __atomic_dec (&__pthread_total); failed_sigstate: __pthread_sigstate_destroy (pthread); failed_setup: __pthread_thread_dealloc (pthread); __pthread_thread_halt (pthread); failed_thread_alloc: __pthread_stack_dealloc (pthread->stackaddr, pthread->stacksize); pthread->stack = 0; failed_stack_alloc: __pthread_dealloc (pthread); failed: return err; }