/* $NetBSD: pthread.c,v 1.153.2.3 2023/12/09 13:24:24 martin Exp $ */ /*- * Copyright (c) 2001, 2002, 2003, 2006, 2007, 2008 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Nathan J. Williams and Andrew Doran. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include __RCSID("$NetBSD: pthread.c,v 1.153.2.3 2023/12/09 13:24:24 martin Exp $"); #define __EXPOSE_STACK 1 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "atexit.h" #include "pthread.h" #include "pthread_int.h" #include "pthread_makelwp.h" #include "reentrant.h" pthread_rwlock_t pthread__alltree_lock = PTHREAD_RWLOCK_INITIALIZER; static rb_tree_t pthread__alltree; static signed int pthread__cmp(void *, const void *, const void *); static const rb_tree_ops_t pthread__alltree_ops = { .rbto_compare_nodes = pthread__cmp, .rbto_compare_key = pthread__cmp, .rbto_node_offset = offsetof(struct __pthread_st, pt_alltree), .rbto_context = NULL }; static void pthread__create_tramp(void *); static void pthread__initthread(pthread_t); static void pthread__scrubthread(pthread_t, char *, int); static void pthread__initmain(pthread_t *); static void pthread__fork_callback(void); static void pthread__reap(pthread_t); static void pthread__child_callback(void); static void pthread__start(void); void pthread__init(void); int pthread__started; int __uselibcstub = 1; pthread_mutex_t pthread__deadqueue_lock = PTHREAD_MUTEX_INITIALIZER; pthread_queue_t pthread__deadqueue; pthread_queue_t pthread__allqueue; static pthread_attr_t pthread_default_attr; static lwpctl_t pthread__dummy_lwpctl = { .lc_curcpu = LWPCTL_CPU_NONE }; enum { DIAGASSERT_ABORT = 1<<0, DIAGASSERT_STDERR = 1<<1, DIAGASSERT_SYSLOG = 1<<2 }; static int pthread__diagassert; int pthread__concurrency; int pthread__nspins; int pthread__unpark_max = PTHREAD__UNPARK_MAX; int pthread__dbg; /* set by libpthread_dbg if active */ /* * We have to initialize the pthread_stack* variables here because * mutexes are used before pthread_init() and thus pthread__initmain() * are called. Since mutexes only save the stack pointer and not a * pointer to the thread data, it is safe to change the mapping from * stack pointer to thread data afterwards. */ size_t pthread__stacksize; size_t pthread__guardsize; size_t pthread__pagesize; static struct __pthread_st *pthread__main; static size_t __pthread_st_size; int _sys___sigprocmask14(int, const sigset_t *, sigset_t *); __strong_alias(__libc_thr_self,pthread_self) __strong_alias(__libc_thr_create,pthread_create) __strong_alias(__libc_thr_exit,pthread_exit) __strong_alias(__libc_thr_errno,pthread__errno) __strong_alias(__libc_thr_setcancelstate,pthread_setcancelstate) __strong_alias(__libc_thr_equal,pthread_equal) __strong_alias(__libc_thr_init,pthread__init) /* * Static library kludge. Place a reference to a symbol any library * file which does not already have a reference here. */ extern int pthread__cancel_stub_binder; void *pthread__static_lib_binder[] = { &pthread__cancel_stub_binder, pthread_cond_init, pthread_mutex_init, pthread_rwlock_init, pthread_barrier_init, pthread_key_create, pthread_setspecific, }; #define NHASHLOCK 64 static union hashlock { pthread_mutex_t mutex; char pad[64]; } hashlocks[NHASHLOCK] __aligned(64); /* * This needs to be started by the library loading code, before main() * gets to run, for various things that use the state of the initial thread * to work properly (thread-specific data is an application-visible example; * spinlock counts for mutexes is an internal example). */ void pthread__init(void) { pthread_t first; char *p; int i; int mib[2]; unsigned int value; size_t len; extern int __isthreaded; /* * Allocate pthread_keys descriptors before * reseting __uselibcstub because otherwise * malloc() will call pthread_keys_create() * while pthread_keys descriptors are not * yet allocated. */ pthread__main = pthread_tsd_init(&__pthread_st_size); if (pthread__main == NULL) err(EXIT_FAILURE, "Cannot allocate pthread storage"); __uselibcstub = 0; pthread__pagesize = (size_t)sysconf(_SC_PAGESIZE); pthread__concurrency = (int)sysconf(_SC_NPROCESSORS_CONF); mib[0] = CTL_VM; mib[1] = VM_THREAD_GUARD_SIZE; len = sizeof(value); if (sysctl(mib, __arraycount(mib), &value, &len, NULL, 0) == 0) pthread__guardsize = value; else pthread__guardsize = pthread__pagesize; /* Initialize locks first; they're needed elsewhere. */ pthread__lockprim_init(); for (i = 0; i < NHASHLOCK; i++) { pthread_mutex_init(&hashlocks[i].mutex, NULL); } /* Fetch parameters. */ i = (int)_lwp_unpark_all(NULL, 0, NULL); if (i == -1) err(EXIT_FAILURE, "_lwp_unpark_all"); if (i < pthread__unpark_max) pthread__unpark_max = i; /* Basic data structure setup */ pthread_attr_init(&pthread_default_attr); PTQ_INIT(&pthread__allqueue); PTQ_INIT(&pthread__deadqueue); rb_tree_init(&pthread__alltree, &pthread__alltree_ops); /* Create the thread structure corresponding to main() */ pthread__initmain(&first); pthread__initthread(first); pthread__scrubthread(first, NULL, 0); first->pt_lid = _lwp_self(); PTQ_INSERT_HEAD(&pthread__allqueue, first, pt_allq); (void)rb_tree_insert_node(&pthread__alltree, first); if (_lwp_ctl(LWPCTL_FEATURE_CURCPU, &first->pt_lwpctl) != 0) { err(EXIT_FAILURE, "_lwp_ctl"); } /* Start subsystems */ PTHREAD_MD_INIT for (p = pthread__getenv("PTHREAD_DIAGASSERT"); p && *p; p++) { switch (*p) { case 'a': pthread__diagassert |= DIAGASSERT_ABORT; break; case 'A': pthread__diagassert &= ~DIAGASSERT_ABORT; break; case 'e': pthread__diagassert |= DIAGASSERT_STDERR; break; case 'E': pthread__diagassert &= ~DIAGASSERT_STDERR; break; case 'l': pthread__diagassert |= DIAGASSERT_SYSLOG; break; case 'L': pthread__diagassert &= ~DIAGASSERT_SYSLOG; break; } } /* Tell libc that we're here and it should role-play accordingly. */ pthread_atfork(NULL, NULL, pthread__fork_callback); __isthreaded = 1; } static void pthread__fork_callback(void) { struct __pthread_st *self = pthread__self(); /* lwpctl state is not copied across fork. */ if (_lwp_ctl(LWPCTL_FEATURE_CURCPU, &self->pt_lwpctl)) { err(EXIT_FAILURE, "_lwp_ctl"); } self->pt_lid = _lwp_self(); } static void pthread__child_callback(void) { /* * Clean up data structures that a forked child process might * trip over. Note that if threads have been created (causing * this handler to be registered) the standards say that the * child will trigger undefined behavior if it makes any * pthread_* calls (or any other calls that aren't * async-signal-safe), so we don't really have to clean up * much. Anything that permits some pthread_* calls to work is * merely being polite. */ pthread__started = 0; } static void pthread__start(void) { /* * Per-process timers are cleared by fork(); despite the * various restrictions on fork() and threads, it's legal to * fork() before creating any threads. */ pthread_atfork(NULL, NULL, pthread__child_callback); } /* General-purpose thread data structure sanitization. */ /* ARGSUSED */ static void pthread__initthread(pthread_t t) { t->pt_self = t; t->pt_magic = PT_MAGIC; t->pt_willpark = 0; t->pt_unpark = 0; t->pt_nwaiters = 0; t->pt_sleepobj = NULL; t->pt_signalled = 0; t->pt_havespecific = 0; t->pt_early = NULL; t->pt_lwpctl = &pthread__dummy_lwpctl; t->pt_droplock = NULL; memcpy(&t->pt_lockops, pthread__lock_ops, sizeof(t->pt_lockops)); pthread_mutex_init(&t->pt_lock, NULL); PTQ_INIT(&t->pt_cleanup_stack); pthread_cond_init(&t->pt_joiners, NULL); } static void pthread__scrubthread(pthread_t t, char *name, int flags) { t->pt_state = PT_STATE_RUNNING; t->pt_exitval = NULL; t->pt_flags = flags; t->pt_cancel = 0; t->pt_errno = 0; t->pt_name = name; t->pt_lid = 0; } static int pthread__getstack(pthread_t newthread, const pthread_attr_t *attr) { void *stackbase, *stackbase2, *redzone; size_t stacksize, guardsize; bool allocated; if (attr != NULL) { pthread_attr_getstack(attr, &stackbase, &stacksize); if (stackbase == NULL) pthread_attr_getguardsize(attr, &guardsize); else guardsize = 0; } else { stackbase = NULL; stacksize = 0; guardsize = pthread__guardsize; } if (stacksize == 0) stacksize = pthread__stacksize; if (newthread->pt_stack_allocated) { if (stackbase == NULL && newthread->pt_stack.ss_size == stacksize && newthread->pt_guardsize == guardsize) return 0; stackbase2 = newthread->pt_stack.ss_sp; #ifndef __MACHINE_STACK_GROWS_UP stackbase2 = (char *)stackbase2 - newthread->pt_guardsize; #endif munmap(stackbase2, newthread->pt_stack.ss_size + newthread->pt_guardsize); newthread->pt_stack.ss_sp = NULL; newthread->pt_stack.ss_size = 0; newthread->pt_guardsize = 0; newthread->pt_stack_allocated = false; } newthread->pt_stack_allocated = false; if (stackbase == NULL) { stacksize = ((stacksize - 1) | (pthread__pagesize - 1)) + 1; guardsize = ((guardsize - 1) | (pthread__pagesize - 1)) + 1; stackbase = mmap(NULL, stacksize + guardsize, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, (off_t)0); if (stackbase == MAP_FAILED) return ENOMEM; allocated = true; } else { allocated = false; } #ifdef __MACHINE_STACK_GROWS_UP redzone = (char *)stackbase + stacksize; stackbase2 = (char *)stackbase; #else redzone = (char *)stackbase; stackbase2 = (char *)stackbase + guardsize; #endif if (allocated && guardsize && mprotect(redzone, guardsize, PROT_NONE) == -1) { munmap(stackbase, stacksize + guardsize); return EPERM; } newthread->pt_stack.ss_size = stacksize; newthread->pt_stack.ss_sp = stackbase2; newthread->pt_guardsize = guardsize; newthread->pt_stack_allocated = allocated; return 0; } int pthread_create(pthread_t *thread, const pthread_attr_t *attr, void *(*startfunc)(void *), void *arg) { pthread_t newthread; pthread_attr_t nattr; struct pthread_attr_private *p; char * volatile name; unsigned long flag; void *private_area; int ret; if (__predict_false(__uselibcstub)) { pthread__errorfunc(__FILE__, __LINE__, __func__, "pthread_create() requires linking with -lpthread"); return __libc_thr_create_stub(thread, attr, startfunc, arg); } if (!pthread__started) { /* * Force the _lwp_park symbol to be resolved before we * begin any activity that might rely on concurrent * wakeups. * * This is necessary because rtld itself uses _lwp_park * and _lwp_unpark internally for its own locking: If * we wait to resolve _lwp_park until there is an * _lwp_unpark from another thread pending in the * current lwp (for example, pthread_mutex_unlock or * pthread_cond_signal), rtld's internal use of * _lwp_park might consume the pending unpark. The * result is a deadlock where libpthread and rtld have * both correctly used _lwp_park and _lwp_unpark for * themselves, but rtld has consumed the wakeup meant * for libpthread so it is lost to libpthread. * * For the very first thread, before pthread__started * is set to true, pthread__self()->pt_lid should have * been initialized in pthread__init by the time we get * here to the correct lid so we go to sleep and wake * ourselves at the same time as a no-op. */ _lwp_park(CLOCK_REALTIME, 0, NULL, pthread__self()->pt_lid, NULL, NULL); } /* * It's okay to check this without a lock because there can * only be one thread before it becomes true. */ if (pthread__started == 0) { pthread__start(); pthread__started = 1; } if (attr == NULL) nattr = pthread_default_attr; else if (attr->pta_magic == PT_ATTR_MAGIC) nattr = *attr; else return EINVAL; /* Fetch misc. attributes from the attr structure. */ name = NULL; if ((p = nattr.pta_private) != NULL) if (p->ptap_name[0] != '\0') if ((name = strdup(p->ptap_name)) == NULL) return ENOMEM; newthread = NULL; /* * Try to reclaim a dead thread. */ if (!PTQ_EMPTY(&pthread__deadqueue)) { pthread_mutex_lock(&pthread__deadqueue_lock); PTQ_FOREACH(newthread, &pthread__deadqueue, pt_deadq) { /* Still running? */ if (newthread->pt_lwpctl->lc_curcpu == LWPCTL_CPU_EXITED || (_lwp_kill(newthread->pt_lid, 0) == -1 && errno == ESRCH)) break; } if (newthread) PTQ_REMOVE(&pthread__deadqueue, newthread, pt_deadq); pthread_mutex_unlock(&pthread__deadqueue_lock); #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II) if (newthread && newthread->pt_tls) { _rtld_tls_free(newthread->pt_tls); newthread->pt_tls = NULL; } #endif } /* * If necessary set up a stack, allocate space for a pthread_st, * and initialize it. */ if (newthread == NULL) { newthread = calloc(1, __pthread_st_size); if (newthread == NULL) { free(name); return ENOMEM; } newthread->pt_stack_allocated = false; if (pthread__getstack(newthread, attr)) { free(newthread); free(name); return ENOMEM; } #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II) newthread->pt_tls = NULL; #endif /* Add to list of all threads. */ pthread_rwlock_wrlock(&pthread__alltree_lock); PTQ_INSERT_TAIL(&pthread__allqueue, newthread, pt_allq); (void)rb_tree_insert_node(&pthread__alltree, newthread); pthread_rwlock_unlock(&pthread__alltree_lock); /* Will be reset by the thread upon exit. */ pthread__initthread(newthread); } else { if (pthread__getstack(newthread, attr)) { pthread_mutex_lock(&pthread__deadqueue_lock); PTQ_INSERT_TAIL(&pthread__deadqueue, newthread, pt_deadq); pthread_mutex_unlock(&pthread__deadqueue_lock); return ENOMEM; } } /* * Create the new LWP. */ pthread__scrubthread(newthread, name, nattr.pta_flags); newthread->pt_func = startfunc; newthread->pt_arg = arg; #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II) private_area = newthread->pt_tls = _rtld_tls_allocate(); newthread->pt_tls->tcb_pthread = newthread; #else private_area = newthread; #endif flag = LWP_DETACHED; if ((newthread->pt_flags & PT_FLAG_SUSPENDED) != 0 || (nattr.pta_flags & PT_FLAG_EXPLICIT_SCHED) != 0) flag |= LWP_SUSPENDED; ret = pthread__makelwp(pthread__create_tramp, newthread, private_area, newthread->pt_stack.ss_sp, newthread->pt_stack.ss_size, flag, &newthread->pt_lid); if (ret != 0) { ret = errno; pthread_mutex_lock(&newthread->pt_lock); /* Will unlock and free name. */ pthread__reap(newthread); return ret; } if ((nattr.pta_flags & PT_FLAG_EXPLICIT_SCHED) != 0) { if (p != NULL) { (void)pthread_setschedparam(newthread, p->ptap_policy, &p->ptap_sp); } if ((newthread->pt_flags & PT_FLAG_SUSPENDED) == 0) { (void)_lwp_continue(newthread->pt_lid); } } *thread = newthread; return 0; } __dead static void pthread__create_tramp(void *cookie) { pthread_t self; void *retval; self = cookie; /* * Throw away some stack in a feeble attempt to reduce cache * thrash. May help for SMT processors. XXX We should not * be allocating stacks on fixed 2MB boundaries. Needs a * thread register or decent thread local storage. * * Note that we may race with the kernel in _lwp_create(), * and so pt_lid can be unset at this point, but we don't * care. */ (void)alloca(((unsigned)self->pt_lid & 7) << 8); if (self->pt_name != NULL) { pthread_mutex_lock(&self->pt_lock); if (self->pt_name != NULL) (void)_lwp_setname(0, self->pt_name); pthread_mutex_unlock(&self->pt_lock); } if (_lwp_ctl(LWPCTL_FEATURE_CURCPU, &self->pt_lwpctl)) { err(EXIT_FAILURE, "_lwp_ctl"); } retval = (*self->pt_func)(self->pt_arg); pthread_exit(retval); /*NOTREACHED*/ pthread__abort(); } int pthread_suspend_np(pthread_t thread) { pthread_t self; self = pthread__self(); if (self == thread) { return EDEADLK; } if (pthread__find(thread) != 0) return ESRCH; if (_lwp_suspend(thread->pt_lid) == 0) return 0; return errno; } int pthread_resume_np(pthread_t thread) { if (pthread__find(thread) != 0) return ESRCH; if (_lwp_continue(thread->pt_lid) == 0) return 0; return errno; } void pthread_exit(void *retval) { pthread_t self; struct pt_clean_t *cleanup; char *name; if (__predict_false(__uselibcstub)) { __libc_thr_exit_stub(retval); goto out; } self = pthread__self(); /* Disable cancellability. */ pthread_mutex_lock(&self->pt_lock); self->pt_flags |= PT_FLAG_CS_DISABLED; self->pt_cancel = 0; /* Call any cancellation cleanup handlers */ if (!PTQ_EMPTY(&self->pt_cleanup_stack)) { pthread_mutex_unlock(&self->pt_lock); while (!PTQ_EMPTY(&self->pt_cleanup_stack)) { cleanup = PTQ_FIRST(&self->pt_cleanup_stack); PTQ_REMOVE(&self->pt_cleanup_stack, cleanup, ptc_next); (*cleanup->ptc_cleanup)(cleanup->ptc_arg); } pthread_mutex_lock(&self->pt_lock); } pthread_mutex_unlock(&self->pt_lock); __cxa_thread_run_atexit(); pthread_mutex_lock(&self->pt_lock); /* Perform cleanup of thread-specific data */ pthread__destroy_tsd(self); /* Signal our exit. */ self->pt_exitval = retval; if (self->pt_flags & PT_FLAG_DETACHED) { self->pt_state = PT_STATE_DEAD; name = self->pt_name; self->pt_name = NULL; pthread_mutex_unlock(&self->pt_lock); if (name != NULL) free(name); pthread_mutex_lock(&pthread__deadqueue_lock); PTQ_INSERT_TAIL(&pthread__deadqueue, self, pt_deadq); pthread_mutex_unlock(&pthread__deadqueue_lock); _lwp_exit(); } else { self->pt_state = PT_STATE_ZOMBIE; pthread_cond_broadcast(&self->pt_joiners); pthread_mutex_unlock(&self->pt_lock); /* Note: name will be freed by the joiner. */ _lwp_exit(); } out: /*NOTREACHED*/ pthread__abort(); exit(1); } int pthread_join(pthread_t thread, void **valptr) { pthread_t self; int error; self = pthread__self(); if (pthread__find(thread) != 0) return ESRCH; if (thread->pt_magic != PT_MAGIC) return EINVAL; if (thread == self) return EDEADLK; self->pt_droplock = &thread->pt_lock; pthread_mutex_lock(&thread->pt_lock); for (;;) { if (thread->pt_state == PT_STATE_ZOMBIE) break; if (thread->pt_state == PT_STATE_DEAD) { pthread_mutex_unlock(&thread->pt_lock); self->pt_droplock = NULL; return ESRCH; } if ((thread->pt_flags & PT_FLAG_DETACHED) != 0) { pthread_mutex_unlock(&thread->pt_lock); self->pt_droplock = NULL; return EINVAL; } error = pthread_cond_wait(&thread->pt_joiners, &thread->pt_lock); if (error != 0) { pthread__errorfunc(__FILE__, __LINE__, __func__, "unexpected return from cond_wait()"); } } pthread__testcancel(self); if (valptr != NULL) *valptr = thread->pt_exitval; /* pthread__reap() will drop the lock. */ pthread__reap(thread); self->pt_droplock = NULL; return 0; } static void pthread__reap(pthread_t thread) { char *name; name = thread->pt_name; thread->pt_name = NULL; thread->pt_state = PT_STATE_DEAD; pthread_mutex_unlock(&thread->pt_lock); pthread_mutex_lock(&pthread__deadqueue_lock); PTQ_INSERT_HEAD(&pthread__deadqueue, thread, pt_deadq); pthread_mutex_unlock(&pthread__deadqueue_lock); if (name != NULL) free(name); } int pthread_equal(pthread_t t1, pthread_t t2) { if (__predict_false(__uselibcstub)) return __libc_thr_equal_stub(t1, t2); /* Nothing special here. */ return (t1 == t2); } int pthread_detach(pthread_t thread) { if (pthread__find(thread) != 0) return ESRCH; if (thread->pt_magic != PT_MAGIC) return EINVAL; pthread_mutex_lock(&thread->pt_lock); thread->pt_flags |= PT_FLAG_DETACHED; if (thread->pt_state == PT_STATE_ZOMBIE) { /* pthread__reap() will drop the lock. */ pthread__reap(thread); } else { /* * Not valid for threads to be waiting in * pthread_join() (there are intractable * sync issues from the application * perspective), but give those threads * a chance anyway. */ pthread_cond_broadcast(&thread->pt_joiners); pthread_mutex_unlock(&thread->pt_lock); } return 0; } int pthread_getname_np(pthread_t thread, char *name, size_t len) { if (pthread__find(thread) != 0) return ESRCH; if (thread->pt_magic != PT_MAGIC) return EINVAL; pthread_mutex_lock(&thread->pt_lock); if (thread->pt_name == NULL) name[0] = '\0'; else strlcpy(name, thread->pt_name, len); pthread_mutex_unlock(&thread->pt_lock); return 0; } int pthread_setname_np(pthread_t thread, const char *name, void *arg) { char *oldname, *cp, newname[PTHREAD_MAX_NAMELEN_NP]; int namelen; if (pthread__find(thread) != 0) return ESRCH; if (thread->pt_magic != PT_MAGIC) return EINVAL; namelen = snprintf(newname, sizeof(newname), name, arg); if (namelen >= PTHREAD_MAX_NAMELEN_NP) return EINVAL; cp = strdup(newname); if (cp == NULL) return ENOMEM; pthread_mutex_lock(&thread->pt_lock); oldname = thread->pt_name; thread->pt_name = cp; (void)_lwp_setname(thread->pt_lid, cp); pthread_mutex_unlock(&thread->pt_lock); if (oldname != NULL) free(oldname); return 0; } /* * XXX There should be a way for applications to use the efficent * inline version, but there are opacity/namespace issues. */ pthread_t pthread_self(void) { if (__predict_false(__uselibcstub)) return (pthread_t)__libc_thr_self_stub(); return pthread__self(); } int pthread_cancel(pthread_t thread) { if (pthread__find(thread) != 0) return ESRCH; pthread_mutex_lock(&thread->pt_lock); thread->pt_flags |= PT_FLAG_CS_PENDING; if ((thread->pt_flags & PT_FLAG_CS_DISABLED) == 0) { thread->pt_cancel = 1; pthread_mutex_unlock(&thread->pt_lock); _lwp_wakeup(thread->pt_lid); } else pthread_mutex_unlock(&thread->pt_lock); return 0; } int pthread_setcancelstate(int state, int *oldstate) { pthread_t self; int retval; if (__predict_false(__uselibcstub)) return __libc_thr_setcancelstate_stub(state, oldstate); self = pthread__self(); retval = 0; pthread_mutex_lock(&self->pt_lock); if (oldstate != NULL) { if (self->pt_flags & PT_FLAG_CS_DISABLED) *oldstate = PTHREAD_CANCEL_DISABLE; else *oldstate = PTHREAD_CANCEL_ENABLE; } if (state == PTHREAD_CANCEL_DISABLE) { self->pt_flags |= PT_FLAG_CS_DISABLED; if (self->pt_cancel) { self->pt_flags |= PT_FLAG_CS_PENDING; self->pt_cancel = 0; } } else if (state == PTHREAD_CANCEL_ENABLE) { self->pt_flags &= ~PT_FLAG_CS_DISABLED; /* * If a cancellation was requested while cancellation * was disabled, note that fact for future * cancellation tests. */ if (self->pt_flags & PT_FLAG_CS_PENDING) { self->pt_cancel = 1; /* This is not a deferred cancellation point. */ if (self->pt_flags & PT_FLAG_CS_ASYNC) { pthread_mutex_unlock(&self->pt_lock); pthread__cancelled(); } } } else retval = EINVAL; pthread_mutex_unlock(&self->pt_lock); return retval; } int pthread_setcanceltype(int type, int *oldtype) { pthread_t self; int retval; self = pthread__self(); retval = 0; pthread_mutex_lock(&self->pt_lock); if (oldtype != NULL) { if (self->pt_flags & PT_FLAG_CS_ASYNC) *oldtype = PTHREAD_CANCEL_ASYNCHRONOUS; else *oldtype = PTHREAD_CANCEL_DEFERRED; } if (type == PTHREAD_CANCEL_ASYNCHRONOUS) { self->pt_flags |= PT_FLAG_CS_ASYNC; if (self->pt_cancel) { pthread_mutex_unlock(&self->pt_lock); pthread__cancelled(); } } else if (type == PTHREAD_CANCEL_DEFERRED) self->pt_flags &= ~PT_FLAG_CS_ASYNC; else retval = EINVAL; pthread_mutex_unlock(&self->pt_lock); return retval; } void pthread_testcancel(void) { pthread_t self; self = pthread__self(); if (self->pt_cancel) pthread__cancelled(); } /* * POSIX requires that certain functions return an error rather than * invoking undefined behavior even when handed completely bogus * pthread_t values, e.g. stack garbage. */ int pthread__find(pthread_t id) { pthread_t target; int error; pthread_rwlock_rdlock(&pthread__alltree_lock); target = rb_tree_find_node(&pthread__alltree, id); error = (target && target->pt_state != PT_STATE_DEAD) ? 0 : ESRCH; pthread_rwlock_unlock(&pthread__alltree_lock); return error; } void pthread__testcancel(pthread_t self) { if (self->pt_cancel) pthread__cancelled(); } void pthread__cancelled(void) { pthread_mutex_t *droplock; pthread_t self; self = pthread__self(); droplock = self->pt_droplock; self->pt_droplock = NULL; if (droplock != NULL && pthread_mutex_held_np(droplock)) pthread_mutex_unlock(droplock); pthread_exit(PTHREAD_CANCELED); } void pthread__cleanup_push(void (*cleanup)(void *), void *arg, void *store) { pthread_t self; struct pt_clean_t *entry; self = pthread__self(); entry = store; entry->ptc_cleanup = cleanup; entry->ptc_arg = arg; PTQ_INSERT_HEAD(&self->pt_cleanup_stack, entry, ptc_next); } void pthread__cleanup_pop(int ex, void *store) { pthread_t self; struct pt_clean_t *entry; self = pthread__self(); entry = store; PTQ_REMOVE(&self->pt_cleanup_stack, entry, ptc_next); if (ex) (*entry->ptc_cleanup)(entry->ptc_arg); } int * pthread__errno(void) { pthread_t self; if (__predict_false(__uselibcstub)) { pthread__errorfunc(__FILE__, __LINE__, __func__, "pthread__errno() requires linking with -lpthread"); return __libc_thr_errno_stub(); } self = pthread__self(); return &(self->pt_errno); } ssize_t _sys_write(int, const void *, size_t); void pthread__assertfunc(const char *file, int line, const char *function, const char *expr) { char buf[1024]; int len; /* * snprintf should not acquire any locks, or we could * end up deadlocked if the assert caller held locks. */ len = snprintf(buf, 1024, "assertion \"%s\" failed: file \"%s\", line %d%s%s%s\n", expr, file, line, function ? ", function \"" : "", function ? function : "", function ? "\"" : ""); _sys_write(STDERR_FILENO, buf, (size_t)len); (void)kill(getpid(), SIGABRT); _exit(1); } void pthread__errorfunc(const char *file, int line, const char *function, const char *msg) { char buf[1024]; size_t len; if (pthread__diagassert == 0) return; /* * snprintf should not acquire any locks, or we could * end up deadlocked if the assert caller held locks. */ len = snprintf(buf, 1024, "%s: Error detected by libpthread: %s.\n" "Detected by file \"%s\", line %d%s%s%s.\n" "See pthread(3) for information.\n", getprogname(), msg, file, line, function ? ", function \"" : "", function ? function : "", function ? "\"" : ""); if (pthread__diagassert & DIAGASSERT_STDERR) _sys_write(STDERR_FILENO, buf, len); if (pthread__diagassert & DIAGASSERT_SYSLOG) syslog(LOG_DEBUG | LOG_USER, "%s", buf); if (pthread__diagassert & DIAGASSERT_ABORT) { (void)kill(getpid(), SIGABRT); _exit(1); } } /* * Thread park/unpark operations. The kernel operations are * modelled after a brief description from "Multithreading in * the Solaris Operating Environment": * * http://www.sun.com/software/whitepapers/solaris9/multithread.pdf */ #define OOPS(msg) \ pthread__errorfunc(__FILE__, __LINE__, __func__, msg) int pthread__park(pthread_t self, pthread_mutex_t *lock, pthread_queue_t *queue, const struct timespec *abstime, int cancelpt, const void *hint) { int rv, error; void *obj; self->pt_willpark = 1; pthread_mutex_unlock(lock); self->pt_willpark = 0; /* * Wait until we are awoken by a pending unpark operation, * a signal, an unpark posted after we have gone asleep, * or an expired timeout. * * It is fine to test the value of pt_sleepobj without * holding any locks, because: * * o Only the blocking thread (this thread) ever sets them * to a non-NULL value. * * o Other threads may set them NULL, but if they do so they * must also make this thread return from _lwp_park. * * o _lwp_park, _lwp_unpark and _lwp_unpark_all are system * calls and all make use of spinlocks in the kernel. So * these system calls act as full memory barriers, and will * ensure that the calling CPU's store buffers are drained. * In combination with the spinlock release before unpark, * this means that modification of pt_sleepobj/onq by another * thread will become globally visible before that thread * schedules an unpark operation on this thread. * * Note: the test in the while() statement dodges the park op if * we have already been awoken, unless there is another thread to * awaken. This saves a syscall - if we were already awakened, * the next call to _lwp_park() would need to return early in order * to eat the previous wakeup. */ rv = 0; do { /* * If we deferred unparking a thread, arrange to * have _lwp_park() restart it before blocking. */ error = _lwp_park(CLOCK_REALTIME, TIMER_ABSTIME, __UNCONST(abstime), self->pt_unpark, hint, hint); self->pt_unpark = 0; if (error != 0) { switch (rv = errno) { case EINTR: case EALREADY: rv = 0; break; case ETIMEDOUT: break; default: OOPS("_lwp_park failed"); break; } } /* Check for cancellation. */ if (cancelpt && self->pt_cancel) rv = EINTR; } while (self->pt_sleepobj != NULL && rv == 0); /* * If we have been awoken early but are still on the queue, * then remove ourself. Again, it's safe to do the test * without holding any locks. */ if (__predict_false(self->pt_sleepobj != NULL)) { pthread_mutex_lock(lock); if ((obj = self->pt_sleepobj) != NULL) { PTQ_REMOVE(queue, self, pt_sleep); self->pt_sleepobj = NULL; if (obj != NULL && self->pt_early != NULL) (*self->pt_early)(obj); } pthread_mutex_unlock(lock); } self->pt_early = NULL; return rv; } void pthread__unpark(pthread_queue_t *queue, pthread_t self, pthread_mutex_t *interlock) { pthread_t target; u_int max; size_t nwaiters; max = pthread__unpark_max; nwaiters = self->pt_nwaiters; target = PTQ_FIRST(queue); if (nwaiters == max) { /* Overflow. */ (void)_lwp_unpark_all(self->pt_waiters, nwaiters, __UNVOLATILE(&interlock->ptm_waiters)); nwaiters = 0; } target->pt_sleepobj = NULL; self->pt_waiters[nwaiters++] = target->pt_lid; PTQ_REMOVE(queue, target, pt_sleep); self->pt_nwaiters = nwaiters; pthread__mutex_deferwake(self, interlock); } void pthread__unpark_all(pthread_queue_t *queue, pthread_t self, pthread_mutex_t *interlock) { pthread_t target; u_int max; size_t nwaiters; max = pthread__unpark_max; nwaiters = self->pt_nwaiters; PTQ_FOREACH(target, queue, pt_sleep) { if (nwaiters == max) { /* Overflow. */ (void)_lwp_unpark_all(self->pt_waiters, nwaiters, __UNVOLATILE(&interlock->ptm_waiters)); nwaiters = 0; } target->pt_sleepobj = NULL; self->pt_waiters[nwaiters++] = target->pt_lid; } self->pt_nwaiters = nwaiters; PTQ_INIT(queue); pthread__mutex_deferwake(self, interlock); } #undef OOPS static void pthread__initmainstack(void) { struct rlimit slimit; const AuxInfo *aux; size_t size, len; int mib[2]; unsigned int value; _DIAGASSERT(_dlauxinfo() != NULL); if (getrlimit(RLIMIT_STACK, &slimit) == -1) err(EXIT_FAILURE, "Couldn't get stack resource consumption limits"); size = slimit.rlim_cur; pthread__main->pt_stack.ss_size = size; pthread__main->pt_guardsize = pthread__pagesize; mib[0] = CTL_VM; mib[1] = VM_GUARD_SIZE; len = sizeof(value); if (sysctl(mib, __arraycount(mib), &value, &len, NULL, 0) == 0) pthread__main->pt_guardsize = value; for (aux = _dlauxinfo(); aux->a_type != AT_NULL; ++aux) { if (aux->a_type == AT_STACKBASE) { #ifdef __MACHINE_STACK_GROWS_UP pthread__main->pt_stack.ss_sp = (void *)aux->a_v; #else pthread__main->pt_stack.ss_sp = (char *)aux->a_v - size; #endif break; } } pthread__copy_tsd(pthread__main); } /* * Set up the slightly special stack for the "initial" thread, which * runs on the normal system stack, and thus gets slightly different * treatment. */ static void pthread__initmain(pthread_t *newt) { char *value; pthread__initmainstack(); value = pthread__getenv("PTHREAD_STACKSIZE"); if (value != NULL) { pthread__stacksize = atoi(value) * 1024; if (pthread__stacksize > pthread__main->pt_stack.ss_size) pthread__stacksize = pthread__main->pt_stack.ss_size; } if (pthread__stacksize == 0) pthread__stacksize = pthread__main->pt_stack.ss_size; pthread__stacksize += pthread__pagesize - 1; pthread__stacksize &= ~(pthread__pagesize - 1); if (pthread__stacksize < 4 * pthread__pagesize) errx(1, "Stacksize limit is too low, minimum %zd kbyte.", 4 * pthread__pagesize / 1024); *newt = pthread__main; #if defined(_PTHREAD_GETTCB_EXT) pthread__main->pt_tls = _PTHREAD_GETTCB_EXT(); #elif defined(__HAVE___LWP_GETTCB_FAST) pthread__main->pt_tls = __lwp_gettcb_fast(); #else pthread__main->pt_tls = _lwp_getprivate(); #endif pthread__main->pt_tls->tcb_pthread = pthread__main; } static signed int /*ARGSUSED*/ pthread__cmp(void *ctx, const void *n1, const void *n2) { const uintptr_t p1 = (const uintptr_t)n1; const uintptr_t p2 = (const uintptr_t)n2; if (p1 < p2) return -1; if (p1 > p2) return 1; return 0; } /* Because getenv() wants to use locks. */ char * pthread__getenv(const char *name) { extern char **environ; size_t l_name, offset; if (issetugid()) return (NULL); l_name = strlen(name); for (offset = 0; environ[offset] != NULL; offset++) { if (strncmp(name, environ[offset], l_name) == 0 && environ[offset][l_name] == '=') { return environ[offset] + l_name + 1; } } return NULL; } pthread_mutex_t * pthread__hashlock(volatile const void *p) { uintptr_t v; v = (uintptr_t)p; return &hashlocks[((v >> 9) ^ (v >> 3)) & (NHASHLOCK - 1)].mutex; } int pthread__checkpri(int pri) { static int havepri; static long min, max; if (!havepri) { min = sysconf(_SC_SCHED_PRI_MIN); max = sysconf(_SC_SCHED_PRI_MAX); havepri = 1; } return (pri < min || pri > max) ? EINVAL : 0; }