thr_create.c revision 256281
1/* 2 * Copyright (c) 2003 Daniel M. Eischen <deischen@gdeb.com> 3 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Neither the name of the author nor the names of any co-contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 * $FreeBSD: stable/10/lib/libkse/thread/thr_create.c 174689 2007-12-16 23:29:57Z deischen $ 31 */ 32 33#include "namespace.h" 34#include <errno.h> 35#include <stdlib.h> 36#include <string.h> 37#include <fcntl.h> 38#include <unistd.h> 39#include <stddef.h> 40#include <sys/time.h> 41#include <machine/reg.h> 42#include <pthread.h> 43#include "un-namespace.h" 44#include "thr_private.h" 45#include "libc_private.h" 46 47static void free_thread(struct pthread *curthread, struct pthread *thread); 48static int create_stack(struct pthread_attr *pattr); 49static void free_stack(struct pthread_attr *pattr); 50static void thread_start(struct pthread *curthread, 51 void *(*start_routine) (void *), void *arg); 52 53__weak_reference(_pthread_create, pthread_create); 54 55/* 56 * Some notes on new thread creation and first time initializion 57 * to enable multi-threading. 58 * 59 * There are basically two things that need to be done. 60 * 61 * 1) The internal library variables must be initialized. 62 * 2) Upcalls need to be enabled to allow multiple threads 63 * to be run. 64 * 65 * The first may be done as a result of other pthread functions 66 * being called. When _thr_initial is null, _libpthread_init is 67 * called to initialize the internal variables; this also creates 68 * or sets the initial thread. It'd be nice to automatically 69 * have _libpthread_init called on program execution so we don't 70 * have to have checks throughout the library. 71 * 72 * The second part is only triggered by the creation of the first 73 * thread (other than the initial/main thread). If the thread 74 * being created is a scope system thread, then a new KSE/KSEG 75 * pair needs to be allocated. Also, if upcalls haven't been 76 * enabled on the initial thread's KSE, they must be now that 77 * there is more than one thread; this could be delayed until 78 * the initial KSEG has more than one thread. 79 */ 80int 81_pthread_create(pthread_t * thread, const pthread_attr_t * attr, 82 void *(*start_routine) (void *), void *arg) 83{ 84 struct pthread *curthread, *new_thread; 85 struct kse *kse = NULL; 86 struct kse_group *kseg = NULL; 87 kse_critical_t crit; 88 int ret = 0; 89 90 if (_thr_initial == NULL) 91 _libpthread_init(NULL); 92 93 /* 94 * Turn on threaded mode, if failed, it is unnecessary to 95 * do further work. 96 */ 97 if (_kse_isthreaded() == 0 && _kse_setthreaded(1)) { 98 return (EAGAIN); 99 } 100 curthread = _get_curthread(); 101 102 /* 103 * Allocate memory for the thread structure. 104 * Some functions use malloc, so don't put it 105 * in a critical region. 106 */ 107 if ((new_thread = _thr_alloc(curthread)) == NULL) { 108 /* Insufficient memory to create a thread: */ 109 ret = EAGAIN; 110 } else { 111 /* Check if default thread attributes are required: */ 112 if (attr == NULL || *attr == NULL) 113 /* Use the default thread attributes: */ 114 new_thread->attr = _pthread_attr_default; 115 else { 116 new_thread->attr = *(*attr); 117 if ((*attr)->sched_inherit == PTHREAD_INHERIT_SCHED) { 118 /* inherit scheduling contention scop */ 119 if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM) 120 new_thread->attr.flags |= PTHREAD_SCOPE_SYSTEM; 121 else 122 new_thread->attr.flags &= ~PTHREAD_SCOPE_SYSTEM; 123 /* 124 * scheduling policy and scheduling parameters will be 125 * inherited in following code. 126 */ 127 } 128 } 129 if (_thread_scope_system > 0) 130 new_thread->attr.flags |= PTHREAD_SCOPE_SYSTEM; 131 else if ((_thread_scope_system < 0) 132 && (thread != &_thr_sig_daemon)) 133 new_thread->attr.flags &= ~PTHREAD_SCOPE_SYSTEM; 134 if (create_stack(&new_thread->attr) != 0) { 135 /* Insufficient memory to create a stack: */ 136 ret = EAGAIN; 137 _thr_free(curthread, new_thread); 138 } 139 else if (((new_thread->attr.flags & PTHREAD_SCOPE_SYSTEM) != 0) && 140 (((kse = _kse_alloc(curthread, 1)) == NULL) 141 || ((kseg = _kseg_alloc(curthread)) == NULL))) { 142 /* Insufficient memory to create a new KSE/KSEG: */ 143 ret = EAGAIN; 144 if (kse != NULL) { 145 kse->k_kcb->kcb_kmbx.km_flags |= KMF_DONE; 146 _kse_free(curthread, kse); 147 } 148 free_stack(&new_thread->attr); 149 _thr_free(curthread, new_thread); 150 } 151 else { 152 if (kseg != NULL) { 153 /* Add the KSE to the KSEG's list of KSEs. */ 154 TAILQ_INSERT_HEAD(&kseg->kg_kseq, kse, k_kgqe); 155 kseg->kg_ksecount = 1; 156 kse->k_kseg = kseg; 157 kse->k_schedq = &kseg->kg_schedq; 158 } 159 /* 160 * Write a magic value to the thread structure 161 * to help identify valid ones: 162 */ 163 new_thread->magic = THR_MAGIC; 164 165 new_thread->slice_usec = -1; 166 new_thread->start_routine = start_routine; 167 new_thread->arg = arg; 168 new_thread->cancelflags = PTHREAD_CANCEL_ENABLE | 169 PTHREAD_CANCEL_DEFERRED; 170 171 /* No thread is wanting to join to this one: */ 172 new_thread->joiner = NULL; 173 174 /* 175 * Initialize the machine context. 176 * Enter a critical region to get consistent context. 177 */ 178 crit = _kse_critical_enter(); 179 THR_GETCONTEXT(&new_thread->tcb->tcb_tmbx.tm_context); 180 /* Initialize the thread for signals: */ 181 new_thread->sigmask = curthread->sigmask; 182 _kse_critical_leave(crit); 183 184 new_thread->tcb->tcb_tmbx.tm_udata = new_thread; 185 new_thread->tcb->tcb_tmbx.tm_context.uc_sigmask = 186 new_thread->sigmask; 187 new_thread->tcb->tcb_tmbx.tm_context.uc_stack.ss_size = 188 new_thread->attr.stacksize_attr; 189 new_thread->tcb->tcb_tmbx.tm_context.uc_stack.ss_sp = 190 new_thread->attr.stackaddr_attr; 191 makecontext(&new_thread->tcb->tcb_tmbx.tm_context, 192 (void (*)(void))thread_start, 3, new_thread, 193 start_routine, arg); 194 /* 195 * Check if this thread is to inherit the scheduling 196 * attributes from its parent: 197 */ 198 if (new_thread->attr.sched_inherit == PTHREAD_INHERIT_SCHED) { 199 /* 200 * Copy the scheduling attributes. 201 * Lock the scheduling lock to get consistent 202 * scheduling parameters. 203 */ 204 THR_SCHED_LOCK(curthread, curthread); 205 new_thread->base_priority = 206 curthread->base_priority & 207 ~THR_SIGNAL_PRIORITY; 208 new_thread->attr.prio = 209 curthread->base_priority & 210 ~THR_SIGNAL_PRIORITY; 211 new_thread->attr.sched_policy = 212 curthread->attr.sched_policy; 213 THR_SCHED_UNLOCK(curthread, curthread); 214 } else { 215 /* 216 * Use just the thread priority, leaving the 217 * other scheduling attributes as their 218 * default values: 219 */ 220 new_thread->base_priority = 221 new_thread->attr.prio; 222 } 223 new_thread->active_priority = new_thread->base_priority; 224 new_thread->inherited_priority = 0; 225 226 /* Initialize the mutex queue: */ 227 TAILQ_INIT(&new_thread->mutexq); 228 229 /* Initialise hooks in the thread structure: */ 230 new_thread->specific = NULL; 231 new_thread->specific_data_count = 0; 232 new_thread->cleanup = NULL; 233 new_thread->flags = 0; 234 new_thread->tlflags = 0; 235 new_thread->sigbackout = NULL; 236 new_thread->continuation = NULL; 237 new_thread->wakeup_time.tv_sec = -1; 238 new_thread->lock_switch = 0; 239 sigemptyset(&new_thread->sigpend); 240 new_thread->check_pending = 0; 241 new_thread->locklevel = 0; 242 new_thread->rdlock_count = 0; 243 new_thread->sigstk.ss_sp = 0; 244 new_thread->sigstk.ss_size = 0; 245 new_thread->sigstk.ss_flags = SS_DISABLE; 246 new_thread->oldsigmask = NULL; 247 248 if (new_thread->attr.suspend == THR_CREATE_SUSPENDED) { 249 new_thread->state = PS_SUSPENDED; 250 new_thread->flags = THR_FLAGS_SUSPENDED; 251 } 252 else 253 new_thread->state = PS_RUNNING; 254 255 /* 256 * System scope threads have their own kse and 257 * kseg. Process scope threads are all hung 258 * off the main process kseg. 259 */ 260 if ((new_thread->attr.flags & PTHREAD_SCOPE_SYSTEM) == 0) { 261 new_thread->kseg = _kse_initial->k_kseg; 262 new_thread->kse = _kse_initial; 263 } 264 else { 265 kse->k_curthread = NULL; 266 kse->k_kseg->kg_flags |= KGF_SINGLE_THREAD; 267 new_thread->kse = kse; 268 new_thread->kseg = kse->k_kseg; 269 kse->k_kcb->kcb_kmbx.km_udata = kse; 270 kse->k_kcb->kcb_kmbx.km_curthread = NULL; 271 } 272 273 /* 274 * Schedule the new thread starting a new KSEG/KSE 275 * pair if necessary. 276 */ 277 ret = _thr_schedule_add(curthread, new_thread); 278 if (ret != 0) 279 free_thread(curthread, new_thread); 280 else { 281 /* Return a pointer to the thread structure: */ 282 (*thread) = new_thread; 283 } 284 } 285 } 286 287 /* Return the status: */ 288 return (ret); 289} 290 291static void 292free_thread(struct pthread *curthread, struct pthread *thread) 293{ 294 free_stack(&thread->attr); 295 if ((thread->attr.flags & PTHREAD_SCOPE_SYSTEM) != 0) { 296 /* Free the KSE and KSEG. */ 297 _kseg_free(thread->kseg); 298 _kse_free(curthread, thread->kse); 299 } 300 _thr_free(curthread, thread); 301} 302 303static int 304create_stack(struct pthread_attr *pattr) 305{ 306 int ret; 307 308 /* Check if a stack was specified in the thread attributes: */ 309 if ((pattr->stackaddr_attr) != NULL) { 310 pattr->guardsize_attr = 0; 311 pattr->flags |= THR_STACK_USER; 312 ret = 0; 313 } 314 else 315 ret = _thr_stack_alloc(pattr); 316 return (ret); 317} 318 319static void 320free_stack(struct pthread_attr *pattr) 321{ 322 struct kse *curkse; 323 kse_critical_t crit; 324 325 if ((pattr->flags & THR_STACK_USER) == 0) { 326 crit = _kse_critical_enter(); 327 curkse = _get_curkse(); 328 KSE_LOCK_ACQUIRE(curkse, &_thread_list_lock); 329 /* Stack routines don't use malloc/free. */ 330 _thr_stack_free(pattr); 331 KSE_LOCK_RELEASE(curkse, &_thread_list_lock); 332 _kse_critical_leave(crit); 333 } 334} 335 336static void 337thread_start(struct pthread *curthread __unused, void *(*start_routine) (void *), 338 void *arg) 339{ 340 /* Run the current thread's start routine with argument: */ 341 _pthread_exit(start_routine(arg)); 342 343 /* This point should never be reached. */ 344 PANIC("Thread has resumed after exit"); 345} 346