lib/libkse/thread/thr_create.c

   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  * $FreeBSD$
  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
  47 static void free_thread(struct pthread *curthread, struct pthread *thread);
  48 static int  create_stack(struct pthread_attr *pattr);
  49 static void free_stack(struct pthread_attr *pattr);
  50 static 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  */
  80 int
  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
 291 static void
 292 free_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
 303 static int
 304 create_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
 319 static void
 320 free_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
 336 static void
 337 thread_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 }