lib/libthr/thread/thr_create.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2003 Daniel M. Eischen <deischen@gdeb.com>
   5  * Copyright (c) 2005, David Xu <davidxu@freebsd.org>
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice unmodified, this list of conditions, and the following
  13  *    disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  */
  29
  30 #include <sys/cdefs.h>
  31 __FBSDID("$FreeBSD$");
  32
  33 #include "namespace.h"
  34 #include <sys/types.h>
  35 #include <sys/rtprio.h>
  36 #include <sys/signalvar.h>
  37 #include <errno.h>
  38 #include <link.h>
  39 #include <stdlib.h>
  40 #include <string.h>
  41 #include <stddef.h>
  42 #include <pthread.h>
  43 #include <pthread_np.h>
  44 #include "un-namespace.h"
  45
  46 #include "libc_private.h"
  47 #include "thr_private.h"
  48
  49 static int  create_stack(struct pthread_attr *pattr);
  50 static void thread_start(struct pthread *curthread);
  51
  52 __weak_reference(_pthread_create, pthread_create);
  53
  54 int
  55 _pthread_create(pthread_t * __restrict thread,
  56     const pthread_attr_t * __restrict attr, void *(*start_routine) (void *),
  57     void * __restrict arg)
  58 {
  59         struct pthread *curthread, *new_thread;
  60         struct thr_param param;
  61         struct sched_param sched_param;
  62         struct rtprio rtp;
  63         sigset_t set, oset;
  64         cpuset_t *cpusetp;
  65         int i, cpusetsize, create_suspended, locked, old_stack_prot, ret;
  66
  67         cpusetp = NULL;
  68         ret = cpusetsize = 0;
  69         _thr_check_init();
  70
  71         /*
  72          * Tell libc and others now they need lock to protect their data.
  73          */
  74         if (_thr_isthreaded() == 0) {
  75                 _malloc_first_thread();
  76                 _thr_setthreaded(1);
  77         }
  78
  79         curthread = _get_curthread();
  80         if ((new_thread = _thr_alloc(curthread)) == NULL)
  81                 return (EAGAIN);
  82
  83         memset(&param, 0, sizeof(param));
  84
  85         if (attr == NULL || *attr == NULL)
  86                 /* Use the default thread attributes: */
  87                 new_thread->attr = _pthread_attr_default;
  88         else {
  89                 new_thread->attr = *(*attr);
  90                 cpusetp = new_thread->attr.cpuset;
  91                 cpusetsize = new_thread->attr.cpusetsize;
  92                 new_thread->attr.cpuset = NULL;
  93                 new_thread->attr.cpusetsize = 0;
  94         }
  95         if (new_thread->attr.sched_inherit == PTHREAD_INHERIT_SCHED) {
  96                 /* inherit scheduling contention scope */
  97                 if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
  98                         new_thread->attr.flags |= PTHREAD_SCOPE_SYSTEM;
  99                 else
 100                         new_thread->attr.flags &= ~PTHREAD_SCOPE_SYSTEM;
 101
 102                 new_thread->attr.prio = curthread->attr.prio;
 103                 new_thread->attr.sched_policy = curthread->attr.sched_policy;
 104         }
 105
 106         new_thread->tid = TID_TERMINATED;
 107
 108         old_stack_prot = _rtld_get_stack_prot();
 109         if (create_stack(&new_thread->attr) != 0) {
 110                 /* Insufficient memory to create a stack: */
 111                 _thr_free(curthread, new_thread);
 112                 return (EAGAIN);
 113         }
 114         /*
 115          * Write a magic value to the thread structure
 116          * to help identify valid ones:
 117          */
 118         new_thread->magic = THR_MAGIC;
 119         new_thread->start_routine = start_routine;
 120         new_thread->arg = arg;
 121         new_thread->cancel_enable = 1;
 122         new_thread->cancel_async = 0;
 123         /* Initialize the mutex queue: */
 124         for (i = 0; i < TMQ_NITEMS; i++)
 125                 TAILQ_INIT(&new_thread->mq[i]);
 126
 127         /* Initialise hooks in the thread structure: */
 128         if (new_thread->attr.suspend == THR_CREATE_SUSPENDED) {
 129                 new_thread->flags = THR_FLAGS_NEED_SUSPEND;
 130                 create_suspended = 1;
 131         } else {
 132                 create_suspended = 0;
 133         }
 134
 135         new_thread->state = PS_RUNNING;
 136
 137         if (new_thread->attr.flags & PTHREAD_CREATE_DETACHED)
 138                 new_thread->flags |= THR_FLAGS_DETACHED;
 139
 140         /* Add the new thread. */
 141         new_thread->refcount = 1;
 142         _thr_link(curthread, new_thread);
 143
 144         /*
 145          * Handle the race between __pthread_map_stacks_exec and
 146          * thread linkage.
 147          */
 148         if (old_stack_prot != _rtld_get_stack_prot())
 149                 _thr_stack_fix_protection(new_thread);
 150
 151         /* Return thread pointer eariler so that new thread can use it. */
 152         (*thread) = new_thread;
 153         if (SHOULD_REPORT_EVENT(curthread, TD_CREATE) || cpusetp != NULL) {
 154                 THR_THREAD_LOCK(curthread, new_thread);
 155                 locked = 1;
 156         } else
 157                 locked = 0;
 158         param.start_func = (void (*)(void *)) thread_start;
 159         param.arg = new_thread;
 160         param.stack_base = new_thread->attr.stackaddr_attr;
 161         param.stack_size = new_thread->attr.stacksize_attr;
 162         param.tls_base = (char *)new_thread->tcb;
 163         param.tls_size = sizeof(struct tcb);
 164         param.child_tid = &new_thread->tid;
 165         param.parent_tid = &new_thread->tid;
 166         param.flags = 0;
 167         if (new_thread->attr.flags & PTHREAD_SCOPE_SYSTEM)
 168                 param.flags |= THR_SYSTEM_SCOPE;
 169         if (new_thread->attr.sched_inherit == PTHREAD_INHERIT_SCHED)
 170                 param.rtp = NULL;
 171         else {
 172                 sched_param.sched_priority = new_thread->attr.prio;
 173                 _schedparam_to_rtp(new_thread->attr.sched_policy,
 174                         &sched_param, &rtp);
 175                 param.rtp = &rtp;
 176         }
 177
 178         /* Schedule the new thread. */
 179         if (create_suspended) {
 180                 SIGFILLSET(set);
 181                 SIGDELSET(set, SIGTRAP);
 182                 __sys_sigprocmask(SIG_SETMASK, &set, &oset);
 183                 new_thread->sigmask = oset;
 184                 SIGDELSET(new_thread->sigmask, SIGCANCEL);
 185         }
 186
 187         ret = thr_new(&param, sizeof(param));
 188
 189         if (ret != 0) {
 190                 ret = errno;
 191                 /*
 192                  * Translate EPROCLIM into well-known POSIX code EAGAIN.
 193                  */
 194                 if (ret == EPROCLIM)
 195                         ret = EAGAIN;
 196         }
 197
 198         if (create_suspended)
 199                 __sys_sigprocmask(SIG_SETMASK, &oset, NULL);
 200
 201         if (ret != 0) {
 202                 if (!locked)
 203                         THR_THREAD_LOCK(curthread, new_thread);
 204                 new_thread->state = PS_DEAD;
 205                 new_thread->tid = TID_TERMINATED;
 206                 new_thread->flags |= THR_FLAGS_DETACHED;
 207                 new_thread->refcount--;
 208                 if (new_thread->flags & THR_FLAGS_NEED_SUSPEND) {
 209                         new_thread->cycle++;
 210                         _thr_umtx_wake(&new_thread->cycle, INT_MAX, 0);
 211                 }
 212                 _thr_try_gc(curthread, new_thread); /* thread lock released */
 213                 atomic_add_int(&_thread_active_threads, -1);
 214         } else if (locked) {
 215                 if (cpusetp != NULL) {
 216                         if (cpuset_setaffinity(CPU_LEVEL_WHICH, CPU_WHICH_TID,
 217                                 TID(new_thread), cpusetsize, cpusetp)) {
 218                                 ret = errno;
 219                                 /* kill the new thread */
 220                                 new_thread->force_exit = 1;
 221                                 new_thread->flags |= THR_FLAGS_DETACHED;
 222                                 _thr_try_gc(curthread, new_thread);
 223                                  /* thread lock released */
 224                                 goto out;
 225                         }
 226                 }
 227
 228                 _thr_report_creation(curthread, new_thread);
 229                 THR_THREAD_UNLOCK(curthread, new_thread);
 230         }
 231 out:
 232         if (ret)
 233                 (*thread) = 0;
 234         return (ret);
 235 }
 236
 237 static int
 238 create_stack(struct pthread_attr *pattr)
 239 {
 240         int ret;
 241
 242         /* Check if a stack was specified in the thread attributes: */
 243         if ((pattr->stackaddr_attr) != NULL) {
 244                 pattr->guardsize_attr = 0;
 245                 pattr->flags |= THR_STACK_USER;
 246                 ret = 0;
 247         }
 248         else
 249                 ret = _thr_stack_alloc(pattr);
 250         return (ret);
 251 }
 252
 253 static void
 254 thread_start(struct pthread *curthread)
 255 {
 256         sigset_t set;
 257
 258         if (curthread->attr.suspend == THR_CREATE_SUSPENDED)
 259                 set = curthread->sigmask;
 260         _thr_signal_block_setup(curthread);
 261
 262         /*
 263          * This is used as a serialization point to allow parent
 264          * to report 'new thread' event to debugger or tweak new thread's
 265          * attributes before the new thread does real-world work.
 266          */
 267         THR_LOCK(curthread);
 268         THR_UNLOCK(curthread);
 269
 270         if (curthread->force_exit)
 271                 _pthread_exit(PTHREAD_CANCELED);
 272
 273         if (curthread->attr.suspend == THR_CREATE_SUSPENDED) {
 274 #if 0
 275                 /* Done in THR_UNLOCK() */
 276                 _thr_ast(curthread);
 277 #endif
 278
 279                 /*
 280                  * Parent thread have stored signal mask for us,
 281                  * we should restore it now.
 282                  */
 283                 __sys_sigprocmask(SIG_SETMASK, &set, NULL);
 284         }
 285
 286 #ifdef _PTHREAD_FORCED_UNWIND
 287         curthread->unwind_stackend = (char *)curthread->attr.stackaddr_attr +
 288                 curthread->attr.stacksize_attr;
 289 #endif
 290
 291         /* Run the current thread's start routine with argument: */
 292         _pthread_exit(curthread->start_routine(curthread->arg));
 293
 294         /* This point should never be reached. */
 295         PANIC("Thread has resumed after exit");
 296 }