lib/libc_r/uthread/uthread_create.c

   1 /*
   2  * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by John Birrell.
  16  * 4. Neither the name of the author nor the names of any co-contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  * $FreeBSD$
  33  */
  34 #include <errno.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include <fcntl.h>
  38 #include <unistd.h>
  39 #include <sys/time.h>
  40 #include <sys/types.h>
  41 #include <sys/mman.h>
  42 #ifdef _THREAD_SAFE
  43 #include <machine/reg.h>
  44 #include <pthread.h>
  45 #include "pthread_private.h"
  46 #include "libc_private.h"
  47
  48 int
  49 pthread_create(pthread_t * thread, const pthread_attr_t * attr,
  50                void *(*start_routine) (void *), void *arg)
  51 {
  52         int             f_gc = 0;
  53         int             i;
  54         int             ret = 0;
  55         int             status;
  56         pthread_t       gc_thread;
  57         pthread_t       new_thread;
  58         pthread_attr_t  pattr;
  59         void           *stack;
  60
  61         /*
  62          * Locking functions in libc are required when there are
  63          * threads other than the initial thread.
  64          */
  65         __isthreaded = 1;
  66
  67         /* Allocate memory for the thread structure: */
  68         if ((new_thread = (pthread_t) malloc(sizeof(struct pthread))) == NULL) {
  69                 /* Insufficient memory to create a thread: */
  70                 ret = EAGAIN;
  71         } else {
  72                 /* Check if default thread attributes are required: */
  73                 if (attr == NULL || *attr == NULL) {
  74                         /* Use the default thread attributes: */
  75                         pattr = &pthread_attr_default;
  76                 } else {
  77                         pattr = *attr;
  78                 }
  79                 /* Check if a stack was specified in the thread attributes: */
  80                 if ((stack = pattr->stackaddr_attr) != NULL) {
  81                 }
  82                 /* Allocate memory for a default-size stack: */
  83                 else if (pattr->stacksize_attr == PTHREAD_STACK_DEFAULT) {
  84                         struct stack    *spare_stack;
  85
  86                         /* Allocate or re-use a default-size stack. */
  87
  88                         /*
  89                          * Use the garbage collector mutex for synchronization
  90                          * of the spare stack list.
  91                          */
  92                         if (pthread_mutex_lock(&_gc_mutex) != 0)
  93                                 PANIC("Cannot lock gc mutex");
  94
  95                         if ((spare_stack = SLIST_FIRST(&_stackq)) != NULL) {
  96                                 /* Use the spare stack. */
  97                                 SLIST_REMOVE_HEAD(&_stackq, qe);
  98
  99                                 /* Unlock the garbage collector mutex. */
 100                                 if (pthread_mutex_unlock(&_gc_mutex) != 0)
 101                                         PANIC("Cannot unlock gc mutex");
 102
 103                                 stack = sizeof(struct stack)
 104                                     + (void *) spare_stack
 105                                     - PTHREAD_STACK_DEFAULT;
 106                         } else {
 107                                 /* Unlock the garbage collector mutex. */
 108                                 if (pthread_mutex_unlock(&_gc_mutex) != 0)
 109                                         PANIC("Cannot unlock gc mutex");
 110
 111                                 /* Allocate a new stack. */
 112                                 stack = _next_stack + PTHREAD_STACK_GUARD;
 113                                 /*
 114                                  * Even if stack allocation fails, we don't want
 115                                  * to try to use this location again, so
 116                                  * unconditionally decrement _next_stack.  Under
 117                                  * normal operating conditions, the most likely
 118                                  * reason for an mmap() error is a stack
 119                                  * overflow of the adjacent thread stack.
 120                                  */
 121                                 _next_stack -= (PTHREAD_STACK_DEFAULT
 122                                                 + PTHREAD_STACK_GUARD);
 123
 124                                 /* Red zone: */
 125                                 if (mmap(_next_stack, PTHREAD_STACK_GUARD, 0,
 126                                          MAP_ANON, -1, 0) == MAP_FAILED) {
 127                                         ret = EAGAIN;
 128                                         free(new_thread);
 129                                 }
 130                                 /* Stack: */
 131                                 else if (mmap(stack,
 132                                               PTHREAD_STACK_DEFAULT,
 133                                               PROT_READ | PROT_WRITE,
 134 #ifdef __i386__
 135                                               MAP_STACK,
 136 #else
 137                                               MAP_ANON,
 138 #endif
 139                                               -1, 0) == MAP_FAILED) {
 140                                         ret = EAGAIN;
 141                                         munmap(_next_stack,
 142                                                PTHREAD_STACK_GUARD);
 143                                         free(new_thread);
 144                                 }
 145                         }
 146                 }
 147                 /*
 148                  * The user wants a stack of a particular size.  Lets hope they
 149                  * really know what they want, and simply malloc the stack.
 150                  */
 151                 else if ((stack = (void *) malloc(pattr->stacksize_attr))
 152                          == NULL) {
 153                         /* Insufficient memory to create a thread: */
 154                         ret = EAGAIN;
 155                         free(new_thread);
 156                 }
 157
 158                 /* Check for errors: */
 159                 if (ret != 0) {
 160                 } else {
 161                         /* Initialise the thread structure: */
 162                         memset(new_thread, 0, sizeof(struct pthread));
 163                         new_thread->slice_usec = -1;
 164                         new_thread->sig_saved = 0;
 165                         new_thread->stack = stack;
 166                         new_thread->start_routine = start_routine;
 167                         new_thread->arg = arg;
 168
 169                         /*
 170                          * Write a magic value to the thread structure
 171                          * to help identify valid ones:
 172                          */
 173                         new_thread->magic = PTHREAD_MAGIC;
 174
 175                         /* Initialise the thread for signals: */
 176                         new_thread->sigmask = _thread_run->sigmask;
 177
 178                         /* Initialise the jump buffer: */
 179                         setjmp(new_thread->saved_jmp_buf);
 180
 181                         /*
 182                          * Set up new stack frame so that it looks like it
 183                          * returned from a longjmp() to the beginning of
 184                          * _thread_start().
 185                          */
 186 #if     defined(__FreeBSD__)
 187 #if     defined(__alpha__)
 188                         new_thread->saved_jmp_buf[0]._jb[2] = (long) _thread_start;
 189                         new_thread->saved_jmp_buf[0]._jb[4 + R_RA] = 0;
 190                         new_thread->saved_jmp_buf[0]._jb[4 + R_T12] = (long) _thread_start;
 191 #else
 192                         new_thread->saved_jmp_buf[0]._jb[0] = (long) _thread_start;
 193 #endif
 194 #elif   defined(__NetBSD__)
 195 #if     defined(__alpha__)
 196                         new_thread->saved_jmp_buf[2] = (long) _thread_start;
 197                         new_thread->saved_jmp_buf[4 + R_RA] = 0;
 198                         new_thread->saved_jmp_buf[4 + R_T12] = (long) _thread_start;
 199 #else
 200                         new_thread->saved_jmp_buf[0] = (long) _thread_start;
 201 #endif
 202 #else
 203 #error  "Don't recognize this operating system!"
 204 #endif
 205
 206                         /* The stack starts high and builds down: */
 207 #if     defined(__FreeBSD__)
 208 #if     defined(__alpha__)
 209                         new_thread->saved_jmp_buf[0]._jb[4 + R_SP] = (long) new_thread->stack + pattr->stacksize_attr - sizeof(double);
 210 #else
 211                         new_thread->saved_jmp_buf[0]._jb[2] = (int) (new_thread->stack + pattr->stacksize_attr - sizeof(double));
 212 #endif
 213 #elif   defined(__NetBSD__)
 214 #if     defined(__alpha__)
 215                         new_thread->saved_jmp_buf[4 + R_SP] = (long) new_thread->stack + pattr->stacksize_attr - sizeof(double);
 216 #else
 217                         new_thread->saved_jmp_buf[2] = (long) new_thread->stack + pattr->stacksize_attr - sizeof(double);
 218 #endif
 219 #else
 220 #error  "Don't recognize this operating system!"
 221 #endif
 222
 223                         /* Copy the thread attributes: */
 224                         memcpy(&new_thread->attr, pattr, sizeof(struct pthread_attr));
 225
 226                         /*
 227                          * Check if this thread is to inherit the scheduling
 228                          * attributes from its parent:
 229                          */
 230                         if (new_thread->attr.flags & PTHREAD_INHERIT_SCHED) {
 231                                 /* Copy the scheduling attributes: */
 232                                 new_thread->base_priority
 233                                     = _thread_run->base_priority;
 234                                 new_thread->attr.prio
 235                                     = _thread_run->base_priority;
 236                                 new_thread->attr.sched_policy
 237                                     = _thread_run->attr.sched_policy;
 238                         } else {
 239                                 /*
 240                                  * Use just the thread priority, leaving the
 241                                  * other scheduling attributes as their
 242                                  * default values:
 243                                  */
 244                                 new_thread->base_priority
 245                                     = new_thread->attr.prio;
 246                         }
 247                         new_thread->active_priority = new_thread->base_priority;
 248                         new_thread->inherited_priority = 0;
 249
 250                         /* Initialise the join queue for the new thread: */
 251                         TAILQ_INIT(&(new_thread->join_queue));
 252
 253                         /* Initialize the mutex queue: */
 254                         TAILQ_INIT(&new_thread->mutexq);
 255
 256                         /* Initialise hooks in the thread structure: */
 257                         new_thread->specific_data = NULL;
 258                         new_thread->cleanup = NULL;
 259                         new_thread->flags = 0;
 260                         new_thread->poll_data.nfds = 0;
 261                         new_thread->poll_data.fds = NULL;
 262
 263                         /*
 264                          * Defer signals to protect the scheduling queues
 265                          * from access by the signal handler:
 266                          */
 267                         _thread_kern_sig_defer();
 268
 269                         /*
 270                          * Check if the garbage collector thread
 271                          * needs to be started.
 272                          */
 273                         f_gc = (TAILQ_FIRST(&_thread_list) == _thread_initial);
 274
 275                         /* Add the thread to the linked list of all threads: */
 276                         TAILQ_INSERT_HEAD(&_thread_list, new_thread, tle);
 277
 278                         if (pattr->suspend == PTHREAD_CREATE_SUSPENDED) {
 279                                 new_thread->state = PS_SUSPENDED;
 280                                 PTHREAD_WAITQ_INSERT(new_thread);
 281                         } else {
 282                                 new_thread->state = PS_RUNNING;
 283                                 PTHREAD_PRIOQ_INSERT_TAIL(new_thread);
 284                         }
 285
 286                         /*
 287                          * Undefer and handle pending signals, yielding
 288                          * if necessary.
 289                          */
 290                         _thread_kern_sig_undefer();
 291
 292                         /* Return a pointer to the thread structure: */
 293                         (*thread) = new_thread;
 294
 295                         /* Schedule the new user thread: */
 296                         _thread_kern_sched(NULL);
 297
 298                         /*
 299                          * Start a garbage collector thread
 300                          * if necessary.
 301                          */
 302                         if (f_gc && pthread_create(&gc_thread,NULL,
 303                                     _thread_gc,NULL) != 0)
 304                                 PANIC("Can't create gc thread");
 305                 }
 306         }
 307
 308         /* Return the status: */
 309         return (ret);
 310 }
 311
 312 void
 313 _thread_start(void)
 314 {
 315         /* We just left the scheduler via longjmp: */
 316         _thread_kern_in_sched = 0;
 317
 318         /* Run the current thread's start routine with argument: */
 319         pthread_exit(_thread_run->start_routine(_thread_run->arg));
 320
 321         /* This point should never be reached. */
 322         PANIC("Thread has resumed after exit");
 323 }
 324 #endif