linuxthreads/manager.c

   1 /* Linuxthreads - a simple clone()-based implementation of Posix        */
   2 /* threads for Linux.                                                   */
   3 /* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr)              */
   4 /*                                                                      */
   5 /* This program is free software; you can redistribute it and/or        */
   6 /* modify it under the terms of the GNU Library General Public License  */
   7 /* as published by the Free Software Foundation; either version 2       */
   8 /* of the License, or (at your option) any later version.               */
   9 /*                                                                      */
  10 /* This program is distributed in the hope that it will be useful,      */
  11 /* but WITHOUT ANY WARRANTY; without even the implied warranty of       */
  12 /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        */
  13 /* GNU Library General Public License for more details.                 */
  14
  15 /* The "thread manager" thread: manages creation and termination of threads */
  16
  17 #include <errno.h>
  18 #include <sched.h>
  19 #include <stddef.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24 #include <sys/poll.h>           /* for poll */
  25 #include <sys/mman.h>           /* for mmap */
  26 #include <sys/param.h>
  27 #include <sys/time.h>
  28 #include <sys/wait.h>           /* for waitpid macros */
  29
  30 #include "pthread.h"
  31 #include "internals.h"
  32 #include "spinlock.h"
  33 #include "restart.h"
  34 #include "semaphore.h"
  35
  36 /* Array of active threads. Entry 0 is reserved for the initial thread. */
  37 struct pthread_handle_struct __pthread_handles[PTHREAD_THREADS_MAX] =
  38 { { LOCK_INITIALIZER, &__pthread_initial_thread, 0},
  39   { LOCK_INITIALIZER, &__pthread_manager_thread, 0}, /* All NULLs */ };
  40
  41 /* For debugging purposes put the maximum number of threads in a variable.  */
  42 const int __linuxthreads_pthread_threads_max = PTHREAD_THREADS_MAX;
  43
  44 /* Indicate whether at least one thread has a user-defined stack (if 1),
  45    or if all threads have stacks supplied by LinuxThreads (if 0). */
  46 int __pthread_nonstandard_stacks;
  47
  48 /* Number of active entries in __pthread_handles (used by gdb) */
  49 volatile int __pthread_handles_num = 2;
  50
  51 /* Whether to use debugger additional actions for thread creation
  52    (set to 1 by gdb) */
  53 volatile int __pthread_threads_debug;
  54
  55 /* Globally enabled events.  */
  56 volatile td_thr_events_t __pthread_threads_events;
  57
  58 /* Pointer to thread descriptor with last event.  */
  59 volatile pthread_descr __pthread_last_event;
  60
  61 /* Mapping from stack segment to thread descriptor. */
  62 /* Stack segment numbers are also indices into the __pthread_handles array. */
  63 /* Stack segment number 0 is reserved for the initial thread. */
  64
  65 static inline pthread_descr thread_segment(int seg)
  66 {
  67   return (pthread_descr)(THREAD_STACK_START_ADDRESS - (seg - 1) * STACK_SIZE)
  68          - 1;
  69 }
  70
  71 /* Flag set in signal handler to record child termination */
  72
  73 static volatile int terminated_children = 0;
  74
  75 /* Flag set when the initial thread is blocked on pthread_exit waiting
  76    for all other threads to terminate */
  77
  78 static int main_thread_exiting = 0;
  79
  80 /* Counter used to generate unique thread identifier.
  81    Thread identifier is pthread_threads_counter + segment. */
  82
  83 static pthread_t pthread_threads_counter = 0;
  84
  85 /* Forward declarations */
  86
  87 static int pthread_handle_create(pthread_t *thread, const pthread_attr_t *attr,
  88                                  void * (*start_routine)(void *), void *arg,
  89                                  sigset_t *mask, int father_pid,
  90                                  int report_events,
  91                                  td_thr_events_t *event_maskp);
  92 static void pthread_handle_free(pthread_t th_id);
  93 static void pthread_handle_exit(pthread_descr issuing_thread, int exitcode);
  94 static void pthread_reap_children(void);
  95 static void pthread_kill_all_threads(int sig, int main_thread_also);
  96
  97 /* The server thread managing requests for thread creation and termination */
  98
  99 int __pthread_manager(void *arg)
 100 {
 101   int reqfd = (int) (long int) arg;
 102   struct pollfd ufd;
 103   sigset_t mask;
 104   int n;
 105   struct pthread_request request;
 106
 107   /* If we have special thread_self processing, initialize it.  */
 108 #ifdef INIT_THREAD_SELF
 109   INIT_THREAD_SELF(&__pthread_manager_thread, 1);
 110 #endif
 111   /* Set the error variable.  */
 112   __pthread_manager_thread.p_errnop = &__pthread_manager_thread.p_errno;
 113   __pthread_manager_thread.p_h_errnop = &__pthread_manager_thread.p_h_errno;
 114   /* Block all signals except __pthread_sig_cancel and SIGTRAP */
 115   sigfillset(&mask);
 116   sigdelset(&mask, __pthread_sig_cancel); /* for thread termination */
 117   sigdelset(&mask, SIGTRAP);            /* for debugging purposes */
 118   if (__pthread_threads_debug && __pthread_sig_debug > 0)
 119     sigdelset(&mask, __pthread_sig_debug);
 120   sigprocmask(SIG_SETMASK, &mask, NULL);
 121   /* Raise our priority to match that of main thread */
 122   __pthread_manager_adjust_prio(__pthread_main_thread->p_priority);
 123   /* Synchronize debugging of the thread manager */
 124   n = __libc_read(reqfd, (char *)&request, sizeof(request));
 125   ASSERT(n == sizeof(request) && request.req_kind == REQ_DEBUG);
 126   ufd.fd = reqfd;
 127   ufd.events = POLLIN;
 128   /* Enter server loop */
 129   while(1) {
 130     n = __poll(&ufd, 1, 2000);
 131
 132     /* Check for termination of the main thread */
 133     if (getppid() == 1) {
 134       pthread_kill_all_threads(SIGKILL, 0);
 135       _exit(0);
 136     }
 137     /* Check for dead children */
 138     if (terminated_children) {
 139       terminated_children = 0;
 140       pthread_reap_children();
 141     }
 142     /* Read and execute request */
 143     if (n == 1 && (ufd.revents & POLLIN)) {
 144       n = __libc_read(reqfd, (char *)&request, sizeof(request));
 145       ASSERT(n == sizeof(request));
 146       switch(request.req_kind) {
 147       case REQ_CREATE:
 148         request.req_thread->p_retcode =
 149           pthread_handle_create((pthread_t *) &request.req_thread->p_retval,
 150                                 request.req_args.create.attr,
 151                                 request.req_args.create.fn,
 152                                 request.req_args.create.arg,
 153                                 &request.req_args.create.mask,
 154                                 request.req_thread->p_pid,
 155                                 request.req_thread->p_report_events,
 156                                 &request.req_thread->p_eventbuf.eventmask);
 157         restart(request.req_thread);
 158         break;
 159       case REQ_FREE:
 160         pthread_handle_free(request.req_args.free.thread_id);
 161         break;
 162       case REQ_PROCESS_EXIT:
 163         pthread_handle_exit(request.req_thread,
 164                             request.req_args.exit.code);
 165         break;
 166       case REQ_MAIN_THREAD_EXIT:
 167         main_thread_exiting = 1;
 168         if (__pthread_main_thread->p_nextlive == __pthread_main_thread) {
 169           restart(__pthread_main_thread);
 170           return 0;
 171         }
 172         break;
 173       case REQ_POST:
 174         __new_sem_post(request.req_args.post);
 175         break;
 176       case REQ_DEBUG:
 177         /* Make gdb aware of new thread and gdb will restart the
 178            new thread when it is ready to handle the new thread. */
 179         if (__pthread_threads_debug && __pthread_sig_debug > 0)
 180           raise(__pthread_sig_debug);
 181         break;
 182       }
 183     }
 184   }
 185 }
 186
 187 int __pthread_manager_event(void *arg)
 188 {
 189   /* If we have special thread_self processing, initialize it.  */
 190 #ifdef INIT_THREAD_SELF
 191   INIT_THREAD_SELF(&__pthread_manager_thread, 1);
 192 #endif
 193
 194   /* Get the lock the manager will free once all is correctly set up.  */
 195   __pthread_lock (THREAD_GETMEM((&__pthread_manager_thread), p_lock), NULL);
 196   /* Free it immediately.  */
 197   __pthread_unlock (THREAD_GETMEM((&__pthread_manager_thread), p_lock));
 198
 199   return __pthread_manager(arg);
 200 }
 201
 202 /* Process creation */
 203
 204 static int pthread_start_thread(void *arg)
 205 {
 206   pthread_descr self = (pthread_descr) arg;
 207   struct pthread_request request;
 208   void * outcome;
 209   /* Initialize special thread_self processing, if any.  */
 210 #ifdef INIT_THREAD_SELF
 211   INIT_THREAD_SELF(self, self->p_nr);
 212 #endif
 213   /* Make sure our pid field is initialized, just in case we get there
 214      before our father has initialized it. */
 215   THREAD_SETMEM(self, p_pid, __getpid());
 216   /* Initial signal mask is that of the creating thread. (Otherwise,
 217      we'd just inherit the mask of the thread manager.) */
 218   sigprocmask(SIG_SETMASK, &self->p_start_args.mask, NULL);
 219   /* Set the scheduling policy and priority for the new thread, if needed */
 220   if (THREAD_GETMEM(self, p_start_args.schedpolicy) >= 0)
 221     /* Explicit scheduling attributes were provided: apply them */
 222     __sched_setscheduler(THREAD_GETMEM(self, p_pid),
 223                          THREAD_GETMEM(self, p_start_args.schedpolicy),
 224                          &self->p_start_args.schedparam);
 225   else if (__pthread_manager_thread.p_priority > 0)
 226     /* Default scheduling required, but thread manager runs in realtime
 227        scheduling: switch new thread to SCHED_OTHER policy */
 228     {
 229       struct sched_param default_params;
 230       default_params.sched_priority = 0;
 231       __sched_setscheduler(THREAD_GETMEM(self, p_pid),
 232                            SCHED_OTHER, &default_params);
 233     }
 234   /* Make gdb aware of new thread */
 235   if (__pthread_threads_debug && __pthread_sig_debug > 0) {
 236     request.req_thread = self;
 237     request.req_kind = REQ_DEBUG;
 238     __libc_write(__pthread_manager_request,
 239                  (char *) &request, sizeof(request));
 240     suspend(self);
 241   }
 242   /* Run the thread code */
 243   outcome = self->p_start_args.start_routine(THREAD_GETMEM(self,
 244                                                            p_start_args.arg));
 245   /* Exit with the given return value */
 246   pthread_exit(outcome);
 247   return 0;
 248 }
 249
 250 static int pthread_start_thread_event(void *arg)
 251 {
 252   pthread_descr self = (pthread_descr) arg;
 253
 254 #ifdef INIT_THREAD_SELF
 255   INIT_THREAD_SELF(self, self->p_nr);
 256 #endif
 257   /* Make sure our pid field is initialized, just in case we get there
 258      before our father has initialized it. */
 259   THREAD_SETMEM(self, p_pid, __getpid());
 260   /* Get the lock the manager will free once all is correctly set up.  */
 261   __pthread_lock (THREAD_GETMEM(self, p_lock), NULL);
 262   /* Free it immediately.  */
 263   __pthread_unlock (THREAD_GETMEM(self, p_lock));
 264
 265   /* Continue with the real function.  */
 266   return pthread_start_thread (arg);
 267 }
 268
 269 static int pthread_allocate_stack(const pthread_attr_t *attr,
 270                                   pthread_descr default_new_thread,
 271                                   int pagesize,
 272                                   pthread_descr * out_new_thread,
 273                                   char ** out_new_thread_bottom,
 274                                   char ** out_guardaddr,
 275                                   size_t * out_guardsize)
 276 {
 277   pthread_descr new_thread;
 278   char * new_thread_bottom;
 279   char * guardaddr;
 280   size_t stacksize, guardsize;
 281
 282   if (attr != NULL && attr->__stackaddr_set)
 283     {
 284       /* The user provided a stack. */
 285       new_thread =
 286         (pthread_descr) ((long)(attr->__stackaddr) & -sizeof(void *)) - 1;
 287       new_thread_bottom = (char *) attr->__stackaddr - attr->__stacksize;
 288       guardaddr = NULL;
 289       guardsize = 0;
 290       __pthread_nonstandard_stacks = 1;
 291     }
 292   else
 293     {
 294       stacksize = STACK_SIZE - pagesize;
 295       if (attr != NULL)
 296         stacksize = MIN (stacksize, roundup(attr->__stacksize, pagesize));
 297       /* Allocate space for stack and thread descriptor at default address */
 298       new_thread = default_new_thread;
 299       new_thread_bottom = (char *) (new_thread + 1) - stacksize;
 300       if (mmap((caddr_t)((char *)(new_thread + 1) - INITIAL_STACK_SIZE),
 301                INITIAL_STACK_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC,
 302                MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED | MAP_GROWSDOWN,
 303                -1, 0) == MAP_FAILED)
 304         /* Bad luck, this segment is already mapped. */
 305         return -1;
 306       /* We manage to get a stack.  Now see whether we need a guard
 307          and allocate it if necessary.  Notice that the default
 308          attributes (stack_size = STACK_SIZE - pagesize) do not need
 309          a guard page, since the RLIMIT_STACK soft limit prevents stacks
 310          from running into one another. */
 311       if (stacksize == STACK_SIZE - pagesize)
 312         {
 313           /* We don't need a guard page. */
 314           guardaddr = NULL;
 315           guardsize = 0;
 316         }
 317       else
 318         {
 319           /* Put a bad page at the bottom of the stack */
 320           guardsize = attr->__guardsize;
 321           guardaddr = (void *)new_thread_bottom - guardsize;
 322           if (mmap ((caddr_t) guardaddr, guardsize, 0, MAP_FIXED, -1, 0)
 323               == MAP_FAILED)
 324             {
 325               /* We don't make this an error.  */
 326               guardaddr = NULL;
 327               guardsize = 0;
 328             }
 329         }
 330     }
 331   /* Clear the thread data structure.  */
 332   memset (new_thread, '\0', sizeof (*new_thread));
 333   *out_new_thread = new_thread;
 334   *out_new_thread_bottom = new_thread_bottom;
 335   *out_guardaddr = guardaddr;
 336   *out_guardsize = guardsize;
 337   return 0;
 338 }
 339
 340 static int pthread_handle_create(pthread_t *thread, const pthread_attr_t *attr,
 341                                  void * (*start_routine)(void *), void *arg,
 342                                  sigset_t * mask, int father_pid,
 343                                  int report_events,
 344                                  td_thr_events_t *event_maskp)
 345 {
 346   size_t sseg;
 347   int pid;
 348   pthread_descr new_thread;
 349   char * new_thread_bottom;
 350   pthread_t new_thread_id;
 351   char *guardaddr = NULL;
 352   size_t guardsize = 0;
 353   int pagesize = __getpagesize();
 354
 355   /* First check whether we have to change the policy and if yes, whether
 356      we can  do this.  Normally this should be done by examining the
 357      return value of the __sched_setscheduler call in pthread_start_thread
 358      but this is hard to implement.  FIXME  */
 359   if (attr != NULL && attr->__schedpolicy != SCHED_OTHER && geteuid () != 0)
 360     return EPERM;
 361   /* Find a free segment for the thread, and allocate a stack if needed */
 362   for (sseg = 2; ; sseg++)
 363     {
 364       if (sseg >= PTHREAD_THREADS_MAX)
 365         return EAGAIN;
 366       if (__pthread_handles[sseg].h_descr != NULL)
 367         continue;
 368       if (pthread_allocate_stack(attr, thread_segment(sseg), pagesize,
 369                                  &new_thread, &new_thread_bottom,
 370                                  &guardaddr, &guardsize) == 0)
 371         break;
 372     }
 373   __pthread_handles_num++;
 374   /* Allocate new thread identifier */
 375   pthread_threads_counter += PTHREAD_THREADS_MAX;
 376   new_thread_id = sseg + pthread_threads_counter;
 377   /* Initialize the thread descriptor.  Elements which have to be
 378      initialized to zero already have this value.  */
 379   new_thread->p_tid = new_thread_id;
 380   new_thread->p_lock = &(__pthread_handles[sseg].h_lock);
 381   new_thread->p_cancelstate = PTHREAD_CANCEL_ENABLE;
 382   new_thread->p_canceltype = PTHREAD_CANCEL_DEFERRED;
 383   new_thread->p_errnop = &new_thread->p_errno;
 384   new_thread->p_h_errnop = &new_thread->p_h_errno;
 385   new_thread->p_resp = &new_thread->p_res;
 386   new_thread->p_guardaddr = guardaddr;
 387   new_thread->p_guardsize = guardsize;
 388   new_thread->p_self = new_thread;
 389   new_thread->p_nr = sseg;
 390   /* Initialize the thread handle */
 391   __pthread_init_lock(&__pthread_handles[sseg].h_lock);
 392   __pthread_handles[sseg].h_descr = new_thread;
 393   __pthread_handles[sseg].h_bottom = new_thread_bottom;
 394   /* Determine scheduling parameters for the thread */
 395   new_thread->p_start_args.schedpolicy = -1;
 396   if (attr != NULL) {
 397     new_thread->p_detached = attr->__detachstate;
 398     new_thread->p_userstack = attr->__stackaddr_set;
 399
 400     switch(attr->__inheritsched) {
 401     case PTHREAD_EXPLICIT_SCHED:
 402       new_thread->p_start_args.schedpolicy = attr->__schedpolicy;
 403       memcpy (&new_thread->p_start_args.schedparam, &attr->__schedparam,
 404               sizeof (struct sched_param));
 405       break;
 406     case PTHREAD_INHERIT_SCHED:
 407       new_thread->p_start_args.schedpolicy = __sched_getscheduler(father_pid);
 408       __sched_getparam(father_pid, &new_thread->p_start_args.schedparam);
 409       break;
 410     }
 411     new_thread->p_priority =
 412       new_thread->p_start_args.schedparam.sched_priority;
 413   }
 414   /* Finish setting up arguments to pthread_start_thread */
 415   new_thread->p_start_args.start_routine = start_routine;
 416   new_thread->p_start_args.arg = arg;
 417   new_thread->p_start_args.mask = *mask;
 418   /* Make the new thread ID available already now.  If any of the later
 419      functions fail we return an error value and the caller must not use
 420      the stored thread ID.  */
 421   *thread = new_thread_id;
 422   /* Raise priority of thread manager if needed */
 423   __pthread_manager_adjust_prio(new_thread->p_priority);
 424   /* Do the cloning.  We have to use two different functions depending
 425      on whether we are debugging or not.  */
 426   pid = 0;      /* Note that the thread never can have PID zero.  */
 427   if (report_events)
 428     {
 429       /* See whether the TD_CREATE event bit is set in any of the
 430          masks.  */
 431       int idx = __td_eventword (TD_CREATE);
 432       uint32_t mask = __td_eventmask (TD_CREATE);
 433
 434       if ((mask & (__pthread_threads_events.event_bits[idx]
 435                    | event_maskp->event_bits[idx])) != 0)
 436         {
 437           /* Lock the mutex the child will use now so that it will stop.  */
 438           __pthread_lock(new_thread->p_lock, NULL);
 439
 440           /* We have to report this event.  */
 441           pid = __clone(pthread_start_thread_event, (void **) new_thread,
 442                         CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND |
 443                         __pthread_sig_cancel, new_thread);
 444           if (pid != -1)
 445             {
 446               /* Now fill in the information about the new thread in
 447                  the newly created thread's data structure.  We cannot let
 448                  the new thread do this since we don't know whether it was
 449                  already scheduled when we send the event.  */
 450               new_thread->p_eventbuf.eventdata = new_thread;
 451               new_thread->p_eventbuf.eventnum = TD_CREATE;
 452               __pthread_last_event = new_thread;
 453
 454               /* We have to set the PID here since the callback function
 455                  in the debug library will need it and we cannot guarantee
 456                  the child got scheduled before the debugger.  */
 457               new_thread->p_pid = pid;
 458
 459               /* Now call the function which signals the event.  */
 460               __linuxthreads_create_event ();
 461
 462               /* Now restart the thread.  */
 463               __pthread_unlock(new_thread->p_lock);
 464             }
 465         }
 466     }
 467   if (pid == 0)
 468     pid = __clone(pthread_start_thread, (void **) new_thread,
 469                   CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND |
 470                   __pthread_sig_cancel, new_thread);
 471   /* Check if cloning succeeded */
 472   if (pid == -1) {
 473     /* Free the stack if we allocated it */
 474     if (attr == NULL || !attr->__stackaddr_set)
 475       {
 476         if (new_thread->p_guardsize != 0)
 477           munmap(new_thread->p_guardaddr, new_thread->p_guardsize);
 478         munmap((caddr_t)((char *)(new_thread+1) - INITIAL_STACK_SIZE),
 479                INITIAL_STACK_SIZE);
 480       }
 481     __pthread_handles[sseg].h_descr = NULL;
 482     __pthread_handles[sseg].h_bottom = NULL;
 483     __pthread_handles_num--;
 484     return errno;
 485   }
 486   /* Insert new thread in doubly linked list of active threads */
 487   new_thread->p_prevlive = __pthread_main_thread;
 488   new_thread->p_nextlive = __pthread_main_thread->p_nextlive;
 489   __pthread_main_thread->p_nextlive->p_prevlive = new_thread;
 490   __pthread_main_thread->p_nextlive = new_thread;
 491   /* Set pid field of the new thread, in case we get there before the
 492      child starts. */
 493   new_thread->p_pid = pid;
 494   return 0;
 495 }
 496
 497
 498 /* Try to free the resources of a thread when requested by pthread_join
 499    or pthread_detach on a terminated thread. */
 500
 501 static void pthread_free(pthread_descr th)
 502 {
 503   pthread_handle handle;
 504   pthread_readlock_info *iter, *next;
 505
 506   ASSERT(th->p_exited);
 507   /* Make the handle invalid */
 508   handle =  thread_handle(th->p_tid);
 509   __pthread_lock(&handle->h_lock, NULL);
 510   handle->h_descr = NULL;
 511   handle->h_bottom = (char *)(-1L);
 512   __pthread_unlock(&handle->h_lock);
 513 #ifdef FREE_THREAD_SELF
 514   FREE_THREAD_SELF(th, th->p_nr);
 515 #endif
 516   /* One fewer threads in __pthread_handles */
 517   __pthread_handles_num--;
 518
 519   /* Destroy read lock list, and list of free read lock structures.
 520      If the former is not empty, it means the thread exited while
 521      holding read locks! */
 522
 523   for (iter = th->p_readlock_list; iter != NULL; iter = next)
 524     {
 525       next = iter->pr_next;
 526       free(iter);
 527     }
 528
 529   for (iter = th->p_readlock_free; iter != NULL; iter = next)
 530     {
 531       next = iter->pr_next;
 532       free(iter);
 533     }
 534
 535   /* If initial thread, nothing to free */
 536   if (th == &__pthread_initial_thread) return;
 537   if (!th->p_userstack)
 538     {
 539       /* Free the stack and thread descriptor area */
 540       if (th->p_guardsize != 0)
 541         munmap(th->p_guardaddr, th->p_guardsize);
 542       munmap((caddr_t) ((char *)(th+1) - STACK_SIZE), STACK_SIZE);
 543     }
 544 }
 545
 546 /* Handle threads that have exited */
 547
 548 static void pthread_exited(pid_t pid)
 549 {
 550   pthread_descr th;
 551   int detached;
 552   /* Find thread with that pid */
 553   for (th = __pthread_main_thread->p_nextlive;
 554        th != __pthread_main_thread;
 555        th = th->p_nextlive) {
 556     if (th->p_pid == pid) {
 557       /* Remove thread from list of active threads */
 558       th->p_nextlive->p_prevlive = th->p_prevlive;
 559       th->p_prevlive->p_nextlive = th->p_nextlive;
 560       /* Mark thread as exited, and if detached, free its resources */
 561       __pthread_lock(th->p_lock, NULL);
 562       th->p_exited = 1;
 563       /* If we have to signal this event do it now.  */
 564       if (th->p_report_events)
 565         {
 566           /* See whether TD_DEATH is in any of the mask.  */
 567           int idx = __td_eventword (TD_REAP);
 568           uint32_t mask = __td_eventmask (TD_REAP);
 569
 570           if ((mask & (__pthread_threads_events.event_bits[idx]
 571                        | th->p_eventbuf.eventmask.event_bits[idx])) != 0)
 572             {
 573               /* Yep, we have to signal the death.  */
 574               th->p_eventbuf.eventnum = TD_DEATH;
 575               th->p_eventbuf.eventdata = th;
 576               __pthread_last_event = th;
 577
 578               /* Now call the function to signal the event.  */
 579               __linuxthreads_reap_event();
 580             }
 581         }
 582       detached = th->p_detached;
 583       __pthread_unlock(th->p_lock);
 584       if (detached)
 585         pthread_free(th);
 586       break;
 587     }
 588   }
 589   /* If all threads have exited and the main thread is pending on a
 590      pthread_exit, wake up the main thread and terminate ourselves. */
 591   if (main_thread_exiting &&
 592       __pthread_main_thread->p_nextlive == __pthread_main_thread) {
 593     restart(__pthread_main_thread);
 594     _exit(0);
 595   }
 596 }
 597
 598 static void pthread_reap_children(void)
 599 {
 600   pid_t pid;
 601   int status;
 602
 603   while ((pid = __libc_waitpid(-1, &status, WNOHANG | __WCLONE)) > 0) {
 604     pthread_exited(pid);
 605     if (WIFSIGNALED(status)) {
 606       /* If a thread died due to a signal, send the same signal to
 607          all other threads, including the main thread. */
 608       pthread_kill_all_threads(WTERMSIG(status), 1);
 609       _exit(0);
 610     }
 611   }
 612 }
 613
 614 /* Try to free the resources of a thread when requested by pthread_join
 615    or pthread_detach on a terminated thread. */
 616
 617 static void pthread_handle_free(pthread_t th_id)
 618 {
 619   pthread_handle handle = thread_handle(th_id);
 620   pthread_descr th;
 621
 622   __pthread_lock(&handle->h_lock, NULL);
 623   if (invalid_handle(handle, th_id)) {
 624     /* pthread_reap_children has deallocated the thread already,
 625        nothing needs to be done */
 626     __pthread_unlock(&handle->h_lock);
 627     return;
 628   }
 629   th = handle->h_descr;
 630   if (th->p_exited) {
 631     __pthread_unlock(&handle->h_lock);
 632     pthread_free(th);
 633   } else {
 634     /* The Unix process of the thread is still running.
 635        Mark the thread as detached so that the thread manager will
 636        deallocate its resources when the Unix process exits. */
 637     th->p_detached = 1;
 638     __pthread_unlock(&handle->h_lock);
 639   }
 640 }
 641
 642 /* Send a signal to all running threads */
 643
 644 static void pthread_kill_all_threads(int sig, int main_thread_also)
 645 {
 646   pthread_descr th;
 647   for (th = __pthread_main_thread->p_nextlive;
 648        th != __pthread_main_thread;
 649        th = th->p_nextlive) {
 650     kill(th->p_pid, sig);
 651   }
 652   if (main_thread_also) {
 653     kill(__pthread_main_thread->p_pid, sig);
 654   }
 655 }
 656
 657 /* Process-wide exit() */
 658
 659 static void pthread_handle_exit(pthread_descr issuing_thread, int exitcode)
 660 {
 661   pthread_descr th;
 662   __pthread_exit_requested = 1;
 663   __pthread_exit_code = exitcode;
 664   /* Send the CANCEL signal to all running threads, including the main
 665      thread, but excluding the thread from which the exit request originated
 666      (that thread must complete the exit, e.g. calling atexit functions
 667      and flushing stdio buffers). */
 668   for (th = issuing_thread->p_nextlive;
 669        th != issuing_thread;
 670        th = th->p_nextlive) {
 671     kill(th->p_pid, __pthread_sig_cancel);
 672   }
 673   /* Now, wait for all these threads, so that they don't become zombies
 674      and their times are properly added to the thread manager's times. */
 675   for (th = issuing_thread->p_nextlive;
 676        th != issuing_thread;
 677        th = th->p_nextlive) {
 678     waitpid(th->p_pid, NULL, __WCLONE);
 679   }
 680   restart(issuing_thread);
 681   _exit(0);
 682 }
 683
 684 /* Handler for __pthread_sig_cancel in thread manager thread */
 685
 686 void __pthread_manager_sighandler(int sig)
 687 {
 688   terminated_children = 1;
 689 }
 690
 691 /* Adjust priority of thread manager so that it always run at a priority
 692    higher than all threads */
 693
 694 void __pthread_manager_adjust_prio(int thread_prio)
 695 {
 696   struct sched_param param;
 697
 698   if (thread_prio <= __pthread_manager_thread.p_priority) return;
 699   param.sched_priority =
 700     thread_prio < __sched_get_priority_max(SCHED_FIFO)
 701     ? thread_prio + 1 : thread_prio;
 702   __sched_setscheduler(__pthread_manager_thread.p_pid, SCHED_FIFO, &param);
 703   __pthread_manager_thread.p_priority = thread_prio;
 704 }