threads/cthreads.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * cthreads.c - by Eric Cooper
  27  *
  28  * Implementation of cthread_fork, cthread_join, cthread_exit, etc.
  29  * HISTORY
  30  * 22-July-93 Blaine Garst
  31  *      fixed association of read_thread info
  32  *      fixed kernel cache set up of cproc info
  33  *
  34  */
  35 #include <stdlib.h>
  36 #include "cthreads.h"
  37 #include "cthread_internals.h"
  38 #include "pthread_internals.h"
  39 /*
  40  * C Threads imports:
  41  */
  42 extern void cproc_init();
  43 extern thread_port_t cproc_create();
  44 extern void mig_init();
  45 extern void _pthread_set_self(pthread_t);
  46
  47 /*
  48  * Mach imports:
  49  */
  50 extern void mig_fork_child();
  51
  52 /*
  53  * C library imports:
  54  */
  55 extern int _setjmp(jmp_buf env);
  56 extern void _longjmp(jmp_buf env, int val);
  57
  58 /*
  59  * Thread status bits.
  60  */
  61 #define T_MAIN          0x1
  62 #define T_RETURNED      0x2
  63 #define T_DETACHED      0x4
  64
  65 #ifdef  CTHREADS_DEBUG
  66 int cthread_debug = FALSE;
  67 #endif  CTHREADS_DEBUG
  68
  69 /*
  70  * Routines for supporting fork() of multi-threaded programs.
  71  */
  72
  73
  74 extern void _malloc_fork_prepare(), _malloc_fork_parent();
  75 extern void _malloc_fork_child();
  76 extern void _cproc_fork_child(), _stack_fork_child();
  77 extern void _lu_fork_child(void);
  78 extern void _pthread_fork_child(void);
  79
  80 static pthread_t psaved_self = 0;
  81 static pthread_lock_t psaved_self_global_lock = LOCK_INITIALIZER;
  82
  83 void _cthread_fork_prepare()
  84 /*
  85  * Prepare cthreads library to fork() a multi-threaded program.  All cthread
  86  * library critical section locks are acquired before a fork() and released
  87  * afterwards to insure no cthread data structure is left in an inconsistent
  88  * state in the child, which comes up with only the forking thread running.
  89  */
  90 {
  91        _spin_lock(&psaved_self_global_lock);
  92        psaved_self = pthread_self();
  93        _spin_lock(&psaved_self->lock);
  94         _malloc_fork_prepare();
  95 }
  96
  97 void _cthread_fork_parent()
  98 /*
  99  * Called in the parent process after a fork syscall.
 100  * Releases locks acquired by cthread_fork_prepare().
 101  */
 102 {
 103         _malloc_fork_parent();
 104         _spin_unlock(&psaved_self->lock);
 105         _spin_unlock(&psaved_self_global_lock);
 106
 107 }
 108
 109 void _cthread_fork_child()
 110 /*
 111  * Called in the child process after a fork syscall.  Releases locks acquired
 112  * by cthread_fork_prepare().  Deallocates cthread data structures which
 113  * described other threads in our parent.  Makes this thread the main thread.
 114  *
 115  * The mach_init() routine must be called in the child before this routine.
 116  */
 117 {
 118         pthread_t p = psaved_self;
 119
 120         _pthread_set_self(p);
 121         _spin_unlock(&psaved_self_global_lock);
 122         mig_fork_child();
 123         _malloc_fork_child();
 124         p->kernel_thread = mach_thread_self();
 125         p->reply_port = MACH_PORT_NULL;
 126         p->mutexes = NULL;
 127         p->cleanup_stack = NULL;
 128         p->death = MACH_PORT_NULL;
 129         p->joiner = NULL;
 130         p->detached |= _PTHREAD_CREATE_PARENT;
 131         _spin_unlock(&p->lock);
 132
 133         _cproc_fork_child();
 134
 135         _lu_fork_child();
 136
 137         _pthread_fork_child();
 138
 139         __is_threaded = 0;
 140
 141         mig_init(1);            /* enable multi-threaded mig interfaces */
 142
 143 }
 144