threads.subproj/cthreads.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * cthreads.c - by Eric Cooper
  24  *
  25  * Implementation of cthread_fork, cthread_join, cthread_exit, etc.
  26  * HISTORY
  27  * 22-July-93 Blaine Garst
  28  *      fixed association of read_thread info
  29  *      fixed kernel cache set up of cproc info
  30  *
  31  */
  32 #include <stdlib.h>
  33 #include "cthreads.h"
  34 #include "cthread_internals.h"
  35 #include "pthread_internals.h"
  36 /*
  37  * C Threads imports:
  38  */
  39 extern void cproc_init();
  40 extern thread_port_t cproc_create();
  41 extern void mig_init();
  42 extern void _pthread_set_self(pthread_t);
  43
  44 /*
  45  * Mach imports:
  46  */
  47 extern void mig_fork_child();
  48
  49 /*
  50  * C library imports:
  51  */
  52 extern int _setjmp(jmp_buf env);
  53 extern void _longjmp(jmp_buf env, int val);
  54
  55 /*
  56  * Thread status bits.
  57  */
  58 #define T_MAIN          0x1
  59 #define T_RETURNED      0x2
  60 #define T_DETACHED      0x4
  61
  62 #ifdef  CTHREADS_DEBUG
  63 int cthread_debug = FALSE;
  64 #endif  CTHREADS_DEBUG
  65
  66 /*
  67  * Routines for supporting fork() of multi-threaded programs.
  68  */
  69
  70
  71 extern void _malloc_fork_prepare(), _malloc_fork_parent();
  72 extern void _malloc_fork_child();
  73 extern void _cproc_fork_child(), _stack_fork_child();
  74 extern void _lu_fork_child(void);
  75 extern void _pthread_fork_child(void);
  76
  77 static pthread_t psaved_self = 0;
  78 static pthread_lock_t psaved_self_global_lock = LOCK_INITIALIZER;
  79
  80 void _cthread_fork_prepare()
  81 /*
  82  * Prepare cthreads library to fork() a multi-threaded program.  All cthread
  83  * library critical section locks are acquired before a fork() and released
  84  * afterwards to insure no cthread data structure is left in an inconsistent
  85  * state in the child, which comes up with only the forking thread running.
  86  */
  87 {
  88        _spin_lock(&psaved_self_global_lock);
  89        psaved_self = pthread_self();
  90         _spin_lock(&psaved_self->lock);
  91         _malloc_fork_prepare();
  92 }
  93
  94 void _cthread_fork_parent()
  95 /*
  96  * Called in the parent process after a fork syscall.
  97  * Releases locks acquired by cthread_fork_prepare().
  98  */
  99 {
 100         _malloc_fork_parent();
 101         _spin_unlock(&psaved_self->lock);
 102         _spin_unlock(&psaved_self_global_lock);
 103
 104 }
 105
 106 void _cthread_fork_child()
 107 /*
 108  * Called in the child process after a fork syscall.  Releases locks acquired
 109  * by cthread_fork_prepare().  Deallocates cthread data structures which
 110  * described other threads in our parent.  Makes this thread the main thread.
 111  *
 112  * The mach_init() routine must be called in the child before this routine.
 113  */
 114 {
 115         pthread_t p = psaved_self;
 116
 117         _pthread_set_self(p);
 118         _spin_unlock(&psaved_self_global_lock);
 119         mig_fork_child();
 120         _malloc_fork_child();
 121         p->kernel_thread = mach_thread_self();
 122         p->reply_port = MACH_PORT_NULL;
 123         p->mutexes = NULL;
 124         p->cleanup_stack = NULL;
 125         p->death = MACH_PORT_NULL;
 126         p->joiners = MACH_PORT_NULL;
 127         p->num_joiners = 0;
 128         p->detached = _PTHREAD_CREATE_PARENT;
 129         _spin_unlock(&p->lock);
 130
 131         _cproc_fork_child();
 132
 133         _lu_fork_child();
 134
 135         _pthread_fork_child();
 136
 137         __is_threaded = 0;
 138         mig_init(1);            /* enable multi-threaded mig interfaces */
 139
 140 }
 141