freebsd-dev/lib/libc_r/uthread/uthread_create.c
Daniel Eischen e5106342c6 Add weak definitions for wrapped system calls. In general:
_foo - wrapped system call
	foo - weak definition to _foo

and for cancellation points:

	_foo - wrapped system call
	__foo - enter cancellation point, call _foo(), leave
	        cancellation point
	foo - weak definition to __foo

Change use of global _thread_run to call a function to get the
currently running thread.

Make all pthread_foo functions weak definitions to _pthread_foo,
where _pthread_foo is the implementation.  This allows an application
to provide its own pthread functions.

Provide slightly different versions of pthread_mutex_lock and
pthread_mutex_init so that we can tell the difference between
a libc mutex and an application mutex.  Threads holding mutexes
internal to libc should never be allowed to exit, call signal
handlers, or cancel.

Approved by:	-arch
2001-01-24 13:03:38 +00:00

331 lines
9.7 KiB
C

/*
* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <stddef.h>
#include <sys/time.h>
#include <sys/param.h>
#include <sys/mman.h>
#include <machine/reg.h>
#include <pthread.h>
#include "pthread_private.h"
#include "libc_private.h"
static u_int64_t next_uniqueid = 1;
#define OFF(f) offsetof(struct pthread, f)
int _thread_next_offset = OFF(tle.tqe_next);
int _thread_uniqueid_offset = OFF(uniqueid);
int _thread_state_offset = OFF(state);
int _thread_name_offset = OFF(name);
int _thread_ctxtype_offset = OFF(ctxtype);
int _thread_ctx_offset = OFF(ctx);
#undef OFF
int _thread_PS_RUNNING_value = PS_RUNNING;
int _thread_PS_DEAD_value = PS_DEAD;
int _thread_CTX_JB_NOSIG_value = CTX_JB_NOSIG;
int _thread_CTX_JB_value = CTX_JB;
int _thread_CTX_SJB_value = CTX_SJB;
int _thread_CTX_UC_value = CTX_UC;
#pragma weak pthread_create=_pthread_create
int
_pthread_create(pthread_t * thread, const pthread_attr_t * attr,
void *(*start_routine) (void *), void *arg)
{
struct pthread *curthread = _get_curthread();
struct itimerval itimer;
int f_gc = 0;
int ret = 0;
pthread_t gc_thread;
pthread_t new_thread;
pthread_attr_t pattr;
void *stack;
/*
* Locking functions in libc are required when there are
* threads other than the initial thread.
*/
__isthreaded = 1;
/* Allocate memory for the thread structure: */
if ((new_thread = (pthread_t) malloc(sizeof(struct pthread))) == NULL) {
/* Insufficient memory to create a thread: */
ret = EAGAIN;
} else {
/* Check if default thread attributes are required: */
if (attr == NULL || *attr == NULL) {
/* Use the default thread attributes: */
pattr = &pthread_attr_default;
} else {
pattr = *attr;
}
/* Check if a stack was specified in the thread attributes: */
if ((stack = pattr->stackaddr_attr) != NULL) {
}
/* Allocate memory for a default-size stack: */
else if (pattr->stacksize_attr == PTHREAD_STACK_DEFAULT) {
struct stack *spare_stack;
/* Allocate or re-use a default-size stack. */
/*
* Use the garbage collector mutex for synchronization
* of the spare stack list.
*/
if (pthread_mutex_lock(&_gc_mutex) != 0)
PANIC("Cannot lock gc mutex");
if ((spare_stack = SLIST_FIRST(&_stackq)) != NULL) {
/* Use the spare stack. */
SLIST_REMOVE_HEAD(&_stackq, qe);
/* Unlock the garbage collector mutex. */
if (pthread_mutex_unlock(&_gc_mutex) != 0)
PANIC("Cannot unlock gc mutex");
stack = sizeof(struct stack)
+ (void *) spare_stack
- PTHREAD_STACK_DEFAULT;
} else {
/* Allocate a new stack. */
stack = _next_stack + PTHREAD_STACK_GUARD;
/*
* Even if stack allocation fails, we don't want
* to try to use this location again, so
* unconditionally decrement _next_stack. Under
* normal operating conditions, the most likely
* reason for an mmap() error is a stack
* overflow of the adjacent thread stack.
*/
_next_stack -= (PTHREAD_STACK_DEFAULT
+ PTHREAD_STACK_GUARD);
/* Unlock the garbage collector mutex. */
if (pthread_mutex_unlock(&_gc_mutex) != 0)
PANIC("Cannot unlock gc mutex");
/* Stack: */
if (mmap(stack, PTHREAD_STACK_DEFAULT,
PROT_READ | PROT_WRITE, MAP_STACK,
-1, 0) == MAP_FAILED) {
ret = EAGAIN;
free(new_thread);
}
}
}
/*
* The user wants a stack of a particular size. Lets hope they
* really know what they want, and simply malloc the stack.
*/
else if ((stack = (void *) malloc(pattr->stacksize_attr))
== NULL) {
/* Insufficient memory to create a thread: */
ret = EAGAIN;
free(new_thread);
}
/* Check for errors: */
if (ret != 0) {
} else {
/* Initialise the thread structure: */
memset(new_thread, 0, sizeof(struct pthread));
new_thread->slice_usec = -1;
new_thread->stack = stack;
new_thread->start_routine = start_routine;
new_thread->arg = arg;
new_thread->cancelflags = PTHREAD_CANCEL_ENABLE |
PTHREAD_CANCEL_DEFERRED;
/*
* Write a magic value to the thread structure
* to help identify valid ones:
*/
new_thread->magic = PTHREAD_MAGIC;
/* Initialise the thread for signals: */
new_thread->sigmask = curthread->sigmask;
new_thread->sigmask_seqno = 0;
/* Initialize the signal frame: */
new_thread->curframe = NULL;
/* Initialise the jump buffer: */
_setjmp(new_thread->ctx.jb);
/*
* Set up new stack frame so that it looks like it
* returned from a longjmp() to the beginning of
* _thread_start().
*/
SET_RETURN_ADDR_JB(new_thread->ctx.jb, _thread_start);
/* The stack starts high and builds down: */
SET_STACK_JB(new_thread->ctx.jb,
(long)new_thread->stack + pattr->stacksize_attr
- sizeof(double));
/* Initialize the rest of the frame: */
new_thread->ctxtype = CTX_JB_NOSIG;
/* Copy the thread attributes: */
memcpy(&new_thread->attr, pattr, sizeof(struct pthread_attr));
/*
* Check if this thread is to inherit the scheduling
* attributes from its parent:
*/
if (new_thread->attr.flags & PTHREAD_INHERIT_SCHED) {
/* Copy the scheduling attributes: */
new_thread->base_priority =
curthread->base_priority &
~PTHREAD_SIGNAL_PRIORITY;
new_thread->attr.prio =
curthread->base_priority &
~PTHREAD_SIGNAL_PRIORITY;
new_thread->attr.sched_policy =
curthread->attr.sched_policy;
} else {
/*
* Use just the thread priority, leaving the
* other scheduling attributes as their
* default values:
*/
new_thread->base_priority =
new_thread->attr.prio;
}
new_thread->active_priority = new_thread->base_priority;
new_thread->inherited_priority = 0;
/* Initialise the join queue for the new thread: */
TAILQ_INIT(&(new_thread->join_queue));
/* Initialize the mutex queue: */
TAILQ_INIT(&new_thread->mutexq);
/* Initialise hooks in the thread structure: */
new_thread->specific_data = NULL;
new_thread->cleanup = NULL;
new_thread->flags = 0;
new_thread->poll_data.nfds = 0;
new_thread->poll_data.fds = NULL;
new_thread->continuation = NULL;
/*
* Defer signals to protect the scheduling queues
* from access by the signal handler:
*/
_thread_kern_sig_defer();
/*
* Initialise the unique id which GDB uses to
* track threads.
*/
new_thread->uniqueid = next_uniqueid++;
/*
* Check if the garbage collector thread
* needs to be started.
*/
f_gc = (TAILQ_FIRST(&_thread_list) == _thread_initial);
/* Add the thread to the linked list of all threads: */
TAILQ_INSERT_HEAD(&_thread_list, new_thread, tle);
if (pattr->suspend == PTHREAD_CREATE_SUSPENDED)
new_thread->state = PS_SUSPENDED;
else {
new_thread->state = PS_RUNNING;
PTHREAD_PRIOQ_INSERT_TAIL(new_thread);
}
/*
* Undefer and handle pending signals, yielding
* if necessary.
*/
_thread_kern_sig_undefer();
/* Return a pointer to the thread structure: */
(*thread) = new_thread;
if (f_gc != 0) {
/* Install the scheduling timer: */
itimer.it_interval.tv_sec = 0;
itimer.it_interval.tv_usec = _clock_res_usec;
itimer.it_value = itimer.it_interval;
if (setitimer(_ITIMER_SCHED_TIMER, &itimer,
NULL) != 0)
PANIC("Cannot set interval timer");
}
/* Schedule the new user thread: */
_thread_kern_sched(NULL);
/*
* Start a garbage collector thread
* if necessary.
*/
if (f_gc && pthread_create(&gc_thread,NULL,
_thread_gc,NULL) != 0)
PANIC("Can't create gc thread");
}
}
/* Return the status: */
return (ret);
}
void
_thread_start(void)
{
struct pthread *curthread = _get_curthread();
/* We just left the scheduler via longjmp: */
_thread_kern_in_sched = 0;
/* Run the current thread's start routine with argument: */
pthread_exit(curthread->start_routine(curthread->arg));
/* This point should never be reached. */
PANIC("Thread has resumed after exit");
}