freebsd-nq/lib/libc_r/uthread/uthread_exit.c
John Birrell 4a027d50c7 Change signal model to match POSIX (i.e. one set of signal handlers
for the process, not a separate set for each thread). By default, the
process now only has signal handlers installed for SIGVTALRM, SIGINFO
and SIGCHLD. The thread kernel signal handler is installed for other
signals on demand. This means that SIG_IGN and SIG_DFL processing is now
left to the kernel, not the thread kernel.

Change the signal dispatch to no longer use a signal thread, and
call the signal handler using the stack of the thread that has the
signal pending.

Change the atomic lock method to use test-and-set asm code with
a yield if blocked. This introduces separate locks for each type
of object instead of blocking signals to prevent a context
switch. It was this blocking of signals that caused the performance
degradation the people have noted.

This is a *big* change!
1998-04-29 09:59:34 +00:00

182 lines
5.3 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 REGENTS 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.
*
*/
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#ifdef _THREAD_SAFE
#include <pthread.h>
#include "pthread_private.h"
void _exit(int status)
{
int flags;
int i;
struct itimerval itimer;
/* Disable the interval timer: */
itimer.it_interval.tv_sec = 0;
itimer.it_interval.tv_usec = 0;
itimer.it_value.tv_sec = 0;
itimer.it_value.tv_usec = 0;
setitimer(ITIMER_VIRTUAL, &itimer, NULL);
/* Close the pthread kernel pipe: */
_thread_sys_close(_thread_kern_pipe[0]);
_thread_sys_close(_thread_kern_pipe[1]);
/*
* Enter a loop to set all file descriptors to blocking
* if they were not created as non-blocking:
*/
for (i = 0; i < _thread_dtablesize; i++) {
/* Check if this file descriptor is in use: */
if (_thread_fd_table[i] != NULL &&
!(_thread_fd_table[i]->flags & O_NONBLOCK)) {
/* Get the current flags: */
flags = _thread_sys_fcntl(i, F_GETFL, NULL);
/* Clear the nonblocking file descriptor flag: */
_thread_sys_fcntl(i, F_SETFL, flags & ~O_NONBLOCK);
}
}
/* Call the _exit syscall: */
_thread_sys__exit(status);
}
void
_thread_exit(char *fname, int lineno, char *string)
{
char s[256];
/* Prepare an error message string: */
strcpy(s, "Fatal error '");
strcat(s, string);
strcat(s, "' at line ? ");
strcat(s, "in file ");
strcat(s, fname);
strcat(s, " (errno = ?");
strcat(s, ")\n");
/* Write the string to the standard error file descriptor: */
_thread_sys_write(2, s, strlen(s));
/* Force this process to exit: */
_exit(1);
}
void
pthread_exit(void *status)
{
int sig;
long l;
pthread_t pthread;
/* Save the return value: */
_thread_run->ret = status;
while (_thread_run->cleanup != NULL) {
pthread_cleanup_pop(1);
}
if (_thread_run->attr.cleanup_attr != NULL) {
_thread_run->attr.cleanup_attr(_thread_run->attr.arg_attr);
}
/* Check if there is thread specific data: */
if (_thread_run->specific_data != NULL) {
/* Run the thread-specific data destructors: */
_thread_cleanupspecific();
}
/* Check if there are any threads joined to this one: */
while ((pthread = _thread_queue_deq(&(_thread_run->join_queue))) != NULL) {
/* Wake the joined thread and let it detach this thread: */
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
}
/* Lock the thread list: */
_lock_thread_list();
/* Check if the running thread is at the head of the linked list: */
if (_thread_link_list == _thread_run) {
/* There is no previous thread: */
_thread_link_list = _thread_run->nxt;
} else {
/* Point to the first thread in the list: */
pthread = _thread_link_list;
/*
* Enter a loop to find the thread in the linked list before
* the running thread:
*/
while (pthread != NULL && pthread->nxt != _thread_run) {
/* Point to the next thread: */
pthread = pthread->nxt;
}
/* Check that a previous thread was found: */
if (pthread != NULL) {
/*
* Point the previous thread to the one after the
* running thread:
*/
pthread->nxt = _thread_run->nxt;
}
}
/* Unlock the thread list: */
_unlock_thread_list();
/* Lock the dead thread list: */
_lock_dead_thread_list();
/*
* This thread will never run again. Add it to the list of dead
* threads:
*/
_thread_run->nxt = _thread_dead;
_thread_dead = _thread_run;
/* Unlock the dead thread list: */
_unlock_dead_thread_list();
/*
* The running thread is no longer in the thread link list so it will
* now die:
*/
_thread_kern_sched_state(PS_DEAD, __FILE__, __LINE__);
/* This point should not be reached. */
PANIC("Dead thread has resumed");
}
#endif