summaryrefslogtreecommitdiff
path: root/lib/libpthread/thread/thr_kern.c
diff options
context:
space:
mode:
Diffstat (limited to 'lib/libpthread/thread/thr_kern.c')
-rw-r--r--lib/libpthread/thread/thr_kern.c470
1 files changed, 35 insertions, 435 deletions
diff --git a/lib/libpthread/thread/thr_kern.c b/lib/libpthread/thread/thr_kern.c
index 3b624223a7f6..36efc31321d6 100644
--- a/lib/libpthread/thread/thr_kern.c
+++ b/lib/libpthread/thread/thr_kern.c
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
+ * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@@ -29,7 +29,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
- * $Id: uthread_kern.c,v 1.8 1998/04/11 07:47:22 jb Exp $
+ * $Id: uthread_kern.c,v 1.9 1998/04/17 09:37:41 jb Exp $
*
*/
#include <errno.h>
@@ -49,15 +49,9 @@
#include <pthread.h>
#include "pthread_private.h"
-/* Static variables: */
-static sigset_t sig_to_block = 0xffffffff;
-static sigset_t sig_to_unblock = 0;
-
/* Static function prototype definitions: */
static void
_thread_kern_select(int wait_reqd);
-static void
-_thread_signal(pthread_t pthread, int sig);
void
_thread_kern_sched(struct sigcontext * scp)
@@ -78,8 +72,12 @@ _thread_kern_sched(struct sigcontext * scp)
struct timeval tv;
struct timeval tv1;
- /* Block signals: */
- _thread_kern_sig_block(NULL);
+ /*
+ * Flag the pthread kernel as executing scheduler code
+ * to avoid a scheduler signal from interrupting this
+ * execution and calling the scheduler again.
+ */
+ _thread_kern_in_sched = 1;
/* Check if this function was called from the signal handler: */
if (scp != NULL) {
@@ -101,14 +99,20 @@ __asm__("fnsave %0": :"m"(*fdata));
_thread_run->sig_saved = 1;
}
/* Save the state of the current thread: */
- else if (_thread_sys_setjmp(_thread_run->saved_jmp_buf) != 0) {
- /* Unblock signals (just in case): */
- _thread_kern_sig_unblock(0);
-
+ else if (setjmp(_thread_run->saved_jmp_buf) != 0) {
/*
* This point is reached when a longjmp() is called to
* restore the state of a thread.
+ *
+ * This is the normal way out of the scheduler.
*/
+ _thread_kern_in_sched = 0;
+
+ /*
+ * There might be pending signals for this thread, so
+ * dispatch any that aren't blocked:
+ */
+ _dispatch_signals();
return;
} else {
/* Flag the jump buffer was the last state saved: */
@@ -135,10 +139,9 @@ __asm__("fnsave %0": :"m"(*fdata));
pthread_prv = pthread;
}
/*
- * Check if this thread has detached or if it is a signal
- * handler thread:
+ * Check if this thread has detached:
*/
- else if (((pthread->attr.flags & PTHREAD_DETACHED) != 0) || pthread->parent_thread != NULL) {
+ else if ((pthread->attr.flags & PTHREAD_DETACHED) != 0) {
/* Check if there is no previous dead thread: */
if (pthread_prv == NULL) {
/*
@@ -210,41 +213,10 @@ __asm__("fnsave %0": :"m"(*fdata));
_thread_kern_select(0);
/*
- * Enter a loop to look for sleeping threads that are ready
- * or threads with pending signals that are no longer
- * blocked:
+ * Enter a loop to look for sleeping threads that are ready:
*/
- for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
- /* Enter a loop to process the sending signals: */
- for (i = 1; i < NSIG; i++) {
- /*
- * Check if there are no pending signals of
- * this type:
- */
- if (pthread->sigpend[i] == 0) {
- }
- /* Check if this signal type is not masked: */
- else if (sigismember(&pthread->sigmask, i) == 0) {
- /*
- * Delete the signal from the set of
- * pending signals for this thread:
- */
- pthread->sigpend[i] -= 1;
-
- /*
- * Act on the signal for the current
- * thread:
- */
- _thread_signal(pthread, i);
- } else {
- /*
- * This signal is masked, so make
- * sure the count does not exceed 1:
- */
- pthread->sigpend[i] = 1;
- }
- }
-
+ for (pthread = _thread_link_list; pthread != NULL;
+ pthread = pthread->nxt) {
/* Check if this thread is to timeout: */
if (pthread->state == PS_COND_WAIT ||
pthread->state == PS_SLEEP_WAIT ||
@@ -369,45 +341,6 @@ __asm__("fnsave %0": :"m"(*fdata));
* priority that is ready to run:
*/
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
- /* Check if in single-threaded mode: */
- if (_thread_single != NULL) {
- /*
- * Check if the current thread is
- * the thread for which single-threaded
- * mode is enabled:
- */
- if (pthread == _thread_single) {
- /*
- * This thread is allowed
- * to run.
- */
- } else {
- /*
- * Walk up the signal handler
- * parent thread tree to see
- * if the current thread is
- * descended from the thread
- * for which single-threaded
- * mode is enabled.
- */
- pthread_nxt = pthread;
- while(pthread_nxt != NULL &&
- pthread_nxt != _thread_single) {
- pthread_nxt = pthread->parent_thread;
- }
- /*
- * Check if the current
- * thread is not descended
- * from the thread for which
- * single-threaded mode is
- * enabled.
- */
- if (pthread_nxt == NULL)
- /* Ignore this thread. */
- continue;
- }
- }
-
/* Check if the current thread is unable to run: */
if (pthread->state != PS_RUNNING) {
}
@@ -433,49 +366,11 @@ __asm__("fnsave %0": :"m"(*fdata));
* least recently.
*/
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
- /* Check if in single-threaded mode: */
- if (_thread_single != NULL) {
- /*
- * Check if the current thread is
- * the thread for which single-threaded
- * mode is enabled:
- */
- if (pthread == _thread_single) {
- /*
- * This thread is allowed
- * to run.
- */
- } else {
- /*
- * Walk up the signal handler
- * parent thread tree to see
- * if the current thread is
- * descended from the thread
- * for which single-threaded
- * mode is enabled.
- */
- pthread_nxt = pthread;
- while(pthread_nxt != NULL &&
- pthread_nxt != _thread_single) {
- pthread_nxt = pthread->parent_thread;
- }
- /*
- * Check if the current
- * thread is not descended
- * from the thread for which
- * single-threaded mode is
- * enabled.
- */
- if (pthread_nxt == NULL)
- /* Ignore this thread. */
- continue;
- }
- }
-
/* Check if the current thread is unable to run: */
if (pthread->state != PS_RUNNING) {
/* Ignore threads that are not ready to run. */
}
+
/*
* Check if the current thread as an agregate
* priority not equal to the highest priority found
@@ -487,6 +382,7 @@ __asm__("fnsave %0": :"m"(*fdata));
* priority.
*/
}
+
/*
* Check if the current thread reached its time slice
* allocation last time it ran (or if it has not run
@@ -494,6 +390,7 @@ __asm__("fnsave %0": :"m"(*fdata));
*/
else if (pthread->slice_usec == -1) {
}
+
/*
* Check if an eligible thread has not been found
* yet, or if the current thread has an inactive time
@@ -526,45 +423,6 @@ __asm__("fnsave %0": :"m"(*fdata));
* priority. 3. Became inactive least recently.
*/
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
- /* Check if in single-threaded mode: */
- if (_thread_single != NULL) {
- /*
- * Check if the current thread is
- * the thread for which single-threaded
- * mode is enabled:
- */
- if (pthread == _thread_single) {
- /*
- * This thread is allowed
- * to run.
- */
- } else {
- /*
- * Walk up the signal handler
- * parent thread tree to see
- * if the current thread is
- * descended from the thread
- * for which single-threaded
- * mode is enabled.
- */
- pthread_nxt = pthread;
- while(pthread_nxt != NULL &&
- pthread_nxt != _thread_single) {
- pthread_nxt = pthread->parent_thread;
- }
- /*
- * Check if the current
- * thread is not descended
- * from the thread for which
- * single-threaded mode is
- * enabled.
- */
- if (pthread_nxt == NULL)
- /* Ignore this thread. */
- continue;
- }
- }
-
/*
* Check if the current thread is unable to
* run:
@@ -804,14 +662,13 @@ __asm__("fnsave %0": :"m"(*fdata));
* was interrupted by a signal:
*/
_thread_sys_sigreturn(&_thread_run->saved_sigcontext);
- } else {
+ } else
/*
* Do a longjmp to restart the thread that
* was context switched out (by a longjmp to
* a different thread):
*/
- _thread_sys_longjmp(_thread_run->saved_jmp_buf, 1);
- }
+ longjmp(_thread_run->saved_jmp_buf, 1);
/* This point should not be reached. */
PANIC("Thread has returned from sigreturn or longjmp");
@@ -822,243 +679,6 @@ __asm__("fnsave %0": :"m"(*fdata));
exit(0);
}
-static void
-_thread_signal(pthread_t pthread, int sig)
-{
- int done;
- long l;
- pthread_t new_pthread;
- struct sigaction act;
- void *arg;
-
- /*
- * Assume that the signal will not be dealt with according
- * to the thread state:
- */
- done = 0;
-
- /* Process according to thread state: */
- switch (pthread->state) {
- /* States which do not change when a signal is trapped: */
- case PS_COND_WAIT:
- case PS_DEAD:
- case PS_FDLR_WAIT:
- case PS_FDLW_WAIT:
- case PS_FILE_WAIT:
- case PS_JOIN:
- case PS_MUTEX_WAIT:
- case PS_RUNNING:
- case PS_STATE_MAX:
- case PS_SIGTHREAD:
- case PS_SUSPENDED:
- /* Nothing to do here. */
- break;
-
- /* Wait for child: */
- case PS_WAIT_WAIT:
- /* Check if the signal is from a child exiting: */
- if (sig == SIGCHLD) {
- /* Reset the error: */
- _thread_seterrno(pthread, 0);
-
- /* Change the state of the thread to run: */
- PTHREAD_NEW_STATE(pthread,PS_RUNNING);
- } else {
- /* Return the 'interrupted' error: */
- _thread_seterrno(pthread, EINTR);
-
- /* Change the state of the thread to run: */
- PTHREAD_NEW_STATE(pthread,PS_RUNNING);
- }
- pthread->interrupted = 1;
- break;
-
- /* Waiting on I/O for zero or more file descriptors: */
- case PS_SELECT_WAIT:
- pthread->data.select_data->nfds = -1;
-
- /* Return the 'interrupted' error: */
- _thread_seterrno(pthread, EINTR);
- pthread->interrupted = 1;
-
- /* Change the state of the thread to run: */
- PTHREAD_NEW_STATE(pthread,PS_RUNNING);
- break;
-
- /*
- * States that are interrupted by the occurrence of a signal
- * other than the scheduling alarm:
- */
- case PS_FDR_WAIT:
- case PS_FDW_WAIT:
- case PS_SLEEP_WAIT:
- case PS_SIGWAIT:
- /* Return the 'interrupted' error: */
- _thread_seterrno(pthread, EINTR);
- pthread->interrupted = 1;
-
- /* Change the state of the thread to run: */
- PTHREAD_NEW_STATE(pthread,PS_RUNNING);
-
- /* Return the signal number: */
- pthread->signo = sig;
- break;
- }
-
- /*
- * Check if this signal has been dealt with, or is being
- * ignored:
- */
- if (done || pthread->act[sig - 1].sa_handler == SIG_IGN) {
- /* Ignore the signal for this thread. */
- }
- /* Check if this signal is to use the default handler: */
- else if (pthread->act[sig - 1].sa_handler == SIG_DFL) {
- /* Process according to signal type: */
- switch (sig) {
- /* Signals which cause core dumps: */
- case SIGQUIT:
- case SIGILL:
- case SIGTRAP:
- case SIGABRT:
- case SIGEMT:
- case SIGFPE:
- case SIGBUS:
- case SIGSEGV:
- case SIGSYS:
- /* Clear the signal action: */
- sigfillset(&act.sa_mask);
- act.sa_handler = SIG_DFL;
- act.sa_flags = SA_RESTART;
- _thread_sys_sigaction(sig, &act, NULL);
-
- /*
- * Do a sigreturn back to where the signal was
- * detected and a core dump should occur:
- */
- _thread_sys_sigreturn(&pthread->saved_sigcontext);
- break;
-
- /*
- * The following signals should terminate the
- * process. Do this by clearing the signal action
- * and then re-throwing the signal.
- */
- case SIGHUP:
- case SIGINT:
- case SIGPIPE:
- case SIGALRM:
- case SIGTERM:
- case SIGXCPU:
- case SIGXFSZ:
- case SIGVTALRM:
- case SIGUSR1:
- case SIGUSR2:
- /* These signals stop the process. Also re-throw them. */
- case SIGTSTP:
- case SIGTTIN:
- case SIGTTOU:
- /* Clear the signal action: */
- sigfillset(&act.sa_mask);
- act.sa_handler = SIG_DFL;
- act.sa_flags = SA_RESTART;
- _thread_sys_sigaction(sig, &act, NULL);
- /* Re-throw to ourselves. */
- kill(getpid(), sig);
- break;
-
- case SIGCONT:
- /*
- * If we get this it means that we were
- * probably stopped and then continued.
- * Reset the handler for the SIGTSTP, SIGTTIN
- * and SIGTTOU signals.
- */
-
- sigfillset(&act.sa_mask);
- act.sa_handler = (void (*) ()) _thread_sig_handler;
- act.sa_flags = SA_RESTART;
-
- /* Initialise the signals for default handling: */
- if (_thread_sys_sigaction(SIGTSTP, &act, NULL) != 0) {
- PANIC("Cannot initialise SIGTSTP signal handler");
- }
- if (_thread_sys_sigaction(SIGTTIN, &act, NULL) != 0) {
- PANIC("Cannot initialise SIGTTIN signal handler");
- }
- if (_thread_sys_sigaction(SIGTTOU, &act, NULL) != 0) {
- PANIC("Cannot initialise SIGTTOU signal handler");
- }
- break;
-
- /* Default processing for other signals: */
- default:
- /*
- * ### Default processing is a problem to resolve!
- * ###
- */
- break;
- }
- } else {
- /*
- * Cast the signal number as a long and then to a void
- * pointer. Sigh. This is POSIX.
- */
- l = (long) sig;
- arg = (void *) l;
-
- /* Create a signal handler thread, but don't run it yet: */
- if (_thread_create(&new_pthread, NULL, (void *) pthread->act[sig - 1].sa_handler, arg, pthread) != 0) {
- /*
- * Error creating signal handler thread, so abort
- * this process:
- */
- PANIC("Cannot create signal handler thread");
- }
- }
-
- /* Nothing to return. */
- return;
-}
-
-void
-_thread_kern_sig_block(int *status)
-{
- sigset_t oset;
-
- /*
- * Block all signals so that the process will not be interrupted by
- * signals:
- */
- _thread_sys_sigprocmask(SIG_SETMASK, &sig_to_block, &oset);
-
- /* Check if the caller wants the current block status returned: */
- if (status != NULL) {
- /* Return the previous signal block status: */
- *status = (oset != 0);
- }
- return;
-}
-
-void
-_thread_kern_sig_unblock(int status)
-{
- sigset_t oset;
-
- /*
- * Check if the caller thinks that signals weren't blocked when it
- * called _thread_kern_sig_block:
- */
- if (status == 0) {
- /*
- * Unblock all signals so that the process will be
- * interrupted when a signal occurs:
- */
- _thread_sys_sigprocmask(SIG_SETMASK, &sig_to_unblock, &oset);
- }
- return;
-}
-
void
_thread_kern_sched_state(enum pthread_state state, char *fname, int lineno)
{
@@ -1382,18 +1002,12 @@ _thread_kern_select(int wait_reqd)
*/
_thread_kern_in_select = 1;
- /* Unblock all signals: */
- _thread_kern_sig_unblock(0);
-
/*
* Wait for a file descriptor to be ready for read, write, or
* an exception, or a timeout to occur:
*/
count = _thread_sys_select(nfds + 1, &fd_set_read, &fd_set_write, &fd_set_except, p_tv);
- /* Block all signals again: */
- _thread_kern_sig_block(NULL);
-
/* Reset the kernel in select flag: */
_thread_kern_in_select = 0;
@@ -1426,10 +1040,10 @@ _thread_kern_select(int wait_reqd)
* signal and each byte is the signal number.
* This data is not used, but the fact that
* the signal handler wrote to the pipe *is*
- * used to cause the _thread_sys_select call
+ * used to cause the _select call
* to complete if the signal occurred between
* the time when signals were unblocked and
- * the _thread_sys_select select call being
+ * the _select select call being
* made.
*/
}
@@ -1439,36 +1053,22 @@ _thread_kern_select(int wait_reqd)
else if (count > 0) {
/*
* Point to the time value structure which has been zeroed so
- * that the call to _thread_sys_select will not wait:
+ * that the call to _select will not wait:
*/
p_tv = &tv;
/* Poll file descrptors without wait: */
count = _thread_sys_select(nfds + 1, &fd_set_read, &fd_set_write, &fd_set_except, p_tv);
}
+
/*
- * Check if the select call was interrupted, or some other error
- * occurred:
+ * Check if any file descriptors are ready:
*/
- if (count < 0) {
- /* Check if the select call was interrupted: */
- if (errno == EINTR) {
- /*
- * Interrupted calls are expected. The interrupting
- * signal will be in the sigpend array.
- */
- } else {
- /* This should not occur: */
- }
- }
- /* Check if no file descriptors are ready: */
- else if (count == 0) {
- /* Nothing to do here. */
- } else {
+ if (count > 0) {
/*
* Enter a loop to look for threads waiting on file
* descriptors that are flagged as available by the
- * _thread_sys_select syscall:
+ * _select syscall:
*/
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
/* Process according to thread state: */
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-31 20:28:23 +0000