diff options
| -rw-r--r-- | sem_timedwait.c | 476 |
1 files changed, 220 insertions, 256 deletions
diff --git a/sem_timedwait.c b/sem_timedwait.c index 7fba45f..01bab42 100644 --- a/sem_timedwait.c +++ b/sem_timedwait.c @@ -1,256 +1,220 @@ -/* - * ------------------------------------------------------------- - * - * Module: sem_timedwait.c - * - * Purpose: - * Semaphores aren't actually part of the PThreads standard. - * They are defined by the POSIX Standard: - * - * POSIX 1003.1b-1993 (POSIX.1b) - * - * ------------------------------------------------------------- - * - * -------------------------------------------------------------------------- - * - * Pthreads-win32 - POSIX Threads Library for Win32 - * Copyright(C) 1998 John E. Bossom - * Copyright(C) 1999,2005 Pthreads-win32 contributors - * - * Contact Email: rpj@callisto.canberra.edu.au - * - * The current list of contributors is contained - * in the file CONTRIBUTORS included with the source - * code distribution. The list can also be seen at the - * following World Wide Web location: - * http://sources.redhat.com/pthreads-win32/contributors.html - * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; either - * version 2 of the License, or (at your option) any later version. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with this library in the file COPYING.LIB; - * if not, write to the Free Software Foundation, Inc., - * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA - */ - -#ifndef _UWIN -//#include <process.h> -#endif -#ifndef NEED_FTIME -#include <sys/timeb.h> -#endif - -#include "pthread.h" -#include "semaphore.h" -#include "implement.h" - -static void PTW32_CDECL -ptw32_sem_timedwait_cleanup (void * sem) -{ - sem_t s = (sem_t) sem; - - if (pthread_mutex_lock (&s->lock) == 0) - { - ++s->value; - /* - * Don't release the W32 sema, it doesn't need adjustment - * because it doesn't record the number of waiters. - */ - (void) pthread_mutex_unlock (&s->lock); - } -} - -int -sem_timedwait (sem_t * sem, const struct timespec *abstime) - /* - * ------------------------------------------------------ - * DOCPUBLIC - * This function waits on a semaphore possibly until - * 'abstime' time. - * - * PARAMETERS - * sem - * pointer to an instance of sem_t - * - * abstime - * pointer to an instance of struct timespec - * - * DESCRIPTION - * This function waits on a semaphore. If the - * semaphore value is greater than zero, it decreases - * its value by one. If the semaphore value is zero, then - * the calling thread (or process) is blocked until it can - * successfully decrease the value or until interrupted by - * a signal. - * - * If 'abstime' is a NULL pointer then this function will - * block until it can successfully decrease the value or - * until interrupted by a signal. - * - * RESULTS - * 0 successfully decreased semaphore, - * -1 failed, error in errno - * ERRNO - * EINVAL 'sem' is not a valid semaphore, - * ENOSYS semaphores are not supported, - * EINTR the function was interrupted by a signal, - * EDEADLK a deadlock condition was detected. - * ETIMEDOUT abstime elapsed before success. - * - * ------------------------------------------------------ - */ -{ - int result = 0; - sem_t s = *sem; - -#ifdef NEED_FTIME - - struct timespec currSysTime; - -#else /* NEED_FTIME */ - - struct _timeb currSysTime; - -#endif /* NEED_FTIME */ - - const int64_t NANOSEC_PER_MILLISEC = 1000000; - const int64_t MILLISEC_PER_SEC = 1000; - DWORD milliseconds; - int64_t tmpAbsMilliseconds; - int64_t tmpCurrMilliseconds; - - if (sem == NULL) - { - result = EINVAL; - } - else - { - if (abstime == NULL) - { - milliseconds = INFINITE; - } - else - { - /* - * Calculate timeout as milliseconds from current system time. - */ - - /* - * subtract current system time from abstime in a way that checks - * that abstime is never in the past, or is never equivalent to the - * defined INFINITE value (0xFFFFFFFF). - * - * Assume all integers are unsigned, i.e. cannot test if less than 0. - */ - tmpAbsMilliseconds = (int64_t)abstime->tv_sec * MILLISEC_PER_SEC; - tmpAbsMilliseconds += ((int64_t)abstime->tv_nsec + (NANOSEC_PER_MILLISEC/2)) / NANOSEC_PER_MILLISEC; - - /* get current system time */ - -#ifdef NEED_FTIME - - { - FILETIME ft; - SYSTEMTIME st; - - GetSystemTime(&st); - SystemTimeToFileTime(&st, &ft); - /* - * GetSystemTimeAsFileTime(&ft); would be faster, - * but it does not exist on WinCE - */ - - ptw32_filetime_to_timespec(&ft, &currSysTime); - } - - tmpCurrMilliseconds = (int64_t)currSysTime.tv_sec * MILLISEC_PER_SEC; - tmpCurrMilliseconds += ((int64_t)currSysTime.tv_nsec + (NANOSEC_PER_MILLISEC/2)) / NANOSEC_PER_MILLISEC; - -#else /* ! NEED_FTIME */ - - _ftime(&currSysTime); - - tmpCurrMilliseconds = (int64_t) currSysTime.time * MILLISEC_PER_SEC; - tmpCurrMilliseconds += (int64_t) currSysTime.millitm; - -#endif /* NEED_FTIME */ - - if (tmpAbsMilliseconds > tmpCurrMilliseconds) - { - milliseconds = (DWORD) (tmpAbsMilliseconds - tmpCurrMilliseconds); - if (milliseconds == INFINITE) - { - /* Timeouts must be finite */ - milliseconds--; - } - } - else - { - /* The abstime given is in the past */ - milliseconds = 0; - } - } - -#ifdef NEED_SEM - - result = (pthreadCancelableTimedWait (s->event, milliseconds)); - -#else /* NEED_SEM */ - - pthread_testcancel(); - - if ((result = pthread_mutex_lock (&s->lock)) == 0) - { - int v = --s->value; - (void) pthread_mutex_unlock (&s->lock); - - if (v < 0) - { - /* Must wait */ -#ifdef _MSC_VER -#pragma inline_depth(0) -#endif - pthread_cleanup_push(ptw32_sem_timedwait_cleanup, (void *) s); - result = pthreadCancelableTimedWait (s->sem, milliseconds); - /* - * Restore the semaphore counter if no longer waiting - * and not taking the semaphore. This will occur if the - * thread is cancelled while waiting, or the wake was - * not the result of a post event given to us, e.g. a timeout. - */ - pthread_cleanup_pop(result); -#ifdef _MSC_VER -#pragma inline_depth() -#endif - } - } - -#endif - - } - - if (result != 0) - { - - errno = result; - return -1; - - } - -#ifdef NEED_SEM - - ptw32_decrease_semaphore (sem); - -#endif /* NEED_SEM */ - - return 0; - -} /* sem_timedwait */ +/*
+ * -------------------------------------------------------------
+ *
+ * Module: sem_timedwait.c
+ *
+ * Purpose:
+ * Semaphores aren't actually part of the PThreads standard.
+ * They are defined by the POSIX Standard:
+ *
+ * POSIX 1003.1b-1993 (POSIX.1b)
+ *
+ * -------------------------------------------------------------
+ *
+ * --------------------------------------------------------------------------
+ *
+ * Pthreads-win32 - POSIX Threads Library for Win32
+ * Copyright(C) 1998 John E. Bossom
+ * Copyright(C) 1999,2005 Pthreads-win32 contributors
+ *
+ * Contact Email: rpj@callisto.canberra.edu.au
+ *
+ * The current list of contributors is contained
+ * in the file CONTRIBUTORS included with the source
+ * code distribution. The list can also be seen at the
+ * following World Wide Web location:
+ * http://sources.redhat.com/pthreads-win32/contributors.html
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library in the file COPYING.LIB;
+ * if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#include "pthread.h"
+#include "semaphore.h"
+#include "implement.h"
+
+
+typedef struct {
+ sem_t sem;
+ int * resultPtr;
+} sem_timedwait_cleanup_args_t;
+
+
+static void PTW32_CDECL
+ptw32_sem_timedwait_cleanup (void * args)
+{
+ sem_timedwait_cleanup_args_t * a = (sem_timedwait_cleanup_args_t *)args;
+ sem_t s = a->sem;
+
+ if (pthread_mutex_lock (&s->lock) == 0)
+ {
+ /*
+ * We either timed out or were cancelled.
+ * If someone posted since then we try to take the semaphore.
+ * Otherwise the semaphore count may be wrong after we
+ * return. In the case of a cancellation, it is as if we
+ * were cancelled just before we return (after taking the semaphore)
+ * which is ok.
+ */
+ if (WaitForSingleObject(s->sem, 0) == WAIT_OBJECT_0)
+ {
+ /* We got the semaphore on the second attempt */
+ *(a->resultPtr) = 0;
+ }
+ else
+ {
+ /* Indicate we're no longer waiting */
+ s->value++;
+#ifdef NEED_SEM
+ if (s->value > 0)
+ {
+ s->leftToUnblock = 0;
+ }
+#else
+ /*
+ * Don't release the W32 sema, it doesn't need adjustment
+ * because it doesn't record the number of waiters.
+ */
+#endif
+ }
+ (void) pthread_mutex_unlock (&s->lock);
+ }
+}
+
+
+int
+sem_timedwait (sem_t * sem, const struct timespec *abstime)
+ /*
+ * ------------------------------------------------------
+ * DOCPUBLIC
+ * This function waits on a semaphore possibly until
+ * 'abstime' time.
+ *
+ * PARAMETERS
+ * sem
+ * pointer to an instance of sem_t
+ *
+ * abstime
+ * pointer to an instance of struct timespec
+ *
+ * DESCRIPTION
+ * This function waits on a semaphore. If the
+ * semaphore value is greater than zero, it decreases
+ * its value by one. If the semaphore value is zero, then
+ * the calling thread (or process) is blocked until it can
+ * successfully decrease the value or until interrupted by
+ * a signal.
+ *
+ * If 'abstime' is a NULL pointer then this function will
+ * block until it can successfully decrease the value or
+ * until interrupted by a signal.
+ *
+ * RESULTS
+ * 0 successfully decreased semaphore,
+ * -1 failed, error in errno
+ * ERRNO
+ * EINVAL 'sem' is not a valid semaphore,
+ * ENOSYS semaphores are not supported,
+ * EINTR the function was interrupted by a signal,
+ * EDEADLK a deadlock condition was detected.
+ * ETIMEDOUT abstime elapsed before success.
+ *
+ * ------------------------------------------------------
+ */
+{
+ int result = 0;
+ sem_t s = *sem;
+
+ if (sem == NULL)
+ {
+ result = EINVAL;
+ }
+ else
+ {
+ DWORD milliseconds;
+
+ if (abstime == NULL)
+ {
+ milliseconds = INFINITE;
+ }
+ else
+ {
+ /*
+ * Calculate timeout as milliseconds from current system time.
+ */
+ milliseconds = ptw32_relmillisecs (abstime);
+ }
+
+ pthread_testcancel();
+
+ if ((result = pthread_mutex_lock (&s->lock)) == 0)
+ {
+ int v = --s->value;
+ (void) pthread_mutex_unlock (&s->lock);
+
+ if (v < 0)
+ {
+#ifdef NEED_SEM
+ int timedout;
+#endif
+ sem_timedwait_cleanup_args_t cleanup_args;
+
+ cleanup_args.sem = s;
+ cleanup_args.resultPtr = &result;
+
+#ifdef _MSC_VER
+#pragma inline_depth(0)
+#endif
+ /* Must wait */
+ pthread_cleanup_push(ptw32_sem_timedwait_cleanup, (void *) &cleanup_args);
+#ifdef NEED_SEM
+ timedout =
+#endif
+ result = pthreadCancelableTimedWait (s->sem, milliseconds);
+ pthread_cleanup_pop(result);
+#ifdef _MSC_VER
+#pragma inline_depth()
+#endif
+
+#ifdef NEED_SEM
+
+ if (!timedout && pthread_mutex_lock (&s->lock) == 0)
+ {
+ if (s->leftToUnblock > 0)
+ {
+ --s->leftToUnblock;
+ SetEvent(s->sem);
+ }
+ (void) pthread_mutex_unlock (&s->lock);
+ }
+
+#endif /* NEED_SEM */
+
+ }
+ }
+
+ }
+
+ if (result != 0)
+ {
+
+ errno = result;
+ return -1;
+
+ }
+
+ return 0;
+
+} /* sem_timedwait */
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