LinuxThreads library.

1998-03-11 00:42  Wolfram Gloger  <wmglo@dent.med.uni-muenchen.de>
	* linuxthreads/manager.c: Enable resetting of the thread
	scheduling policy to SCHED_OTHER when the parent thread
	has a different one.
1998-02-01 13:51  Ulrich Drepper  <drepper@cygnus.com>
	* sysdeps/unix/sysv/linux/bits/posix_opt.h: Define
	_POSIX_ASYNCHRONOUS_IO.
	* sysdeps/pthread/pthread.h: Define bits for Unix98 variants of
	mutexes.
	* mutex.c: Implement new mutex types.
	* internals.h: Include <signal.h>.
	* libpthread.map: Add __erno_location and __h_errno_location.
	* errno.c: Return pointer to variable actually in use.  This might
	not be the one in the thread structure.
	* internals.h (struct _pthread_descr_struct): Add new fields p_errnop
	and p_h_errnop.
	* manager.c (__pthread_manager): Set p_errnop and p_h_errnop member
	of manager thread structure.
	(pthread_handle_create): Set p_errnop and p_h_errnop members for new
	thread.
	* pthread.c: Adapt initializer for thread structures.
	(__pthread_initial_thread): Set p_errnop and p_h_errnop member.
	(__pthread_reset_main_thread): Reset p_errnop and p_h_errnop of
	current thread to global variables.
1998-01-31 17:27  Ulrich Drepper  <drepper@cygnus.com>
	* rwlock.c: New file.
	* Makefile (libpthread-routines): Add rwlock.
	* sysdeps/pthread/pthread.h: Define data structures and declare
	functions.
	* libpthread.map: Add new functions.
1997-12-18 13:50  Philip Blundell  <pb@nexus.co.uk>
	* sysdeps/arm/pt-machine.h: New file; add ARM support.
	* sysdeps/arm/Implies: likewise.
	* README: Document it.
1997-12-13  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>
	* signals.c: Remove unneeded initializer for sigwaited, saving a
1997-04-11 01:18  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>
	* semaphore.c (sem_init): Set sem_spinlock only if available.
1997-12-04 01:48  Ulrich Drepper  <drepper@cygnus.com>
	* mutex.c: Implement PTHREAD_MUTEX_CHECKERROR.
	* sysdeps/pthread/pthread.h: Define PTHREAD_MUTEX_CHECKERROR.
	* Makefile: Update from LinuxThreads 0.7.
	* internals.h. Likewise.
	* manager.c: Likewise.
	* mutex.c: Likewise.
	* pthread.c: Likewise.
	* signals.c: Likewise.
	* specific.c: Likewise.
	* Examples/ex3.c: Likewise.
1997-11-20 18:13  Ulrich Drepper  <drepper@cygnus.com>
	* pthread.c (__pthread_reset_main_thread): Close pipe only if still
	open.
1997-10-29 05:38  Ulrich Drepper  <drepper@cygnus.com>

	* wrapsyscall.c: Add socket functions which are also cancelation
	points.

1997-10-19 21:40  Wolfram Gloger  <wg@wolfram.dent.med.uni-muenchen.de>

	* specific.c (__libc_internal_tsd_set, __libc_internal_tsd_get):
	New functions for fast thread specific data within libc.

	* internals.h: Add new array p_libc_specific to struct
	_pthread_descr_struct.

	* sysdeps/pthread/bits/libc-lock.h: Declare new functions.

1997-10-13 05:39  Ulrich Drepper  <drepper@cygnus.com>

	* semaphore.h: Add __BEGIN_DECLS/__END_DECLS.
	Reported by Ralf Corsepius <corsepiu@faw.uni-ulm.de>.

1997-08-29 03:05  Ulrich Drepper  <drepper@cygnus.com>

	* internals.h (struct _pthread_descr_struct): Add definitions for
	two-level specific key handling.
	* manager.c (pthread_handle_create): Initialize specific memory array.
	* specific.c: Implement two-level key handling.
	* weaks.c: Don't provide dummy key handling.
	* sysdeps/pthread/bits/libc-lock.h: Typedef __libc_lock_t (no #define).
	Add definition of __libc_key_t.
	* sysdeps/unix/sysv/linux/bits/local_lim.h: Define PTHREAD_KEYS_MAX
	as 1024.
	Add definition of _POSIX_THREAD_DESTRUCTOR_ITERATIONS and
	PTHREAD_DESTRUCTOR_ITERATIONS.

	* manager.c (pthread_handle_create): Compare mmap result with
	MAP_FAILED.

	* ptfork.c: Rename to __pthread_atfork and make old name a weak alias.
	* sysdeps/pthread/bits/pthread.h: Add prototype for __pthread_atfork.

1997-08-22 19:04  Richard Henderson  <rth@cygnus.com>

	sysdeps/sparc -> sysdeps/sparc/sparc32
	sysdeps/sparc64 -> sysdeps/sparc/sparc64

	* internals.h: Change definition of THREAD_SELF to be an expression,
	not a statement that did a return.
	* sysdeps/alpha/pt-machine.h (THREAD_SELF): Update accordingly.
	* sysdeps/sparc/sparc32/pt-machine.h (THREAD_SELF, INIT_THREAD_SELF):
	Follow Solaris and use a "system reserved" register (%g6) to hold
	the thread descriptor.
	* sysdeps/sparc/sparc64/pt-machine.h: Likewise.

1997-08-03 00:09  Ulrich Drepper  <drepper@cygnus.com>

	* mutex.c: Correct pthread_once.  Patch by Xavier Leroy.
	* sysdeps/pthread/pthread.h: Add prototype for __pthread_once.
	* sysdeps/pthread/bits/pthread.h: Add macros for __libc_once.

	* semaphore.c: Include spinlock.h only when needed.

	* specific.c (__pthread_setsepcific, __pthread_getspecific): Reject
	keys for entries not in use.

	* weaks.c: Implement key handling functions for real.

1997-06-29  01:04  Richard Henderson  <richard@gnu.ai.mit.edu>

	Initial sparc64-linux support:
	* linuxthreads/sysdeps/sparc64/Implies: New file.
	* linuxthreads/sysdeps/sparc64/pt-machine.h: Likewise.

1997-06-29 00:48  Ulrich Drepper  <drepper@cygnus.com>

	* semaphore.c: Include spinlock.h at correct place.
	Patch by HJ Lu.

1997-06-13 10:06  Richard Henderson  <rth@tamu.edu>

	The Great Bit File Move:
	* sysdeps/alpha/semaphorebits.h: -> .../bits/semaphore.h.
	* sysdeps/powerpc/semaphorebits.h: Likewise.
	* sysdeps/pthread/cmpxchg/semaphorebits.h: Likewise.
	* sysdeps/pthread/no-cmpxchg/semaphorebits.h: Likewise.
	* sysdeps/pthread/libc-lock.h: -> bits/
	* sysdeps/pthread/stdio-lock.h: Likewise.
	* sysdeps/unix/sysv/linux/local_lim.h: Likewise.
	* sysdeps/unix/sysv/linux/posix_opt.h: Likewise.
	* semaphore.h: Likewise.
	* sysdeps/pthread/pthread.h: Likewise.

	* lockfile.c: <foo.h> -> <bits/foo.h>.
	* semaphore.h: Likewise.

	* Makefile: (headers): foo.h -> bits/foo.h.
	* sysdeps/pthread/Makefile: Likewise.

1997-04-11 01:18  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* semaphore.c (sem_init): Set sem_spinlock only if available.

	* sysdeps/m68k/pt-machine.h (testandset, __compare_and_swap): Fix
	asm constraints.

1997-04-09 03:00  Ulrich Drepper  <drepper@cygnus.com>

	Update from LinuxThreads 0.6.

	* attr.c (pthread_attr_getdetachstate): Use __sched_get_priority_max
	and __sched_get_priority_min instead of names without `__'.

	* manager.c: Rewrite large parts to implement opaque pthread_t.

	* cancel.c: Adapt for opaque pthread_t type.
	* condvar.c: Likewise.
	* errno.c: Likewise.
	* join.c: Likewise.
	* mutex.c: Likewise.
	* pthread.c: Likewise.
	* signals.c: Likewise.
	* specific.c: Likewise.
	* restart.h: Likewise.
	* queue.h: Likewise.
	* Examples/ex3.c: Likewise.
	* Examples/ex4.c: Likewise.
	* sysdeps/pthread/pthread.h: Likewise.

	* pthread.c: Accumulate time for all threads in thread manager.

	* semaphore.c: Implement fallback implementation for architectures
	sometimes missing compare-exchange operations.

	* cancel.c (pthread_cancel): Validate handle argument.
	* join.c (pthread_join): Likewise.
	(pthread_detach): Likewise.
	* signals.c (pthread_kill): Likewise.

	* spinlock.h (acquire): Use __sched_yield not sched_yield.

	* queue.h (enqueue): Enqueue thread according to priority.

	* internals.c (struct pthread_start_args): New struct for passing
	args to cloning function.
	(struct _pthread): Rename to _pthread_descr_struct and adapt for
	opaque pthread_t.

	* Examples/Makefile (clean): Pass -f option to rm.

	* sysdeps/i386/pt-machine.h: Add check for compare-exchange instruction
	and define TEST_FOR_COMPARE_AND_SWAP.
	* sysdeps/i386/i486/pt-machine.h: Removed.

	* sysdeps/unix/sysv/linux/local_lim.h (PTHREAD_THREADS_MAX): Increase
	to 1024.

1997-04-04 16:38  Ulrich Drepper  <drepper@cygnus.com>

	* restart.h (suspend): Clear p_signal before suspending.
	(suspend_with_cancellation): Likewise.
	Patch by Xavier Leroy <Xavier.Leroy@inria.fr>.

	* weaks.c: Make __pthread_key_create return 1.
	* sysdeps/pthread/libc-lock.h: Define __libc_key_create,
	__libc_getspecific, __libc_setspecific, and __libc_key_t.
	* sysdeps/pthread/stdio-lock.h: Don't care for implementation not
	using libio.

1997-03-19 15:13  Miguel de Icaza  <miguel@nuclecu.unam.mx>

	* sysdeps/sparc/pt-machine (RELEASE): Fix.

1997-03-01 07:55  Geoff Keating  <geoffk@ozemail.com.au>

	* sysdeps/powerpc/Implies: Added.
	* sysdeps/powerpc/pt-machine.h: Added.
	* sysdeps/powerpc/semaphorebits.h: Added.

1997-01-22 01:22  Ulrich Drepper  <drepper@cygnus.com>

	* linuxtheads/pthread.c (__pthread_initial_thread): Correct
	initializer.
	(__pthread_manager_thread): Likewise.
	Reported by Andreas Jaeger.

1997-01-18 22:15  Richard Henderson  <rth@tamu.edu>

	Since sigset_t no longer fits in a register, we can't pass in the
	thread's initial mask so easily.  Take this opportunity to simplify
	the clone implementation by only accepting a single void* argument.

	* linuxthreads/manager.c (__pthread_manager): Put thread vitals
	in the thread struct instead of as arguments through clone.
	(pthread_start_thread): Look for them there.
	* linuxthreads/internals.h (struct _pthread): Add p_initial_fn,
	p_initial_fn_arg, p_initial_mask.  Fix __pthread_manager proto.
	* linuxthreads/pthread.c (pthread_initialize_manager): Revise
	clone invocation.

1 files changed, 236 insertions, 0 deletions

diff --git a/linuxthreads/semaphore.c b/linuxthreads/semaphore.c
new file mode 100644
index 0000000..bd07439
--- /dev/null
+++ b/linuxthreads/semaphore.c
@@ -0,0 +1,236 @@
+/* Linuxthreads - a simple clone()-based implementation of Posix        */
+/* threads for Linux.                                                   */
+/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr)              */
+/*                                                                      */
+/* This program is free software; you can redistribute it and/or        */
+/* modify it under the terms of the GNU Library General Public License  */
+/* as published by the Free Software Foundation; either version 2       */
+/* of the License, or (at your option) any later version.               */
+/*                                                                      */
+/* This program 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 Library General Public License for more details.                 */
+
+/* Semaphores a la POSIX 1003.1b */
+
+#include "pthread.h"
+#include "semaphore.h"
+#include "internals.h"
+#include "restart.h"
+
+
+#if !defined HAS_COMPARE_AND_SWAP && !defined TEST_FOR_COMPARE_AND_SWAP
+/* If we have no atomic compare and swap, fake it using an extra spinlock.  */
+
+#include "spinlock.h"
+static inline int sem_compare_and_swap(sem_t *sem, long oldval, long newval)
+{
+  int ret;
+  acquire(&sem->sem_spinlock);
+  ret = (sem->sem_status == oldval);
+  if (ret) sem->sem_status = newval;
+  release(&sem->sem_spinlock);
+  return ret;
+}
+
+#elif defined TEST_FOR_COMPARE_AND_SWAP
+
+#include "spinlock.h"
+static int has_compare_and_swap = -1; /* to be determined at run-time */
+
+static inline int sem_compare_and_swap(sem_t *sem, long oldval, long newval)
+{
+  int ret;
+
+  if (has_compare_and_swap == 1)
+    return __compare_and_swap(&sem->sem_status, oldval, newval);
+
+  acquire(&sem->sem_spinlock);
+  ret = (sem->sem_status == oldval);
+  if (ret) sem->sem_status = newval;
+  release(&sem->sem_spinlock);
+  return ret;
+}
+
+#else
+/* But if we do have an atomic compare and swap, use it!  */
+
+static inline int sem_compare_and_swap(sem_t *sem, long oldval, long newval)
+{
+  return __compare_and_swap(&sem->sem_status, oldval, newval);
+}
+
+#endif
+
+
+/* The state of a semaphore is represented by a long int encoding
+   either the semaphore count if >= 0 and no thread is waiting on it,
+   or the head of the list of threads waiting for the semaphore.
+   To distinguish the two cases, we encode the semaphore count N
+   as 2N+1, so that it has the lowest bit set.
+
+   A sequence of sem_wait operations on a semaphore initialized to N
+   result in the following successive states:
+     2N+1, 2N-1, ..., 3, 1, &first_waiting_thread, &second_waiting_thread, ...
+*/
+
+static void sem_restart_list(pthread_descr waiting);
+
+int sem_init(sem_t *sem, int pshared, unsigned int value)
+{
+  if ((long)value > SEM_VALUE_MAX) {
+    errno = EINVAL;
+    return -1;
+  }
+  if (pshared) {
+    errno = ENOSYS;
+    return -1;
+  }
+#ifdef TEST_FOR_COMPARE_AND_SWAP
+  if (has_compare_and_swap == -1) {
+    has_compare_and_swap = compare_and_swap_is_available();
+  }
+#endif
+#if !defined HAS_COMPARE_AND_SWAP || defined TEST_FOR_COMPARE_AND_SWAP
+  sem->sem_spinlock = 0;
+#endif
+  sem->sem_status = ((long)value << 1) + 1;
+  return 0;
+}
+
+int sem_wait(sem_t * sem)
+{
+  long oldstatus, newstatus;
+  volatile pthread_descr self = thread_self();
+  pthread_descr * th;
+
+  while (1) {
+    do {
+      oldstatus = sem->sem_status;
+      if ((oldstatus & 1) && (oldstatus != 1))
+        newstatus = oldstatus - 2;
+      else {
+        newstatus = (long) self;
+        self->p_nextwaiting = (pthread_descr) oldstatus;
+      }
+    }
+    while (! sem_compare_and_swap(sem, oldstatus, newstatus));
+    if (newstatus & 1)
+      /* We got the semaphore. */
+      return 0;
+    /* Wait for sem_post or cancellation */
+    suspend_with_cancellation(self);
+    /* This is a cancellation point */
+    if (self->p_canceled && self->p_cancelstate == PTHREAD_CANCEL_ENABLE) {
+      /* Remove ourselves from the waiting list if we're still on it */
+      /* First check if we're at the head of the list. */
+      do {
+        oldstatus = sem->sem_status;
+        if (oldstatus != (long) self) break;
+        newstatus = (long) self->p_nextwaiting;
+      }
+      while (! sem_compare_and_swap(sem, oldstatus, newstatus));
+      /* Now, check if we're somewhere in the list.
+         There's a race condition with sem_post here, but it does not matter:
+         the net result is that at the time pthread_exit is called,
+         self is no longer reachable from sem->sem_status. */
+      if (oldstatus != (long) self && (oldstatus & 1) == 0) {
+	for (th = &(((pthread_descr) oldstatus)->p_nextwaiting);
+	     *th != NULL && *th != (pthread_descr) 1;
+	     th = &((*th)->p_nextwaiting)) {
+          if (*th == self) {
+            *th = self->p_nextwaiting;
+            break;
+          }
+        }
+      }
+      pthread_exit(PTHREAD_CANCELED);
+    }
+  }
+}
+
+int sem_trywait(sem_t * sem)
+{
+  long oldstatus, newstatus;
+
+  do {
+    oldstatus = sem->sem_status;
+    if ((oldstatus & 1) == 0 || (oldstatus == 1)) {
+      errno = EAGAIN;
+      return -1;
+    }
+    newstatus = oldstatus - 2;
+  }
+  while (! sem_compare_and_swap(sem, oldstatus, newstatus));
+  return 0;
+}
+
+int sem_post(sem_t * sem)
+{
+  long oldstatus, newstatus;
+
+  do {
+    oldstatus = sem->sem_status;
+    if ((oldstatus & 1) == 0)
+      newstatus = 3;
+    else {
+      if (oldstatus >= SEM_VALUE_MAX) {
+        /* Overflow */
+        errno = ERANGE;
+        return -1;
+      }
+      newstatus = oldstatus + 2;
+    }
+  }
+  while (! sem_compare_and_swap(sem, oldstatus, newstatus));
+  if ((oldstatus & 1) == 0)
+    sem_restart_list((pthread_descr) oldstatus);
+  return 0;
+}
+
+int sem_getvalue(sem_t * sem, int * sval)
+{
+  long status = sem->sem_status;
+  if (status & 1)
+    *sval = (int)((unsigned long) status >> 1);
+  else
+    *sval = 0;
+  return 0;
+}
+
+int sem_destroy(sem_t * sem)
+{
+  if ((sem->sem_status & 1) == 0) {
+    errno = EBUSY;
+    return -1;
+  }
+  return 0;
+}
+
+/* Auxiliary function for restarting all threads on a waiting list,
+   in priority order. */
+
+static void sem_restart_list(pthread_descr waiting)
+{
+  pthread_descr th, towake, *p;
+
+  /* Sort list of waiting threads by decreasing priority (insertion sort) */
+  towake = NULL;
+  while (waiting != (pthread_descr) 1) {
+    th = waiting;
+    waiting = waiting->p_nextwaiting;
+    p = &towake;
+    while (*p != NULL && th->p_priority < (*p)->p_priority)
+      p = &((*p)->p_nextwaiting);
+    th->p_nextwaiting = *p;
+    *p = th;
+  }
+  /* Wake up threads in priority order */
+  while (towake != NULL) {
+    th = towake;
+    towake = towake->p_nextwaiting;
+    th->p_nextwaiting = NULL;
+    restart(th);
+  }
+}