about summary refs log tree commit diff
path: root/linuxthreads/rwlock.c
diff options
context:
space:
mode:
authorUlrich Drepper <drepper@redhat.com>1998-03-11 12:42:25 +0000
committerUlrich Drepper <drepper@redhat.com>1998-03-11 12:42:25 +0000
commit5afdca0087dad2994ad4fcdfe7f489f4dbcab7b3 (patch)
treec9c82db2ff92537b921361a02a284b0e18a594b8 /linuxthreads/rwlock.c
parent3d76e7784700c20fc222920b2a22baba006daa15 (diff)
downloadglibc-5afdca0087dad2994ad4fcdfe7f489f4dbcab7b3.tar.gz
glibc-5afdca0087dad2994ad4fcdfe7f489f4dbcab7b3.tar.xz
glibc-5afdca0087dad2994ad4fcdfe7f489f4dbcab7b3.zip
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.
Diffstat (limited to 'linuxthreads/rwlock.c')
-rw-r--r--linuxthreads/rwlock.c276
1 files changed, 276 insertions, 0 deletions
diff --git a/linuxthreads/rwlock.c b/linuxthreads/rwlock.c
new file mode 100644
index 0000000000..c6b281551a
--- /dev/null
+++ b/linuxthreads/rwlock.c
@@ -0,0 +1,276 @@
+/* Read-write lock implementation.
+   Copyright (C) 1998 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Xavier Leroy <Xavier.Leroy@inria.fr>
+   and Ulrich Drepper <drepper@cygnus.com>, 1998.
+
+   The GNU C Library 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.
+
+   The GNU C 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <errno.h>
+#include <pthread.h>
+#include "internals.h"
+#include "queue.h"
+#include "restart.h"
+#include "spinlock.h"
+
+int
+pthread_rwlock_init (pthread_rwlock_t *rwlock,
+		     const pthread_rwlockattr_t *attr)
+{
+  rwlock->rw_spinlock = 0;
+  rwlock->rw_readers = 0;
+  rwlock->rw_writer = NULL;
+
+  queue_init(&rwlock->rw_read_waiting);
+  queue_init(&rwlock->rw_write_waiting);
+
+  if (attr == NULL)
+    {
+      rwlock->rw_kind = PTHREAD_RWLOCK_DEFAULT_NP;
+      rwlock->rw_pshared = PTHREAD_PROCESS_PRIVATE;
+    }
+  else
+    {
+      rwlock->rw_kind = attr->lockkind;
+      rwlock->rw_pshared = attr->pshared;
+    }
+
+  return 0;
+}
+
+
+int
+pthread_rwlock_destroy (pthread_rwlock_t *rwlock)
+{
+  int readers;
+  _pthread_descr writer;
+
+  acquire (&rwlock->rw_spinlock);
+  readers = rwlock->rw_readers;
+  writer = rwlock->rw_writer;
+  release (&rwlock->rw_spinlock);
+
+  if (readers > 0 || writer != NULL)
+    return EBUSY;
+
+  return 0;
+}
+
+
+int
+pthread_rwlock_rdlock (pthread_rwlock_t *rwlock)
+{
+  pthread_descr self;
+
+  while (1)
+    {
+      acquire (&rwlock->rw_spinlock);
+      if (rwlock->rw_writer == NULL
+	  || (rwlock->rw_kind == PTHREAD_RWLOCK_PREFER_READER_NP
+	      && rwlock->rw_readers != 0))
+	/* We can add a reader lock.  */
+	break;
+
+      /* Suspend ourselves, then try again */
+      self = thread_self ();
+      enqueue (&rwlock->rw_read_waiting, self);
+      release (&rwlock->rw_spinlock);
+      suspend (self); /* This is not a cancellation point */
+    }
+
+  ++rwlock->rw_readers;
+  release (&rwlock->rw_spinlock);
+
+  return 0;
+}
+
+
+int
+pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock)
+{
+  int result = EBUSY;
+
+  acquire (&rwlock->rw_spinlock);
+  if (rwlock->rw_writer == NULL
+      || (rwlock->rw_kind == PTHREAD_RWLOCK_PREFER_READER_NP
+	  && rwlock->rw_readers != 0))
+    {
+      ++rwlock->rw_readers;
+      result = 0;
+    }
+  release (&rwlock->rw_spinlock);
+
+  return result;
+}
+
+
+int
+pthread_rwlock_wrlock (pthread_rwlock_t *rwlock)
+{
+  pthread_descr self = thread_self ();
+
+  while(1)
+    {
+      acquire (&rwlock->rw_spinlock);
+      if (rwlock->rw_readers == 0 && rwlock->rw_writer == NULL)
+	{
+	  rwlock->rw_writer = self;
+	  release (&rwlock->rw_spinlock);
+	  return 0;
+	}
+
+      /* Suspend ourselves, then try again */
+      enqueue (&rwlock->rw_write_waiting, self);
+      release (&rwlock->rw_spinlock);
+      suspend (self); /* This is not a cancellation point */
+    }
+}
+
+
+int
+pthread_rwlock_trywrlock (pthread_rwlock_t *rwlock)
+{
+  int result = EBUSY;
+
+  acquire (&rwlock->rw_spinlock);
+  if (rwlock->rw_readers == 0 && rwlock->rw_writer == NULL)
+    {
+      rwlock->rw_writer = thread_self ();
+      result = 0;
+    }
+  release (&rwlock->rw_spinlock);
+
+  return result;
+}
+
+
+int
+pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
+{
+  struct _pthread_queue torestart;
+  pthread_descr th;
+
+  acquire (&rwlock->rw_spinlock);
+  if (rwlock->rw_writer != NULL)
+    {
+      /* Unlocking a write lock.  */
+      if (rwlock->rw_writer != thread_self ())
+	{
+	  release (&rwlock->rw_spinlock);
+	  return EPERM;
+	}
+      rwlock->rw_writer = NULL;
+
+      if (rwlock->rw_kind == PTHREAD_RWLOCK_PREFER_READER_NP
+	  || (th = dequeue (&rwlock->rw_write_waiting)) == NULL)
+	{
+	  /* Restart all waiting readers.  */
+	  torestart = rwlock->rw_read_waiting;
+	  queue_init (&rwlock->rw_read_waiting);
+	  release (&rwlock->rw_spinlock);
+	  while ((th = dequeue (&torestart)) != NULL)
+	    restart (th);
+	}
+      else
+	{
+	  /* Restart one waiting writer.  */
+	  release (&rwlock->rw_spinlock);
+	  restart (th);
+	}
+    }
+  else
+    {
+      /* Unlocking a read lock.  */
+      if (rwlock->rw_readers == 0)
+	{
+	  release (&rwlock->rw_spinlock);
+	  return EPERM;
+	}
+
+      --rwlock->rw_readers;
+      if (rwlock->rw_readers == 0)
+	/* Restart one waiting writer, if any.  */
+	th = dequeue (&rwlock->rw_write_waiting);
+      else
+	th = NULL;
+
+      release (&rwlock->rw_spinlock);
+      if (th != NULL)
+	restart (th);
+    }
+
+  return 0;
+}
+
+
+
+int
+pthread_rwlockattr_init (pthread_rwlockattr_t *attr)
+{
+  attr->lockkind = 0;
+  attr->pshared = 0;
+
+  return 0;
+}
+
+
+int
+pthread_rwlockattr_destroy (pthread_rwlockattr_t *attr)
+{
+  return 0;
+}
+
+
+int
+pthread_rwlockattr_getpshared (const pthread_rwlockattr_t *attr, int *pshared)
+{
+  *pshared = attr->pshared;
+  return 0;
+}
+
+
+int
+pthread_rwlockattr_setpshared (pthread_rwlockattr_t *attr, int pshared)
+{
+  if (pshared != PTHREAD_PROCESS_PRIVATE && pshared != PTHREAD_PROCESS_SHARED)
+    return EINVAL;
+
+  attr->pshared = pshared;
+
+  return 0;
+}
+
+
+int
+pthread_rwlockattr_getkind_np (const pthread_rwlockattr_t *attr, int *pref)
+{
+  *pref = attr->lockkind;
+  return 0;
+}
+
+
+int
+pthread_rwlockattr_setkind_np (pthread_rwlockattr_t *attr, int pref)
+{
+  if (pref != PTHREAD_RWLOCK_PREFER_READER_NP
+      && pref != PTHREAD_RWLOCK_PREFER_WRITER_NP
+      && pref != PTHREAD_RWLOCK_DEFAULT_NP)
+    return EINVAL;
+
+  attr->lockkind = pref;
+
+  return 0;
+}