libpthread/nptl: core of the "Native Posix Threading Library" for uClibc

targetting arm,sh,i386,mips,sparc for now

Signed-off-by: Austin Foxley <austinf@cetoncorp.com>

1 files changed, 104 insertions, 0 deletions

diff --git a/libpthread/nptl/pthread_cancel.c b/libpthread/nptl/pthread_cancel.c
new file mode 100644
index 000000000..0ea990693
--- /dev/null
+++ b/libpthread/nptl/pthread_cancel.c
@@ -0,0 +1,104 @@
+/* Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
+
+   The GNU C 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 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <errno.h>
+#include <signal.h>
+#include "pthreadP.h"
+#include "atomic.h"
+#include <sysdep.h>
+#include <bits/kernel-features.h>
+
+
+int
+pthread_cancel (th)
+     pthread_t th;
+{
+  volatile struct pthread *pd = (volatile struct pthread *) th;
+
+  /* Make sure the descriptor is valid.  */
+  if (INVALID_TD_P (pd))
+    /* Not a valid thread handle.  */
+    return ESRCH;
+
+#ifdef SHARED
+  pthread_cancel_init ();
+#endif
+  int result = 0;
+  int oldval;
+  int newval;
+  do
+    {
+      oldval = pd->cancelhandling;
+      newval = oldval | CANCELING_BITMASK | CANCELED_BITMASK;
+
+      /* Avoid doing unnecessary work.  The atomic operation can
+	 potentially be expensive if the bug has to be locked and
+	 remote cache lines have to be invalidated.  */
+      if (oldval == newval)
+	break;
+
+      /* If the cancellation is handled asynchronously just send a
+	 signal.  We avoid this if possible since it's more
+	 expensive.  */
+      if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval))
+	{
+	  /* Mark the cancellation as "in progress".  */
+	  atomic_bit_set (&pd->cancelhandling, CANCELING_BIT);
+
+	  /* The cancellation handler will take care of marking the
+	     thread as canceled.  */
+	  INTERNAL_SYSCALL_DECL (err);
+
+	  /* One comment: The PID field in the TCB can temporarily be
+	     changed (in fork).  But this must not affect this code
+	     here.  Since this function would have to be called while
+	     the thread is executing fork, it would have to happen in
+	     a signal handler.  But this is no allowed, pthread_cancel
+	     is not guaranteed to be async-safe.  */
+	  int val;
+#if __ASSUME_TGKILL
+	  val = INTERNAL_SYSCALL (tgkill, err, 3,
+				  THREAD_GETMEM (THREAD_SELF, pid), pd->tid,
+				  SIGCANCEL);
+#else
+# ifdef __NR_tgkill
+	  val = INTERNAL_SYSCALL (tgkill, err, 3,
+				  THREAD_GETMEM (THREAD_SELF, pid), pd->tid,
+				  SIGCANCEL);
+	  if (INTERNAL_SYSCALL_ERROR_P (val, err)
+	      && INTERNAL_SYSCALL_ERRNO (val, err) == ENOSYS)
+# endif
+	    val = INTERNAL_SYSCALL (tkill, err, 2, pd->tid, SIGCANCEL);
+#endif
+
+	  if (INTERNAL_SYSCALL_ERROR_P (val, err))
+	    result = INTERNAL_SYSCALL_ERRNO (val, err);
+
+	  break;
+	}
+    }
+  /* Mark the thread as canceled.  This has to be done
+     atomically since other bits could be modified as well.  */
+  while (atomic_compare_and_exchange_bool_acq (&pd->cancelhandling, newval,
+					       oldval));
+
+  return result;
+}
+
+PTHREAD_STATIC_FN_REQUIRE (pthread_create)