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, 255 insertions, 0 deletions

diff --git a/libpthread/nptl/sysdeps/pthread/createthread.c b/libpthread/nptl/sysdeps/pthread/createthread.c
new file mode 100644
index 000000000..88ffe09d3
--- /dev/null
+++ b/libpthread/nptl/sysdeps/pthread/createthread.c
@@ -0,0 +1,255 @@
+/* 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 <sched.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <atomic.h>
+#include <ldsodefs.h>
+#include <tls.h>
+
+#include <bits/kernel-features.h>
+
+
+#define CLONE_SIGNAL    	(CLONE_SIGHAND | CLONE_THREAD)
+
+/* Unless otherwise specified, the thread "register" is going to be
+   initialized with a pointer to the TCB.  */
+#ifndef TLS_VALUE
+# define TLS_VALUE pd
+#endif
+
+#ifndef ARCH_CLONE
+# define ARCH_CLONE __clone
+#endif
+
+
+#ifndef TLS_MULTIPLE_THREADS_IN_TCB
+/* Pointer to the corresponding variable in libc.  */
+int *__libc_multiple_threads_ptr attribute_hidden;
+#endif
+
+
+static int
+do_clone (struct pthread *pd, const struct pthread_attr *attr,
+	  int clone_flags, int (*fct) (void *), STACK_VARIABLES_PARMS,
+	  int stopped)
+{
+#ifdef PREPARE_CREATE
+  PREPARE_CREATE;
+#endif
+
+  if (stopped)
+    /* We Make sure the thread does not run far by forcing it to get a
+       lock.  We lock it here too so that the new thread cannot continue
+       until we tell it to.  */
+    lll_lock (pd->lock);
+
+  /* One more thread.  We cannot have the thread do this itself, since it
+     might exist but not have been scheduled yet by the time we've returned
+     and need to check the value to behave correctly.  We must do it before
+     creating the thread, in case it does get scheduled first and then
+     might mistakenly think it was the only thread.  In the failure case,
+     we momentarily store a false value; this doesn't matter because there
+     is no kosher thing a signal handler interrupting us right here can do
+     that cares whether the thread count is correct.  */
+  atomic_increment (&__nptl_nthreads);
+
+  if (ARCH_CLONE (fct, STACK_VARIABLES_ARGS, clone_flags,
+		  pd, &pd->tid, TLS_VALUE, &pd->tid) == -1)
+    {
+      atomic_decrement (&__nptl_nthreads); /* Oops, we lied for a second.  */
+
+      /* Failed.  If the thread is detached, remove the TCB here since
+	 the caller cannot do this.  The caller remembered the thread
+	 as detached and cannot reverify that it is not since it must
+	 not access the thread descriptor again.  */
+      if (IS_DETACHED (pd))
+	__deallocate_stack (pd);
+
+      return errno;
+    }
+
+  /* Now we have the possibility to set scheduling parameters etc.  */
+  if (__builtin_expect (stopped != 0, 0))
+    {
+      INTERNAL_SYSCALL_DECL (err);
+      int res = 0;
+
+      /* Set the affinity mask if necessary.  */
+      if (attr->cpuset != NULL)
+	{
+	  res = INTERNAL_SYSCALL (sched_setaffinity, err, 3, pd->tid,
+				  sizeof (cpu_set_t), attr->cpuset);
+
+	  if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (res, err), 0))
+	    {
+	      /* The operation failed.  We have to kill the thread.  First
+		 send it the cancellation signal.  */
+	      INTERNAL_SYSCALL_DECL (err2);
+	    err_out:
+#if __ASSUME_TGKILL
+	      (void) INTERNAL_SYSCALL (tgkill, err2, 3,
+				       THREAD_GETMEM (THREAD_SELF, pid),
+				       pd->tid, SIGCANCEL);
+#else
+	      (void) INTERNAL_SYSCALL (tkill, err2, 2, pd->tid, SIGCANCEL);
+#endif
+
+	      return (INTERNAL_SYSCALL_ERROR_P (res, err)
+		      ? INTERNAL_SYSCALL_ERRNO (res, err)
+		      : 0);
+	    }
+	}
+
+      /* Set the scheduling parameters.  */
+      if ((attr->flags & ATTR_FLAG_NOTINHERITSCHED) != 0)
+	{
+	  res = INTERNAL_SYSCALL (sched_setscheduler, err, 3, pd->tid,
+				  pd->schedpolicy, &pd->schedparam);
+
+	  if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (res, err), 0))
+	    goto err_out;
+	}
+    }
+
+  /* We now have for sure more than one thread.  The main thread might
+     not yet have the flag set.  No need to set the global variable
+     again if this is what we use.  */
+  THREAD_SETMEM (THREAD_SELF, header.multiple_threads, 1);
+
+  return 0;
+}
+
+
+static int
+create_thread (struct pthread *pd, const struct pthread_attr *attr,
+	       STACK_VARIABLES_PARMS)
+{
+#ifdef TLS_TCB_AT_TP
+  assert (pd->header.tcb != NULL);
+#endif
+
+  /* We rely heavily on various flags the CLONE function understands:
+
+     CLONE_VM, CLONE_FS, CLONE_FILES
+	These flags select semantics with shared address space and
+	file descriptors according to what POSIX requires.
+
+     CLONE_SIGNAL
+	This flag selects the POSIX signal semantics.
+
+     CLONE_SETTLS
+	The sixth parameter to CLONE determines the TLS area for the
+	new thread.
+
+     CLONE_PARENT_SETTID
+	The kernels writes the thread ID of the newly created thread
+	into the location pointed to by the fifth parameters to CLONE.
+
+	Note that it would be semantically equivalent to use
+	CLONE_CHILD_SETTID but it is be more expensive in the kernel.
+
+     CLONE_CHILD_CLEARTID
+	The kernels clears the thread ID of a thread that has called
+	sys_exit() in the location pointed to by the seventh parameter
+	to CLONE.
+
+     CLONE_DETACHED
+	No signal is generated if the thread exists and it is
+	automatically reaped.
+
+     The termination signal is chosen to be zero which means no signal
+     is sent.  */
+  int clone_flags = (CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGNAL
+		     | CLONE_SETTLS | CLONE_PARENT_SETTID
+		     | CLONE_CHILD_CLEARTID | CLONE_SYSVSEM
+#if __ASSUME_NO_CLONE_DETACHED == 0
+		     | CLONE_DETACHED
+#endif
+		     | 0);
+
+  if (__builtin_expect (THREAD_GETMEM (THREAD_SELF, report_events), 0))
+    {
+      /* The parent thread is supposed to report events.  Check whether
+	 the TD_CREATE event is needed, too.  */
+      const int _idx = __td_eventword (TD_CREATE);
+      const uint32_t _mask = __td_eventmask (TD_CREATE);
+
+      if ((_mask & (__nptl_threads_events.event_bits[_idx]
+		    | pd->eventbuf.eventmask.event_bits[_idx])) != 0)
+	{
+	  /* We always must have the thread start stopped.  */
+	  pd->stopped_start = true;
+
+	  /* Create the thread.  We always create the thread stopped
+	     so that it does not get far before we tell the debugger.  */
+	  int res = do_clone (pd, attr, clone_flags, start_thread,
+			      STACK_VARIABLES_ARGS, 1);
+	  if (res == 0)
+	    {
+	      /* Now fill in the information about the new thread in
+		 the newly created thread's data structure.  We cannot let
+		 the new thread do this since we don't know whether it was
+		 already scheduled when we send the event.  */
+	      pd->eventbuf.eventnum = TD_CREATE;
+	      pd->eventbuf.eventdata = pd;
+
+	      /* Enqueue the descriptor.  */
+	      do
+		pd->nextevent = __nptl_last_event;
+	      while (atomic_compare_and_exchange_bool_acq (&__nptl_last_event,
+							   pd, pd->nextevent)
+		     != 0);
+
+	      /* Now call the function which signals the event.  */
+	      __nptl_create_event ();
+
+	      /* And finally restart the new thread.  */
+	      lll_unlock (pd->lock);
+	    }
+
+	  return res;
+	}
+    }
+
+#ifdef NEED_DL_SYSINFO
+  assert (THREAD_SELF_SYSINFO == THREAD_SYSINFO (pd));
+#endif
+
+  /* Determine whether the newly created threads has to be started
+     stopped since we have to set the scheduling parameters or set the
+     affinity.  */
+  bool stopped = false;
+  if (attr != NULL && (attr->cpuset != NULL
+		       || (attr->flags & ATTR_FLAG_NOTINHERITSCHED) != 0))
+    stopped = true;
+  pd->stopped_start = stopped;
+
+  /* Actually create the thread.  */
+  int res = do_clone (pd, attr, clone_flags, start_thread,
+		      STACK_VARIABLES_ARGS, stopped);
+
+  if (res == 0 && stopped)
+    /* And finally restart the new thread.  */
+    lll_unlock (pd->lock);
+
+  return res;
+}