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authorAustin Foxley <austinf@cetoncorp.com>2009-10-17 12:26:24 -0700
committerAustin Foxley <austinf@cetoncorp.com>2009-10-17 12:26:24 -0700
commitc68d0fa2d88fc2134a38d99e7e944828384a7671 (patch)
tree6596943bd1c77f18d6e49d4153ddd3f3d67b49f5 /libpthread/nptl/sysdeps/pthread/createthread.c
parent9a03e98a3b418f33c347a6023e9320f3a42cb9e4 (diff)
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>
Diffstat (limited to 'libpthread/nptl/sysdeps/pthread/createthread.c')
-rw-r--r--libpthread/nptl/sysdeps/pthread/createthread.c255
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;
+}