253 lines
8.0 KiB
C
253 lines
8.0 KiB
C
/* Copyright (C) 2002-2012 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, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include <sched.h>
|
|
#include <setjmp.h>
|
|
#include <signal.h>
|
|
#include <stdlib.h>
|
|
#include <atomic.h>
|
|
#include <ldsodefs.h>
|
|
#include <tls.h>
|
|
|
|
#include "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 (__builtin_expect (stopped != 0, 0))
|
|
/* 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, LLL_PRIVATE);
|
|
|
|
/* 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);
|
|
|
|
int rc = ARCH_CLONE (fct, STACK_VARIABLES_ARGS, clone_flags,
|
|
pd, &pd->tid, TLS_VALUE, &pd->tid);
|
|
|
|
if (__builtin_expect (rc == -1, 0))
|
|
{
|
|
atomic_decrement (&__nptl_nthreads); /* Oops, we lied for a second. */
|
|
|
|
/* Perhaps a thread wants to change the IDs and if waiting
|
|
for this stillborn thread. */
|
|
if (__builtin_expect (atomic_exchange_acq (&pd->setxid_futex, 0)
|
|
== -2, 0))
|
|
lll_futex_wake (&pd->setxid_futex, 1, LLL_PRIVATE);
|
|
|
|
/* Free the resources. */
|
|
__deallocate_stack (pd);
|
|
|
|
/* We have to translate error codes. */
|
|
return errno == ENOMEM ? EAGAIN : 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,
|
|
attr->cpusetsize, 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:
|
|
(void) INTERNAL_SYSCALL (tgkill, err2, 3,
|
|
THREAD_GETMEM (THREAD_SELF, pid),
|
|
pd->tid, SIGCANCEL);
|
|
|
|
/* We do not free the stack here because the canceled thread
|
|
itself will do this. */
|
|
|
|
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.
|
|
|
|
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
|
|
| 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, LLL_PRIVATE);
|
|
}
|
|
|
|
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;
|
|
pd->parent_cancelhandling = THREAD_GETMEM (THREAD_SELF, cancelhandling);
|
|
|
|
/* 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, LLL_PRIVATE);
|
|
|
|
return res;
|
|
}
|