glibc/nptl/pthread_create.c
Ulrich Drepper 877e51b20f (deallocate_tsd): Don't take parameter. Adjust caller. Optimize to avoid often unecessary local variable.
(start_thread): Initialize cleanup_jmp_buf element if own thread descriptor.
2003-04-12 00:25:27 +00:00

485 lines
13 KiB
C

/* Copyright (C) 2002, 2003 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 <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include "pthreadP.h"
#include <hp-timing.h>
#include <ldsodefs.h>
#include <atomic.h>
#include <libc-internal.h>
#include <shlib-compat.h>
/* Local function to start thread and handle cleanup. */
static int start_thread (void *arg);
/* Similar version used when debugging. */
static int start_thread_debug (void *arg);
/* Nozero if debugging mode is enabled. */
int __pthread_debug;
/* Globally enabled events. */
static td_thr_events_t __nptl_threads_events;
/* Pointer to descriptor with the last event. */
static struct pthread *__nptl_last_event;
/* Number of threads running. */
unsigned int __nptl_nthreads = 1;
/* Code to allocate and deallocate a stack. */
#include "allocatestack.c"
/* Code to create the thread. */
#include "createthread.c"
/* Table of the key information. */
struct pthread_key_struct __pthread_keys[PTHREAD_KEYS_MAX]
__attribute__ ((nocommon));
hidden_data_def (__pthread_keys)
/* This is for libthread_db only. */
const int __pthread_pthread_sizeof_descr = sizeof (struct pthread);
struct pthread *
internal_function
__find_in_stack_list (pd)
struct pthread *pd;
{
list_t *entry;
struct pthread *result = NULL;
lll_lock (stack_cache_lock);
list_for_each (entry, &stack_used)
{
struct pthread *curp;
curp = list_entry (entry, struct pthread, list);
if (curp == pd)
{
result = curp;
break;
}
}
if (result == NULL)
list_for_each (entry, &__stack_user)
{
struct pthread *curp;
curp = list_entry (entry, struct pthread, list);
if (curp == pd)
{
result = curp;
break;
}
}
lll_unlock (stack_cache_lock);
return result;
}
/* Deallocate POSIX thread-local-storage. */
static void
internal_function
deallocate_tsd (void)
{
struct pthread *self = THREAD_SELF;
/* Maybe no data was ever allocated. This happens often so we have
a flag for this. */
if (THREAD_GETMEM (self, specific_used))
{
size_t round;
size_t cnt;
round = 0;
do
{
size_t idx;
/* So far no new nonzero data entry. */
THREAD_SETMEM (self, specific_used, false);
for (cnt = idx = 0; cnt < PTHREAD_KEY_1STLEVEL_SIZE; ++cnt)
{
struct pthread_key_data *level2;
level2 = THREAD_GETMEM_NC (self, specific, cnt);
if (level2 != NULL)
{
size_t inner;
for (inner = 0; inner < PTHREAD_KEY_2NDLEVEL_SIZE;
++inner, ++idx)
{
void *data = level2[inner].data;
if (data != NULL)
{
/* Always clear the data. */
level2[inner].data = NULL;
/* Make sure the data corresponds to a valid
key. This test fails if the key was
deallocated and also if it was
re-allocated. It is the user's
responsibility to free the memory in this
case. */
if (level2[inner].seq
== __pthread_keys[idx].seq
/* It is not necessary to register a destructor
function. */
&& __pthread_keys[idx].destr != NULL)
/* Call the user-provided destructor. */
__pthread_keys[idx].destr (data);
}
}
}
else
idx += PTHREAD_KEY_1STLEVEL_SIZE;
}
if (THREAD_GETMEM (self, specific_used) == 0)
/* No data has been modified. */
goto just_free;
}
/* We only repeat the process a fixed number of times. */
while (__builtin_expect (++round < PTHREAD_DESTRUCTOR_ITERATIONS, 0));
/* Just clear the memory of the first block for reuse. */
memset (&THREAD_SELF->specific_1stblock, '\0',
sizeof (self->specific_1stblock));
just_free:
/* Free the memory for the other blocks. */
for (cnt = 1; cnt < PTHREAD_KEY_1STLEVEL_SIZE; ++cnt)
{
struct pthread_key_data *level2;
level2 = THREAD_GETMEM_NC (self, specific, cnt);
if (level2 != NULL)
{
/* The first block is allocated as part of the thread
descriptor. */
free (level2);
THREAD_SETMEM_NC (self, specific, cnt, NULL);
}
}
THREAD_SETMEM (self, specific_used, false);
}
}
/* Deallocate a thread's stack after optionally making sure the thread
descriptor is still valid. */
void
internal_function
__free_tcb (struct pthread *pd)
{
/* The thread is exiting now. */
if (__builtin_expect (atomic_bit_test_set (&pd->cancelhandling,
TERMINATED_BIT) == 0, 1))
{
/* Remove the descriptor from the list. */
if (DEBUGGING_P && __find_in_stack_list (pd) == NULL)
/* Something is really wrong. The descriptor for a still
running thread is gone. */
abort ();
/* Queue the stack memory block for reuse and exit the process. The
kernel will signal via writing to the address returned by
QUEUE-STACK when the stack is available. */
__deallocate_stack (pd);
}
}
static int
start_thread (void *arg)
{
/* One more thread. */
atomic_increment (&__nptl_nthreads);
struct pthread *pd = (struct pthread *) arg;
#if HP_TIMING_AVAIL
/* Remember the time when the thread was started. */
hp_timing_t now;
HP_TIMING_NOW (now);
THREAD_SETMEM (pd, cpuclock_offset, now);
#endif
/* This is where the try/finally block should be created. For
compilers without that support we do use setjmp. */
struct pthread_unwind_buf unwind_buf;
/* No previous handlers. */
unwind_buf.priv.data.prev = NULL;
unwind_buf.priv.data.cleanup = NULL;
int not_first_call;
not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
if (__builtin_expect (! not_first_call, 1))
{
/* Store the new cleanup handler info. */
THREAD_SETMEM (pd, cleanup_jmp_buf, &unwind_buf);
/* Run the code the user provided. */
#ifdef CALL_THREAD_FCT
THREAD_SETMEM (pd, result, CALL_THREAD_FCT (pd));
#else
THREAD_SETMEM (pd, result, pd->start_routine (pd->arg));
#endif
}
/* Run the destructor for the thread-local data. */
deallocate_tsd ();
/* Clean up any state libc stored in thread-local variables. */
__libc_thread_freeres ();
/* If this is the last thread we terminate the process now. We
do not notify the debugger, it might just irritate it if there
is no thread left. */
if (__builtin_expect (atomic_decrement_and_test (&__nptl_nthreads), 0))
/* This was the last thread. */
exit (0);
/* Report the death of the thread if this is wanted. */
if (__builtin_expect (pd->report_events, 0))
{
/* See whether TD_DEATH is in any of the mask. */
const int idx = __td_eventword (TD_DEATH);
const uint32_t mask = __td_eventmask (TD_DEATH);
if ((mask & (__nptl_threads_events.event_bits[idx]
| pd->eventbuf.eventmask.event_bits[idx])) != 0)
{
/* Yep, we have to signal the death. Add the descriptor to
the list but only if it is not already on it. */
if (pd->nextevent == NULL)
{
pd->eventbuf.eventnum = TD_DEATH;
pd->eventbuf.eventdata = pd;
do
pd->nextevent = __nptl_last_event;
while (atomic_compare_and_exchange_bool_acq (&__nptl_last_event,
pd, pd->nextevent));
}
/* Now call the function to signal the event. */
__nptl_death_event ();
}
}
/* The thread is exiting now. Don't set this bit until after we've hit
the event-reporting breakpoint, so that td_thr_get_info on us while at
the breakpoint reports TD_THR_RUN state rather than TD_THR_ZOMBIE. */
atomic_bit_set (&pd->cancelhandling, EXITING_BIT);
/* If the thread is detached free the TCB. */
if (IS_DETACHED (pd))
/* Free the TCB. */
__free_tcb (pd);
/* We cannot call '_exit' here. '_exit' will terminate the process.
The 'exit' implementation in the kernel will signal when the
process is really dead since 'clone' got passed the CLONE_CLEARTID
flag. The 'tid' field in the TCB will be set to zero.
The exit code is zero since in case all threads exit by calling
'pthread_exit' the exit status must be 0 (zero). */
__exit_thread_inline (0);
/* NOTREACHED */
return 0;
}
/* Just list start_thread but we do some more things needed for a run
with a debugger attached. */
static int
start_thread_debug (void *arg)
{
struct pthread *pd = (struct pthread *) arg;
/* Get the lock the parent locked to force synchronization. */
lll_lock (pd->lock);
/* And give it up right away. */
lll_unlock (pd->lock);
/* Now do the actual startup. */
return start_thread (arg);
}
/* Default thread attributes for the case when the user does not
provide any. */
static const struct pthread_attr default_attr =
{
/* Just some value > 0 which gets rounded to the nearest page size. */
.guardsize = 1,
};
int
__pthread_create_2_1 (newthread, attr, start_routine, arg)
pthread_t *newthread;
const pthread_attr_t *attr;
void *(*start_routine) (void *);
void *arg;
{
STACK_VARIABLES;
const struct pthread_attr *iattr;
struct pthread *pd;
int err;
iattr = (struct pthread_attr *) attr;
if (iattr == NULL)
/* Is this the best idea? On NUMA machines this could mean
accessing far-away memory. */
iattr = &default_attr;
err = ALLOCATE_STACK (iattr, &pd);
if (__builtin_expect (err != 0, 0))
/* Something went wrong. Maybe a parameter of the attributes is
invalid or we could not allocate memory. */
return err;
/* Initialize the TCB. All initializations with zero should be
performed in 'get_cached_stack'. This way we avoid doing this if
the stack freshly allocated with 'mmap'. */
#ifdef TLS_TCB_AT_TP
/* Reference to the TCB itself. */
pd->header.self = pd;
/* Self-reference for TLS. */
pd->header.tcb = pd;
#endif
/* Store the address of the start routine and the parameter. Since
we do not start the function directly the stillborn thread will
get the information from its thread descriptor. */
pd->start_routine = start_routine;
pd->arg = arg;
/* Copy the thread attribute flags. */
pd->flags = iattr->flags;
/* Initialize the field for the ID of the thread which is waiting
for us. This is a self-reference in case the thread is created
detached. */
pd->joinid = iattr->flags & ATTR_FLAG_DETACHSTATE ? pd : NULL;
/* The debug events are inherited from the parent. */
pd->eventbuf = THREAD_SELF->eventbuf;
/* Determine scheduling parameters for the thread.
XXX How to determine whether scheduling handling is needed? */
if (0 && attr != NULL)
{
if (iattr->flags & ATTR_FLAG_NOTINHERITSCHED)
{
/* Use the scheduling parameters the user provided. */
pd->schedpolicy = iattr->schedpolicy;
memcpy (&pd->schedparam, &iattr->schedparam,
sizeof (struct sched_param));
}
else
{
/* Just store the scheduling attributes of the parent. */
pd->schedpolicy = __sched_getscheduler (0);
__sched_getparam (0, &pd->schedparam);
}
}
/* Pass the descriptor to the caller. */
*newthread = (pthread_t) pd;
/* Start the thread. */
err = create_thread (pd, STACK_VARIABLES_ARGS);
if (err != 0)
{
/* Something went wrong. Free the resources. */
__deallocate_stack (pd);
return err;
}
return 0;
}
versioned_symbol (libpthread, __pthread_create_2_1, pthread_create, GLIBC_2_1);
#if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
int
__pthread_create_2_0 (newthread, attr, start_routine, arg)
pthread_t *newthread;
const pthread_attr_t *attr;
void *(*start_routine) (void *);
void *arg;
{
/* The ATTR attribute is not really of type `pthread_attr_t *'. It has
the old size and access to the new members might crash the program.
We convert the struct now. */
struct pthread_attr new_attr;
if (attr != NULL)
{
struct pthread_attr *iattr = (struct pthread_attr *) attr;
size_t ps = __getpagesize ();
/* Copy values from the user-provided attributes. */
new_attr.schedparam = iattr->schedparam;
new_attr.schedpolicy = iattr->schedpolicy;
new_attr.flags = iattr->flags;
/* Fill in default values for the fields not present in the old
implementation. */
new_attr.guardsize = ps;
new_attr.stackaddr = NULL;
new_attr.stacksize = 0;
/* We will pass this value on to the real implementation. */
attr = (pthread_attr_t *) &new_attr;
}
return __pthread_create_2_1 (newthread, attr, start_routine, arg);
}
compat_symbol (libpthread, __pthread_create_2_0, pthread_create,
GLIBC_2_0);
#endif