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Modify the code path of the ifdef NOTYET part of _kse_single_thread():

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o  Don't reinitialise the atfork() handler list in the child.  We
   are meant to call the child handler, and on subsequent fork()s
   should call all three functions as normal.
o  Don't reinitialise the thread specific keyed data in the
   child after a fork.  Applications may require this for context.
o  Reinitialise curthread->tlflags after removing ourselves from
   (and reinitialising) the various internal thread lists.
o  Reinitialise __malloc_lock in the child after fork() (to balance
   our explicitly taking the lock prior to the fork()).

With these changes, it is possible to enable the NOTYET code in
thr_kern.c to allow the use of non-async-safe functions after
fork()ing from a threaded program.

Reviewed by:	Daniel Eischen <deischen@freebsd.org>
[_malloc_lock reinitialisation has since been moved to avoid polluting the
!NOTYET code]
This commit is contained in:
brian 2005-09-24 01:19:53 +00:00
parent f1b94d803f
commit a49729bb2d
4 changed files with 22 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
lib/libkse/thread/thr_init.c
View File

@ -437,6 +437,7 @@ init_private(void)
}
_pthread_attr_default.guardsize_attr = _thr_guard_default;
_pthread_attr_default.stacksize_attr = _thr_stack_default;
TAILQ_INIT(&_thr_atfork_list);
init_once = 1; /* Don't do this again. */
} else {
/*
@ -453,7 +454,6 @@ init_private(void)
/* Initialize everything else. */
TAILQ_INIT(&_thread_list);
TAILQ_INIT(&_thread_gc_list);
TAILQ_INIT(&_thr_atfork_list);
_pthread_mutex_init(&_thr_atfork_mutex, NULL);
/*

17
lib/libkse/thread/thr_kern.c
View File

@ -55,6 +55,9 @@ __FBSDID("$FreeBSD$");
#include "atomic_ops.h"
#include "thr_private.h"
#include "libc_private.h"
#ifdef NOTYET
#include "spinlock.h"
#endif
/* #define DEBUG_THREAD_KERN */
#ifdef DEBUG_THREAD_KERN
@ -210,9 +213,9 @@ _kse_single_thread(struct pthread *curthread)
struct kse *kse;
struct kse_group *kseg;
struct pthread *thread;
kse_critical_t crit;
int i;
_thr_spinlock_init();
*__malloc_lock = (spinlock_t)_SPINLOCK_INITIALIZER;
if (__isthreaded) {
_thr_rtld_fini();
_thr_signal_deinit();
@ -250,11 +253,8 @@ _kse_single_thread(struct pthread *curthread)
curthread->joiner = NULL; /* no joining threads yet */
curthread->refcount = 0;
SIGEMPTYSET(curthread->sigpend); /* clear pending signals */
if (curthread->specific != NULL) {
free(curthread->specific);
curthread->specific = NULL;
curthread->specific_data_count = 0;
}
/* Don't free thread-specific data as the caller may require it */
/* Free the free KSEs: */
while ((kse = TAILQ_FIRST(&free_kseq)) != NULL) {
@ -317,6 +317,9 @@ _kse_single_thread(struct pthread *curthread)
curthread->attr.flags &= ~PTHREAD_SCOPE_SYSTEM;
curthread->attr.flags |= PTHREAD_SCOPE_PROCESS;
/* We're no longer part of any lists */
curthread->tlflags = 0;
/*
* After a fork, we are still operating on the thread's original
* stack. Don't clear the THR_FLAGS_USER from the thread's

2
lib/libpthread/thread/thr_init.c
View File

@ -437,6 +437,7 @@ init_private(void)
}
_pthread_attr_default.guardsize_attr = _thr_guard_default;
_pthread_attr_default.stacksize_attr = _thr_stack_default;
TAILQ_INIT(&_thr_atfork_list);
init_once = 1; /* Don't do this again. */
} else {
/*
@ -453,7 +454,6 @@ init_private(void)
/* Initialize everything else. */
TAILQ_INIT(&_thread_list);
TAILQ_INIT(&_thread_gc_list);
TAILQ_INIT(&_thr_atfork_list);
_pthread_mutex_init(&_thr_atfork_mutex, NULL);
/*

17
lib/libpthread/thread/thr_kern.c
View File

@ -55,6 +55,9 @@ __FBSDID("$FreeBSD$");
#include "atomic_ops.h"
#include "thr_private.h"
#include "libc_private.h"
#ifdef NOTYET
#include "spinlock.h"
#endif
/* #define DEBUG_THREAD_KERN */
#ifdef DEBUG_THREAD_KERN
@ -210,9 +213,9 @@ _kse_single_thread(struct pthread *curthread)
struct kse *kse;
struct kse_group *kseg;
struct pthread *thread;
kse_critical_t crit;
int i;
_thr_spinlock_init();
*__malloc_lock = (spinlock_t)_SPINLOCK_INITIALIZER;
if (__isthreaded) {
_thr_rtld_fini();
_thr_signal_deinit();
@ -250,11 +253,8 @@ _kse_single_thread(struct pthread *curthread)
curthread->joiner = NULL; /* no joining threads yet */
curthread->refcount = 0;
SIGEMPTYSET(curthread->sigpend); /* clear pending signals */
if (curthread->specific != NULL) {
free(curthread->specific);
curthread->specific = NULL;
curthread->specific_data_count = 0;
}
/* Don't free thread-specific data as the caller may require it */
/* Free the free KSEs: */
while ((kse = TAILQ_FIRST(&free_kseq)) != NULL) {
@ -317,6 +317,9 @@ _kse_single_thread(struct pthread *curthread)
curthread->attr.flags &= ~PTHREAD_SCOPE_SYSTEM;
curthread->attr.flags |= PTHREAD_SCOPE_PROCESS;
/* We're no longer part of any lists */
curthread->tlflags = 0;
/*
* After a fork, we are still operating on the thread's original
* stack. Don't clear the THR_FLAGS_USER from the thread's