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2002-09-17 Robert Collins <rbtcollins@hotmail.com> 

This work inspires by Thomas Pfaff's pthread_fork patch (1).
        * fork.cc (fork_child): Remove MTinterface fixup call, it's
        adsorbed by pthread::atforkchild.
        Rename __pthread_atforkchild to pthread::atforkchild to give
        access to private members.
        (fork_parent): Rename __pthread_atforkparent to
        pthread::atforkparent to give it access to private members.
        Ditto for __pthread_atforkprepare.
        * thread.cc: Fix some formatting problems throughout.
        (MTinterface::fixup_before_fork): Implement.
        (MTinterface::fixup_after_fork): Fix pthread_keys.
        (pthread_key::keys): Implement.
        (pthread_key::fixup_before_fork): Ditto.
        (pthread_key::fixup_after_fork): Ditto.
        (pthread_key::pthread_key): Add to pthread_key::keys.
        (pthread_key::~pthread_key): Remove from pthread_key::keys.
        (pthread_key::saveKeyToBuffer): Implement.
        (pthread_key::recreateKeyFromBuffer): Ditto.
        (pthread::atforkprepare): Prepare all MT classes for fork.
        (pthread::atforkchild): And fix them up afterwards.
        * thread.h (pthread_key): Buffer the key value during
        fork in fork_buf.
        List the keys needing to be fixed up in a linked list with
        head pthread_key::keys.
        (pthread): Move atfork cygwin internal calls into the class.
        (MTInterface): Provide a fixup_before_fork for objecst that
        need to save state.
        (__pthread_atforkprepare): Remove.
        (__pthread_atforkparent): Remove.
        (__pthread_atforkchild): Remove.
This commit is contained in:
Robert Collins 2002-09-17 09:12:36 +00:00
parent cbb704cf60
commit f1f1379560
4 changed files with 148 additions and 37 deletions
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33
winsup/cygwin/ChangeLog
View File

@ -1,3 +1,36 @@
2002-09-17 Robert Collins <rbtcollins@hotmail.com>
This work inspires by Thomas Pfaff's pthread_fork patch (1).
* fork.cc (fork_child): Remove MTinterface fixup call, it's
adsorbed by pthread::atforkchild.
Rename __pthread_atforkchild to pthread::atforkchild to give
access to private members.
(fork_parent): Rename __pthread_atforkparent to
pthread::atforkparent to give it access to private members.
Ditto for __pthread_atforkprepare.
* thread.cc: Fix some formatting problems throughout.
(MTinterface::fixup_before_fork): Implement.
(MTinterface::fixup_after_fork): Fix pthread_keys.
(pthread_key::keys): Implement.
(pthread_key::fixup_before_fork): Ditto.
(pthread_key::fixup_after_fork): Ditto.
(pthread_key::pthread_key): Add to pthread_key::keys.
(pthread_key::~pthread_key): Remove from pthread_key::keys.
(pthread_key::saveKeyToBuffer): Implement.
(pthread_key::recreateKeyFromBuffer): Ditto.
(pthread::atforkprepare): Prepare all MT classes for fork.
(pthread::atforkchild): And fix them up afterwards.
* thread.h (pthread_key): Buffer the key value during
fork in fork_buf.
List the keys needing to be fixed up in a linked list with
head pthread_key::keys.
(pthread): Move atfork cygwin internal calls into the class.
(MTInterface): Provide a fixup_before_fork for objecst that
need to save state.
(__pthread_atforkprepare): Remove.
(__pthread_atforkparent): Remove.
(__pthread_atforkchild): Remove.
2002-09-16 Christopher Faylor <cgf@redhat.com>
* init.cc: Cleanup slightly and remove obsolete code.

9
winsup/cygwin/fork.cc
View File

@ -313,10 +313,8 @@ fork_child (HANDLE& hParent, dll *&first_dll, bool& load_dlls)
if ((*t)->clear_on_fork ())
(*t)->set ();
user_data->threadinterface->fixup_after_fork ();
wait_for_sigthread ();
__pthread_atforkchild ();
pthread::atforkchild ();
cygbench ("fork-child");
return 0;
}
@ -354,8 +352,7 @@ fork_parent (HANDLE& hParent, dll *&first_dll,
DWORD rc;
PROCESS_INFORMATION pi = {0, NULL, 0, 0};
/* call the pthread_atfork prepare functions */
__pthread_atforkprepare ();
pthread::atforkprepare ();
subproc_init ();
@ -601,7 +598,7 @@ fork_parent (HANDLE& hParent, dll *&first_dll,
ForceCloseHandle (forker_finished);
forker_finished = NULL;
pi.hThread = NULL;
__pthread_atforkparent ();
pthread::atforkparent ();
return forked->pid;

77
winsup/cygwin/thread.cc
View File

@ -314,10 +314,17 @@ MTinterface::Init (int forked)
#endif
}
void
MTinterface::fixup_before_fork (void)
{
pthread_key::fixup_before_fork ();
}
/* This function is called from a single threaded process */
void
MTinterface::fixup_after_fork (void)
{
pthread_key::fixup_after_fork ();
pthread_mutex *mutex = mutexs;
debug_printf ("mutexs is %x",mutexs);
while (mutex)
@ -375,6 +382,8 @@ pthread::setTlsSelfPointer(pthread *thisThread)
TlsSetValue (MT_INTERFACE->thread_self_dwTlsIndex, thisThread);
}
/* member methods */
pthread::pthread ():verifyable_object (PTHREAD_MAGIC), win32_obj_id (0),
cancelstate (0), canceltype (0), cancel_event (0),
@ -1018,6 +1027,35 @@ pthread_cond::fixup_after_fork ()
#endif
}
/* pthread_key */
/* static members */
pthread_key *pthread_key::keys = NULL;
void
pthread_key::fixup_before_fork ()
{
pthread_key *key = keys;
debug_printf ("keys is %x",keys);
while (key)
{
key->saveKeyToBuffer ();
key = key->next;
}
}
void
pthread_key::fixup_after_fork ()
{
pthread_key *key = keys;
debug_printf ("keys is %x",keys);
while (key)
{
key->recreateKeyFromBuffer ();
key = key->next;
}
}
/* non-static members */
pthread_key::pthread_key (void (*destructor) (void *)):verifyable_object (PTHREAD_KEY_MAGIC)
{
@ -1029,6 +1067,8 @@ pthread_key::pthread_key (void (*destructor) (void *)):verifyable_object (PTHREA
MT_INTERFACE->destructors.
Insert (new pthread_key_destructor (destructor, this));
}
/* threadsafe addition is easy */
next = (pthread_key *) InterlockedExchangePointer (&keys, this);
}
pthread_key::~pthread_key ()
@ -1036,6 +1076,18 @@ pthread_key::~pthread_key ()
if (pthread_key_destructor *dest = MT_INTERFACE->destructors.Remove (this))
delete dest;
TlsFree (dwTlsIndex);
/* I'm not 100% sure the next bit is threadsafe. I think it is... */
if (keys == this)
InterlockedExchangePointer (keys, this->next);
else
{
pthread_key *tempkey = keys;
while (tempkey->next && tempkey->next != this)
tempkey = tempkey->next;
/* but there may be a race between the loop above and this statement */
InterlockedExchangePointer (&tempkey->next, this->next);
}
}
int
@ -1053,6 +1105,21 @@ pthread_key::get ()
return TlsGetValue (dwTlsIndex);
}
void
pthread_key::saveKeyToBuffer ()
{
fork_buf = get ();
}
void
pthread_key::recreateKeyFromBuffer ()
{
dwTlsIndex = TlsAlloc ();
if (dwTlsIndex == TLS_OUT_OF_INDEXES)
api_fatal ("pthread_key::recreateKeyFromBuffer () failed to reallocate Tls storage");
set (fork_buf);
}
/*pshared mutexs:
* REMOVED FROM CURRENT. These can be reinstated with the daemon, when all the
@ -1448,8 +1515,10 @@ __pthread_cancel (pthread_t thread)
*If yes, we're safe, if no, we're not.
*/
void
__pthread_atforkprepare (void)
pthread::atforkprepare (void)
{
MT_INTERFACE->fixup_before_fork ();
callback *cb = MT_INTERFACE->pthread_prepare;
while (cb)
{
@ -1459,7 +1528,7 @@ __pthread_atforkprepare (void)
}
void
__pthread_atforkparent (void)
pthread::atforkparent (void)
{
callback *cb = MT_INTERFACE->pthread_parent;
while (cb)
@ -1470,8 +1539,10 @@ __pthread_atforkparent (void)
}
void
__pthread_atforkchild (void)
pthread::atforkchild (void)
{
MT_INTERFACE->fixup_after_fork ();
callback *cb = MT_INTERFACE->pthread_child;
while (cb)
{

20
winsup/cygwin/thread.h
View File

@ -178,11 +178,21 @@ class pthread_key:public verifyable_object
public:
DWORD dwTlsIndex;
void *fork_buf;
class pthread_key *next;
int set (const void *);
void *get ();
pthread_key (void (*)(void *));
~pthread_key ();
static void fixup_before_fork();
static void fixup_after_fork();
private:
// lists of objects. USE THREADSAFE INSERTS AND DELETES.
static pthread_key * keys;
void saveKeyToBuffer ();
void recreateKeyFromBuffer ();
};
/* FIXME: test using multiple inheritance and merging key_destructor into pthread_key
@ -281,6 +291,9 @@ public:
static void initMainThread(pthread *, HANDLE);
static bool isGoodObject(pthread_t *);
static void atforkprepare();
static void atforkparent();
static void atforkchild();
virtual void exit (void *value_ptr);
@ -421,12 +434,13 @@ public:
callback *pthread_child;
callback *pthread_parent;
// list of mutex's. USE THREADSAFE INSERTS AND DELETES.
// lists of pthread objects. USE THREADSAFE INSERTS AND DELETES.
class pthread_mutex * mutexs;
class pthread_cond * conds;
class semaphore * semaphores;
void Init (int);
void fixup_before_fork (void);
void fixup_after_fork (void);
MTinterface ():reent_index (0), indexallocated (0), threadcount (1)
@ -437,10 +451,6 @@ public:
}
};
void __pthread_atforkprepare(void);
void __pthread_atforkparent(void);
void __pthread_atforkchild(void);
/* Cancellation */
int __pthread_cancel (pthread_t thread);