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620a70615e
libxml2/threads.c
Steve Nairn 620a70615e Fix the fix to Windows locking 
For https://bugzilla.gnome.org/show_bug.cgi?id=737851

Unfortunately this change has introduced a problem which results in
occasional hangs on Windows when running multi-threaded on a multi-core
host.

When locking the xmlRMutex the count field is increment inside the
critical section but when unlocking the count field is decremented
outside the critical section. The increment/decrement is not atomic so
this can result in the count field being updated incorrectly.

The solution is to change xmlRMutexUnlock to decrement the count field
before leaving the critical section rather than after.
2015-03-03 19:42:01 +08:00

1040 lines
26 KiB
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/**
* threads.c: set of generic threading related routines
*
* See Copyright for the status of this software.
*
* Gary Pennington <Gary.Pennington@uk.sun.com>
* daniel@veillard.com
*/
#define IN_LIBXML
#include "libxml.h"
#include <string.h>
#include <libxml/threads.h>
#include <libxml/globals.h>
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_PTHREAD_H
#include <pthread.h>
#elif defined HAVE_WIN32_THREADS
#include <windows.h>
#ifndef HAVE_COMPILER_TLS
#include <process.h>
#endif
#endif
#ifdef HAVE_BEOS_THREADS
#include <OS.h>
#include <TLS.h>
#endif
#if defined(SOLARIS)
#include <note.h>
#endif
/* #define DEBUG_THREADS */
#ifdef HAVE_PTHREAD_H
static int libxml_is_threaded = -1;
#if defined(__GNUC__) && defined(__GLIBC__)
#ifdef linux
#if (__GNUC__ == 3 && __GNUC_MINOR__ >= 3) || (__GNUC__ > 3)
extern int pthread_once (pthread_once_t *__once_control,
void (*__init_routine) (void))
__attribute((weak));
extern void *pthread_getspecific (pthread_key_t __key)
__attribute((weak));
extern int pthread_setspecific (pthread_key_t __key,
__const void *__pointer)
__attribute((weak));
extern int pthread_key_create (pthread_key_t *__key,
void (*__destr_function) (void *))
__attribute((weak));
extern int pthread_key_delete (pthread_key_t __key)
__attribute((weak));
extern int pthread_mutex_init ()
__attribute((weak));
extern int pthread_mutex_destroy ()
__attribute((weak));
extern int pthread_mutex_lock ()
__attribute((weak));
extern int pthread_mutex_unlock ()
__attribute((weak));
extern int pthread_cond_init ()
__attribute((weak));
extern int pthread_cond_destroy ()
__attribute((weak));
extern int pthread_cond_wait ()
__attribute((weak));
extern int pthread_equal ()
__attribute((weak));
extern pthread_t pthread_self ()
__attribute((weak));
extern int pthread_key_create ()
__attribute((weak));
extern int pthread_key_delete ()
__attribute((weak));
extern int pthread_cond_signal ()
__attribute((weak));
#endif
#endif /* linux */
#endif /* defined(__GNUC__) && defined(__GLIBC__) */
#endif /* HAVE_PTHREAD_H */
/*
* TODO: this module still uses malloc/free and not xmlMalloc/xmlFree
* to avoid some crazyness since xmlMalloc/xmlFree may actually
* be hosted on allocated blocks needing them for the allocation ...
*/
/*
* xmlMutex are a simple mutual exception locks
*/
struct _xmlMutex {
#ifdef HAVE_PTHREAD_H
pthread_mutex_t lock;
#elif defined HAVE_WIN32_THREADS
HANDLE mutex;
#elif defined HAVE_BEOS_THREADS
sem_id sem;
thread_id tid;
#else
int empty;
#endif
};
/*
* xmlRMutex are reentrant mutual exception locks
*/
struct _xmlRMutex {
#ifdef HAVE_PTHREAD_H
pthread_mutex_t lock;
unsigned int held;
unsigned int waiters;
pthread_t tid;
pthread_cond_t cv;
#elif defined HAVE_WIN32_THREADS
CRITICAL_SECTION cs;
unsigned int count;
#elif defined HAVE_BEOS_THREADS
xmlMutexPtr lock;
thread_id tid;
int32 count;
#else
int empty;
#endif
};
/*
* This module still has some internal static data.
* - xmlLibraryLock a global lock
* - globalkey used for per-thread data
*/
#ifdef HAVE_PTHREAD_H
static pthread_key_t globalkey;
static pthread_t mainthread;
static pthread_once_t once_control = PTHREAD_ONCE_INIT;
static pthread_once_t once_control_init = PTHREAD_ONCE_INIT;
static pthread_mutex_t global_init_lock = PTHREAD_MUTEX_INITIALIZER;
#elif defined HAVE_WIN32_THREADS
#if defined(HAVE_COMPILER_TLS)
static __declspec(thread) xmlGlobalState tlstate;
static __declspec(thread) int tlstate_inited = 0;
#else /* HAVE_COMPILER_TLS */
static DWORD globalkey = TLS_OUT_OF_INDEXES;
#endif /* HAVE_COMPILER_TLS */
static DWORD mainthread;
static struct {
DWORD done;
DWORD control;
} run_once = { 0, 0};
static volatile LPCRITICAL_SECTION global_init_lock = NULL;
/* endif HAVE_WIN32_THREADS */
#elif defined HAVE_BEOS_THREADS
int32 globalkey = 0;
thread_id mainthread = 0;
int32 run_once_init = 0;
static int32 global_init_lock = -1;
static vint32 global_init_count = 0;
#endif
static xmlRMutexPtr xmlLibraryLock = NULL;
#ifdef LIBXML_THREAD_ENABLED
static void xmlOnceInit(void);
#endif
/**
* xmlNewMutex:
*
* xmlNewMutex() is used to allocate a libxml2 token struct for use in
* synchronizing access to data.
*
* Returns a new simple mutex pointer or NULL in case of error
*/
xmlMutexPtr
xmlNewMutex(void)
{
xmlMutexPtr tok;
if ((tok = malloc(sizeof(xmlMutex))) == NULL)
return (NULL);
#ifdef HAVE_PTHREAD_H
if (libxml_is_threaded != 0)
pthread_mutex_init(&tok->lock, NULL);
#elif defined HAVE_WIN32_THREADS
tok->mutex = CreateMutex(NULL, FALSE, NULL);
#elif defined HAVE_BEOS_THREADS
if ((tok->sem = create_sem(1, "xmlMutex")) < B_OK) {
free(tok);
return NULL;
}
tok->tid = -1;
#endif
return (tok);
}
/**
* xmlFreeMutex:
* @tok: the simple mutex
*
* xmlFreeMutex() is used to reclaim resources associated with a libxml2 token
* struct.
*/
void
xmlFreeMutex(xmlMutexPtr tok)
{
if (tok == NULL)
return;
#ifdef HAVE_PTHREAD_H
if (libxml_is_threaded != 0)
pthread_mutex_destroy(&tok->lock);
#elif defined HAVE_WIN32_THREADS
CloseHandle(tok->mutex);
#elif defined HAVE_BEOS_THREADS
delete_sem(tok->sem);
#endif
free(tok);
}
/**
* xmlMutexLock:
* @tok: the simple mutex
*
* xmlMutexLock() is used to lock a libxml2 token.
*/
void
xmlMutexLock(xmlMutexPtr tok)
{
if (tok == NULL)
return;
#ifdef HAVE_PTHREAD_H
if (libxml_is_threaded != 0)
pthread_mutex_lock(&tok->lock);
#elif defined HAVE_WIN32_THREADS
WaitForSingleObject(tok->mutex, INFINITE);
#elif defined HAVE_BEOS_THREADS
if (acquire_sem(tok->sem) != B_NO_ERROR) {
#ifdef DEBUG_THREADS
xmlGenericError(xmlGenericErrorContext,
"xmlMutexLock():BeOS:Couldn't aquire semaphore\n");
#endif
}
tok->tid = find_thread(NULL);
#endif
}
/**
* xmlMutexUnlock:
* @tok: the simple mutex
*
* xmlMutexUnlock() is used to unlock a libxml2 token.
*/
void
xmlMutexUnlock(xmlMutexPtr tok)
{
if (tok == NULL)
return;
#ifdef HAVE_PTHREAD_H
if (libxml_is_threaded != 0)
pthread_mutex_unlock(&tok->lock);
#elif defined HAVE_WIN32_THREADS
ReleaseMutex(tok->mutex);
#elif defined HAVE_BEOS_THREADS
if (tok->tid == find_thread(NULL)) {
tok->tid = -1;
release_sem(tok->sem);
}
#endif
}
/**
* xmlNewRMutex:
*
* xmlRNewMutex() is used to allocate a reentrant mutex for use in
* synchronizing access to data. token_r is a re-entrant lock and thus useful
* for synchronizing access to data structures that may be manipulated in a
* recursive fashion.
*
* Returns the new reentrant mutex pointer or NULL in case of error
*/
xmlRMutexPtr
xmlNewRMutex(void)
{
xmlRMutexPtr tok;
if ((tok = malloc(sizeof(xmlRMutex))) == NULL)
return (NULL);
#ifdef HAVE_PTHREAD_H
if (libxml_is_threaded != 0) {
pthread_mutex_init(&tok->lock, NULL);
tok->held = 0;
tok->waiters = 0;
pthread_cond_init(&tok->cv, NULL);
}
#elif defined HAVE_WIN32_THREADS
InitializeCriticalSection(&tok->cs);
tok->count = 0;
#elif defined HAVE_BEOS_THREADS
if ((tok->lock = xmlNewMutex()) == NULL) {
free(tok);
return NULL;
}
tok->count = 0;
#endif
return (tok);
}
/**
* xmlFreeRMutex:
* @tok: the reentrant mutex
*
* xmlRFreeMutex() is used to reclaim resources associated with a
* reentrant mutex.
*/
void
xmlFreeRMutex(xmlRMutexPtr tok ATTRIBUTE_UNUSED)
{
if (tok == NULL)
return;
#ifdef HAVE_PTHREAD_H
if (libxml_is_threaded != 0) {
pthread_mutex_destroy(&tok->lock);
pthread_cond_destroy(&tok->cv);
}
#elif defined HAVE_WIN32_THREADS
DeleteCriticalSection(&tok->cs);
#elif defined HAVE_BEOS_THREADS
xmlFreeMutex(tok->lock);
#endif
free(tok);
}
/**
* xmlRMutexLock:
* @tok: the reentrant mutex
*
* xmlRMutexLock() is used to lock a libxml2 token_r.
*/
void
xmlRMutexLock(xmlRMutexPtr tok)
{
if (tok == NULL)
return;
#ifdef HAVE_PTHREAD_H
if (libxml_is_threaded == 0)
return;
pthread_mutex_lock(&tok->lock);
if (tok->held) {
if (pthread_equal(tok->tid, pthread_self())) {
tok->held++;
pthread_mutex_unlock(&tok->lock);
return;
} else {
tok->waiters++;
while (tok->held)
pthread_cond_wait(&tok->cv, &tok->lock);
tok->waiters--;
}
}
tok->tid = pthread_self();
tok->held = 1;
pthread_mutex_unlock(&tok->lock);
#elif defined HAVE_WIN32_THREADS
EnterCriticalSection(&tok->cs);
tok->count++;
#elif defined HAVE_BEOS_THREADS
if (tok->lock->tid == find_thread(NULL)) {
tok->count++;
return;
} else {
xmlMutexLock(tok->lock);
tok->count = 1;
}
#endif
}
/**
* xmlRMutexUnlock:
* @tok: the reentrant mutex
*
* xmlRMutexUnlock() is used to unlock a libxml2 token_r.
*/
void
xmlRMutexUnlock(xmlRMutexPtr tok ATTRIBUTE_UNUSED)
{
if (tok == NULL)
return;
#ifdef HAVE_PTHREAD_H
if (libxml_is_threaded == 0)
return;
pthread_mutex_lock(&tok->lock);
tok->held--;
if (tok->held == 0) {
if (tok->waiters)
pthread_cond_signal(&tok->cv);
memset(&tok->tid, 0, sizeof(tok->tid));
}
pthread_mutex_unlock(&tok->lock);
#elif defined HAVE_WIN32_THREADS
if (tok->count > 0) {
tok->count--;
LeaveCriticalSection(&tok->cs);
}
#elif defined HAVE_BEOS_THREADS
if (tok->lock->tid == find_thread(NULL)) {
tok->count--;
if (tok->count == 0) {
xmlMutexUnlock(tok->lock);
}
return;
}
#endif
}
/**
* xmlGlobalInitMutexLock
*
* Makes sure that the global initialization mutex is initialized and
* locks it.
*/
void
__xmlGlobalInitMutexLock(void)
{
/* Make sure the global init lock is initialized and then lock it. */
#ifdef HAVE_PTHREAD_H
/* The mutex is statically initialized, so we just lock it. */
if (pthread_mutex_lock != NULL)
pthread_mutex_lock(&global_init_lock);
#elif defined HAVE_WIN32_THREADS
LPCRITICAL_SECTION cs;
/* Create a new critical section */
if (global_init_lock == NULL) {
cs = malloc(sizeof(CRITICAL_SECTION));
if (cs == NULL) {
xmlGenericError(xmlGenericErrorContext,
"xmlGlobalInitMutexLock: out of memory\n");
return;
}
InitializeCriticalSection(cs);
/* Swap it into the global_init_lock */
#ifdef InterlockedCompareExchangePointer
InterlockedCompareExchangePointer(&global_init_lock, cs, NULL);
#else /* Use older void* version */
InterlockedCompareExchange((void **) &global_init_lock,
(void *) cs, NULL);
#endif /* InterlockedCompareExchangePointer */
/* If another thread successfully recorded its critical
* section in the global_init_lock then discard the one
* allocated by this thread. */
if (global_init_lock != cs) {
DeleteCriticalSection(cs);
free(cs);
}
}
/* Lock the chosen critical section */
EnterCriticalSection(global_init_lock);
#elif defined HAVE_BEOS_THREADS
int32 sem;
/* Allocate a new semaphore */
sem = create_sem(1, "xmlGlobalinitMutex");
while (global_init_lock == -1) {
if (atomic_add(&global_init_count, 1) == 0) {
global_init_lock = sem;
} else {
snooze(1);
atomic_add(&global_init_count, -1);
}
}
/* If another thread successfully recorded its critical
* section in the global_init_lock then discard the one
* allocated by this thread. */
if (global_init_lock != sem)
delete_sem(sem);
/* Acquire the chosen semaphore */
if (acquire_sem(global_init_lock) != B_NO_ERROR) {
#ifdef DEBUG_THREADS
xmlGenericError(xmlGenericErrorContext,
"xmlGlobalInitMutexLock():BeOS:Couldn't acquire semaphore\n");
#endif
}
#endif
}
void
__xmlGlobalInitMutexUnlock(void)
{
#ifdef HAVE_PTHREAD_H
if (pthread_mutex_unlock != NULL)
pthread_mutex_unlock(&global_init_lock);
#elif defined HAVE_WIN32_THREADS
if (global_init_lock != NULL) {
LeaveCriticalSection(global_init_lock);
}
#elif defined HAVE_BEOS_THREADS
release_sem(global_init_lock);
#endif
}
/**
* xmlGlobalInitMutexDestroy
*
* Makes sure that the global initialization mutex is destroyed before
* application termination.
*/
void
__xmlGlobalInitMutexDestroy(void)
{
#ifdef HAVE_PTHREAD_H
#elif defined HAVE_WIN32_THREADS
if (global_init_lock != NULL) {
DeleteCriticalSection(global_init_lock);
free(global_init_lock);
global_init_lock = NULL;
}
#endif
}
/************************************************************************
* *
* Per thread global state handling *
* *
************************************************************************/
#ifdef LIBXML_THREAD_ENABLED
#ifdef xmlLastError
#undef xmlLastError
#endif
/**
* xmlFreeGlobalState:
* @state: a thread global state
*
* xmlFreeGlobalState() is called when a thread terminates with a non-NULL
* global state. It is is used here to reclaim memory resources.
*/
static void
xmlFreeGlobalState(void *state)
{
xmlGlobalState *gs = (xmlGlobalState *) state;
/* free any memory allocated in the thread's xmlLastError */
xmlResetError(&(gs->xmlLastError));
free(state);
}
/**
* xmlNewGlobalState:
*
* xmlNewGlobalState() allocates a global state. This structure is used to
* hold all data for use by a thread when supporting backwards compatibility
* of libxml2 to pre-thread-safe behaviour.
*
* Returns the newly allocated xmlGlobalStatePtr or NULL in case of error
*/
static xmlGlobalStatePtr
xmlNewGlobalState(void)
{
xmlGlobalState *gs;
gs = malloc(sizeof(xmlGlobalState));
if (gs == NULL) {
xmlGenericError(xmlGenericErrorContext,
"xmlGetGlobalState: out of memory\n");
return (NULL);
}
memset(gs, 0, sizeof(xmlGlobalState));
xmlInitializeGlobalState(gs);
return (gs);
}
#endif /* LIBXML_THREAD_ENABLED */
#ifdef HAVE_PTHREAD_H
#elif defined HAVE_WIN32_THREADS
#if !defined(HAVE_COMPILER_TLS)
#if defined(LIBXML_STATIC) && !defined(LIBXML_STATIC_FOR_DLL)
typedef struct _xmlGlobalStateCleanupHelperParams {
HANDLE thread;
void *memory;
} xmlGlobalStateCleanupHelperParams;
static void XMLCDECL
xmlGlobalStateCleanupHelper(void *p)
{
xmlGlobalStateCleanupHelperParams *params =
(xmlGlobalStateCleanupHelperParams *) p;
WaitForSingleObject(params->thread, INFINITE);
CloseHandle(params->thread);
xmlFreeGlobalState(params->memory);
free(params);
_endthread();
}
#else /* LIBXML_STATIC && !LIBXML_STATIC_FOR_DLL */
typedef struct _xmlGlobalStateCleanupHelperParams {
void *memory;
struct _xmlGlobalStateCleanupHelperParams *prev;
struct _xmlGlobalStateCleanupHelperParams *next;
} xmlGlobalStateCleanupHelperParams;
static xmlGlobalStateCleanupHelperParams *cleanup_helpers_head = NULL;
static CRITICAL_SECTION cleanup_helpers_cs;
#endif /* LIBXMLSTATIC && !LIBXML_STATIC_FOR_DLL */
#endif /* HAVE_COMPILER_TLS */
#endif /* HAVE_WIN32_THREADS */
#if defined HAVE_BEOS_THREADS
/**
* xmlGlobalStateCleanup:
* @data: unused parameter
*
* Used for Beos only
*/
void
xmlGlobalStateCleanup(void *data)
{
void *globalval = tls_get(globalkey);
if (globalval != NULL)
xmlFreeGlobalState(globalval);
}
#endif
/**
* xmlGetGlobalState:
*
* xmlGetGlobalState() is called to retrieve the global state for a thread.
*
* Returns the thread global state or NULL in case of error
*/
xmlGlobalStatePtr
xmlGetGlobalState(void)
{
#ifdef HAVE_PTHREAD_H
xmlGlobalState *globalval;
if (libxml_is_threaded == 0)
return (NULL);
pthread_once(&once_control, xmlOnceInit);
if ((globalval = (xmlGlobalState *)
pthread_getspecific(globalkey)) == NULL) {
xmlGlobalState *tsd = xmlNewGlobalState();
if (tsd == NULL)
return(NULL);
pthread_setspecific(globalkey, tsd);
return (tsd);
}
return (globalval);
#elif defined HAVE_WIN32_THREADS
#if defined(HAVE_COMPILER_TLS)
if (!tlstate_inited) {
tlstate_inited = 1;
xmlInitializeGlobalState(&tlstate);
}
return &tlstate;
#else /* HAVE_COMPILER_TLS */
xmlGlobalState *globalval;
xmlGlobalStateCleanupHelperParams *p;
xmlOnceInit();
#if defined(LIBXML_STATIC) && !defined(LIBXML_STATIC_FOR_DLL)
globalval = (xmlGlobalState *) TlsGetValue(globalkey);
#else
p = (xmlGlobalStateCleanupHelperParams *) TlsGetValue(globalkey);
globalval = (xmlGlobalState *) (p ? p->memory : NULL);
#endif
if (globalval == NULL) {
xmlGlobalState *tsd = xmlNewGlobalState();
if (tsd == NULL)
return(NULL);
p = (xmlGlobalStateCleanupHelperParams *)
malloc(sizeof(xmlGlobalStateCleanupHelperParams));
if (p == NULL) {
xmlGenericError(xmlGenericErrorContext,
"xmlGetGlobalState: out of memory\n");
xmlFreeGlobalState(tsd);
return(NULL);
}
p->memory = tsd;
#if defined(LIBXML_STATIC) && !defined(LIBXML_STATIC_FOR_DLL)
DuplicateHandle(GetCurrentProcess(), GetCurrentThread(),
GetCurrentProcess(), &p->thread, 0, TRUE,
DUPLICATE_SAME_ACCESS);
TlsSetValue(globalkey, tsd);
_beginthread(xmlGlobalStateCleanupHelper, 0, p);
#else
EnterCriticalSection(&cleanup_helpers_cs);
if (cleanup_helpers_head != NULL) {
cleanup_helpers_head->prev = p;
}
p->next = cleanup_helpers_head;
p->prev = NULL;
cleanup_helpers_head = p;
TlsSetValue(globalkey, p);
LeaveCriticalSection(&cleanup_helpers_cs);
#endif
return (tsd);
}
return (globalval);
#endif /* HAVE_COMPILER_TLS */
#elif defined HAVE_BEOS_THREADS
xmlGlobalState *globalval;
xmlOnceInit();
if ((globalval = (xmlGlobalState *) tls_get(globalkey)) == NULL) {
xmlGlobalState *tsd = xmlNewGlobalState();
if (tsd == NULL)
return (NULL);
tls_set(globalkey, tsd);
on_exit_thread(xmlGlobalStateCleanup, NULL);
return (tsd);
}
return (globalval);
#else
return (NULL);
#endif
}
/************************************************************************
* *
* Library wide thread interfaces *
* *
************************************************************************/
/**
* xmlGetThreadId:
*
* xmlGetThreadId() find the current thread ID number
* Note that this is likely to be broken on some platforms using pthreads
* as the specification doesn't mandate pthread_t to be an integer type
*
* Returns the current thread ID number
*/
int
xmlGetThreadId(void)
{
#ifdef HAVE_PTHREAD_H
pthread_t id;
int ret;
if (libxml_is_threaded == 0)
return (0);
id = pthread_self();
/* horrible but preserves compat, see warning above */
memcpy(&ret, &id, sizeof(ret));
return (ret);
#elif defined HAVE_WIN32_THREADS
return GetCurrentThreadId();
#elif defined HAVE_BEOS_THREADS
return find_thread(NULL);
#else
return ((int) 0);
#endif
}
/**
* xmlIsMainThread:
*
* xmlIsMainThread() check whether the current thread is the main thread.
*
* Returns 1 if the current thread is the main thread, 0 otherwise
*/
int
xmlIsMainThread(void)
{
#ifdef HAVE_PTHREAD_H
if (libxml_is_threaded == -1)
xmlInitThreads();
if (libxml_is_threaded == 0)
return (1);
pthread_once(&once_control, xmlOnceInit);
#elif defined HAVE_WIN32_THREADS
xmlOnceInit();
#elif defined HAVE_BEOS_THREADS
xmlOnceInit();
#endif
#ifdef DEBUG_THREADS
xmlGenericError(xmlGenericErrorContext, "xmlIsMainThread()\n");
#endif
#ifdef HAVE_PTHREAD_H
return (pthread_equal(mainthread,pthread_self()));
#elif defined HAVE_WIN32_THREADS
return (mainthread == GetCurrentThreadId());
#elif defined HAVE_BEOS_THREADS
return (mainthread == find_thread(NULL));
#else
return (1);
#endif
}
/**
* xmlLockLibrary:
*
* xmlLockLibrary() is used to take out a re-entrant lock on the libxml2
* library.
*/
void
xmlLockLibrary(void)
{
#ifdef DEBUG_THREADS
xmlGenericError(xmlGenericErrorContext, "xmlLockLibrary()\n");
#endif
xmlRMutexLock(xmlLibraryLock);
}
/**
* xmlUnlockLibrary:
*
* xmlUnlockLibrary() is used to release a re-entrant lock on the libxml2
* library.
*/
void
xmlUnlockLibrary(void)
{
#ifdef DEBUG_THREADS
xmlGenericError(xmlGenericErrorContext, "xmlUnlockLibrary()\n");
#endif
xmlRMutexUnlock(xmlLibraryLock);
}
/**
* xmlInitThreads:
*
* xmlInitThreads() is used to to initialize all the thread related
* data of the libxml2 library.
*/
void
xmlInitThreads(void)
{
#ifdef HAVE_PTHREAD_H
if (libxml_is_threaded == -1) {
if ((pthread_once != NULL) &&
(pthread_getspecific != NULL) &&
(pthread_setspecific != NULL) &&
(pthread_key_create != NULL) &&
(pthread_key_delete != NULL) &&
(pthread_mutex_init != NULL) &&
(pthread_mutex_destroy != NULL) &&
(pthread_mutex_lock != NULL) &&
(pthread_mutex_unlock != NULL) &&
(pthread_cond_init != NULL) &&
(pthread_cond_destroy != NULL) &&
(pthread_cond_wait != NULL) &&
(pthread_equal != NULL) &&
(pthread_self != NULL) &&
(pthread_cond_signal != NULL)) {
libxml_is_threaded = 1;
/* fprintf(stderr, "Running multithreaded\n"); */
} else {
/* fprintf(stderr, "Running without multithread\n"); */
libxml_is_threaded = 0;
}
}
#elif defined(HAVE_WIN32_THREADS) && !defined(HAVE_COMPILER_TLS) && (!defined(LIBXML_STATIC) || defined(LIBXML_STATIC_FOR_DLL))
InitializeCriticalSection(&cleanup_helpers_cs);
#endif
}
/**
* xmlCleanupThreads:
*
* xmlCleanupThreads() is used to to cleanup all the thread related
* data of the libxml2 library once processing has ended.
*
* WARNING: if your application is multithreaded or has plugin support
* calling this may crash the application if another thread or
* a plugin is still using libxml2. It's sometimes very hard to
* guess if libxml2 is in use in the application, some libraries
* or plugins may use it without notice. In case of doubt abstain
* from calling this function or do it just before calling exit()
* to avoid leak reports from valgrind !
*/
void
xmlCleanupThreads(void)
{
#ifdef DEBUG_THREADS
xmlGenericError(xmlGenericErrorContext, "xmlCleanupThreads()\n");
#endif
#ifdef HAVE_PTHREAD_H
if ((libxml_is_threaded) && (pthread_key_delete != NULL))
pthread_key_delete(globalkey);
once_control = once_control_init;
#elif defined(HAVE_WIN32_THREADS) && !defined(HAVE_COMPILER_TLS) && (!defined(LIBXML_STATIC) || defined(LIBXML_STATIC_FOR_DLL))
if (globalkey != TLS_OUT_OF_INDEXES) {
xmlGlobalStateCleanupHelperParams *p;
EnterCriticalSection(&cleanup_helpers_cs);
p = cleanup_helpers_head;
while (p != NULL) {
xmlGlobalStateCleanupHelperParams *temp = p;
p = p->next;
xmlFreeGlobalState(temp->memory);
free(temp);
}
cleanup_helpers_head = 0;
LeaveCriticalSection(&cleanup_helpers_cs);
TlsFree(globalkey);
globalkey = TLS_OUT_OF_INDEXES;
}
DeleteCriticalSection(&cleanup_helpers_cs);
#endif
}
#ifdef LIBXML_THREAD_ENABLED
/**
* xmlOnceInit
*
* xmlOnceInit() is used to initialize the value of mainthread for use
* in other routines. This function should only be called using
* pthread_once() in association with the once_control variable to ensure
* that the function is only called once. See man pthread_once for more
* details.
*/
static void
xmlOnceInit(void)
{
#ifdef HAVE_PTHREAD_H
(void) pthread_key_create(&globalkey, xmlFreeGlobalState);
mainthread = pthread_self();
__xmlInitializeDict();
#elif defined(HAVE_WIN32_THREADS)
if (!run_once.done) {
if (InterlockedIncrement(&run_once.control) == 1) {
#if !defined(HAVE_COMPILER_TLS)
globalkey = TlsAlloc();
#endif
mainthread = GetCurrentThreadId();
__xmlInitializeDict();
run_once.done = 1;
} else {
/* Another thread is working; give up our slice and
* wait until they're done. */
while (!run_once.done)
Sleep(0);
}
}
#elif defined HAVE_BEOS_THREADS
if (atomic_add(&run_once_init, 1) == 0) {
globalkey = tls_allocate();
tls_set(globalkey, NULL);
mainthread = find_thread(NULL);
__xmlInitializeDict();
} else
atomic_add(&run_once_init, -1);
#endif
}
#endif
/**
* DllMain:
* @hinstDLL: handle to DLL instance
* @fdwReason: Reason code for entry
* @lpvReserved: generic pointer (depends upon reason code)
*
* Entry point for Windows library. It is being used to free thread-specific
* storage.
*
* Returns TRUE always
*/
#ifdef HAVE_PTHREAD_H
#elif defined(HAVE_WIN32_THREADS) && !defined(HAVE_COMPILER_TLS) && (!defined(LIBXML_STATIC) || defined(LIBXML_STATIC_FOR_DLL))
#if defined(LIBXML_STATIC_FOR_DLL)
BOOL XMLCALL
xmlDllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
#else
BOOL WINAPI
DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
#endif
{
switch (fdwReason) {
case DLL_THREAD_DETACH:
if (globalkey != TLS_OUT_OF_INDEXES) {
xmlGlobalState *globalval = NULL;
xmlGlobalStateCleanupHelperParams *p =
(xmlGlobalStateCleanupHelperParams *)
TlsGetValue(globalkey);
globalval = (xmlGlobalState *) (p ? p->memory : NULL);
if (globalval) {
xmlFreeGlobalState(globalval);
TlsSetValue(globalkey, NULL);
}
if (p) {
EnterCriticalSection(&cleanup_helpers_cs);
if (p == cleanup_helpers_head)
cleanup_helpers_head = p->next;
else
p->prev->next = p->next;
if (p->next != NULL)
p->next->prev = p->prev;
LeaveCriticalSection(&cleanup_helpers_cs);
free(p);
}
}
break;
}
return TRUE;
}
#endif
#define bottom_threads
#include "elfgcchack.h"
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