threads.c File Reference

#include "libxml.h"
#include <string.h>
#include <stdlib.h>
#include <libxml/threads.h>
#include <libxml/parser.h>
#include "private/dict.h"
#include "private/enc.h"
#include "private/globals.h"
#include "private/memory.h"
#include "private/threads.h"
#include "private/xpath.h"

Include dependency graph for threads.c:

Go to the source code of this file.

Classes
struct	_xmlRMutex

Macros
#define	IN_LIBXML
#define	XML_IS_THREADED()   1
#define	XML_IS_NEVER_THREADED()   0

Functions
void	xmlInitMutex (xmlMutexPtr mutex)
xmlMutexPtr	xmlNewMutex (void)
void	xmlCleanupMutex (xmlMutexPtr mutex)
void	xmlFreeMutex (xmlMutexPtr tok)
void	xmlMutexLock (xmlMutexPtr tok)
void	xmlMutexUnlock (xmlMutexPtr tok)
xmlRMutexPtr	xmlNewRMutex (void)
void	xmlFreeRMutex (xmlRMutexPtr tok ATTRIBUTE_UNUSED)
void	xmlRMutexLock (xmlRMutexPtr tok)
void	xmlRMutexUnlock (xmlRMutexPtr tok ATTRIBUTE_UNUSED)
int	xmlGetThreadId (void)
void	xmlLockLibrary (void)
void	xmlUnlockLibrary (void)
void	xmlInitThreads (void)
void	xmlCleanupThreads (void)
static void	xmlGlobalInitMutexLock (void)
static void	xmlGlobalInitMutexUnlock (void)
static void	xmlGlobalInitMutexDestroy (void)
void	xmlInitParser (void)
void	xmlCleanupParser (void)

Variables
static xmlRMutexPtr	xmlLibraryLock = NULL
static int	xmlParserInitialized = 0
static int	xmlParserInnerInitialized = 0

Macro Definition Documentation

IN_LIBXML

#define IN_LIBXML

threads.c: set of generic threading related routines

See Copyright for the status of this software.

Gary Pennington Gary..nosp@m.Penn.nosp@m.ingto.nosp@m.n@uk.nosp@m..sun..nosp@m.com danie.nosp@m.l@ve.nosp@m.illar.nosp@m.d.co.nosp@m.m

Definition at line 10 of file threads.c.

XML_IS_NEVER_THREADED

#define XML_IS_NEVER_THREADED

(

)

0

Definition at line 92 of file threads.c.

XML_IS_THREADED

#define XML_IS_THREADED

(

)

1

Definition at line 91 of file threads.c.

Function Documentation

xmlCleanupMutex()

void xmlCleanupMutex

(

xmlMutexPtr

mutex

)

xmlCleanupMutex: @mutex: the simple mutex

Reclaim resources associated with a mutex.

Definition at line 166 of file threads.c.

{
#ifdef HAVE_POSIX_THREADS
    if (XML_IS_NEVER_THREADED() == 0)
        pthread_mutex_destroy(&mutex->lock);
#elif defined HAVE_WIN32_THREADS
    DeleteCriticalSection(&mutex->cs);
#else
    (void) mutex;
#endif
}

Referenced by xmlCleanupDictInternal(), xmlCleanupGlobalsInternal(), xmlCleanupMemoryInternal(), xmlCleanupRandom(), and xmlFreeMutex().

xmlCleanupParser()

void xmlCleanupParser

(

void

)

xmlCleanupParser:

This function name is somewhat misleading. It does not clean up parser state, it cleans up memory allocated by the library itself. It is a cleanup function for the XML library. It tries to reclaim all related global memory allocated for the library processing. It doesn't deallocate any document related memory. One should call xmlCleanupParser() only when the process has finished using the library and all XML/HTML documents built with it. See also xmlInitParser() which has the opposite function of preparing the library for operations.

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 !

Definition at line 630 of file threads.c.

                       {
    if (!xmlParserInitialized)
        return;
 
    /* These functions can call xmlFree. */
 
    xmlCleanupCharEncodingHandlers();
#ifdef LIBXML_CATALOG_ENABLED
    xmlCatalogCleanup();
#endif
#ifdef LIBXML_SCHEMAS_ENABLED
    xmlSchemaCleanupTypes();
    xmlRelaxNGCleanupTypes();
#endif
 
    /* These functions should never call xmlFree. */
 
    xmlCleanupInputCallbacks();
#ifdef LIBXML_OUTPUT_ENABLED
    xmlCleanupOutputCallbacks();
#endif
 
    xmlCleanupDictInternal();
    xmlCleanupRandom();
    xmlCleanupGlobalsInternal();
    /*
     * Must come last. On Windows, xmlCleanupGlobalsInternal can call
     * xmlFree which uses xmlMemMutex in debug mode.
     */
    xmlCleanupMemoryInternal();
 
    xmlGlobalInitMutexDestroy();
 
    xmlParserInitialized = 0;
    xmlParserInnerInitialized = 0;
}

Referenced by DllMain(), and xmlInitParser().

xmlCleanupThreads()

void xmlCleanupThreads

(

void

)

xmlCleanupThreads:

DEPRECATED: This function is a no-op. Call xmlCleanupParser to free global state but see the warnings there. xmlCleanupParser should be only called once at program exit. In most cases, you don't have call cleanup functions at all.

Definition at line 435 of file threads.c.

{
}

xmlFreeMutex()

void xmlFreeMutex

(

xmlMutexPtr

tok

)

xmlFreeMutex: @tok: the simple mutex

Free a mutex.

Definition at line 185 of file threads.c.

{
    if (tok == NULL)
        return;
 
    xmlCleanupMutex(tok);
    free(tok);
}

Referenced by xsltCleanupGlobals().

xmlFreeRMutex()

void xmlFreeRMutex

(

xmlRMutexPtr tok

ATTRIBUTE_UNUSED

)

xmlFreeRMutex: @tok: the reentrant mutex

xmlRFreeMutex() is used to reclaim resources associated with a reentrant mutex.

Definition at line 275 of file threads.c.

{
    if (tok == NULL)
        return;
#ifdef HAVE_POSIX_THREADS
    if (XML_IS_NEVER_THREADED() == 0) {
        pthread_mutex_destroy(&tok->lock);
        pthread_cond_destroy(&tok->cv);
    }
#elif defined HAVE_WIN32_THREADS
    DeleteCriticalSection(&tok->cs);
#endif
    free(tok);
}

Referenced by xsltUninit().

xmlGetThreadId()

int xmlGetThreadId

(

void

)

xmlGetThreadId:

DEPRECATED: Internal function, do not use.

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

Definition at line 372 of file threads.c.

{
#ifdef HAVE_POSIX_THREADS
    pthread_t id;
    int ret;
 
    if (XML_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();
#else
    return ((int) 0);
#endif
}

xmlGlobalInitMutexDestroy()

static void xmlGlobalInitMutexDestroy ( void  )

static

xmlGlobalInitMutexDestroy

Makes sure that the global initialization mutex is destroyed before application termination.

Definition at line 549 of file threads.c.

                                {
#ifdef HAVE_POSIX_THREADS
#elif defined HAVE_WIN32_THREADS
    if (global_init_lock != NULL) {
        DeleteCriticalSection(global_init_lock);
        free(global_init_lock);
        global_init_lock = NULL;
    }
#endif
}

Referenced by xmlCleanupParser().

xmlGlobalInitMutexLock()

static void xmlGlobalInitMutexLock ( void  )

static

xmlGlobalInitMutexLock

Makes sure that the global initialization mutex is initialized and locks it.

Definition at line 462 of file threads.c.

                             {
#ifdef HAVE_POSIX_THREADS
 
#ifdef XML_PTHREAD_WEAK
    /*
     * This is somewhat unreliable since libpthread could be loaded
     * later with dlopen() and threads could be created. But it's
     * long-standing behavior and hard to work around.
     */
    if (libxml_is_threaded == -1)
        libxml_is_threaded =
            (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 can be inline, resuting in -Waddress warnings.
             * Let's assume it's available if all the other functions are.
             */
            /* (pthread_equal != NULL) && */
            (pthread_self != NULL) &&
            (pthread_cond_signal != NULL);
#endif
 
    /* The mutex is statically initialized, so we just lock it. */
    if (XML_IS_THREADED() != 0)
        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((void **) &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);
 
#endif
}

Referenced by xmlInitParser().

xmlGlobalInitMutexUnlock()

static void xmlGlobalInitMutexUnlock ( void  )

static

Definition at line 532 of file threads.c.

                               {
#ifdef HAVE_POSIX_THREADS
    if (XML_IS_THREADED() != 0)
        pthread_mutex_unlock(&global_init_lock);
#elif defined HAVE_WIN32_THREADS
    if (global_init_lock != NULL)
    LeaveCriticalSection(global_init_lock);
#endif
}

Referenced by xmlInitParser().

xmlInitMutex()

void xmlInitMutex

(

xmlMutexPtr

mutex

)

xmlInitMutex: @mutex: the mutex

Initialize a mutex.

Definition at line 128 of file threads.c.

{
#ifdef HAVE_POSIX_THREADS
    if (XML_IS_NEVER_THREADED() == 0)
        pthread_mutex_init(&mutex->lock, NULL);
#elif defined HAVE_WIN32_THREADS
    InitializeCriticalSection(&mutex->cs);
#else
    (void) mutex;
#endif
}

Referenced by xmlInitDictInternal(), xmlInitGlobalsInternal(), xmlInitMemoryInternal(), xmlInitRandom(), and xmlNewMutex().

xmlInitParser()

void xmlInitParser

(

void

)

xmlInitParser:

Initialization function for the XML parser.

Call once from the main thread before using the library in multithreaded programs.

Definition at line 569 of file threads.c.

                    {
    /*
     * Note that the initialization code must not make memory allocations.
     */
    if (xmlParserInitialized != 0)
        return;
 
    xmlGlobalInitMutexLock();
 
    if (xmlParserInnerInitialized == 0) {
#if defined(_WIN32) && \
    !defined(LIBXML_THREAD_ALLOC_ENABLED) && \
    (!defined(LIBXML_STATIC) || defined(LIBXML_STATIC_FOR_DLL))
        if (xmlFree == free)
            atexit(xmlCleanupParser);
#endif
 
        xmlInitMemoryInternal(); /* Should come second */
        xmlInitGlobalsInternal();
        xmlInitRandom();
        xmlInitDictInternal();
        xmlInitEncodingInternal();
#if defined(LIBXML_XPATH_ENABLED) || defined(LIBXML_SCHEMAS_ENABLED)
        xmlInitXPathInternal();
#endif
 
        xmlRegisterDefaultInputCallbacks();
#ifdef LIBXML_OUTPUT_ENABLED
        xmlRegisterDefaultOutputCallbacks();
#endif /* LIBXML_OUTPUT_ENABLED */
 
        xmlParserInnerInitialized = 1;
    }
 
    xmlGlobalInitMutexUnlock();
 
    xmlParserInitialized = 1;
}

Referenced by DllMain(), xmlCheckVersion(), xmlCtxtReadDoc(), xmlCtxtReadFd(), xmlCtxtReadFile(), xmlCtxtReadIO(), xmlCtxtReadMemory(), xmlDictCreate(), xmlHashCreate(), xmlInitCharEncodingHandlers(), xmlInitGlobals(), xmlInitializeDict(), xmlInitMemory(), xmlInitSAXParserCtxt(), xmlInitThreads(), xmlIsMainThreadInternal(), xmlMallocAtomicLoc(), xmlMallocLoc(), xmlMemStrdupLoc(), xmlParseDocument(), xmlReadDoc(), xmlReadFd(), xmlReadFile(), xmlReadIO(), xmlReadMemory(), and xmlReallocLoc().

xmlInitThreads()

void xmlInitThreads

(

void

)

xmlInitThreads:

DEPRECATED: Alias for xmlInitParser.

Definition at line 421 of file threads.c.

{
    xmlInitParser();
}

xmlLockLibrary()

void xmlLockLibrary

(

void

)

xmlLockLibrary:

xmlLockLibrary() is used to take out a re-entrant lock on the libxml2 library.

Definition at line 398 of file threads.c.

{
    xmlRMutexLock(xmlLibraryLock);
}

xmlMutexLock()

void xmlMutexLock

(

xmlMutexPtr

tok

)

xmlMutexLock: @tok: the simple mutex

xmlMutexLock() is used to lock a libxml2 token.

Definition at line 201 of file threads.c.

{
    if (tok == NULL)
        return;
#ifdef HAVE_POSIX_THREADS
    /*
     * This assumes that __libc_single_threaded won't change while the
     * lock is held.
     */
    if (XML_IS_THREADED() != 0)
        pthread_mutex_lock(&tok->lock);
#elif defined HAVE_WIN32_THREADS
    EnterCriticalSection(&tok->cs);
#endif
 
}

Referenced by xmlDictFree(), xmlDictReference(), xmlMallocAtomicLoc(), xmlMallocLoc(), xmlMemBlocks(), xmlMemDisplay(), xmlMemDisplayLast(), xmlMemFree(), xmlMemShow(), xmlMemStrdupLoc(), xmlRandom(), xmlReallocLoc(), xmlThrDefBufferAllocScheme(), xmlThrDefDefaultBufferSize(), xmlThrDefDeregisterNodeDefault(), xmlThrDefDoValidityCheckingDefaultValue(), xmlThrDefGetWarningsDefaultValue(), xmlThrDefKeepBlanksDefaultValue(), xmlThrDefLineNumbersDefaultValue(), xmlThrDefLoadExtDtdDefaultValue(), xmlThrDefOutputBufferCreateFilenameDefault(), xmlThrDefParserDebugEntities(), xmlThrDefParserInputBufferCreateFilenameDefault(), xmlThrDefPedanticParserDefaultValue(), xmlThrDefRegisterNodeDefault(), xmlThrDefSetGenericErrorFunc(), xmlThrDefSetStructuredErrorFunc(), xmlThrDefSubstituteEntitiesDefaultValue(), xsltCleanupGlobals(), xsltDebugDumpExtensions(), xsltExtModuleElementLookup(), xsltExtModuleElementPreComputeLookup(), xsltExtModuleFunctionLookup(), xsltExtModuleTopLevelLookup(), xsltGetExtData(), xsltPreComputeExtModuleElement(), xsltRegisterExtModuleElement(), xsltRegisterExtModuleFull(), xsltRegisterExtModuleFunction(), xsltRegisterExtModuleTopLevel(), xsltRegisterExtPrefix(), xsltStyleInitializeStylesheetModule(), xsltUnregisterAllExtModuleElement(), xsltUnregisterAllExtModuleFunction(), xsltUnregisterAllExtModules(), xsltUnregisterAllExtModuleTopLevel(), xsltUnregisterExtModule(), xsltUnregisterExtModuleElement(), xsltUnregisterExtModuleFunction(), and xsltUnregisterExtModuleTopLevel().

xmlMutexUnlock()

void xmlMutexUnlock

(

xmlMutexPtr

tok

)

xmlMutexUnlock: @tok: the simple mutex

xmlMutexUnlock() is used to unlock a libxml2 token.

Definition at line 225 of file threads.c.

{
    if (tok == NULL)
        return;
#ifdef HAVE_POSIX_THREADS
    if (XML_IS_THREADED() != 0)
        pthread_mutex_unlock(&tok->lock);
#elif defined HAVE_WIN32_THREADS
    LeaveCriticalSection(&tok->cs);
#endif
}

Referenced by xmlDictFree(), xmlDictReference(), xmlMallocAtomicLoc(), xmlMallocLoc(), xmlMemBlocks(), xmlMemDisplay(), xmlMemDisplayLast(), xmlMemFree(), xmlMemShow(), xmlMemStrdupLoc(), xmlRandom(), xmlReallocLoc(), xmlThrDefBufferAllocScheme(), xmlThrDefDefaultBufferSize(), xmlThrDefDeregisterNodeDefault(), xmlThrDefDoValidityCheckingDefaultValue(), xmlThrDefGetWarningsDefaultValue(), xmlThrDefKeepBlanksDefaultValue(), xmlThrDefLineNumbersDefaultValue(), xmlThrDefLoadExtDtdDefaultValue(), xmlThrDefOutputBufferCreateFilenameDefault(), xmlThrDefParserDebugEntities(), xmlThrDefParserInputBufferCreateFilenameDefault(), xmlThrDefPedanticParserDefaultValue(), xmlThrDefRegisterNodeDefault(), xmlThrDefSetGenericErrorFunc(), xmlThrDefSetStructuredErrorFunc(), xmlThrDefSubstituteEntitiesDefaultValue(), xsltCleanupGlobals(), xsltDebugDumpExtensions(), xsltExtModuleElementLookup(), xsltExtModuleElementPreComputeLookup(), xsltExtModuleFunctionLookup(), xsltExtModuleTopLevelLookup(), xsltGetExtData(), xsltPreComputeExtModuleElement(), xsltRegisterExtModuleElement(), xsltRegisterExtModuleFull(), xsltRegisterExtModuleFunction(), xsltRegisterExtModuleTopLevel(), xsltRegisterExtPrefix(), xsltStyleInitializeStylesheetModule(), xsltUnregisterAllExtModuleElement(), xsltUnregisterAllExtModuleFunction(), xsltUnregisterAllExtModules(), xsltUnregisterAllExtModuleTopLevel(), xsltUnregisterExtModule(), xsltUnregisterExtModuleElement(), xsltUnregisterExtModuleFunction(), and xsltUnregisterExtModuleTopLevel().

xmlNewMutex()

xmlMutexPtr xmlNewMutex

(

void

)

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

Definition at line 149 of file threads.c.

{
    xmlMutexPtr tok;
 
    if ((tok = malloc(sizeof(xmlMutex))) == NULL)
        return (NULL);
    xmlInitMutex(tok);
    return (tok);
}

Referenced by xsltInitGlobals().

xmlNewRMutex()

xmlRMutexPtr xmlNewRMutex

(

void

)

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

Definition at line 248 of file threads.c.

{
    xmlRMutexPtr tok;
 
    if ((tok = malloc(sizeof(xmlRMutex))) == NULL)
        return (NULL);
#ifdef HAVE_POSIX_THREADS
    if (XML_IS_NEVER_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);
#endif
    return (tok);
}

Referenced by xsltInit().

xmlRMutexLock()

void xmlRMutexLock

(

xmlRMutexPtr

tok

)

xmlRMutexLock: @tok: the reentrant mutex

xmlRMutexLock() is used to lock a libxml2 token_r.

Definition at line 297 of file threads.c.

{
    if (tok == NULL)
        return;
#ifdef HAVE_POSIX_THREADS
    if (XML_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);
#endif
}

Referenced by xmlLockLibrary(), and xsltFreeLocales().

xmlRMutexUnlock()

void xmlRMutexUnlock

(

xmlRMutexPtr tok

ATTRIBUTE_UNUSED

)

xmlRMutexUnlock: @tok: the reentrant mutex

xmlRMutexUnlock() is used to unlock a libxml2 token_r.

Definition at line 333 of file threads.c.

{
    if (tok == NULL)
        return;
#ifdef HAVE_POSIX_THREADS
    if (XML_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
    LeaveCriticalSection(&tok->cs);
#endif
}

Referenced by xmlUnlockLibrary(), and xsltFreeLocales().

xmlUnlockLibrary()

void xmlUnlockLibrary

(

void

)

xmlUnlockLibrary:

xmlUnlockLibrary() is used to release a re-entrant lock on the libxml2 library.

Definition at line 410 of file threads.c.

{
    xmlRMutexUnlock(xmlLibraryLock);
}

Variable Documentation

xmlLibraryLock

xmlRMutexPtr xmlLibraryLock = NULL

static

Definition at line 119 of file threads.c.

Referenced by xmlLockLibrary(), and xmlUnlockLibrary().

xmlParserInitialized

int xmlParserInitialized = 0

static

Definition at line 445 of file threads.c.

Referenced by xmlCleanupParser(), and xmlInitParser().

xmlParserInnerInitialized

int xmlParserInnerInitialized = 0

static

Definition at line 446 of file threads.c.

Referenced by xmlCleanupParser(), and xmlInitParser().