diff options
Diffstat (limited to 'runtime/modules.c')
| -rw-r--r-- | runtime/modules.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/runtime/modules.c b/runtime/modules.c index 9fdb48e7..32ae659f 100644 --- a/runtime/modules.c +++ b/runtime/modules.c @@ -40,6 +40,7 @@ #include <time.h> #include <assert.h> #include <errno.h> +#include <pthread.h> #ifdef OS_BSD # include "libgen.h" #endif @@ -61,6 +62,14 @@ DEFobjStaticHelpers DEFobjCurrIf(errmsg) +/* we must ensure that only one thread at one time tries to load or unload + * modules, otherwise we may see race conditions. This first came up with + * imdiag/imtcp, which both use the same stream drivers. Below is the mutex + * for that handling. + * rgerhards, 2009-05-25 + */ +static pthread_mutex_t mutLoadUnload; + static modInfo_t *pLoadedModules = NULL; /* list of currently-loaded modules */ static modInfo_t *pLoadedModulesLast = NULL; /* tail-pointer */ @@ -479,6 +488,8 @@ modUnlinkAndDestroy(modInfo_t **ppThis) pThis = *ppThis; assert(pThis != NULL); + pthread_mutex_lock(&mutLoadUnload); + /* first check if we are permitted to unload */ if(pThis->eType == eMOD_LIB) { if(pThis->uRefCnt > 0) { @@ -513,6 +524,7 @@ modUnlinkAndDestroy(modInfo_t **ppThis) moduleDestruct(pThis); finalize_it: + pthread_mutex_unlock(&mutLoadUnload); RETiRet; } @@ -587,6 +599,8 @@ Load(uchar *pModName) assert(pModName != NULL); dbgprintf("Requested to load module '%s'\n", pModName); + pthread_mutex_lock(&mutLoadUnload); + iModNameLen = strlen((char *) pModName); if(iModNameLen > 3 && !strcmp((char *) pModName + iModNameLen - 3, ".so")) { iModNameLen -= 3; @@ -696,6 +710,7 @@ Load(uchar *pModName) } finalize_it: + pthread_mutex_unlock(&mutLoadUnload); RETiRet; } @@ -791,6 +806,15 @@ BEGINObjClassExit(module, OBJ_IS_LOADABLE_MODULE) /* CHANGE class also in END MA CODESTARTObjClassExit(module) /* release objects we no longer need */ objRelease(errmsg, CORE_COMPONENT); + /* We have a problem in our reference counting, which leads to this function + * being called too early. This usually is no problem, but if we destroy + * the mutex object, we get into trouble. So rather than finding the root cause, + * we do not release the mutex right now and have a very, very slight leak. + * We know that otherwise no bad effects happen, so this acceptable for the + * time being. -- rgerhards, 2009-05-25 + * + * TODO: add again: pthread_mutex_destroy(&mutLoadUnload); + */ # ifdef DEBUG modUsrPrintAll(); /* debug aid - TODO: integrate with debug.c, at least the settings! */ @@ -833,6 +857,7 @@ ENDobjQueryInterface(module) */ BEGINAbstractObjClassInit(module, 1, OBJ_IS_CORE_MODULE) /* class, version - CHANGE class also in END MACRO! */ uchar *pModPath; + pthread_mutexattr_t mutAttr; /* use any module load path specified in the environment */ if((pModPath = (uchar*) getenv("RSYSLOG_MODDIR")) != NULL) { @@ -850,6 +875,10 @@ BEGINAbstractObjClassInit(module, 1, OBJ_IS_CORE_MODULE) /* class, version - CHA SetModDir(glblModPath); } + pthread_mutexattr_init(&mutAttr); + pthread_mutexattr_settype(&mutAttr, PTHREAD_MUTEX_RECURSIVE); + pthread_mutex_init(&mutLoadUnload, &mutAttr); + /* request objects we use */ CHKiRet(objUse(errmsg, CORE_COMPONENT)); ENDObjClassInit(module) |