/*============================================================================= curlMulti =============================================================================== This is an extension to Curl's CURLM object. The extensions are: 1) It has a lock so multiple threads can use it simultaneously. 2) Its "select" file descriptor vectors are self-contained. CURLM requires the user to maintain them separately. =============================================================================*/ #include "xmlrpc_config.h" #include #if !MSVCRT #include #endif #include #include #include #include #include "mallocvar.h" #include "xmlrpc-c/util.h" #include "xmlrpc-c/string_int.h" #include "curlversion.h" #include "lock.h" #include "lock_pthread.h" #include "curlmulti.h" static void interpretCurlMultiError(const char ** const descriptionP, CURLMcode const code) { #if HAVE_CURL_STRERROR *descriptionP = strdup(curl_multi_strerror(code)); #else xmlrpc_asprintf(descriptionP, "Curl error code (CURLMcode) %d", code); #endif } struct curlMulti { CURLM * curlMultiP; lock * lockP; /* Hold this lock while accessing or using *curlMultiP. You're using the multi manager whenever you're calling a Curl library multi manager function. */ /* The following file descriptor sets are an integral part of the CURLM object; Our curlMulti_fdset() routine binds them to the CURLM object, and said object expects us to use them in a very specific way, including doing a select() on them. It is very, very messy. */ fd_set readFdSet; fd_set writeFdSet; fd_set exceptFdSet; }; curlMulti * curlMulti_create(void) { curlMulti * retval; curlMulti * curlMultiP; MALLOCVAR(curlMultiP); if (curlMultiP == NULL) retval = NULL; else { curlMultiP->lockP = curlLock_create_pthread(); if (curlMultiP->lockP == NULL) retval = NULL; else { curlMultiP->curlMultiP = curl_multi_init(); if (curlMultiP->curlMultiP == NULL) retval = NULL; else retval = curlMultiP; if (retval == NULL) curlMultiP->lockP->destroy(curlMultiP->lockP); } if (retval == NULL) free(curlMultiP); } return retval; } void curlMulti_destroy(curlMulti * const curlMultiP) { curl_multi_cleanup(curlMultiP->curlMultiP); curlMultiP->lockP->destroy(curlMultiP->lockP); free(curlMultiP); } void curlMulti_perform(xmlrpc_env * const envP, curlMulti * const curlMultiP, bool * const immediateWorkToDoP, int * const runningHandlesP) { /*---------------------------------------------------------------------------- Do whatever work is ready to be done under the control of multi manager 'curlMultiP'. E.g. if HTTP response data has recently arrived from the network, process it as an HTTP response. Iff this results in some work being finished from our point of view, return *immediateWorkToDoP. (Caller can query the multi manager for messages and find out what it is). Return as *runningHandlesP the number of Curl easy handles under the multi manager's control that are still running -- yet to finish. -----------------------------------------------------------------------------*/ CURLMcode rc; curlMultiP->lockP->acquire(curlMultiP->lockP); rc = curl_multi_perform(curlMultiP->curlMultiP, runningHandlesP); curlMultiP->lockP->release(curlMultiP->lockP); if (rc == CURLM_CALL_MULTI_PERFORM) { *immediateWorkToDoP = true; } else { *immediateWorkToDoP = false; if (rc != CURLM_OK) { const char * reason; interpretCurlMultiError(&reason, rc); xmlrpc_faultf(envP, "Impossible failure of curl_multi_perform(): " "%s", reason); xmlrpc_strfree(reason); } } } void curlMulti_addHandle(xmlrpc_env * const envP, curlMulti * const curlMultiP, CURL * const curlSessionP) { CURLMcode rc; curlMultiP->lockP->acquire(curlMultiP->lockP); rc = curl_multi_add_handle(curlMultiP->curlMultiP, curlSessionP); curlMultiP->lockP->release(curlMultiP->lockP); if (rc != CURLM_OK) { const char * reason; interpretCurlMultiError(&reason, rc); xmlrpc_faultf(envP, "Could not add Curl session to the " "curl multi manager. curl_multi_add_handle() " "failed: %s", reason); xmlrpc_strfree(reason); } } void curlMulti_removeHandle(curlMulti * const curlMultiP, CURL * const curlSessionP) { curlMultiP->lockP->acquire(curlMultiP->lockP); curl_multi_remove_handle(curlMultiP->curlMultiP, curlSessionP); curlMultiP->lockP->release(curlMultiP->lockP); } void curlMulti_getMessage(curlMulti * const curlMultiP, bool * const endOfMessagesP, CURLMsg * const curlMsgP) { /*---------------------------------------------------------------------------- Get the next message from the queue of things the Curl multi manager wants to say to us. Return the message as *curlMsgP. Iff there are no messages in the queue, return *endOfMessagesP == true. -----------------------------------------------------------------------------*/ int remainingMsgCount; CURLMsg * privateCurlMsgP; /* Note that this is a pointer into the multi manager's memory, so we have to use it under lock. */ curlMultiP->lockP->acquire(curlMultiP->lockP); privateCurlMsgP = curl_multi_info_read(curlMultiP->curlMultiP, &remainingMsgCount); if (privateCurlMsgP == NULL) *endOfMessagesP = true; else { *endOfMessagesP = false; *curlMsgP = *privateCurlMsgP; } curlMultiP->lockP->release(curlMultiP->lockP); } void curlMulti_fdset(xmlrpc_env * const envP, curlMulti * const curlMultiP, fd_set * const readFdSetP, fd_set * const writeFdSetP, fd_set * const exceptFdSetP, int * const maxFdP) { /*---------------------------------------------------------------------------- Set the CURLM object's file descriptor sets to those in the curlMulti object, update those file descriptor sets with the current needs of the multi manager, and return the resulting values of the file descriptor sets. This is a bizarre operation, but is necessary because of the nonmodular way in which the Curl multi interface works with respect to waiting for work with select(). -----------------------------------------------------------------------------*/ CURLMcode rc; curlMultiP->lockP->acquire(curlMultiP->lockP); /* curl_multi_fdset() doesn't _set_ the fdsets. It adds to existing ones (so you can easily do a select() on other fds and Curl fds at the same time). So we have to clear first: */ FD_ZERO(&curlMultiP->readFdSet); FD_ZERO(&curlMultiP->writeFdSet); FD_ZERO(&curlMultiP->exceptFdSet); /* WARNING: curl_multi_fdset() doesn't just update the fdsets pointed to by its arguments. It makes the CURLM object remember those pointers and refer back to them later! In fact, curl_multi_perform expects its caller to have done a select() on those masks. No, really. The man page even admits it. Inspection of the Libcurl code in March 2007 indicates that this isn't actually true -- curl_multi_fdset() updates your fdset and doesn't remember the pointer at all. I.e. it's just what you would expect. The man pages still says it's as described above. My guess is that Libcurl was fixed at some time and the man page not updated. In any case, we have to work with old Libcurl if at all possible, so we still maintain these fdsets as if they belong to the CURLM object. */ rc = curl_multi_fdset(curlMultiP->curlMultiP, &curlMultiP->readFdSet, &curlMultiP->writeFdSet, &curlMultiP->exceptFdSet, maxFdP); *readFdSetP = curlMultiP->readFdSet; *writeFdSetP = curlMultiP->writeFdSet; *exceptFdSetP = curlMultiP->exceptFdSet; curlMultiP->lockP->release(curlMultiP->lockP); if (rc != CURLM_OK) { const char * reason; interpretCurlMultiError(&reason, rc); xmlrpc_faultf(envP, "Impossible failure of curl_multi_fdset(): %s", reason); xmlrpc_strfree(reason); } } void curlMulti_updateFdSet(curlMulti * const curlMultiP, fd_set const readFdSet, fd_set const writeFdSet, fd_set const exceptFdSet) { /*---------------------------------------------------------------------------- curl_multi_perform() expects the file descriptor sets, which were bound to the CURLM object via a prior curlMulti_fdset(), to contain the results of a recent select(). This subroutine provides you a way to supply those. -----------------------------------------------------------------------------*/ curlMultiP->readFdSet = readFdSet; curlMultiP->writeFdSet = writeFdSet; curlMultiP->exceptFdSet = exceptFdSet; }