diff options
Diffstat (limited to 'Frameworks/MCPKit/MCPFoundationKit/MCPConnection.m')
| -rw-r--r-- | Frameworks/MCPKit/MCPFoundationKit/MCPConnection.m | 298 |
1 files changed, 134 insertions, 164 deletions
diff --git a/Frameworks/MCPKit/MCPFoundationKit/MCPConnection.m b/Frameworks/MCPKit/MCPFoundationKit/MCPConnection.m index 3dab324d..2008a3aa 100644 --- a/Frameworks/MCPKit/MCPFoundationKit/MCPConnection.m +++ b/Frameworks/MCPKit/MCPFoundationKit/MCPConnection.m @@ -41,13 +41,6 @@ #include <mach/mach_time.h> #include <SystemConfiguration/SystemConfiguration.h> -BOOL lastPingSuccess; -BOOL pingActive; -NSInteger pingFailureCount; -BOOL keepAliveActive; - -static void forceThreadExit(int signalNumber); - const NSUInteger kMCPConnectionDefaultOption = CLIENT_COMPRESS | CLIENT_REMEMBER_OPTIONS | CLIENT_MULTI_RESULTS; const char *kMCPConnectionDefaultSocket = MYSQL_UNIX_ADDR; const char *kMCPSSLCipherList = "DHE-RSA-AES256-SHA:AES256-SHA:DHE-RSA-AES128-SHA:AES128-SHA:AES256-RMD:AES128-RMD:DES-CBC3-RMD:DHE-RSA-AES256-RMD:DHE-RSA-AES128-RMD:DHE-RSA-DES-CBC3-RMD:RC4-SHA:RC4-MD5:DES-CBC3-SHA:DES-CBC-SHA:EDH-RSA-DES-CBC3-SHA:EDH-RSA-DES-CBC-SHA"; @@ -118,7 +111,6 @@ static BOOL sTruncateLongFieldInLogs = YES; sslKeyFilePath = nil; sslCertificatePath = nil; sslCACertificatePath = nil; - keepAliveThread = NULL; lastKeepAliveTime = 0; pingThread = NULL; connectionProxy = nil; @@ -132,6 +124,9 @@ static BOOL sTruncateLongFieldInLogs = YES; isDisconnecting = NO; userTriggeredDisconnect = NO; automaticReconnectAttempts = 0; + lastPingSuccess = NO; + lastPingBlocked = NO; + pingThreadActive = NO; pingFailureCount = 0; // Initialize ivar defaults @@ -696,7 +691,7 @@ static BOOL sTruncateLongFieldInLogs = YES; BOOL connectionVerified = FALSE; // Check whether the connection is still operational via a wrapped version of MySQL ping. - connectionVerified = [self pingConnection]; + connectionVerified = [self pingConnectionUsingLoopDelay:400]; // If the connection doesn't appear to be responding, and we can still attempt an automatic // reconnect (only once each connection - eg an automatic reconnect failure prevents loops, @@ -751,58 +746,155 @@ static BOOL sTruncateLongFieldInLogs = YES; } /** + * Restore the connection encoding details as necessary based on the delegate-provided + * details. + */ +- (void)restoreConnectionDetails +{ + connectionThreadId = mConnection->thread_id; + connectionStartTime = mach_absolute_time(); + [self fetchMaxAllowedPacket]; + + [self setEncoding:encoding]; + [self setEncodingUsesLatin1Transport:encodingUsesLatin1Transport]; +} + +/** + * Allow controlling over whether queries are allowed to retry after a connection failure. + * This defaults to YES on init, and is intended to allow temporary disabling in situations + * where the query result is checked and displayed to the user without any repurcussions on + * failure. + */ +- (void)setAllowQueryRetries:(BOOL)allow +{ + retryAllowed = allow; +} + +/** + * Retrieve the time elapsed since the connection was established, in seconds. + * This time is retrieved in a monotonically increasing fashion and is high + * precision; it is used internally for query timing, and is reset on reconnections. + */ +- (double)timeConnected +{ + if (connectionStartTime == -1) return -1; + + uint64_t currentTime_t = mach_absolute_time() - connectionStartTime; + Nanoseconds elapsedTime = AbsoluteToNanoseconds(*(AbsoluteTime *)&(currentTime_t)); + + return (((double)UnsignedWideToUInt64(elapsedTime)) * 1e-9); +} + +#pragma mark - +#pragma mark Pinging and keepalive + +/** * This function provides a method of pinging the remote server while also enforcing * the specified connection time. This is required because low-level net reads can * block indefinitely if the remote server disappears or on network issues - setting * the MYSQL_OPT_READ_TIMEOUT (and the WRITE equivalent) would "fix" ping, but cause * long queries to be terminated. + * The supplied loop delay number controls how tight the thread checking loop is, in + * microseconds, to allow differentiating foreground and background pings. * Unlike mysql_ping, this function returns FALSE on failure and TRUE on success. */ -- (BOOL)pingConnection +- (BOOL)pingConnectionUsingLoopDelay:(NSUInteger)loopDelay { + if (!mConnected) return NO; + + uint64_t pingStartTime_t, currentTime_t; + Nanoseconds elapsedNanoseconds; + BOOL threadCancelled = NO; + // Set up a query lock [self lockConnection]; - uint64_t currentTime_t; - Nanoseconds elapsedTime; - uint64_t pingStartTime_t = mach_absolute_time(); - lastPingSuccess = FALSE; - pingActive = YES; + lastPingSuccess = NO; + lastPingBlocked = NO; + pingThreadActive = YES; + + // Use a ping timeout defaulting to thirty seconds, but using the connection timeout if set + NSInteger pingTimeout = 30; + if (connectionTimeout > 0) pingTimeout = connectionTimeout; + + // Set up a struct containing details the ping task will need + MCPConnectionPingDetails pingDetails; + pingDetails.mySQLConnection = mConnection; + pingDetails.lastPingSuccessPointer = &lastPingSuccess; + pingDetails.pingActivePointer = &pingThreadActive; - // Create a pthread for the ping, so we can force it to end after the connection timeout + // Create a pthread for the ping pthread_attr_t attr; pthread_attr_init(&attr); pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); - pthread_create(&pingThread, NULL, (void *)&pingConnectionTask, (void *)mConnection); + pthread_create(&pingThread, &attr, (void *)&backgroundPingTask, &pingDetails); - // Loop tightly until the ping responds, or the elapsed time exceeds the connection timeout - while (pingActive) { - currentTime_t = mach_absolute_time() - pingStartTime_t; - elapsedTime = AbsoluteToNanoseconds(*(AbsoluteTime *)&(currentTime_t)); - if (((double)UnsignedWideToUInt64(elapsedTime)) * 1e-9 > connectionTimeout) break; - usleep(400); - } + // Record the ping start time + pingStartTime_t = mach_absolute_time(); - // If the connection timed out, kill the thread and set status to failed - if (pingActive) { - pthread_cancel(pingThread); - lastPingSuccess = FALSE; - } + // Loop until the ping completes + do { + usleep(loopDelay); + + // If the ping timeout has been exceeded, force a timeout; double-check that the + // thread is still active. + currentTime_t = mach_absolute_time() - pingStartTime_t ; + elapsedNanoseconds = AbsoluteToNanoseconds(*(AbsoluteTime *)&(currentTime_t)); + if (((double)UnsignedWideToUInt64(elapsedNanoseconds)) * 1e-9 > pingTimeout && pingThreadActive && !threadCancelled) { + pthread_cancel(pingThread); + threadCancelled = YES; + + // If the timeout has been exceeded by an additional two seconds, and the thread is + // still active, kill the thread. This can occur in certain network conditions causing + // a blocking read. + } else if (((double)UnsignedWideToUInt64(elapsedNanoseconds)) * 1e-9 > (pingTimeout + 2) && pingThreadActive) { + pthread_kill(pingThread, SIGUSR1); + pingThreadActive = NO; + lastPingBlocked = YES; + } + } while (pingThreadActive); + + // Clean up + pingThread = NULL; pthread_attr_destroy(&attr); + // Unlock the connection [self unlockConnection]; return lastPingSuccess; } /** - * This function is paired with pingConnection, and performs the checking ping in a pthread, - * allowing the thread to be cancelled if it does not respond. + * Actually perform a keepalive ping - intended for use within a pthread. + */ +void backgroundPingTask(void *ptr) +{ + MCPConnectionPingDetails *pingDetails = (MCPConnectionPingDetails *)ptr; + + // Set up a cleanup routine + pthread_cleanup_push(pingThreadCleanup, pingDetails); + + // Set up a signal handler for SIGUSR1, to handle forced timeouts. + signal(SIGUSR1, forceThreadExit); + + // Perform a ping + *(pingDetails->lastPingSuccessPointer) = (BOOL)(!mysql_ping(pingDetails->mySQLConnection)); + + // Call the cleanup routine + pthread_cleanup_pop(1); +} + +/** + * Support forcing a thread to exit as a result of a signal. */ -void pingConnectionTask(void *ptr) +void forceThreadExit(int signalNumber) +{ + pthread_exit(NULL); +} + +void pingThreadCleanup(MCPConnectionPingDetails *pingDetails) { - lastPingSuccess = (BOOL)(!mysql_ping((MYSQL *)ptr)); - pingActive = NO; + *(pingDetails->pingActivePointer) = NO; } /** @@ -827,9 +919,10 @@ void pingConnectionTask(void *ptr) return; } - // Attempt to lock the connection. If the connection currently is busy, + // Attempt to lock the connection. If the connection is currently busy, // we don't need a ping. if (![self tryLockConnection]) return; + [self unlockConnection]; // Store the ping time lastKeepAliveTime = timeConnected; @@ -844,145 +937,22 @@ void pingConnectionTask(void *ptr) */ - (void)threadedKeepAlive { - uint64_t currentTime_t; - Nanoseconds currentNanoseconds; - double pingStartTime; - BOOL threadCancelled = NO; - - if (!mConnected || keepAliveThread != NULL) { - // unlock the connection now. it has been locked in keepAlive: - [self unlockConnection]; - return; - } // If the maximum number of ping failures has been reached, trigger a reconnect - if (pingFailureCount >= 3) { + if (lastPingBlocked || pingFailureCount >= 3) { NSAutoreleasePool *connectionPool = [[NSAutoreleasePool alloc] init]; - [self unlockConnection]; [self reconnect]; [connectionPool drain]; return; } - // Use a ping timeout between zero and thirty seconds - NSInteger pingTimeout = 30; - if (connectionTimeout > 0 && connectionTimeout < pingTimeout) pingTimeout = connectionTimeout; - - // Create a pthread for the actual keepalive - keepAliveActive = YES; - pthread_attr_t attr; - pthread_attr_init(&attr); - pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); - pthread_create(&keepAliveThread, &attr, (void *)&performThreadedKeepAlive, (void *)mConnection); - - // Record the ping start time - currentTime_t = mach_absolute_time() - connectionStartTime; - currentNanoseconds = AbsoluteToNanoseconds(*(AbsoluteTime *)&(currentTime_t)); - pingStartTime = UnsignedWideToUInt64(currentNanoseconds); - - // Loop until the ping completes - do { - usleep(10000); - - // If the ping timeout has been exceeded, force a timeout; double-check that keepAliveActive - // is still set to NO, as otherwise the thread id may have already been reused causing - // cancellation of the incorrect thread. - currentTime_t = mach_absolute_time() - connectionStartTime; - currentNanoseconds = AbsoluteToNanoseconds(*(AbsoluteTime *)&(currentTime_t)); - if ((UnsignedWideToUInt64(currentNanoseconds) - pingStartTime) * 1e-9 > pingTimeout && keepAliveActive && !threadCancelled) { - pthread_cancel(keepAliveThread); - threadCancelled = YES; - - // If the timeout has been exceeded by an additional two seconds, kill the thread. - } else if ((UnsignedWideToUInt64(currentNanoseconds) - pingStartTime) * 1e-9 > (pingTimeout + 2) && keepAliveActive) { - pthread_kill(keepAliveThread, SIGUSR1); - keepAliveActive = NO; - } - } while (keepAliveActive); - - // Unlock the connection now, locked in keepAlive: at the start of the ping - [self unlockConnection]; - - // Clean up - keepAliveThread = NULL; - pthread_attr_destroy(&attr); -} - -/** - * Actually perform a keepalive ping - intended for use within a pthread. - */ -void performThreadedKeepAlive(void *ptr) -{ - - // Set up a signal handler for SIGUSR1, to handle forced timeouts. - struct sigaction timeoutAction; - timeoutAction.sa_handler = forceThreadExit; - sigemptyset(&timeoutAction.sa_mask); - timeoutAction.sa_flags = 0; - sigaction(SIGUSR1, &timeoutAction, NULL); - - if (mysql_ping((MYSQL *)ptr)) { - pingFailureCount++; - } else { + // Otherwise, perform a background ping. + BOOL pingResult = [self pingConnectionUsingLoopDelay:10000]; + if (pingResult) { pingFailureCount = 0; + } else { + pingFailureCount++; } - keepAliveActive = NO; - - - // Reset and clear the SIGUSR1 used to check connection timeouts. - timeoutAction.sa_handler = SIG_IGN; - sigemptyset(&timeoutAction.sa_mask); - timeoutAction.sa_flags = 0; - sigaction(SIGUSR1, &timeoutAction, NULL); -} - -/** - * Support forcing a thread to exit as a result of a signal. - */ -static void forceThreadExit(int signalNumber) -{ - pthread_exit(NULL); -} - - -/** - * Restore the connection encoding details as necessary based on the delegate-provided - * details. - */ -- (void)restoreConnectionDetails -{ - connectionThreadId = mConnection->thread_id; - connectionStartTime = mach_absolute_time(); - [self fetchMaxAllowedPacket]; - - [self setEncoding:encoding]; - [self setEncodingUsesLatin1Transport:encodingUsesLatin1Transport]; -} - -/** - * Allow controlling over whether queries are allowed to retry after a connection failure. - * This defaults to YES on init, and is intended to allow temporary disabling in situations - * where the query result is checked and displayed to the user without any repurcussions on - * failure. - */ -- (void)setAllowQueryRetries:(BOOL)allow -{ - retryAllowed = allow; -} - -/** - * Retrieve the time elapsed since the connection was established, in seconds. - * This time is retrieved in a monotonically increasing fashion and is high - * precision; it is used internally for query timing, and is reset on reconnections. - */ -- (double)timeConnected -{ - if (connectionStartTime == -1) return -1; - - uint64_t currentTime_t = mach_absolute_time() - connectionStartTime; - Nanoseconds elapsedTime = AbsoluteToNanoseconds(*(AbsoluteTime *)&(currentTime_t)); - - return (((double)UnsignedWideToUInt64(elapsedTime)) * 1e-9); } #pragma mark - |