From ba2e716a8357496c3a834a8e799583ef58f95f82 Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Mon, 27 Nov 2023 16:57:05 +0100
Subject: Add autorestart option to exit(1) on unresponsive upstream

---
 helper.c |  1 +
 helper.h |  3 +++
 ldadp.c  |  2 ++
 proxy.c  | 51 ++++++++++++++++++++++++++++++++++++++++-----------
 4 files changed, 46 insertions(+), 11 deletions(-)

diff --git a/helper.c b/helper.c
index 6c51bab..93ed207 100644
--- a/helper.c
+++ b/helper.c
@@ -12,6 +12,7 @@
 #include <stdarg.h>
 
 DebugLevel _debugLevel = DEBUG_WARNING;
+int _autoRestart = 0;
 
 void bail(char *args, ...)
 {
diff --git a/helper.h b/helper.h
index 7aaece7..3b20545 100644
--- a/helper.h
+++ b/helper.h
@@ -33,7 +33,10 @@ typedef enum {
 	DEBUG_TRACE = 4,
 } DebugLevel;
 
+/** Debug level for logging */
 extern DebugLevel _debugLevel;
+/** Automatically restart on connection errors? */
+extern int _autoRestart;
 
 void plog(const DebugLevel messageLevel, char *args, ...);
 
diff --git a/ldadp.c b/ldadp.c
index 3f69745..2152903 100644
--- a/ldadp.c
+++ b/ldadp.c
@@ -155,6 +155,8 @@ static int loadConfig_handler(void *stuff, const char *section, const char *key,
 			keyFile = strdup(value);
 		} else if (strcmp(key, "debug") == 0) {
 			_debugLevel = atoi(value);
+		} else if (strcmp(key, "autorestart") == 0) {
+			_autoRestart = atoi(value) != 0;
 		} else {
 			printf("Unknown local config option '%s'\n", key);
 		}
diff --git a/proxy.c b/proxy.c
index f3588ef..0df3729 100644
--- a/proxy.c
+++ b/proxy.c
@@ -48,10 +48,12 @@ typedef struct
 	unsigned long serverMessageId;
 	epoll_client_t *client;
 	attr_t attr;
+	time_t started;
 } pending_t;
 
 static pending_t _pendingRequest[MAXPENDING];
 static int _pendingCount = 0;
+static int _problemCount = 0;
 
 // Attributes
 static struct string s_uid, s_sAMAccountName, s_objectSid, s_homeMount, s_memberUid, s_realAccount;
@@ -242,15 +244,27 @@ BOOL proxy_fromClient(epoll_client_t *client, const size_t maxLen)
 	return TRUE;
 }
 
+/**
+ * Client notifies us about how it's disconnecting
+ */
 void proxy_removeClient(epoll_client_t * const client)
 {
 	int i, lastValid = -1;
+	BOOL problem = FALSE;
 	for (i = 0; i < _pendingCount; ++i) {
 		if (_pendingRequest[i].client == client) {
 			plog(DEBUG_TRACE, "RemoveClient success %p", client);
 			_pendingRequest[i].client = NULL;
+			if (_autoRestart && _pendingRequest[i].started + 10 < time(NULL)) {
+				plog(DEBUG_WARNING, "Client has pending request, age %d", (int)(time(NULL) - _pendingRequest[i].started));
+				problem = TRUE;
+			}
+		} else if (_pendingRequest[i].client != NULL) {
+			lastValid = i;
 		}
-		else if (_pendingRequest[i].client != NULL) lastValid = i;
+	}
+	if (problem && ++_problemCount > 5) {
+		bail("Too many unanswered requests, bailing out");
 	}
 	_pendingCount = lastValid + 1;
 	if (client->fixedServer != NULL) {
@@ -260,6 +274,9 @@ void proxy_removeClient(epoll_client_t * const client)
 	}
 }
 
+/**
+ * Server is closing the connection, get rid of according
+ */
 void proxy_removeServer(epoll_server_t * const server)
 {
 	if (server->fixedClient != NULL) {
@@ -304,6 +321,9 @@ BOOL proxy_fromServer(epoll_server_t *server, const size_t maxLen)
 		return proxy_serverBindResponse(server, messageId, res, maxLen);
 	case SearchResultEntry:
 	case SearchResultDone:
+		if (_autoRestart && _problemCount > 0) {
+			--_problemCount;
+		}
 		return proxy_serverSearchResult(server, messageId, op, res, maxLen);
 	case SearchResultReference:
 		// Just ignore these for now
@@ -327,19 +347,28 @@ BOOL proxy_fromServer(epoll_server_t *server, const size_t maxLen)
 
 static pending_t* proxy_getFreePendingSlot(epoll_client_t *client)
 {
-	for (int i = 0; i < _pendingCount; ++i) {
-		if (_pendingRequest[i].client == NULL) {
-			memset(&_pendingRequest[i], 0, sizeof(pending_t));
-			_pendingRequest[i].client = client;
-			return &_pendingRequest[i];
+	time_t oldest = 0;
+	int i;
+	for (i = 0; i < _pendingCount; ++i) {
+		if (_pendingRequest[i].client == NULL)
+			break;
+		if (oldest == 0 || oldest > _pendingRequest[i].started) {
+			oldest = _pendingRequest[i].started;
 		}
 	}
-	if (_pendingCount < MAXPENDING) {
-		memset(&_pendingRequest[_pendingCount], 0, sizeof(pending_t));
-		_pendingRequest[_pendingCount].client = client;
-		return &_pendingRequest[_pendingCount++];
+	if (i == _pendingCount) {
+		if (_pendingCount >= MAXPENDING) {
+			if (_autoRestart && oldest + 30 < time(NULL)) {
+				bail("Bailing out: Request queue full and auto-restart enabled!");
+			}
+			return NULL;
+		}
+		i = _pendingCount++;
 	}
-	return NULL;
+	memset(&_pendingRequest[i], 0, sizeof(pending_t));
+	_pendingRequest[i].client = client;
+	_pendingRequest[i].started = time(NULL);
+	return &_pendingRequest[i];
 }
 
 /*
-- 
cgit v1.2.3-55-g7522