Resolves: #403351

Summary: LongDuration: Error log Rotation test suite causes slapd hang
Problem description: LDAPDebug eventually calls slapd_log_error_proc_internal,
which obtains the lock.  If any functions called in the lock tries to log into
the errors log, it tries to get the same lock and it hangs there since the
underlying PR_Lock is not reentrant.
Fix description: log__enough_freespace and log__delete_error_logfile could be
called indirectly from slapd_log_error_proc_internal.  Instead of LDAPDebug,
changed these functions to call log__error_emergency when necessary.

ldap/servers/slapd/log.c

@@ -116,7 +116,7 @@ static int	log__open_errorlogfile(int logfile_type, int locked);
 static int	log__open_auditlogfile(int logfile_type, int locked);
 static int	log__needrotation(LOGFD fp, int logtype);
 static int	log__delete_access_logfile();
-static int	log__delete_error_logfile();
+static int	log__delete_error_logfile(int locked);
 static int	log__delete_audit_logfile();
 static int 	log__access_rotationinfof(char *pathname);
 static int 	log__error_rotationinfof(char *pathname);
@@ -2926,10 +2926,14 @@ char rootpath[4];
 	if (statvfs(path, &buf) == -1)
 #endif
 	{
-		int	oserr = errno;
-		LDAPDebug(LDAP_DEBUG_ANY, 
-			  "log__enough_freespace: Unable to get the free space (errno:%d)\n",
-				oserr,0,0);
+		char buffer[BUFSIZ];
+		PR_snprintf(buffer, sizeof(buffer),
+			  		"log__enough_freespace: Unable to get the free space (errno:%d)\n",
+					errno);
+		/* This function could be called in the ERROR WRITE LOCK,
+		 * which causes the self deadlock if you call LDAPDebug for logging.
+		 * Thus, instead of LDAPDebug, call log__error_emergency with locked == 1. */
+		log__error_emergency(buffer, 0, 1);
 		return 1;
 	} else {
 	    LL_UI2L(freeBytes, buf.f_bavail);
@@ -3024,7 +3028,7 @@ log_get_loglist(int logtype)
 ******************************************************************************/ 
 
 static int
-log__delete_error_logfile()
+log__delete_error_logfile(int locked)
 {
 
 	struct logfileinfo	*logp = NULL;
@@ -3044,18 +3048,27 @@ log__delete_error_logfile()
 	/* If we have only one log, then  will delete this one */
 	if (loginfo.log_error_maxnumlogs == 1) {
 		LOG_CLOSE(loginfo.log_error_fdes);
-                loginfo.log_error_fdes = NULL;
+		loginfo.log_error_fdes = NULL;
 		PR_snprintf (buffer, sizeof(buffer), "%s", loginfo.log_error_file);
 		if (PR_Delete(buffer) != PR_SUCCESS) {
-			LDAPDebug(LDAP_DEBUG_TRACE, 
-				"LOGINFO:Unable to remove file:%s\n", loginfo.log_error_file,0,0);
+			if (!locked) {
+				/* if locked, we should not call LDAPDebug, 
+				   which tries to get a lock internally. */
+				LDAPDebug(LDAP_DEBUG_TRACE, 
+					"LOGINFO:Unable to remove file:%s\n", loginfo.log_error_file,0,0);
+			}
 		}
 
 		/* Delete the rotation file also. */
 		PR_snprintf (buffer, sizeof(buffer), "%s.rotationinfo", loginfo.log_error_file);
 		if (PR_Delete(buffer) != PR_SUCCESS) {
-			LDAPDebug(LDAP_DEBUG_TRACE, 
-				"LOGINFO:Unable to remove file:%s.rotationinfo\n", loginfo.log_error_file,0,0);
+			if (!locked) {
+				/* if locked, we should not call LDAPDebug, 
+				   which tries to get a lock internally. */
+				LDAPDebug(LDAP_DEBUG_TRACE, 
+					"LOGINFO:Unable to remove file:%s.rotationinfo\n", 
+					loginfo.log_error_file,0,0);
+			}
 		}
 		return 0;
 	}
@@ -3084,7 +3097,7 @@ log__delete_error_logfile()
 		}
 
 		/* If we have exceeded the max disk space or we have less than the
-  		** minimum, then we have to delete a file.
+		** minimum, then we have to delete a file.
 		*/
 		if (total_size >= loginfo.log_error_maxdiskspace)  {
 			logstr = "exceeded maximum log disk space";
@@ -3145,10 +3158,14 @@ delete_logfile:
 			return 0;
 		}
 	} 
-	LDAPDebug(LDAP_DEBUG_TRACE, 
+	if (!locked) {
+		/* if locked, we should not call LDAPDebug, 
+		   which tries to get a lock internally. */
+		LDAPDebug(LDAP_DEBUG_TRACE, 
 			   "LOGINFO:Removing file:%s.%s because of (%s)\n",
 					loginfo.log_error_file, tbuf,
 					logstr);
+	}
 
 	if (p_delete_logp == delete_logp) {
 		/* then we are deleteing the first one */
@@ -3161,8 +3178,12 @@ delete_logfile:
 	log_convert_time (delete_logp->l_ctime, tbuf, 1 /*short */);
 	PR_snprintf (buffer, sizeof(buffer), "%s.%s", loginfo.log_error_file, tbuf);
 	if (PR_Delete(buffer) != PR_SUCCESS) {
-		LDAPDebug(LDAP_DEBUG_ANY, "LOGINFO:Unable to remove file:%s.%s\n",
-				   loginfo.log_audit_file, tbuf,0);
+		/* This function could be called in the ERROR WRITE LOCK,
+		 * which causes the self deadlock if you call LDAPDebug for logging.
+		 * Thus, instead of LDAPDebug, call log__error_emergency with locked == 1. */
+		PR_snprintf(buffer, sizeof(buffer), "LOGINFO:Unable to remove file:%s.%s\n",
+				   loginfo.log_audit_file, tbuf);
+		log__error_emergency(buffer, 0, locked);
 	}
 	slapi_ch_free((void**)&delete_logp);
 	loginfo.log_numof_error_logs--;
@@ -3580,7 +3601,7 @@ log__open_errorlogfile(int logfile_state, int locked)
 
 
 		/*  Check if I have to delete any old file, delete it if it is required.*/
-		while (log__delete_error_logfile());
+		while (log__delete_error_logfile(1));
 
 		/* close the file */
 		if ( loginfo.log_error_fdes != NULL ) {