Change control file of GTM into a text file

This includes latest GXID and sequence information. This configuration
allows an external operator to modify sequence information with a simple
text editor before restarting a GTM.
Some functionalities have been added to include sequence name encoding and
decoding when interacting with control file.

Patch by Andrei Martsinchyk

6 files changed, 195 insertions, 65 deletions

diff --git a/src/gtm/main/gtm_seq.c b/src/gtm/main/gtm_seq.c
index b050e7a411..d3b2f3339a 100644
--- a/src/gtm/main/gtm_seq.c
+++ b/src/gtm/main/gtm_seq.c
@@ -35,9 +35,6 @@ typedef struct GTM_SeqInfoHashBucket
 	GTM_RWLock	shb_lock;
 } GTM_SeqInfoHashBucket;
 
-static int SeqStartMagic =	0xfafafafa;
-static int SeqEndMagic =	0xfefefefe;
-
 #define SEQ_HASH_TABLE_SIZE		1024
 static GTM_SeqInfoHashBucket GTMSequences[SEQ_HASH_TABLE_SIZE];
 
@@ -1610,13 +1607,129 @@ ProcessSequenceRenameCommand(Port *myport, StringInfo message, bool is_backup)
 	/* FIXME: need to check errors */
 }
 
+
+/*
+ * Escape whitespace and non-printable characters in the sequence name to
+ * store it to the control file.
+ */
+static void
+encode_seq_key(GTM_SequenceKey seqkey, char *buffer)
+{
+	int 	i;
+	char	c;
+	char   *out;
+
+	out = buffer;
+	for (i = 0; i < seqkey->gsk_keylen; i++)
+	{
+		c = seqkey->gsk_key[i];
+
+		if (c == '\\') /* double backslach */
+		{
+			*out++ = '\\';
+			*out++ = '\\';
+		}
+		else if (c > ' ') /* no need to escape */
+		{
+			*out++ = c;
+		}
+		else if (c == '\n') /* below some known non-printable chars */
+		{
+			*out++ = '\\';
+			*out++ = 'n';
+		}
+		else if (c == '\r')
+		{
+			*out++ = '\\';
+			*out++ = 'r';
+		}
+		else if (c == '\t')
+		{
+			*out++ = '\\';
+			*out++ = 't';
+		}
+		else /* other non-printable chars */
+		{
+			*out++ = '\\';
+			if ((int) c < 10)
+			{
+				*out++ = '0';
+				*out++ = (char) ((int) '0' + (int) c);
+			}
+			else
+			{
+				*out++ = (char) ((int) '0' + ((int) c) / 10);
+				*out++ = (char) ((int) '0' + ((int) c) % 10);
+			}
+		}
+	}
+	/* Add NULL terminator */
+	*out++ = '\0';
+}
+
+
+/*
+ * Decode the string encoded by the encode_seq_key function
+ */
+static void
+decode_seq_key(char* value, GTM_SequenceKey seqkey)
+{
+	char   *in;
+	char 	out[1024];
+	int		len = 0;
+
+	in = value;
+	while (*in != '\0')
+	{
+		if (*in == '\\') /* get escaped character */
+		{
+			in++; /* next value */
+			if (*in == '\\')
+				out[len++] = *in++;
+			else if (*in == 'n')
+			{
+				out[len++] = '\n';
+				in++;
+			}
+			else if (*in == 'r')
+			{
+				out[len++] = '\r';
+				in++;
+			}
+			else if (*in == 't')
+			{
+				out[len++] = '\t';
+				in++;
+			}
+			else /* \nn format */
+			{
+				int val;
+				val = ((int) *in++ - (int) '0');
+				val *= 10;
+				val += ((int) *in++ - (int) '0');
+				out[len++] = (char) val;
+			}
+		}
+		else /* get plain character */
+		{
+			out[len++] = *in++;
+		}
+	}
+	/* copy result to palloc'ed memory */
+	seqkey->gsk_keylen = len;
+	seqkey->gsk_key = (char *) palloc(len);
+	memcpy(seqkey->gsk_key, out, len);
+}
+
+
 void
-GTM_SaveSeqInfo(int ctlfd)
+GTM_SaveSeqInfo(FILE *ctlf)
 {
 	GTM_SeqInfoHashBucket *bucket;
 	gtm_ListCell *elem;
 	GTM_SeqInfo *seqinfo = NULL;
 	int hash;
+	char buffer[1024];
 
 	for (hash = 0; hash < SEQ_HASH_TABLE_SIZE; hash++)
 	{
@@ -1635,18 +1748,14 @@ GTM_SaveSeqInfo(int ctlfd)
 
 			GTM_RWLockAcquire(&seqinfo->gs_lock, GTM_LOCKMODE_READ);
 
-			write(ctlfd, &SeqStartMagic, sizeof (SeqStartMagic));
-			write(ctlfd, &seqinfo->gs_key->gsk_keylen, sizeof (uint32));
-			write(ctlfd, seqinfo->gs_key->gsk_key, seqinfo->gs_key->gsk_keylen);
-			write(ctlfd, &seqinfo->gs_value, sizeof (GTM_Sequence));
-			write(ctlfd, &seqinfo->gs_init_value, sizeof (GTM_Sequence));
-			write(ctlfd, &seqinfo->gs_increment_by, sizeof (GTM_Sequence));
-			write(ctlfd, &seqinfo->gs_min_value, sizeof (GTM_Sequence));
-			write(ctlfd, &seqinfo->gs_max_value, sizeof (GTM_Sequence));
-			write(ctlfd, &seqinfo->gs_cycle, sizeof (bool));
-			write(ctlfd, &seqinfo->gs_called, sizeof (bool));
-			write(ctlfd, &seqinfo->gs_state, sizeof (int32));
-			write(ctlfd, &SeqEndMagic, sizeof(SeqEndMagic));
+			encode_seq_key(seqinfo->gs_key, buffer);
+			fprintf(ctlf, "%s\t%ld\t%ld\t%ld\t%ld\t%ld\t%c\t%c\t%x\n",
+					buffer, seqinfo->gs_value,
+					seqinfo->gs_init_value, seqinfo->gs_increment_by,
+					seqinfo->gs_min_value, seqinfo->gs_max_value,
+					(seqinfo->gs_cycle ? 't' : 'f'),
+					(seqinfo->gs_called ? 't' : 'f'),
+					seqinfo->gs_state);
 
 			GTM_RWLockRelease(&seqinfo->gs_lock);
 		}
@@ -1656,15 +1765,16 @@ GTM_SaveSeqInfo(int ctlfd)
 
 }
 
+
 void
-GTM_RestoreSeqInfo(int ctlfd)
+GTM_RestoreSeqInfo(FILE *ctlf)
 {
-	int magic;
+	char seqname[1024];
 
-	if (ctlfd == -1)
+	if (ctlf == NULL)
 		return;
 
-	while (read(ctlfd, &magic, sizeof (SeqStartMagic)) == sizeof (SeqStartMagic))
+	while (fscanf(ctlf, "%s", seqname) == 1)
 	{
 		GTM_SequenceKeyData seqkey;
 		GTM_Sequence increment_by;
@@ -1675,38 +1785,58 @@ GTM_RestoreSeqInfo(int ctlfd)
 		int32 state;
 		bool cycle;
 		bool called;
+		char boolval[16];
 
-		if (magic != SeqStartMagic)
+		decode_seq_key(seqname, &seqkey);
+
+		if (fscanf(ctlf, "%ld", &curval) != 1)
 		{
-			elog(LOG, "Start magic mismatch %x - %x", magic, SeqStartMagic);
-			break;
+			elog(WARNING, "Corrupted control file");
+			return;
 		}
-
-		if (read(ctlfd, &seqkey.gsk_keylen, sizeof (uint32)) != sizeof (uint32))
+		if (fscanf(ctlf, "%ld", &startval) != 1)
 		{
-			elog(LOG, "Failed to read keylen");
-			break;
+			elog(WARNING, "Corrupted control file");
+			return;
 		}
-
-		seqkey.gsk_key = palloc(seqkey.gsk_keylen);
-		read(ctlfd, seqkey.gsk_key, seqkey.gsk_keylen);
-
-		read(ctlfd, &curval, sizeof (GTM_Sequence));
-		read(ctlfd, &startval, sizeof (GTM_Sequence));
-		read(ctlfd, &increment_by, sizeof (GTM_Sequence));
-		read(ctlfd, &minval, sizeof (GTM_Sequence));
-		read(ctlfd, &maxval, sizeof (GTM_Sequence));
-		read(ctlfd, &cycle, sizeof (bool));
-		read(ctlfd, &called, sizeof (bool));
-		read(ctlfd, &state, sizeof (int32));
-		read(ctlfd, &magic, sizeof(SeqEndMagic));
-
-		if (magic != SeqEndMagic)
+		if (fscanf(ctlf, "%ld", &increment_by) != 1)
+		{
+			elog(WARNING, "Corrupted control file");
+			return;
+		}
+		if (fscanf(ctlf, "%ld", &minval) != 1)
+		{
+			elog(WARNING, "Corrupted control file");
+			return;
+		}
+		if (fscanf(ctlf, "%ld", &maxval) != 1)
+		{
+			elog(WARNING, "Corrupted control file");
+			return;
+		}
+		if (fscanf(ctlf, "%s", boolval) == 1)
+		{
+			cycle = (*boolval == 't');
+		}
+		else
+		{
+			elog(WARNING, "Corrupted control file");
+			return;
+		}
+		if (fscanf(ctlf, "%s", boolval) == 1)
+		{
+			called = (*boolval == 't');
+		}
+		else
+		{
+			elog(WARNING, "Corrupted control file");
+			return;
+		}
+		if (fscanf(ctlf, "%x", &state) != 1)
 		{
 			elog(WARNING, "Corrupted control file");
 			return;
 		}
-
 		GTM_SeqRestore(&seqkey, increment_by, minval, maxval, startval, curval,
 					   state, cycle, called);
 	}
diff --git a/src/gtm/main/gtm_standby.c b/src/gtm/main/gtm_standby.c
index 575d2a12ad..5c2c8f0a4d 100644
--- a/src/gtm/main/gtm_standby.c
+++ b/src/gtm/main/gtm_standby.c
@@ -71,7 +71,7 @@ gtm_standby_restore_next_gxid(void)
 	GlobalTransactionId next_gxid = InvalidGlobalTransactionId;
 
 	next_gxid = get_next_gxid(GTM_ActiveConn);
-	GTM_RestoreTxnInfo(-1, next_gxid);
+	GTM_RestoreTxnInfo(NULL, next_gxid);
 
 	elog(LOG, "Restoring the next GXID done.");
 	return 1;
diff --git a/src/gtm/main/gtm_txn.c b/src/gtm/main/gtm_txn.c
index f507c988e2..ccfd602864 100644
--- a/src/gtm/main/gtm_txn.c
+++ b/src/gtm/main/gtm_txn.c
@@ -2578,13 +2578,13 @@ GTM_SetShuttingDown(void)
 }
 
 void
-GTM_RestoreTxnInfo(int ctlfd, GlobalTransactionId next_gxid)
+GTM_RestoreTxnInfo(FILE *ctlf, GlobalTransactionId next_gxid)
 {
 	GlobalTransactionId saved_gxid;
 
-	if (ctlfd != -1)
+	if (ctlf)
 	{
-		if ((read(ctlfd, &saved_gxid, sizeof (saved_gxid)) != sizeof (saved_gxid)) &&
+		if ((fscanf(ctlf, "%u", &saved_gxid) != 1) &&
 			(!GlobalTransactionIdIsValid(next_gxid)))
 			next_gxid = InitialGXIDValue_Default;
 		else if (!GlobalTransactionIdIsValid(next_gxid))
@@ -2603,7 +2603,7 @@ GTM_RestoreTxnInfo(int ctlfd, GlobalTransactionId next_gxid)
 }
 
 void
-GTM_SaveTxnInfo(int ctlfd)
+GTM_SaveTxnInfo(FILE *ctlf)
 {
 	GlobalTransactionId next_gxid;
 
@@ -2611,7 +2611,7 @@ GTM_SaveTxnInfo(int ctlfd)
 
 	elog(LOG, "Saving transaction info - next_gxid: %u", next_gxid);
 
-	write(ctlfd, &next_gxid, sizeof (next_gxid));
+	fprintf(ctlf, "%u\n", next_gxid);
 }
 /*
  * TODO
diff --git a/src/gtm/main/main.c b/src/gtm/main/main.c
index cca3c5d1cd..f6c5e8d58e 100644
--- a/src/gtm/main/main.c
+++ b/src/gtm/main/main.c
@@ -286,7 +286,7 @@ main(int argc, char *argv[])
 	int			status;
 	int			i;
 	GlobalTransactionId next_gxid = InvalidGlobalTransactionId;
-	int			ctlfd;
+	FILE	   *ctlf;
 
 	/*
 	 * Local variable to hold command line options.
@@ -584,10 +584,11 @@ main(int argc, char *argv[])
 	}
 	else
 	{
-		ctlfd = open(GTMControlFile, O_RDONLY);
-		GTM_RestoreTxnInfo(ctlfd, next_gxid);
-		GTM_RestoreSeqInfo(ctlfd);
-		close(ctlfd);
+		ctlf = fopen(GTMControlFile, "r");
+		GTM_RestoreTxnInfo(ctlf, next_gxid);
+		GTM_RestoreSeqInfo(ctlf);
+		if (ctlf)
+			fclose(ctlf);
 	}
 
 	if (Recovery_IsStandby())
@@ -768,7 +769,7 @@ ServerLoop(void)
 
 		if (GTMAbortPending)
 		{
-			int ctlfd;
+			FILE *ctlf;
 
 			/*
 			 * XXX We should do a clean shutdown here. For the time being, just
@@ -783,16 +784,15 @@ ServerLoop(void)
 			 */
 			GTM_SetShuttingDown();
 
-			ctlfd = open(GTMControlFile, O_WRONLY | O_TRUNC | O_CREAT,
-						 S_IRUSR | S_IWUSR);
-			if (ctlfd == -1)
+			ctlf = fopen(GTMControlFile, "w");
+			if (ctlf == NULL)
 			{
 				fprintf(stderr, "Failed to create/open the control file\n");
 				exit(2);
 			}
 
-			GTM_SaveTxnInfo(ctlfd);
-			GTM_SaveSeqInfo(ctlfd);
+			GTM_SaveTxnInfo(ctlf);
+			GTM_SaveSeqInfo(ctlf);
 
 #if 0
 			/*
@@ -808,7 +808,7 @@ ServerLoop(void)
 			}
 #endif
 
-			close(ctlfd);
+			fclose(ctlf);
 
 			exit(1);
 		}
diff --git a/src/include/gtm/gtm_seq.h b/src/include/gtm/gtm_seq.h
index 3cd218f3bf..b6fcdc61a9 100644
--- a/src/include/gtm/gtm_seq.h
+++ b/src/include/gtm/gtm_seq.h
@@ -87,8 +87,8 @@ void ProcessSequenceAlterCommand(Port *myport, StringInfo message, bool is_backu
 
 void ProcessSequenceListCommand(Port *myport, StringInfo message);
 
-void GTM_SaveSeqInfo(int ctlfd);
-void GTM_RestoreSeqInfo(int ctlfd);
+void GTM_SaveSeqInfo(FILE *ctlf);
+void GTM_RestoreSeqInfo(FILE *ctlf);
 int GTM_SeqRestore(GTM_SequenceKey seqkey,
 			   GTM_Sequence increment_by,
 			   GTM_Sequence minval,
diff --git a/src/include/gtm/gtm_txn.h b/src/include/gtm/gtm_txn.h
index 0089064cb0..2b29b68735 100644
--- a/src/include/gtm/gtm_txn.h
+++ b/src/include/gtm/gtm_txn.h
@@ -247,8 +247,8 @@ void ProcessBeginTransactionGetGXIDCommandMulti(Port *myport, StringInfo message
 void ProcessCommitTransactionCommandMulti(Port *myport, StringInfo message, bool is_backup);
 void ProcessRollbackTransactionCommandMulti(Port *myport, StringInfo message, bool is_backup) ;
 
-void GTM_SaveTxnInfo(int ctlfd);
-void GTM_RestoreTxnInfo(int ctlfd, GlobalTransactionId next_gxid);
+void GTM_SaveTxnInfo(FILE *ctlf);
+void GTM_RestoreTxnInfo(FILE *ctlf, GlobalTransactionId next_gxid);
 void GTM_BkupBeginTransaction(char *coord_name,
 							  GTM_TransactionHandle txn,
 							  GTM_IsolationLevel isolevel,