Fix history file parsing. (#995)

The previous coding used a statically allocated array of pointers to
newlines in that file, limiting our parsing abilities to files of 1024 lines
maximum. Apparently that's not a good limit, so use dynamically allocated
memory instead.

Fixes #991.

src/bin/pg_autoctl/pgsql.c

@@ -3094,18 +3094,18 @@ bool
 parseTimeLineHistory(const char *filename, const char *content,
 					 IdentifySystem *system)
 {
-	char *historyLines[BUFSIZE] = { 0 };
-	int lineCount = splitLines((char *) content, historyLines, BUFSIZE);
+	int lineCount = countLines((char *) content);
+	char **historyLines = (char **) calloc(lineCount, sizeof(char *));
 	int lineNumber = 0;
 
-	if (lineCount >= PG_AUTOCTL_MAX_TIMELINES)
+	if (historyLines == NULL)
 	{
-		log_error("history file \"%s\" contains %d lines, "
-				  "pg_autoctl only supports up to %d lines",
-				  filename, lineCount, PG_AUTOCTL_MAX_TIMELINES - 1);
+		log_error(ALLOCATION_FAILED_ERROR);
 		return false;
 	}
 
+	splitLines((char *) content, historyLines, lineCount);
+
 	uint64_t prevend = InvalidXLogRecPtr;
 
 	system->timelines.count = 0;
@@ -3141,6 +3141,7 @@ parseTimeLineHistory(const char *filename, const char *content,
 		{
 			log_error("Failed to parse history file line %d: \"%s\"",
 					  lineNumber, ptr);
+			free(historyLines);
 			return false;
 		}
 
@@ -3149,6 +3150,7 @@ parseTimeLineHistory(const char *filename, const char *content,
 		if (!stringToUInt(historyLines[lineNumber], &(entry->tli)))
 		{
 			log_error("Failed to parse history timeline \"%s\"", tabptr);
+			free(historyLines);
 			return false;
 		}
 
@@ -3167,6 +3169,7 @@ parseTimeLineHistory(const char *filename, const char *content,
 		{
 			log_error("Failed to parse history timeline %d LSN \"%s\"",
 					  entry->tli, lsn);
+			free(historyLines);
 			return false;
 		}
 
@@ -3184,6 +3187,8 @@ parseTimeLineHistory(const char *filename, const char *content,
 		entry = &(system->timelines.history[++system->timelines.count]);
 	}
 
+	free(historyLines);
+
 	/*
 	 * Create one more entry for the "tip" of the timeline, which has no entry
 	 * in the history file.

src/bin/pg_autoctl/string_utils.c

@@ -495,6 +495,43 @@ IntervalToString(double seconds, char *buffer, size_t size)
 }
 
 
+/*
+ * countLines returns how many line separators (\n) are found in the given
+ * string.
+ */
+int
+countLines(char *buffer)
+{
+	int lineNumber = 0;
+	char *currentLine = buffer;
+
+	if (buffer == NULL)
+	{
+		return 0;
+	}
+
+	do {
+		char *newLinePtr = strchr(currentLine, '\n');
+
+		if (newLinePtr == NULL)
+		{
+			if (strlen(currentLine) > 0)
+			{
+				++lineNumber;
+			}
+			currentLine = NULL;
+		}
+		else
+		{
+			++lineNumber;
+			currentLine = ++newLinePtr;
+		}
+	} while (currentLine != NULL && *currentLine != '\0');
+
+	return lineNumber;
+}
+
+
 /*
  * splitLines prepares a multi-line error message in a way that calling code
  * can loop around one line at a time and call log_error() or log_warn() on

src/bin/pg_autoctl/string_utils.h

@@ -37,6 +37,7 @@ bool stringToUInt32(const char *str, uint32_t *number);
 bool stringToDouble(const char *str, double *number);
 bool IntervalToString(double seconds, char *buffer, size_t size);
 
+int countLines(char *buffer);
 int splitLines(char *errorMessage, char **linesArray, int size);
 void processBufferCallback(const char *buffer, bool error);