Move SplitGUCList() to fe_utils

This is needed so that all versions of pg_upgrade that migrate logical
replication slots can parse the new output_plugin_libraries GUC.

Backpatch-through: 17
Security: CVE-2026-6471

src/backend/utils/adt/varlena.c

@@ -3731,7 +3731,7 @@ SplitDirectoriesString(char *rawstring, char separator,
  * However, it's not clear that having one function with a bunch of option
  * flags would be much better.
  *
- * XXX there is a version of this function in src/bin/pg_dump/dumputils.c.
+ * XXX there is a version of this function in src/fe_utils/string_utils.c.
  * Be sure to update that if you have to change this.
  *
  * Inputs:

src/bin/pg_dump/dumputils.c

@@ -737,115 +737,6 @@ variable_is_guc_list_quote(const char *name)
 		return false;
 }
 
-/*
- * SplitGUCList --- parse a string containing identifiers or file names
- *
- * This is used to split the value of a GUC_LIST_QUOTE GUC variable, without
- * presuming whether the elements will be taken as identifiers or file names.
- * See comparable code in src/backend/utils/adt/varlena.c.
- *
- * Inputs:
- *	rawstring: the input string; must be overwritable!	On return, it's
- *			   been modified to contain the separated identifiers.
- *	separator: the separator punctuation expected between identifiers
- *			   (typically '.' or ',').  Whitespace may also appear around
- *			   identifiers.
- * Outputs:
- *	namelist: receives a malloc'd, null-terminated array of pointers to
- *			  identifiers within rawstring.  Caller should free this
- *			  even on error return.
- *
- * Returns true if okay, false if there is a syntax error in the string.
- */
-bool
-SplitGUCList(char *rawstring, char separator,
-			 char ***namelist)
-{
-	char	   *nextp = rawstring;
-	bool		done = false;
-	char	  **nextptr;
-
-	/*
-	 * Since we disallow empty identifiers, this is a conservative
-	 * overestimate of the number of pointers we could need.  Allow one for
-	 * list terminator.
-	 */
-	*namelist = nextptr = (char **)
-		pg_malloc((strlen(rawstring) / 2 + 2) * sizeof(char *));
-	*nextptr = NULL;
-
-	while (isspace((unsigned char) *nextp))
-		nextp++;				/* skip leading whitespace */
-
-	if (*nextp == '\0')
-		return true;			/* allow empty string */
-
-	/* At the top of the loop, we are at start of a new identifier. */
-	do
-	{
-		char	   *curname;
-		char	   *endp;
-
-		if (*nextp == '"')
-		{
-			/* Quoted name --- collapse quote-quote pairs */
-			curname = nextp + 1;
-			for (;;)
-			{
-				endp = strchr(nextp + 1, '"');
-				if (endp == NULL)
-					return false;	/* mismatched quotes */
-				if (endp[1] != '"')
-					break;		/* found end of quoted name */
-				/* Collapse adjacent quotes into one quote, and look again */
-				memmove(endp, endp + 1, strlen(endp));
-				nextp = endp;
-			}
-			/* endp now points at the terminating quote */
-			nextp = endp + 1;
-		}
-		else
-		{
-			/* Unquoted name --- extends to separator or whitespace */
-			curname = nextp;
-			while (*nextp && *nextp != separator &&
-				   !isspace((unsigned char) *nextp))
-				nextp++;
-			endp = nextp;
-			if (curname == nextp)
-				return false;	/* empty unquoted name not allowed */
-		}
-
-		while (isspace((unsigned char) *nextp))
-			nextp++;			/* skip trailing whitespace */
-
-		if (*nextp == separator)
-		{
-			nextp++;
-			while (isspace((unsigned char) *nextp))
-				nextp++;		/* skip leading whitespace for next */
-			/* we expect another name, so done remains false */
-		}
-		else if (*nextp == '\0')
-			done = true;
-		else
-			return false;		/* invalid syntax */
-
-		/* Now safe to overwrite separator with a null */
-		*endp = '\0';
-
-		/*
-		 * Finished isolating current name --- add it to output array
-		 */
-		*nextptr++ = curname;
-
-		/* Loop back if we didn't reach end of string */
-	} while (!done);
-
-	*nextptr = NULL;
-	return true;
-}
-
 /*
  * Helper function for dumping "ALTER DATABASE/ROLE SET ..." commands.
  *

src/bin/pg_dump/dumputils.h

@@ -56,9 +56,6 @@ extern void emitShSecLabels(PGconn *conn, PGresult *res,
 
 extern bool variable_is_guc_list_quote(const char *name);
 
-extern bool SplitGUCList(char *rawstring, char separator,
-						 char ***namelist);
-
 extern void makeAlterConfigCommand(PGconn *conn, const char *configitem,
 								   const char *type, const char *name,
 								   const char *type2, const char *name2,

src/fe_utils/string_utils.c

@@ -805,6 +805,116 @@ appendPsqlMetaConnect(PQExpBuffer buf, const char *dbname)
 }
 
 
+/*
+ * SplitGUCList --- parse a string containing identifiers or file names
+ *
+ * This is used to split the value of a GUC_LIST_QUOTE GUC variable, without
+ * presuming whether the elements will be taken as identifiers or file names.
+ * See comparable code in src/backend/utils/adt/varlena.c.
+ *
+ * Inputs:
+ *	rawstring: the input string; must be overwritable!	On return, it's
+ *			   been modified to contain the separated identifiers.
+ *	separator: the separator punctuation expected between identifiers
+ *			   (typically '.' or ',').  Whitespace may also appear around
+ *			   identifiers.
+ * Outputs:
+ *	namelist: receives a malloc'd, null-terminated array of pointers to
+ *			  identifiers within rawstring.  Caller should free this
+ *			  even on error return.
+ *
+ * Returns true if okay, false if there is a syntax error in the string.
+ */
+bool
+SplitGUCList(char *rawstring, char separator,
+			 char ***namelist)
+{
+	char	   *nextp = rawstring;
+	bool		done = false;
+	char	  **nextptr;
+
+	/*
+	 * Since we disallow empty identifiers, this is a conservative
+	 * overestimate of the number of pointers we could need.  Allow one for
+	 * list terminator.
+	 */
+	*namelist = nextptr =
+		pg_malloc_array(char *, (strlen(rawstring) / 2 + 2));
+	*nextptr = NULL;
+
+	while (isspace((unsigned char) *nextp))
+		nextp++;				/* skip leading whitespace */
+
+	if (*nextp == '\0')
+		return true;			/* allow empty string */
+
+	/* At the top of the loop, we are at start of a new identifier. */
+	do
+	{
+		char	   *curname;
+		char	   *endp;
+
+		if (*nextp == '"')
+		{
+			/* Quoted name --- collapse quote-quote pairs */
+			curname = nextp + 1;
+			for (;;)
+			{
+				endp = strchr(nextp + 1, '"');
+				if (endp == NULL)
+					return false;	/* mismatched quotes */
+				if (endp[1] != '"')
+					break;		/* found end of quoted name */
+				/* Collapse adjacent quotes into one quote, and look again */
+				memmove(endp, endp + 1, strlen(endp));
+				nextp = endp;
+			}
+			/* endp now points at the terminating quote */
+			nextp = endp + 1;
+		}
+		else
+		{
+			/* Unquoted name --- extends to separator or whitespace */
+			curname = nextp;
+			while (*nextp && *nextp != separator &&
+				   !isspace((unsigned char) *nextp))
+				nextp++;
+			endp = nextp;
+			if (curname == nextp)
+				return false;	/* empty unquoted name not allowed */
+		}
+
+		while (isspace((unsigned char) *nextp))
+			nextp++;			/* skip trailing whitespace */
+
+		if (*nextp == separator)
+		{
+			nextp++;
+			while (isspace((unsigned char) *nextp))
+				nextp++;		/* skip leading whitespace for next */
+			/* we expect another name, so done remains false */
+		}
+		else if (*nextp == '\0')
+			done = true;
+		else
+			return false;		/* invalid syntax */
+
+		/* Now safe to overwrite separator with a null */
+		*endp = '\0';
+
+		/*
+		 * Finished isolating current name --- add it to output array
+		 */
+		*nextptr++ = curname;
+
+		/* Loop back if we didn't reach end of string */
+	} while (!done);
+
+	*nextptr = NULL;
+	return true;
+}
+
+
 /*
  * Deconstruct the text representation of a 1-dimensional Postgres array
  * into individual items.

src/include/fe_utils/string_utils.h

@@ -48,6 +48,8 @@ extern bool appendShellStringNoError(PQExpBuffer buf, const char *str);
 extern void appendConnStrVal(PQExpBuffer buf, const char *str);
 extern void appendPsqlMetaConnect(PQExpBuffer buf, const char *dbname);
 
+extern bool SplitGUCList(char *rawstring, char separator, char ***namelist);
+
 extern bool parsePGArray(const char *atext, char ***itemarray, int *nitems);
 extern void appendPGArray(PQExpBuffer buffer, const char *value);