Simplify pg_upgrade's handling when returning directory listings.

Backpatch to 9.2.

contrib/pg_upgrade/file.c

@@ -225,23 +225,21 @@ copy_file(const char *srcfile, const char *dstfile, bool force)
  * load_directory()
  *
  * Read all the file names in the specified directory, and return them as
- * an array of "struct dirent" pointers.  The array address is returned in
+ * an array of "char *" pointers.  The array address is returned in
  * *namelist, and the function result is the count of file names.
  *
- * To free the result data, free each namelist array member, then free the
+ * To free the result data, free each (char *) array member, then free the
  * namelist array itself.
  */
 int
-load_directory(const char *dirname, struct dirent *** namelist)
+load_directory(const char *dirname, char ***namelist)
 {
 	DIR		   *dirdesc;
 	struct dirent *direntry;
 	int			count = 0;
-	int			allocsize = 64;
-	size_t		entrysize;
+	int			allocsize = 64;		/* initial array size */
 
-	*namelist = (struct dirent **)
-		pg_malloc(allocsize * sizeof(struct dirent *));
+	*namelist = (char **) pg_malloc(allocsize * sizeof(char *));
 
 	if ((dirdesc = opendir(dirname)) == NULL)
 		pg_log(PG_FATAL, "could not open directory \"%s\": %s\n",
@@ -252,18 +250,11 @@ load_directory(const char *dirname, struct dirent *** namelist)
 		if (count >= allocsize)
 		{
 			allocsize *= 2;
-			*namelist = (struct dirent **)
-				pg_realloc(*namelist, allocsize * sizeof(struct dirent *));
+			*namelist = (char **)
+						pg_realloc(*namelist, allocsize * sizeof(char *));
 		}
 
-		entrysize = offsetof(struct dirent, d_name) +
-			strlen(direntry->d_name) + 1;
-
-		(*namelist)[count] = (struct dirent *) pg_malloc(entrysize);
-
-		memcpy((*namelist)[count], direntry, entrysize);
-
-		count++;
+		(*namelist)[count++] = pg_strdup(direntry->d_name);
 	}
 
 #ifdef WIN32

contrib/pg_upgrade/pg_upgrade.h

@@ -357,7 +357,7 @@ const char *setupPageConverter(pageCnvCtx **result);
 typedef void *pageCnvCtx;
 #endif
 
-int			load_directory(const char *dirname, struct dirent *** namelist);
+int			load_directory(const char *dirname, char ***namelist);
 const char *copyAndUpdateFile(pageCnvCtx *pageConverter, const char *src,
 				  const char *dst, bool force);
 const char *linkAndUpdateFile(pageCnvCtx *pageConverter, const char *src,

contrib/pg_upgrade/relfilenode.c

@@ -133,7 +133,7 @@ transfer_single_new_db(pageCnvCtx *pageConverter,
 {
 	char		old_dir[MAXPGPATH];
 	char		file_pattern[MAXPGPATH];
-	struct dirent **namelist = NULL;
+	char		**namelist = NULL;
 	int			numFiles = 0;
 	int			mapnum;
 	int			fileno;
@@ -192,21 +192,21 @@ transfer_single_new_db(pageCnvCtx *pageConverter,
 
 			for (fileno = 0; fileno < numFiles; fileno++)
 			{
-				char	   *vm_offset = strstr(namelist[fileno]->d_name, "_vm");
+				char	   *vm_offset = strstr(namelist[fileno], "_vm");
 				bool		is_vm_file = false;
 
 				/* Is a visibility map file? (name ends with _vm) */
 				if (vm_offset && strlen(vm_offset) == strlen("_vm"))
 					is_vm_file = true;
 
-				if (strncmp(namelist[fileno]->d_name, file_pattern,
+				if (strncmp(namelist[fileno], file_pattern,
 							strlen(file_pattern)) == 0 &&
 					(!is_vm_file || !vm_crashsafe_change))
 				{
 					snprintf(old_file, sizeof(old_file), "%s/%s", maps[mapnum].old_dir,
-							 namelist[fileno]->d_name);
+							 namelist[fileno]);
 					snprintf(new_file, sizeof(new_file), "%s/%u%s", maps[mapnum].new_dir,
-							 maps[mapnum].new_relfilenode, strchr(namelist[fileno]->d_name, '_'));
+							 maps[mapnum].new_relfilenode, strchr(namelist[fileno], '_'));
 
 					unlink(new_file);
 					transfer_relfile(pageConverter, old_file, new_file,
@@ -227,13 +227,13 @@ transfer_single_new_db(pageCnvCtx *pageConverter,
 
 		for (fileno = 0; fileno < numFiles; fileno++)
 		{
-			if (strncmp(namelist[fileno]->d_name, file_pattern,
+			if (strncmp(namelist[fileno], file_pattern,
 						strlen(file_pattern)) == 0)
 			{
 				snprintf(old_file, sizeof(old_file), "%s/%s", maps[mapnum].old_dir,
-						 namelist[fileno]->d_name);
+						 namelist[fileno]);
 				snprintf(new_file, sizeof(new_file), "%s/%u%s", maps[mapnum].new_dir,
-						 maps[mapnum].new_relfilenode, strchr(namelist[fileno]->d_name, '.'));
+						 maps[mapnum].new_relfilenode, strchr(namelist[fileno], '.'));
 
 				unlink(new_file);
 				transfer_relfile(pageConverter, old_file, new_file,