Further cleanup for directory creation on pg_dump/pg_dumpall

Instead of two separate (and different) implementations, refactor to use
a single common routine.

Along the way, remove use of a hardcoded file permissions constant in
favor of the common project setting for directory creation.

Author: Mahendra Singh Thalor <mahi6run@gmail.com>

Discussion: https://postgr.es/m/CAKYtNApihL8X1h7XO-zOjznc8Ca66Aevgvhc9zOTh6DBh2iaeA@mail.gmail.com

src/bin/pg_dump/dumputils.c

@@ -16,6 +16,8 @@
 
 #include <ctype.h>
 
+#include "common/file_perm.h"
+#include "common/logging.h"
 #include "dumputils.h"
 #include "fe_utils/string_utils.h"
 
@@ -884,3 +886,37 @@ makeAlterConfigCommand(PGconn *conn, const char *configitem,
 
 	pg_free(mine);
 }
+
+/*
+ * create_or_open_dir
+ *
+ * This will create a new directory with the given dirname. If there is
+ * already an empty directory with that name, then use it.
+ */
+void
+create_or_open_dir(const char *dirname)
+{
+	int			ret;
+
+	switch ((ret = pg_check_dir(dirname)))
+	{
+		case -1:
+			/* opendir failed but not with ENOENT */
+			pg_fatal("could not open directory \"%s\": %m", dirname);
+			break;
+		case 0:
+			/* directory does not exist */
+			if (mkdir(dirname, pg_dir_create_mode) < 0)
+				pg_fatal("could not create directory \"%s\": %m", dirname);
+			break;
+		case 1:
+			/* exists and is empty, fix perms */
+			if (chmod(dirname, pg_dir_create_mode) != 0)
+				pg_fatal("could not change permissions of directory \"%s\": %m",
+						 dirname);
+			break;
+		default:
+			/* exists and is not empty */
+			pg_fatal("directory \"%s\" is not empty", dirname);
+	}
+}

src/bin/pg_dump/dumputils.h

@@ -62,5 +62,6 @@ extern void makeAlterConfigCommand(PGconn *conn, const char *configitem,
 								   const char *type, const char *name,
 								   const char *type2, const char *name2,
 								   PQExpBuffer buf);
+extern void create_or_open_dir(const char *dirname);
 
 #endif							/* DUMPUTILS_H */

src/bin/pg_dump/pg_backup_directory.c

@@ -41,6 +41,7 @@
 
 #include "common/file_utils.h"
 #include "compress_io.h"
+#include "dumputils.h"
 #include "parallel.h"
 #include "pg_backup_utils.h"
 
@@ -156,41 +157,8 @@ InitArchiveFmt_Directory(ArchiveHandle *AH)
 
 	if (AH->mode == archModeWrite)
 	{
-		struct stat st;
-		bool		is_empty = false;
-
 		/* we accept an empty existing directory */
-		if (stat(ctx->directory, &st) == 0 && S_ISDIR(st.st_mode))
-		{
-			DIR		   *dir = opendir(ctx->directory);
-
-			if (dir)
-			{
-				struct dirent *d;
-
-				is_empty = true;
-				while (errno = 0, (d = readdir(dir)))
-				{
-					if (strcmp(d->d_name, ".") != 0 && strcmp(d->d_name, "..") != 0)
-					{
-						is_empty = false;
-						break;
-					}
-				}
-
-				if (errno)
-					pg_fatal("could not read directory \"%s\": %m",
-							 ctx->directory);
-
-				if (closedir(dir))
-					pg_fatal("could not close directory \"%s\": %m",
-							 ctx->directory);
-			}
-		}
-
-		if (!is_empty && mkdir(ctx->directory, 0700) < 0)
-			pg_fatal("could not create directory \"%s\": %m",
-					 ctx->directory);
+		create_or_open_dir(ctx->directory);
 	}
 	else
 	{							/* Read Mode */

src/bin/pg_dump/pg_dumpall.c

@@ -15,7 +15,6 @@
 
 #include "postgres_fe.h"
 
-#include <sys/stat.h>
 #include <time.h>
 #include <unistd.h>
 
@@ -78,7 +77,6 @@ static void executeCommand(PGconn *conn, const char *query);
 static void expand_dbname_patterns(PGconn *conn, SimpleStringList *patterns,
 								   SimpleStringList *names);
 static void read_dumpall_filters(const char *filename, SimpleStringList *pattern);
-static void create_or_open_dir(const char *dirname);
 static ArchiveFormat parseDumpFormat(const char *format);
 
 static char pg_dump_bin[MAXPGPATH];
@@ -1655,7 +1653,7 @@ dumpDatabases(PGconn *conn, ArchiveFormat archDumpFormat)
 		snprintf(db_subdir, MAXPGPATH, "%s/databases", filename);
 
 		/* Create a subdirectory with 'databases' name under main directory. */
-		if (mkdir(db_subdir, 0755) != 0)
+		if (mkdir(db_subdir, pg_dir_create_mode) != 0)
 			pg_fatal("could not create subdirectory \"%s\": %m", db_subdir);
 
 		snprintf(map_file_path, MAXPGPATH, "%s/map.dat", filename);
@@ -1946,41 +1944,6 @@ read_dumpall_filters(const char *filename, SimpleStringList *pattern)
 	filter_free(&fstate);
 }
 
-/*
- * create_or_open_dir
- *
- * This will create a new directory with the given dirname. If there is
- * already an empty directory with that name, then use it.
- */
-static void
-create_or_open_dir(const char *dirname)
-{
-	int			ret;
-
-	switch ((ret = pg_check_dir(dirname)))
-	{
-		case -1:
-			/* opendir failed but not with ENOENT */
-			pg_fatal("could not open directory \"%s\": %m", dirname);
-			break;
-		case 0:
-			/* directory does not exist */
-			if (mkdir(dirname, pg_dir_create_mode) < 0)
-				pg_fatal("could not create directory \"%s\": %m", dirname);
-			break;
-		case 1:
-			/* exists and is empty, fix perms */
-			if (chmod(dirname, pg_dir_create_mode) != 0)
-				pg_fatal("could not change permissions of directory \"%s\": %m",
-						 dirname);
-
-			break;
-		default:
-			/* exists and is not empty */
-			pg_fatal("directory \"%s\" is not empty", dirname);
-	}
-}
-
 /*
  * parseDumpFormat
  *