Refactor dir/file permissions

Consolidate directory and file create permissions for tools which work
with the PG data directory by adding a new module (common/file_perm.c)
that contains variables (pg_file_create_mode, pg_dir_create_mode) and
constants to initialize them (0600 for files and 0700 for directories).

Convert mkdir() calls in the backend to MakePGDirectory() if the
original call used default permissions (always the case for regular PG
directories).

Add tests to make sure permissions in PGDATA are set correctly by the
tools which modify the PG data directory.

Authors: David Steele <david@pgmasters.net>,
         Adam Brightwell <adam.brightwell@crunchydata.com>
Reviewed-By: Michael Paquier, with discussion amongst many others.
Discussion: https://postgr.es/m/ad346fe6-b23e-59f1-ecb7-0e08390ad629%40pgmasters.net

1 files changed, 4 insertions, 2 deletions

diff --git a/src/bin/pg_basebackup/walmethods.c b/src/bin/pg_basebackup/walmethods.c
index b4558a01847..267a40debbf 100644
--- a/src/bin/pg_basebackup/walmethods.c
+++ b/src/bin/pg_basebackup/walmethods.c
@@ -22,6 +22,7 @@
 #endif
 
 #include "pgtar.h"
+#include "common/file_perm.h"
 #include "common/file_utils.h"
 
 #include "receivelog.h"
@@ -89,7 +90,7 @@ dir_open_for_write(const char *pathname, const char *temp_suffix, size_t pad_to_
 	 * does not do any system calls to fsync() to make changes permanent on
 	 * disk.
 	 */
-	fd = open(tmppath, O_WRONLY | O_CREAT | PG_BINARY, S_IRUSR | S_IWUSR);
+	fd = open(tmppath, O_WRONLY | O_CREAT | PG_BINARY, pg_file_create_mode);
 	if (fd < 0)
 		return NULL;
 
@@ -534,7 +535,8 @@ tar_open_for_write(const char *pathname, const char *temp_suffix, size_t pad_to_
 		 * We open the tar file only when we first try to write to it.
 		 */
 		tar_data->fd = open(tar_data->tarfilename,
-							O_WRONLY | O_CREAT | PG_BINARY, S_IRUSR | S_IWUSR);
+							O_WRONLY | O_CREAT | PG_BINARY,
+							pg_file_create_mode);
 		if (tar_data->fd < 0)
 			return NULL;