1 files changed, 91 insertions, 0 deletions
diff --git a/src/common/file_perm.c b/src/common/file_perm.c
new file mode 100644
index 0000000..ab85765
--- /dev/null
+++ b/src/common/file_perm.c
@@ -0,0 +1,91 @@
+/*-------------------------------------------------------------------------
+ *
+ * File and directory permission routines
+ *
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/common/file_perm.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "c.h"
+
+#include "common/file_perm.h"
+
+/* Modes for creating directories and files in the data directory */
+int			pg_dir_create_mode = PG_DIR_MODE_OWNER;
+int			pg_file_create_mode = PG_FILE_MODE_OWNER;
+
+/*
+ * Mode mask to pass to umask().  This is more of a preventative measure since
+ * all file/directory creates should be performed using the create modes above.
+ */
+int			pg_mode_mask = PG_MODE_MASK_OWNER;
+
+/*
+ * Set create modes and mask to use when writing to PGDATA based on the data
+ * directory mode passed.  If group read/execute are present in the mode, then
+ * create modes and mask will be relaxed to allow group read/execute on all
+ * newly created files and directories.
+ */
+void
+SetDataDirectoryCreatePerm(int dataDirMode)
+{
+	/* If the data directory mode has group access */
+	if ((PG_DIR_MODE_GROUP & dataDirMode) == PG_DIR_MODE_GROUP)
+	{
+		pg_dir_create_mode = PG_DIR_MODE_GROUP;
+		pg_file_create_mode = PG_FILE_MODE_GROUP;
+		pg_mode_mask = PG_MODE_MASK_GROUP;
+	}
+	/* Else use default permissions */
+	else
+	{
+		pg_dir_create_mode = PG_DIR_MODE_OWNER;
+		pg_file_create_mode = PG_FILE_MODE_OWNER;
+		pg_mode_mask = PG_MODE_MASK_OWNER;
+	}
+}
+
+#ifdef FRONTEND
+
+/*
+ * Get the create modes and mask to use when writing to PGDATA by examining the
+ * mode of the PGDATA directory and calling SetDataDirectoryCreatePerm().
+ *
+ * Errors are not handled here and should be reported by the application when
+ * false is returned.
+ *
+ * Suppress when on Windows, because there may not be proper support for Unix-y
+ * file permissions.
+ */
+bool
+GetDataDirectoryCreatePerm(const char *dataDir)
+{
+#if !defined(WIN32) && !defined(__CYGWIN__)
+	struct stat statBuf;
+
+	/*
+	 * If an error occurs getting the mode then return false.  The caller is
+	 * responsible for generating an error, if appropriate, indicating that we
+	 * were unable to access the data directory.
+	 */
+	if (stat(dataDir, &statBuf) == -1)
+		return false;
+
+	/* Set permissions */
+	SetDataDirectoryCreatePerm(statBuf.st_mode);
+	return true;
+#else							/* !defined(WIN32) && !defined(__CYGWIN__) */
+	/*
+	 * On Windows, we don't have anything to do here since they don't have
+	 * Unix-y permissions.
+	 */
+	return true;
+#endif
+}
+
+
+#endif							/* FRONTEND */