Fix a number of places that were making file-type tests infelicitously.

The places that did, eg,
	(statbuf.st_mode & S_IFMT) == S_IFDIR
were correct, but there is no good reason not to use S_ISDIR() instead,
especially when that's what the other 90% of our code does.  The places
that did, eg,
	(statbuf.st_mode & S_IFDIR)
were flat out *wrong* and would fail in various platform-specific ways,
eg a symlink could be mistaken for a regular file on most Unixen.

The actual impact of this is probably small, since the problem cases
seem to always involve symlinks or sockets, which are unlikely to be
found in the directories that PG code might be scanning.  But it's
clearly trouble waiting to happen, so patch all the way back anyway.
(There seem to be no occurrences of the mistake in 7.4.)

5 files changed, 9 insertions, 9 deletions

diff --git a/src/backend/utils/adt/dbsize.c b/src/backend/utils/adt/dbsize.c
index d648d84303..a7ba411760 100644
--- a/src/backend/utils/adt/dbsize.c
+++ b/src/backend/utils/adt/dbsize.c
@@ -209,7 +209,7 @@ calculate_tablespace_size(Oid tblspcOid)
 						 errmsg("could not stat file \"%s\": %m", pathname)));
 		}
 
-		if (fst.st_mode & S_IFDIR)
+		if (S_ISDIR(fst.st_mode))
 			totalsize += db_dir_size(pathname);
 
 		totalsize += fst.st_size;
diff --git a/src/backend/utils/adt/genfile.c b/src/backend/utils/adt/genfile.c
index 7835a632ba..211e17a27d 100644
--- a/src/backend/utils/adt/genfile.c
+++ b/src/backend/utils/adt/genfile.c
@@ -198,7 +198,7 @@ pg_stat_file(PG_FUNCTION_ARGS)
 	isnull[3] = true;
 	values[4] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));
 #endif
-	values[5] = BoolGetDatum(fst.st_mode & S_IFDIR);
+	values[5] = BoolGetDatum(S_ISDIR(fst.st_mode));
 
 	tuple = heap_form_tuple(tupdesc, values, isnull);
 
diff --git a/src/port/copydir.c b/src/port/copydir.c
index 73b227bf57..8d8c24f5bf 100644
--- a/src/port/copydir.c
+++ b/src/port/copydir.c
@@ -80,13 +80,13 @@ copydir(char *fromdir, char *todir, bool recurse)
 					(errcode_for_file_access(),
 					 errmsg("could not stat file \"%s\": %m", fromfile)));
 
-		if (fst.st_mode & S_IFDIR)
+		if (S_ISDIR(fst.st_mode))
 		{
 			/* recurse to handle subdirectories */
 			if (recurse)
 				copydir(fromfile, tofile, true);
 		}
-		else if (fst.st_mode & S_IFREG)
+		else if (S_ISREG(fst.st_mode))
 			copy_file(fromfile, tofile);
 	}
 
diff --git a/src/port/exec.c b/src/port/exec.c
index fd8a2fba98..3210686dcb 100644
--- a/src/port/exec.c
+++ b/src/port/exec.c
@@ -80,8 +80,8 @@ validate_exec(const char *path)
 #else
 	char		path_exe[MAXPGPATH + sizeof(".exe") - 1];
 #endif
-	int			is_r = 0;
-	int			is_x = 0;
+	int			is_r;
+	int			is_x;
 
 #ifdef WIN32
 	/* Win32 requires a .exe suffix for stat() */
@@ -103,7 +103,7 @@ validate_exec(const char *path)
 	if (stat(path, &buf) < 0)
 		return -1;
 
-	if ((buf.st_mode & S_IFMT) != S_IFREG)
+	if (!S_ISREG(buf.st_mode))
 		return -1;
 
 	/*
@@ -331,7 +331,7 @@ resolve_symlinks(char *path)
 			fname = path;
 
 		if (lstat(fname, &buf) < 0 ||
-			(buf.st_mode & S_IFMT) != S_IFLNK)
+			!S_ISLNK(buf.st_mode))
 			break;
 
 		rllen = readlink(fname, link_buf, sizeof(link_buf));
diff --git a/src/test/regress/pg_regress.c b/src/test/regress/pg_regress.c
index 3264c7e867..b028e343d4 100644
--- a/src/test/regress/pg_regress.c
+++ b/src/test/regress/pg_regress.c
@@ -1102,7 +1102,7 @@ directory_exists(const char *dir)
 
 	if (stat(dir, &st) != 0)
 		return false;
-	if (st.st_mode & S_IFDIR)
+	if (S_ISDIR(st.st_mode))
 		return true;
 	return false;
 }