Add test for dirent d_type

co-authored by @sjshuck

Author: hasufell

configure.ac

@@ -65,6 +65,66 @@ FP_CHECK_CONST([DT_WHT], [
 #include <dirent.h>
 #endif], [-9])
 
+AC_LANG(C)
+AC_MSG_CHECKING(whether kernel returns a useful d_type)
+AC_RUN_IFELSE(
+  [AC_LANG_SOURCE([[
+#if HAVE_STRUCT_DIRENT_D_TYPE
+#include <dirent.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+
+void check_error(const char *msg) {
+    if (errno) {
+        perror(msg);
+        exit(1);
+    }
+}
+
+int main() {
+    DIR *dir = opendir(".");
+    check_error("opendir");
+
+    struct dirent *de = NULL;
+
+    do {
+        de = readdir(dir);
+        check_error("readdir");
+    } while (de && strcmp(de->d_name, ".") != 0);
+    // We found the . dir or encountered end of dir stream
+
+    int status = 0;
+
+    if (!de) {
+        status = 1;
+    } else if (de->d_type == DT_DIR) {
+    } else if (de->d_type == DT_UNKNOWN) {
+        // Signal that we should skip test for non-zero d_type
+        status = 2;
+    } else {
+        status = 1;
+    }
+
+    closedir(dir);
+    check_error("closedir");
+
+    exit(status);
+}
+#else
+int main() { exit(2); }
+#endif
+]])],
+  [AC_MSG_RESULT(yes)],
+  [if test $? -eq 1 ; then
+     AC_MSG_FAILURE(Unexpected failure when testing for kernels d_type)
+   else
+     AC_MSG_RESULT(no (skipping DirEnt test))
+	 AC_DEFINE([NO_DTIR_TEST], [1], [Define to 1 if we want to stkip DirEnt test.])
+   fi])
+
 AC_CHECK_FUNCS([getgrgid_r getgrnam_r getpwnam_r getpwuid_r getpwnam getpwuid])
 AC_CHECK_FUNCS([getpwent getgrent])
 AC_CHECK_FUNCS([lchown setenv sysconf unsetenv clearenv])

tests/DirEnt.hsc

@@ -0,0 +1,38 @@
+{-# LANGUAGE LambdaCase #-}
+
+#include "HsUnixConfig.h"
+
+module Main (main) where
+#if defined(NO_DTIR_TEST)
+main :: IO ()
+main = do
+    putStrLn "Skipping DirEnt test, since kernel seems to always return DT_UNKNOWN"
+#else
+
+import Control.Exception                (bracket, finally)
+import Foreign.C.String                 (peekCString)
+import System.Exit
+import System.Posix.Directory
+import System.Posix.Directory.Internals
+
+peekDirEnt :: DirEnt -> IO (String, DirType)
+peekDirEnt dirEnt = do
+    dName <- dirEntName dirEnt >>= peekCString
+    dType <- dirEntType dirEnt
+    return (dName, dType)
+
+testDirTypeOfDot :: DirStream -> IO ()
+testDirTypeOfDot dirStream = go where
+    go = readDirStreamWith peekDirEnt dirStream >>= \case
+        Just (".", DirectoryType) -> do
+            putStrLn "Got DirectoryType for . dir"
+            exitSuccess
+        Just (".", dType) -> die $ "Got " ++ show dType ++ " for . dir!"
+        Just _ -> go
+        Nothing -> die "Read cwd in Haskell and didn't find . dir!"
+
+main :: IO ()
+main = do
+    putStrLn "Running Haskell test of dirEntType"
+    bracket (openDirStream ".") closeDirStream testDirTypeOfDot
+#endif

unix.cabal

@@ -382,3 +382,12 @@ test-suite T13660
     else
       build-depends: filepath >= 1.4.100.0 && < 1.5.0.0
     ghc-options: -Wall
+
+test-suite DirEnt
+    hs-source-dirs: tests
+    main-is: DirEnt.hs
+    type: exitcode-stdio-1.0
+    default-language: Haskell2010
+    build-depends: base, unix
+    ghc-options: -Wall
+