os: return nil slice when ReadDir is used with a file on file_windows

ReadDir should return (nil, ENOTDIR) when the path points to a file
instead of a directory. That's the behavior on Unix systems, and it also
used to be the behavior on Windows. However, Windows currently returns
([]DirEntry{}, ENOTDIR).

We should change the implementation to match the expected behavior.

Fixed #75157

Change-Id: I3a3ddb71b5cd6e51dbca435a1585f01116844d4a
Reviewed-on: https://go-review.googlesource.com/c/go/+/699375
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Steven Hartland <stevenmhartland@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

diff --git a/src/internal/syscall/windows/at_windows.go b/src/internal/syscall/windows/at_windows.go
index 8b19a03e7e240cb36047bc1e6838fecb26e1d9e5..8dc3ac0e40fc6799967ff0974518449533875dd1 100644 (file)
--- a/src/internal/syscall/windows/at_windows.go
+++ b/src/internal/syscall/windows/at_windows.go
@@ -11,6 +11,11 @@ import (
        "unsafe"
 )
 
+// Openat flags supported by syscall.Open.
+const (
+       O_DIRECTORY = 0x04000 // target must be a directory
+)
+
 // Openat flags not supported by syscall.Open.
 //
 // These are invented values, use values in the 33-63 bit range
@@ -20,7 +25,6 @@ import (
 // the set of invented O_ values in syscall/types_windows.go
 // to avoid overlap.
 const (
-       O_DIRECTORY    = 0x100000000 // target must be a directory
        O_NOFOLLOW_ANY = 0x200000000 // disallow symlinks anywhere in the path
        O_OPEN_REPARSE = 0x400000000 // FILE_OPEN_REPARSE_POINT, used by Lstat
        O_WRITE_ATTRS  = 0x800000000 // FILE_WRITE_ATTRIBUTES, used by Chmod

diff --git a/src/os/file_windows.go b/src/os/file_windows.go
index 7e943287109a5f1defaf0ff86707f0f609d0be98..9f96aa8f89bb37b2203e42f6b58c31a443c98679 100644 (file)
--- a/src/os/file_windows.go
+++ b/src/os/file_windows.go
@@ -125,7 +125,7 @@ func openFileNolog(name string, flag int, perm FileMode) (*File, error) {
 }
 
 func openDirNolog(name string) (*File, error) {
-       return openFileNolog(name, O_RDONLY, 0)
+       return openFileNolog(name, O_RDONLY|windows.O_DIRECTORY, 0)
 }
 
 func (file *file) close() error {

diff --git a/src/os/read_test.go b/src/os/read_test.go
index 4659191d83a0c17245a3639cf4d84dfbdb7ef5ca..e5fd941d0fc1f67e1c6de5d6276e17eb0ef6de5c 100644 (file)
--- a/src/os/read_test.go
+++ b/src/os/read_test.go
@@ -6,9 +6,11 @@ package os_test
 
 import (
        "bytes"
+       "errors"
        . "os"
        "path/filepath"
        "runtime"
+       "syscall"
        "testing"
 )
 
@@ -103,11 +105,20 @@ func TestReadDir(t *testing.T) {
        t.Parallel()
 
        dirname := "rumpelstilzchen"
-       _, err := ReadDir(dirname)
-       if err == nil {
+       if _, err := ReadDir(dirname); err == nil {
                t.Fatalf("ReadDir %s: error expected, none found", dirname)
        }
 
+       filename := filepath.Join(t.TempDir(), "foo")
+       f, err := Create(filename)
+       if err != nil {
+               t.Fatal(err)
+       }
+       f.Close()
+       if list, err := ReadDir(filename); list != nil || !errors.Is(err, syscall.ENOTDIR) {
+               t.Fatalf("ReadDir %s: (nil, ENOTDIR) expected, got (%v, %v)", filename, list, err)
+       }
+
        dirname = "."
        list, err := ReadDir(dirname)
        if err != nil {

diff --git a/src/syscall/syscall_windows.go b/src/syscall/syscall_windows.go
index c1416b3731056b7736413453fa71ef847fbb38fb..6ee2e463ed3d6f3dd392b31daa656546985be037 100644 (file)
--- a/src/syscall/syscall_windows.go
+++ b/src/syscall/syscall_windows.go
@@ -443,6 +443,18 @@ func Open(name string, flag int, perm uint32) (fd Handle, err error) {
                }
                return h, err
        }
+       if flag&o_DIRECTORY != 0 {
+               // Check if the file is a directory, else return ENOTDIR.
+               var fi ByHandleFileInformation
+               if err := GetFileInformationByHandle(h, &fi); err != nil {
+                       CloseHandle(h)
+                       return InvalidHandle, err
+               }
+               if fi.FileAttributes&FILE_ATTRIBUTE_DIRECTORY == 0 {
+                       CloseHandle(h)
+                       return InvalidHandle, ENOTDIR
+               }
+       }
        // Ignore O_TRUNC if the file has just been created.
        if flag&O_TRUNC == O_TRUNC &&
                (createmode == OPEN_EXISTING || (createmode == OPEN_ALWAYS && err == ERROR_ALREADY_EXISTS)) {

diff --git a/src/syscall/types_windows.go b/src/syscall/types_windows.go
index dd21fc83294af76fe8c4d1466c150953c957811c..8578763284b8eb043c38d4c6406128aeac0286e7 100644 (file)
--- a/src/syscall/types_windows.go
+++ b/src/syscall/types_windows.go
@@ -47,8 +47,8 @@ const (
        O_APPEND       = 0x00400
        O_SYNC         = 0x01000
        O_ASYNC        = 0x02000
+       o_DIRECTORY    = 0x04000
        O_CLOEXEC      = 0x80000
-       o_DIRECTORY    = 0x100000000 // used by internal/syscall/windows
        o_NOFOLLOW_ANY = 0x200000000 // used by internal/syscall/windows
        o_OPEN_REPARSE = 0x400000000 // used by internal/syscall/windows
        o_WRITE_ATTRS  = 0x800000000 // used by internal/syscall/windows