syscall,os: move flags validation from os.OpenFile to syscall.Open

syscall.Open is the functions that maps Unix/Go flags into Windows
concepts. Part of the flag validation logic was still implemented
in os.OpenFile, move it to syscall.Open for consistency.

A nice side effect is that we don't have to translate the file name
twice in case of an access denied error.

Change-Id: I32c647a9a2a066277c78f53bacb45fb3036f6353
Reviewed-on: https://go-review.googlesource.com/c/go/+/619275
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>

diff --git a/src/os/file_windows.go b/src/os/file_windows.go
index cf652ca1bb3f17dbdda543814de451dec8901337..f8a6c09bb5c45c3a66135a1aba4ccd60352fbadd 100644 (file)
--- a/src/os/file_windows.go
+++ b/src/os/file_windows.go
@@ -103,20 +103,9 @@ func openFileNolog(name string, flag int, perm FileMode) (*File, error) {
                return nil, &PathError{Op: "open", Path: name, Err: syscall.ENOENT}
        }
        path := fixLongPath(name)
-       r, e := syscall.Open(path, flag|syscall.O_CLOEXEC, syscallMode(perm))
-       if e != nil {
-               // We should return EISDIR when we are trying to open a directory with write access.
-               if e == syscall.ERROR_ACCESS_DENIED && (flag&O_WRONLY != 0 || flag&O_RDWR != 0) {
-                       pathp, e1 := syscall.UTF16PtrFromString(path)
-                       if e1 == nil {
-                               var fa syscall.Win32FileAttributeData
-                               e1 = syscall.GetFileAttributesEx(pathp, syscall.GetFileExInfoStandard, (*byte)(unsafe.Pointer(&fa)))
-                               if e1 == nil && fa.FileAttributes&syscall.FILE_ATTRIBUTE_DIRECTORY != 0 {
-                                       e = syscall.EISDIR
-                               }
-                       }
-               }
-               return nil, &PathError{Op: "open", Path: name, Err: e}
+       r, err := syscall.Open(path, flag|syscall.O_CLOEXEC, syscallMode(perm))
+       if err != nil {
+               return nil, &PathError{Op: "open", Path: name, Err: err}
        }
        return newFile(r, name, "file"), nil
 }

diff --git a/src/syscall/syscall_windows.go b/src/syscall/syscall_windows.go
index 08120b3f2a62393f6d345b6aed0969e2003c61f9..6f6f9e4bdecd1249c4349ef73f2b9b656a66d906 100644 (file)
--- a/src/syscall/syscall_windows.go
+++ b/src/syscall/syscall_windows.go
@@ -398,6 +398,13 @@ func Open(path string, mode int, perm uint32) (fd Handle, err error) {
        }
        h, err := CreateFile(pathp, access, sharemode, sa, createmode, attrs, 0)
        if err != nil {
+               if err == ERROR_ACCESS_DENIED && (mode&O_WRONLY != 0 || mode&O_RDWR != 0) {
+                       // We should return EISDIR when we are trying to open a directory with write access.
+                       fa, e1 := GetFileAttributes(pathp)
+                       if e1 == nil && fa&FILE_ATTRIBUTE_DIRECTORY != 0 {
+                               err = EISDIR
+                       }
+               }
                return InvalidHandle, err
        }
        if mode&O_TRUNC == O_TRUNC {

diff --git a/src/syscall/syscall_windows_test.go b/src/syscall/syscall_windows_test.go
index c26c8eac10773e21ce8843f8bd22dee5e18936f6..9773cfbfa22631df70be7f91da80247f9975baf6 100644 (file)
--- a/src/syscall/syscall_windows_test.go
+++ b/src/syscall/syscall_windows_test.go
@@ -16,24 +16,29 @@ import (
 )
 
 func TestOpen_Dir(t *testing.T) {
-       dir := t.TempDir()
+       t.Parallel()
 
-       h, err := syscall.Open(dir, syscall.O_RDONLY, 0)
-       if err != nil {
-               t.Fatalf("Open failed: %v", err)
-       }
-       syscall.CloseHandle(h)
-       h, err = syscall.Open(dir, syscall.O_RDONLY|syscall.O_TRUNC, 0)
-       if err == nil {
-               t.Error("Open should have failed")
-       } else {
-               syscall.CloseHandle(h)
-       }
-       h, err = syscall.Open(dir, syscall.O_RDONLY|syscall.O_CREAT, 0)
-       if err == nil {
-               t.Error("Open should have failed")
-       } else {
-               syscall.CloseHandle(h)
+       dir := t.TempDir()
+       tests := []struct {
+               mode int
+               err  error
+       }{
+               {syscall.O_RDONLY, nil},
+               {syscall.O_CREAT, syscall.ERROR_ACCESS_DENIED},                    // TODO(qmuntal): should be allowed.
+               {syscall.O_RDONLY | syscall.O_CREAT, syscall.ERROR_ACCESS_DENIED}, // TODO(qmuntal): should be allowed.
+               {syscall.O_RDONLY | syscall.O_TRUNC, syscall.ERROR_ACCESS_DENIED},
+               {syscall.O_WRONLY | syscall.O_RDWR, syscall.EISDIR},
+               {syscall.O_WRONLY, syscall.EISDIR},
+               {syscall.O_RDWR, syscall.EISDIR},
+       }
+       for i, tt := range tests {
+               h, err := syscall.Open(dir, tt.mode, 0)
+               if err == nil {
+                       syscall.CloseHandle(h)
+               }
+               if err != tt.err {
+                       t.Errorf("%d: Open got %v, want %v", i, err, tt.err)
+               }
        }
 }