diff options
Diffstat (limited to 'atomicfile')
| -rw-r--r-- | atomicfile/atomicfile.go | 102 | ||||
| -rw-r--r-- | atomicfile/atomicfile_test.go | 94 |
2 files changed, 98 insertions, 98 deletions
diff --git a/atomicfile/atomicfile.go b/atomicfile/atomicfile.go index 5c18e85a8..b95c7cbe1 100644 --- a/atomicfile/atomicfile.go +++ b/atomicfile/atomicfile.go @@ -1,51 +1,51 @@ -// Copyright (c) Tailscale Inc & AUTHORS -// SPDX-License-Identifier: BSD-3-Clause - -// Package atomicfile contains code related to writing to filesystems -// atomically. -// -// This package should be considered internal; its API is not stable. -package atomicfile // import "tailscale.com/atomicfile" - -import ( - "fmt" - "os" - "path/filepath" - "runtime" -) - -// WriteFile writes data to filename+some suffix, then renames it into filename. -// The perm argument is ignored on Windows. If the target filename already -// exists but is not a regular file, WriteFile returns an error. -func WriteFile(filename string, data []byte, perm os.FileMode) (err error) { - fi, err := os.Stat(filename) - if err == nil && !fi.Mode().IsRegular() { - return fmt.Errorf("%s already exists and is not a regular file", filename) - } - f, err := os.CreateTemp(filepath.Dir(filename), filepath.Base(filename)+".tmp") - if err != nil { - return err - } - tmpName := f.Name() - defer func() { - if err != nil { - f.Close() - os.Remove(tmpName) - } - }() - if _, err := f.Write(data); err != nil { - return err - } - if runtime.GOOS != "windows" { - if err := f.Chmod(perm); err != nil { - return err - } - } - if err := f.Sync(); err != nil { - return err - } - if err := f.Close(); err != nil { - return err - } - return os.Rename(tmpName, filename) -} +// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Package atomicfile contains code related to writing to filesystems
+// atomically.
+//
+// This package should be considered internal; its API is not stable.
+package atomicfile // import "tailscale.com/atomicfile"
+
+import (
+ "fmt"
+ "os"
+ "path/filepath"
+ "runtime"
+)
+
+// WriteFile writes data to filename+some suffix, then renames it into filename.
+// The perm argument is ignored on Windows. If the target filename already
+// exists but is not a regular file, WriteFile returns an error.
+func WriteFile(filename string, data []byte, perm os.FileMode) (err error) {
+ fi, err := os.Stat(filename)
+ if err == nil && !fi.Mode().IsRegular() {
+ return fmt.Errorf("%s already exists and is not a regular file", filename)
+ }
+ f, err := os.CreateTemp(filepath.Dir(filename), filepath.Base(filename)+".tmp")
+ if err != nil {
+ return err
+ }
+ tmpName := f.Name()
+ defer func() {
+ if err != nil {
+ f.Close()
+ os.Remove(tmpName)
+ }
+ }()
+ if _, err := f.Write(data); err != nil {
+ return err
+ }
+ if runtime.GOOS != "windows" {
+ if err := f.Chmod(perm); err != nil {
+ return err
+ }
+ }
+ if err := f.Sync(); err != nil {
+ return err
+ }
+ if err := f.Close(); err != nil {
+ return err
+ }
+ return os.Rename(tmpName, filename)
+}
diff --git a/atomicfile/atomicfile_test.go b/atomicfile/atomicfile_test.go index 78c93e664..b7a78765b 100644 --- a/atomicfile/atomicfile_test.go +++ b/atomicfile/atomicfile_test.go @@ -1,47 +1,47 @@ -// Copyright (c) Tailscale Inc & AUTHORS -// SPDX-License-Identifier: BSD-3-Clause - -//go:build !js && !windows - -package atomicfile - -import ( - "net" - "os" - "path/filepath" - "runtime" - "strings" - "testing" -) - -func TestDoesNotOverwriteIrregularFiles(t *testing.T) { - // Per tailscale/tailscale#7658 as one example, almost any imagined use of - // atomicfile.Write should likely not attempt to overwrite an irregular file - // such as a device node, socket, or named pipe. - - const filename = "TestDoesNotOverwriteIrregularFiles" - var path string - // macOS private temp does not allow unix socket creation, but /tmp does. - if runtime.GOOS == "darwin" { - path = filepath.Join("/tmp", filename) - t.Cleanup(func() { os.Remove(path) }) - } else { - path = filepath.Join(t.TempDir(), filename) - } - - // The least troublesome thing to make that is not a file is a unix socket. - // Making a null device sadly requires root. - l, err := net.ListenUnix("unix", &net.UnixAddr{Name: path, Net: "unix"}) - if err != nil { - t.Fatal(err) - } - defer l.Close() - - err = WriteFile(path, []byte("hello"), 0644) - if err == nil { - t.Fatal("expected error, got nil") - } - if !strings.Contains(err.Error(), "is not a regular file") { - t.Fatalf("unexpected error: %v", err) - } -} +// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build !js && !windows
+
+package atomicfile
+
+import (
+ "net"
+ "os"
+ "path/filepath"
+ "runtime"
+ "strings"
+ "testing"
+)
+
+func TestDoesNotOverwriteIrregularFiles(t *testing.T) {
+ // Per tailscale/tailscale#7658 as one example, almost any imagined use of
+ // atomicfile.Write should likely not attempt to overwrite an irregular file
+ // such as a device node, socket, or named pipe.
+
+ const filename = "TestDoesNotOverwriteIrregularFiles"
+ var path string
+ // macOS private temp does not allow unix socket creation, but /tmp does.
+ if runtime.GOOS == "darwin" {
+ path = filepath.Join("/tmp", filename)
+ t.Cleanup(func() { os.Remove(path) })
+ } else {
+ path = filepath.Join(t.TempDir(), filename)
+ }
+
+ // The least troublesome thing to make that is not a file is a unix socket.
+ // Making a null device sadly requires root.
+ l, err := net.ListenUnix("unix", &net.UnixAddr{Name: path, Net: "unix"})
+ if err != nil {
+ t.Fatal(err)
+ }
+ defer l.Close()
+
+ err = WriteFile(path, []byte("hello"), 0644)
+ if err == nil {
+ t.Fatal("expected error, got nil")
+ }
+ if !strings.Contains(err.Error(), "is not a regular file") {
+ t.Fatalf("unexpected error: %v", err)
+ }
+}
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