From: Simon Ruderich <simon@ruderich.org>
Date: Sun, 4 Apr 2021 08:35:22 +0000 (+0200)
Subject: sync: refactor file opening into OpenFileNoFollow()
X-Git-Url: https://ruderich.org/simon/gitweb/?p=safcm%2Fsafcm.git;a=commitdiff_plain;h=713cde4bd701dd53ed46d01f43c9e9e7b82dc514

sync: refactor file opening into OpenFileNoFollow()

Make it public because it will be used by other packages in the next
commit.
---

diff --git a/cmd/safcm-remote/sync/files.go b/cmd/safcm-remote/sync/files.go
index 06bc406..12508ce 100644
--- a/cmd/safcm-remote/sync/files.go
+++ b/cmd/safcm-remote/sync/files.go
@@ -110,10 +110,7 @@ func (s *Sync) syncFile(file *safcm.File, changed *bool) error {
 
 	var oldStat fs.FileInfo
 reopen:
-	oldFh, err := os.OpenFile(file.Path,
-		// O_NOFOLLOW prevents symlink attacks
-		// O_NONBLOCK is necessary to prevent blocking on FIFOs
-		os.O_RDONLY|syscall.O_NOFOLLOW|syscall.O_NONBLOCK, 0)
+	oldFh, err := OpenFileNoFollow(file.Path)
 	if err != nil {
 		err := err.(*fs.PathError)
 		if err.Err == syscall.ELOOP {
@@ -273,8 +270,7 @@ reopen:
 		// a symlink at this point. There's no lchmod so open the
 		// directory.
 		debugf("chmodding %s", file.Mode)
-		dh, err := os.OpenFile(file.Path,
-			os.O_RDONLY|syscall.O_NOFOLLOW|syscall.O_NONBLOCK, 0)
+		dh, err := OpenFileNoFollow(file.Path)
 		if err != nil {
 			return err
 		}
@@ -502,6 +498,13 @@ func diffData(oldData []byte, newData []byte) (string, error) {
 	return result, nil
 }
 
+func OpenFileNoFollow(path string) (*os.File, error) {
+	return os.OpenFile(path,
+		// O_NOFOLLOW prevents symlink attacks
+		// O_NONBLOCK is necessary to prevent blocking on FIFOs
+		os.O_RDONLY|syscall.O_NOFOLLOW|syscall.O_NONBLOCK, 0)
+}
+
 // syncPath syncs path, which should be a directory. To guarantee durability
 // it must be called on a parent directory after adding, renaming or removing
 // files therein.