From 19db697a5aca74352967dbc3432bfe0ef59d278d Mon Sep 17 00:00:00 2001
From: Sebastiaan van Stijn <github@gone.nl>
Date: Tue, 30 Aug 2022 15:19:58 +0200
Subject: [PATCH] archive: replace tarName() with filepath.ToSlash()

This code was copied from github.com/moby/moby/pkg/archive;
https://github.com/moby/moby/commit/28842d3f093e69cf62a090a532aacba1e6ff6d1c,
which got later simplified in
https://github.com/moby/moby/commit/a5aed699cfaa4d84b1b134033fb468b3a7a874f0

This patch aligns the containerd implementation with those changes, and uses
filepath.ToSlash() unconditionally on all platforms, as it's a no-op on platforms
that use a forward-slash; https://github.com/golang/go/blob/go1.19/src/path/filepath/path.go#L175-L183

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
---
 archive/tar.go         |  8 +++-----
 archive/tar_unix.go    |  4 ----
 archive/tar_windows.go | 15 ---------------
 3 files changed, 3 insertions(+), 24 deletions(-)

diff --git a/archive/tar.go b/archive/tar.go
index 1ea14d31d..2be4a9051 100644
--- a/archive/tar.go
+++ b/archive/tar.go
@@ -574,11 +574,9 @@ func (cw *ChangeWriter) HandleChange(k fs.ChangeKind, p string, f os.FileInfo, e
 				return fmt.Errorf("failed to make path relative: %w", err)
 			}
 		}
-		name, err = tarName(name)
-		if err != nil {
-			return fmt.Errorf("cannot canonicalize path: %w", err)
-		}
-		// suffix with '/' for directories
+		// Canonicalize to POSIX-style paths using forward slashes. Directory
+		// entries must end with a slash.
+		name = filepath.ToSlash(name)
 		if f.IsDir() && !strings.HasSuffix(name, "/") {
 			name += "/"
 		}
diff --git a/archive/tar_unix.go b/archive/tar_unix.go
index 2f3a3a392..ed2b5e696 100644
--- a/archive/tar_unix.go
+++ b/archive/tar_unix.go
@@ -34,10 +34,6 @@ import (
 	"golang.org/x/sys/unix"
 )
 
-func tarName(p string) (string, error) {
-	return p, nil
-}
-
 func chmodTarEntry(perm os.FileMode) os.FileMode {
 	return perm
 }
diff --git a/archive/tar_windows.go b/archive/tar_windows.go
index 4b71c1e30..ca5ba422f 100644
--- a/archive/tar_windows.go
+++ b/archive/tar_windows.go
@@ -26,21 +26,6 @@ import (
 	"github.com/containerd/containerd/sys"
 )
 
-// tarName returns platform-specific filepath
-// to canonical posix-style path for tar archival. p is relative
-// path.
-func tarName(p string) (string, error) {
-	// windows: convert windows style relative path with backslashes
-	// into forward slashes. Since windows does not allow '/' or '\'
-	// in file names, it is mostly safe to replace however we must
-	// check just in case
-	if strings.Contains(p, "/") {
-		return "", fmt.Errorf("windows path contains forward slash: %s", p)
-	}
-
-	return strings.Replace(p, string(os.PathSeparator), "/", -1), nil
-}
-
 // chmodTarEntry is used to adjust the file permissions used in tar header based
 // on the platform the archival is done.
 func chmodTarEntry(perm os.FileMode) os.FileMode {