From 3d478c1043434edf347e8758f9ed4085bc70e6eb Mon Sep 17 00:00:00 2001
From: Alexander Larsson <alexl@redhat.com>
Date: Fri, 14 Feb 2014 14:24:37 +0100
Subject: [PATCH] Archive: Add Add Lgetxattr and Lsetxattr implementations

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
Upstream-commit: d19e998e7a99d24122da3e98d9886e3b7b4b3501
Component: engine
---
 components/engine/archive/stat_linux.go       | 53 +++++++++++++++++++
 components/engine/archive/stat_unsupported.go |  8 +++
 2 files changed, 61 insertions(+)

diff --git a/components/engine/archive/stat_linux.go b/components/engine/archive/stat_linux.go
index f87a99c55a..2910ce5bab 100644
--- a/components/engine/archive/stat_linux.go
+++ b/components/engine/archive/stat_linux.go
@@ -37,3 +37,56 @@ func UtimesNano(path string, ts []syscall.Timespec) error {
 	}
 	return nil
 }
+
+// Returns a nil slice and nil error if the xattr is not set
+func Lgetxattr(path string, attr string) ([]byte, error) {
+	pathBytes, err := syscall.BytePtrFromString(path)
+	if err != nil {
+		return nil, err
+	}
+	attrBytes, err := syscall.BytePtrFromString(attr)
+	if err != nil {
+		return nil, err
+	}
+
+	dest := make([]byte, 128)
+	destBytes := unsafe.Pointer(&dest[0])
+	sz, _, errno := syscall.Syscall6(syscall.SYS_LGETXATTR, uintptr(unsafe.Pointer(pathBytes)), uintptr(unsafe.Pointer(attrBytes)), uintptr(destBytes), uintptr(len(dest)), 0, 0)
+	if errno == syscall.ENODATA {
+		return nil, nil
+	}
+	if errno == syscall.ERANGE {
+		dest = make([]byte, sz)
+		destBytes := unsafe.Pointer(&dest[0])
+		sz, _, errno = syscall.Syscall6(syscall.SYS_LGETXATTR, uintptr(unsafe.Pointer(pathBytes)), uintptr(unsafe.Pointer(attrBytes)), uintptr(destBytes), uintptr(len(dest)), 0, 0)
+	}
+	if errno != 0 {
+		return nil, errno
+	}
+
+	return dest[:sz], nil
+}
+
+var _zero uintptr
+
+func Lsetxattr(path string, attr string, data []byte, flags int) error {
+	pathBytes, err := syscall.BytePtrFromString(path)
+	if err != nil {
+		return err
+	}
+	attrBytes, err := syscall.BytePtrFromString(attr)
+	if err != nil {
+		return err
+	}
+	var dataBytes unsafe.Pointer
+	if len(data) > 0 {
+		dataBytes = unsafe.Pointer(&data[0])
+	} else {
+		dataBytes = unsafe.Pointer(&_zero)
+	}
+	_, _, errno := syscall.Syscall6(syscall.SYS_LSETXATTR, uintptr(unsafe.Pointer(pathBytes)), uintptr(unsafe.Pointer(attrBytes)), uintptr(dataBytes), uintptr(len(data)), uintptr(flags), 0)
+	if errno != 0 {
+		return errno
+	}
+	return nil
+}
diff --git a/components/engine/archive/stat_unsupported.go b/components/engine/archive/stat_unsupported.go
index 50ca461867..99f1fbc7da 100644
--- a/components/engine/archive/stat_unsupported.go
+++ b/components/engine/archive/stat_unsupported.go
@@ -19,3 +19,11 @@ func LUtimesNano(path string, ts []syscall.Timespec) error {
 func UtimesNano(path string, ts []syscall.Timespec) error {
 	return ErrNotImplemented
 }
+
+func Lgetxattr(path string, attr string) ([]byte, error) {
+	return nil, ErrNotImplemented
+}
+
+func Lsetxattr(path string, attr string, data []byte, flags int) error {
+	return ErrNotImplemented
+}