Use github.com/pkg/xattr for extended attributes

vendor/src/github.com/pkg/xattr/LICENSE

@@ -0,0 +1,25 @@
+Copyright (c) 2012 Dave Cheney. All rights reserved.
+Copyright (c) 2014 Kuba Podgórski. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/src/github.com/pkg/xattr/README.md

@@ -0,0 +1,21 @@
+xattr
+=====
+Extended attribute support for Go (linux + darwin + freebsd).
+
+"Extended attributes are name:value pairs associated permanently with files and directories, similar to the environment strings associated with a process. An attribute may be defined or undefined. If it is defined, its value may be empty or non-empty." [See more...](https://en.wikipedia.org/wiki/Extended_file_attributes)
+
+
+### Example
+```
+  const path = "/tmp/myfile"
+  const prefix = "user."
+
+  if err = Setxattr(path, prefix+"test", []byte("test-attr-value")); err != nil {
+    t.Fatal(err)
+  }
+
+  var data []byte
+  data, err = Getxattr(path, prefix+"test"); err != nil {
+    t.Fatal(err)
+  }
+```

vendor/src/github.com/pkg/xattr/syscall_darwin.go

@@ -0,0 +1,39 @@
+// +build darwin
+
+package xattr
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+func getxattr(path string, name string, value *byte, size int, pos int, options int) (int, error) {
+
+	r0, _, e1 := syscall.Syscall6(syscall.SYS_GETXATTR, uintptr(unsafe.Pointer(syscall.StringBytePtr(path))), uintptr(unsafe.Pointer(syscall.StringBytePtr(name))), uintptr(unsafe.Pointer(value)), uintptr(size), uintptr(pos), uintptr(options))
+	if e1 != syscall.Errno(0) {
+		return int(r0), e1
+	}
+	return int(r0), nil
+}
+
+func listxattr(path string, namebuf *byte, size int, options int) (int, error) {
+	r0, _, e1 := syscall.Syscall6(syscall.SYS_LISTXATTR, uintptr(unsafe.Pointer(syscall.StringBytePtr(path))), uintptr(unsafe.Pointer(namebuf)), uintptr(size), uintptr(options), 0, 0)
+	if e1 != syscall.Errno(0) {
+		return int(r0), e1
+	}
+	return int(r0), nil
+}
+
+func setxattr(path string, name string, value *byte, size int, pos int, options int) error {
+	if _, _, e1 := syscall.Syscall6(syscall.SYS_SETXATTR, uintptr(unsafe.Pointer(syscall.StringBytePtr(path))), uintptr(unsafe.Pointer(syscall.StringBytePtr(name))), uintptr(unsafe.Pointer(value)), uintptr(size), uintptr(pos), uintptr(options)); e1 != syscall.Errno(0) {
+		return e1
+	}
+	return nil
+}
+
+func removexattr(path string, name string, options int) error {
+	if _, _, e1 := syscall.Syscall(syscall.SYS_REMOVEXATTR, uintptr(unsafe.Pointer(syscall.StringBytePtr(path))), uintptr(unsafe.Pointer(syscall.StringBytePtr(name))), uintptr(options)); e1 != syscall.Errno(0) {
+		return e1
+	}
+	return nil
+}

vendor/src/github.com/pkg/xattr/syscall_freebsd.go

@@ -0,0 +1,91 @@
+// +build freebsd
+
+package xattr
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+/*
+   ssize_t
+   extattr_get_file(const char *path, int attrnamespace,
+       const char *attrname, void *data, size_t nbytes);
+
+   ssize_t
+   extattr_set_file(const char *path, int attrnamespace,
+       const char *attrname, const void *data, size_t nbytes);
+
+   int
+   extattr_delete_file(const char *path, int attrnamespace,
+       const char *attrname);
+
+   ssize_t
+   extattr_list_file(const char *path, int attrnamespace, void *data,
+       size_t nbytes);
+*/
+
+func extattr_get_file(path string, attrnamespace int, attrname string, data *byte, nbytes int) (int, error) {
+	r, _, e := syscall.Syscall6(
+		syscall.SYS_EXTATTR_GET_FILE,
+		uintptr(unsafe.Pointer(syscall.StringBytePtr(path))),
+		uintptr(attrnamespace),
+		uintptr(unsafe.Pointer(syscall.StringBytePtr(attrname))),
+		uintptr(unsafe.Pointer(data)),
+		uintptr(nbytes),
+		0,
+	)
+	var err error
+	if e != 0 {
+		err = e
+	}
+	return int(r), err
+}
+
+func extattr_set_file(path string, attrnamespace int, attrname string, data *byte, nbytes int) (int, error) {
+	r, _, e := syscall.Syscall6(
+		syscall.SYS_EXTATTR_SET_FILE,
+		uintptr(unsafe.Pointer(syscall.StringBytePtr(path))),
+		uintptr(attrnamespace),
+		uintptr(unsafe.Pointer(syscall.StringBytePtr(attrname))),
+		uintptr(unsafe.Pointer(data)),
+		uintptr(nbytes),
+		0,
+	)
+	var err error
+	if e != 0 {
+		err = e
+	}
+	return int(r), err
+}
+
+func extattr_delete_file(path string, attrnamespace int, attrname string) error {
+	_, _, e := syscall.Syscall(
+		syscall.SYS_EXTATTR_DELETE_FILE,
+		uintptr(unsafe.Pointer(syscall.StringBytePtr(path))),
+		uintptr(attrnamespace),
+		uintptr(unsafe.Pointer(syscall.StringBytePtr(attrname))),
+	)
+	var err error
+	if e != 0 {
+		err = e
+	}
+	return err
+}
+
+func extattr_list_file(path string, attrnamespace int, data *byte, nbytes int) (int, error) {
+	r, _, e := syscall.Syscall6(
+		syscall.SYS_EXTATTR_LIST_FILE,
+		uintptr(unsafe.Pointer(syscall.StringBytePtr(path))),
+		uintptr(attrnamespace),
+		uintptr(unsafe.Pointer(data)),
+		uintptr(nbytes),
+		0,
+		0,
+	)
+	var err error
+	if e != 0 {
+		err = e
+	}
+	return int(r), err
+}

vendor/src/github.com/pkg/xattr/xattr.go

@@ -0,0 +1,26 @@
+package xattr
+
+// XAttrError records an error and the operation, file path and attribute that caused it.
+type XAttrError struct {
+	Op   string
+	Path string
+	Name string
+	Err  error
+}
+
+func (e *XAttrError) Error() string {
+	return e.Op + " " + e.Path + " " + e.Name + ": " + e.Err.Error()
+}
+
+// Convert an array of NULL terminated UTF-8 strings
+// to a []string.
+func nullTermToStrings(buf []byte) (result []string) {
+	offset := 0
+	for index, b := range buf {
+		if b == 0 {
+			result = append(result, string(buf[offset:index]))
+			offset = index + 1
+		}
+	}
+	return
+}

vendor/src/github.com/pkg/xattr/xattr_darwin.go

@@ -0,0 +1,56 @@
+// +build darwin
+
+package xattr
+
+// Retrieve extended attribute data associated with path.
+func Getxattr(path, name string) ([]byte, error) {
+	// find size.
+	size, err := getxattr(path, name, nil, 0, 0, 0)
+	if err != nil {
+		return nil, &XAttrError{"getxattr", path, name, err}
+	}
+	buf := make([]byte, size)
+	// Read into buffer of that size.
+	read, err := getxattr(path, name, &buf[0], size, 0, 0)
+	if err != nil {
+		return nil, &XAttrError{"getxattr", path, name, err}
+	}
+	return buf[:read], nil
+}
+
+// Retrieves a list of names of extended attributes associated with the
+// given path in the file system.
+func Listxattr(path string) ([]string, error) {
+	// find size.
+	size, err := listxattr(path, nil, 0, 0)
+	if err != nil {
+		return nil, &XAttrError{"listxattr", path, "", err}
+	}
+	if size == 0 {
+		return []string{}, nil
+	}
+
+	buf := make([]byte, size)
+	// Read into buffer of that size.
+	read, err := listxattr(path, &buf[0], size, 0)
+	if err != nil {
+		return nil, &XAttrError{"listxattr", path, "", err}
+	}
+	return nullTermToStrings(buf[:read]), nil
+}
+
+// Associates name and data together as an attribute of path.
+func Setxattr(path, name string, data []byte) error {
+	if err := setxattr(path, name, &data[0], len(data), 0, 0); err != nil {
+		return &XAttrError{"setxattr", path, name, err}
+	}
+	return nil
+}
+
+// Remove the attribute.
+func Removexattr(path, name string) error {
+	if err := removexattr(path, name, 0); err != nil {
+		return &XAttrError{"removexattr", path, name, err}
+	}
+	return nil
+}

vendor/src/github.com/pkg/xattr/xattr_freebsd.go

@@ -0,0 +1,79 @@
+// +build freebsd
+
+package xattr
+
+import (
+	"syscall"
+)
+
+const (
+	EXTATTR_NAMESPACE_USER = 1
+)
+
+// Retrieve extended attribute data associated with path.
+func Getxattr(path, name string) ([]byte, error) {
+	// find size.
+	size, err := extattr_get_file(path, EXTATTR_NAMESPACE_USER, name, nil, 0)
+	if err != nil {
+		return nil, &XAttrError{"extattr_get_file", path, name, err}
+	}
+	buf := make([]byte, size)
+	// Read into buffer of that size.
+	read, err := extattr_get_file(path, EXTATTR_NAMESPACE_USER, name, &buf[0], size)
+	if err != nil {
+		return nil, &XAttrError{"extattr_get_file", path, name, err}
+	}
+	return buf[:read], nil
+}
+
+// Retrieves a list of names of extended attributes associated with the
+// given path in the file system.
+func Listxattr(path string) ([]string, error) {
+	// find size.
+	size, err := extattr_list_file(path, EXTATTR_NAMESPACE_USER, nil, 0)
+	if err != nil {
+		return nil, &XAttrError{"extattr_list_file", path, "", err}
+	}
+	buf := make([]byte, size)
+	// Read into buffer of that size.
+	read, err := extattr_list_file(path, EXTATTR_NAMESPACE_USER, &buf[0], size)
+	if err != nil {
+		return nil, &XAttrError{"extattr_list_file", path, "", err}
+	}
+	return attrListToStrings(buf[:read]), nil
+}
+
+// Associates name and data together as an attribute of path.
+func Setxattr(path, name string, data []byte) error {
+	written, err := extattr_set_file(path, EXTATTR_NAMESPACE_USER, name, &data[0], len(data))
+	if err != nil {
+		return &XAttrError{"extattr_set_file", path, name, err}
+	}
+	if written != len(data) {
+		return &XAttrError{"extattr_set_file", path, name, syscall.E2BIG}
+	}
+	return nil
+}
+
+// Remove the attribute.
+func Removexattr(path, name string) error {
+	if err := extattr_delete_file(path, EXTATTR_NAMESPACE_USER, name); err != nil {
+		return &XAttrError{"extattr_delete_file", path, name, err}
+	}
+	return nil
+}
+
+// Convert a sequnce of attribute name entries to a []string.
+// Each entry consists of a single byte containing the length
+// of the attribute name, followed by the attribute name.
+// The name is _not_ terminated by NUL.
+func attrListToStrings(buf []byte) []string {
+	var result []string
+	index := 0
+	for index < len(buf) {
+		next := index + 1 + int(buf[index])
+		result = append(result, string(buf[index+1:next]))
+		index = next
+	}
+	return result
+}

vendor/src/github.com/pkg/xattr/xattr_linux.go

@@ -0,0 +1,54 @@
+// +build linux
+
+package xattr
+
+import "syscall"
+
+// Retrieve extended attribute data associated with path.
+func Getxattr(path, name string) ([]byte, error) {
+	// find size.
+	size, err := syscall.Getxattr(path, name, nil)
+	if err != nil {
+		return nil, &XAttrError{"getxattr", path, name, err}
+	}
+	data := make([]byte, size)
+	// Read into buffer of that size.
+	read, err := syscall.Getxattr(path, name, data)
+	if err != nil {
+		return nil, &XAttrError{"getxattr", path, name, err}
+	}
+	return data[:read], nil
+}
+
+// Retrieves a list of names of extended attributes associated with the
+// given path in the file system.
+func Listxattr(path string) ([]string, error) {
+	// find size.
+	size, err := syscall.Listxattr(path, nil)
+	if err != nil {
+		return nil, &XAttrError{"listxattr", path, "", err}
+	}
+	buf := make([]byte, size)
+	// Read into buffer of that size.
+	read, err := syscall.Listxattr(path, buf)
+	if err != nil {
+		return nil, &XAttrError{"listxattr", path, "", err}
+	}
+	return nullTermToStrings(buf[:read]), nil
+}
+
+// Associates name and data together as an attribute of path.
+func Setxattr(path, name string, data []byte) error {
+	if err := syscall.Setxattr(path, name, data, 0); err != nil {
+		return &XAttrError{"setxattr", path, name, err}
+	}
+	return nil
+}
+
+// Remove the attribute.
+func Removexattr(path, name string) error {
+	if err := syscall.Removexattr(path, name); err != nil {
+		return &XAttrError{"removexattr", path, name, err}
+	}
+	return nil
+}

vendor/src/github.com/pkg/xattr/xattr_test.go

@@ -0,0 +1,57 @@
+// +build linux darwin freebsd
+
+package xattr
+
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+)
+
+const UserPrefix = "user."
+
+func Test_setxattr(t *testing.T) {
+	tmp, err := ioutil.TempFile("", "")
+
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.Remove(tmp.Name())
+
+	err = Setxattr(tmp.Name(), UserPrefix+"test", []byte("test-attr-value"))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	list, err := Listxattr(tmp.Name())
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	found := false
+	for _, name := range list {
+		if name == UserPrefix+"test" {
+			found = true
+		}
+	}
+
+	if !found {
+		t.Fatal("Listxattr did not return test attribute")
+	}
+
+	var data []byte
+	data, err = Getxattr(tmp.Name(), UserPrefix+"test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	value := string(data)
+	t.Log(value)
+	if "test-attr-value" != value {
+		t.Fail()
+	}
+
+	err = Removexattr(tmp.Name(), UserPrefix+"test")
+	if err != nil {
+		t.Fatal(err)
+	}
+}