Check in gVisor.

PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

1 files changed, 232 insertions, 0 deletions

diff --git a/pkg/abi/linux/file.go b/pkg/abi/linux/file.go
new file mode 100644
index 000000000..44672647b
--- /dev/null
+++ b/pkg/abi/linux/file.go
@@ -0,0 +1,232 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package linux
+
+import (
+	"fmt"
+	"strings"
+
+	"gvisor.googlesource.com/gvisor/pkg/abi"
+)
+
+// Constants for open(2).
+const (
+	O_NONBLOCK = 00004000
+	O_CLOEXEC  = 02000000
+	O_PATH     = 010000000
+)
+
+// Constants for fstatat(2).
+const (
+	AT_SYMLINK_NOFOLLOW = 0x100
+)
+
+// Constants for mount(2).
+const (
+	MS_RDONLY      = 0x1
+	MS_NOSUID      = 0x2
+	MS_NODEV       = 0x4
+	MS_NOEXEC      = 0x8
+	MS_SYNCHRONOUS = 0x10
+	MS_REMOUNT     = 0x20
+	MS_MANDLOCK    = 0x40
+	MS_DIRSYNC     = 0x80
+	MS_NOATIME     = 0x400
+	MS_NODIRATIME  = 0x800
+	MS_BIND        = 0x1000
+	MS_MOVE        = 0x2000
+	MS_REC         = 0x4000
+
+	MS_POSIXACL    = 0x10000
+	MS_UNBINDABLE  = 0x20000
+	MS_PRIVATE     = 0x40000
+	MS_SLAVE       = 0x80000
+	MS_SHARED      = 0x100000
+	MS_RELATIME    = 0x200000
+	MS_KERNMOUNT   = 0x400000
+	MS_I_VERSION   = 0x800000
+	MS_STRICTATIME = 0x1000000
+
+	MS_MGC_VAL = 0xC0ED0000
+	MS_MGC_MSK = 0xffff0000
+)
+
+// Constants for umount2(2).
+const (
+	MNT_FORCE       = 0x1
+	MNT_DETACH      = 0x2
+	MNT_EXPIRE      = 0x4
+	UMOUNT_NOFOLLOW = 0x8
+)
+
+// Constants for unlinkat(2).
+const (
+	AT_REMOVEDIR = 0x200
+)
+
+// Constants for linkat(2) and fchownat(2).
+const (
+	AT_SYMLINK_FOLLOW = 0x400
+	AT_EMPTY_PATH     = 0x1000
+)
+
+// Constants for all file-related ...at(2) syscalls.
+const (
+	AT_FDCWD = -100
+)
+
+// Special values for the ns field in utimensat(2).
+const (
+	UTIME_NOW  = ((1 << 30) - 1)
+	UTIME_OMIT = ((1 << 30) - 2)
+)
+
+// MaxSymlinkTraversals is the maximum number of links that will be followed by
+// the kernel to resolve a symlink.
+const MaxSymlinkTraversals = 40
+
+// Constants for flock(2).
+const (
+	LOCK_SH = 1 // shared lock
+	LOCK_EX = 2 // exclusive lock
+	LOCK_NB = 4 // or'd with one of the above to prevent blocking
+	LOCK_UN = 8 // remove lock
+)
+
+// Values for mode_t.
+const (
+	FileTypeMask        = 0170000
+	ModeSocket          = 0140000
+	ModeSymlink         = 0120000
+	ModeRegular         = 0100000
+	ModeBlockDevice     = 060000
+	ModeDirectory       = 040000
+	ModeCharacterDevice = 020000
+	ModeNamedPipe       = 010000
+
+	ModeSetUID = 04000
+	ModeSetGID = 02000
+	ModeSticky = 01000
+
+	ModeUserAll     = 0700
+	ModeUserRead    = 0400
+	ModeUserWrite   = 0200
+	ModeUserExec    = 0100
+	ModeGroupAll    = 0070
+	ModeGroupRead   = 0040
+	ModeGroupWrite  = 0020
+	ModeGroupExec   = 0010
+	ModeOtherAll    = 0007
+	ModeOtherRead   = 0004
+	ModeOtherWrite  = 0002
+	ModeOtherExec   = 0001
+	PermissionsMask = 0777
+)
+
+// Stat represents struct stat.
+type Stat struct {
+	Dev      uint64
+	Ino      uint64
+	Nlink    uint64
+	Mode     uint32
+	UID      uint32
+	GID      uint32
+	X_pad0   int32
+	Rdev     uint64
+	Size     int64
+	Blksize  int64
+	Blocks   int64
+	ATime    Timespec
+	MTime    Timespec
+	CTime    Timespec
+	X_unused [3]int64
+}
+
+// FileMode represents a mode_t.
+type FileMode uint
+
+// Permissions returns just the permission bits.
+func (m FileMode) Permissions() FileMode {
+	return m & PermissionsMask
+}
+
+// FileType returns just the file type bits.
+func (m FileMode) FileType() FileMode {
+	return m & FileTypeMask
+}
+
+// ExtraBits returns everything but the file type and permission bits.
+func (m FileMode) ExtraBits() FileMode {
+	return m &^ (PermissionsMask | FileTypeMask)
+}
+
+// String returns a string representation of m.
+func (m FileMode) String() string {
+	var s []string
+	if ft := m.FileType(); ft != 0 {
+		s = append(s, fileType.Parse(uint64(ft)))
+	}
+	if eb := m.ExtraBits(); eb != 0 {
+		s = append(s, modeExtraBits.Parse(uint64(eb)))
+	}
+	s = append(s, fmt.Sprintf("0o%o", m.Permissions()))
+	return strings.Join(s, "|")
+}
+
+var modeExtraBits = abi.FlagSet{
+	{
+		Flag: ModeSetUID,
+		Name: "S_ISUID",
+	},
+	{
+		Flag: ModeSetGID,
+		Name: "S_ISGID",
+	},
+	{
+		Flag: ModeSticky,
+		Name: "S_ISVTX",
+	},
+}
+
+var fileType = abi.ValueSet{
+	{
+		Value: ModeSocket,
+		Name:  "S_IFSOCK",
+	},
+	{
+		Value: ModeSymlink,
+		Name:  "S_IFLINK",
+	},
+	{
+		Value: ModeRegular,
+		Name:  "S_IFREG",
+	},
+	{
+		Value: ModeBlockDevice,
+		Name:  "S_IFBLK",
+	},
+	{
+		Value: ModeDirectory,
+		Name:  "S_IFDIR",
+	},
+	{
+		Value: ModeCharacterDevice,
+		Name:  "S_IFCHR",
+	},
+	{
+		Value: ModeNamedPipe,
+		Name:  "S_IFIFO",
+	},
+}