379 lines
8.5 KiB
Go
379 lines
8.5 KiB
Go
// Copyright 2018 The gVisor Authors.
|
|
//
|
|
// 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.dev/gvisor/pkg/abi"
|
|
"gvisor.dev/gvisor/pkg/binary"
|
|
)
|
|
|
|
// Constants for open(2).
|
|
const (
|
|
O_ACCMODE = 000000003
|
|
O_RDONLY = 000000000
|
|
O_WRONLY = 000000001
|
|
O_RDWR = 000000002
|
|
O_CREAT = 000000100
|
|
O_EXCL = 000000200
|
|
O_NOCTTY = 000000400
|
|
O_TRUNC = 000001000
|
|
O_APPEND = 000002000
|
|
O_NONBLOCK = 000004000
|
|
O_DSYNC = 000010000
|
|
O_ASYNC = 000020000
|
|
O_NOATIME = 001000000
|
|
O_CLOEXEC = 002000000
|
|
O_SYNC = 004000000 // __O_SYNC in Linux
|
|
O_PATH = 010000000
|
|
O_TMPFILE = 020000000 // __O_TMPFILE in Linux
|
|
)
|
|
|
|
// 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 (
|
|
S_IFMT = 0170000
|
|
S_IFSOCK = 0140000
|
|
S_IFLNK = 0120000
|
|
S_IFREG = 0100000
|
|
S_IFBLK = 060000
|
|
S_IFDIR = 040000
|
|
S_IFCHR = 020000
|
|
S_IFIFO = 010000
|
|
|
|
FileTypeMask = S_IFMT
|
|
ModeSocket = S_IFSOCK
|
|
ModeSymlink = S_IFLNK
|
|
ModeRegular = S_IFREG
|
|
ModeBlockDevice = S_IFBLK
|
|
ModeDirectory = S_IFDIR
|
|
ModeCharacterDevice = S_IFCHR
|
|
ModeNamedPipe = S_IFIFO
|
|
|
|
S_ISUID = 04000
|
|
S_ISGID = 02000
|
|
S_ISVTX = 01000
|
|
|
|
ModeSetUID = S_ISUID
|
|
ModeSetGID = S_ISGID
|
|
ModeSticky = S_ISVTX
|
|
|
|
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
|
|
)
|
|
|
|
// Values for linux_dirent64.d_type.
|
|
const (
|
|
DT_UNKNOWN = 0
|
|
DT_FIFO = 1
|
|
DT_CHR = 2
|
|
DT_DIR = 4
|
|
DT_BLK = 6
|
|
DT_REG = 8
|
|
DT_LNK = 10
|
|
DT_SOCK = 12
|
|
DT_WHT = 14
|
|
)
|
|
|
|
// DirentType are the friendly strings for linux_dirent64.d_type.
|
|
var DirentType = abi.ValueSet{
|
|
DT_UNKNOWN: "DT_UNKNOWN",
|
|
DT_FIFO: "DT_FIFO",
|
|
DT_CHR: "DT_CHR",
|
|
DT_DIR: "DT_DIR",
|
|
DT_BLK: "DT_BLK",
|
|
DT_REG: "DT_REG",
|
|
DT_LNK: "DT_LNK",
|
|
DT_SOCK: "DT_SOCK",
|
|
DT_WHT: "DT_WHT",
|
|
}
|
|
|
|
// Values for preadv2/pwritev2.
|
|
const (
|
|
// Note: gVisor does not implement the RWF_HIPRI feature, but the flag is
|
|
// accepted as a valid flag argument for preadv2/pwritev2.
|
|
RWF_HIPRI = 0x00000001
|
|
RWF_DSYNC = 0x00000002
|
|
RWF_SYNC = 0x00000004
|
|
RWF_VALID = RWF_HIPRI | RWF_DSYNC | RWF_SYNC
|
|
)
|
|
|
|
// SizeOfStat is the size of a Stat struct.
|
|
var SizeOfStat = binary.Size(Stat{})
|
|
|
|
// Flags for statx.
|
|
const (
|
|
AT_STATX_SYNC_TYPE = 0x6000
|
|
AT_STATX_SYNC_AS_STAT = 0x0000
|
|
AT_STATX_FORCE_SYNC = 0x2000
|
|
AT_STATX_DONT_SYNC = 0x4000
|
|
)
|
|
|
|
// Mask values for statx.
|
|
const (
|
|
STATX_TYPE = 0x00000001
|
|
STATX_MODE = 0x00000002
|
|
STATX_NLINK = 0x00000004
|
|
STATX_UID = 0x00000008
|
|
STATX_GID = 0x00000010
|
|
STATX_ATIME = 0x00000020
|
|
STATX_MTIME = 0x00000040
|
|
STATX_CTIME = 0x00000080
|
|
STATX_INO = 0x00000100
|
|
STATX_SIZE = 0x00000200
|
|
STATX_BLOCKS = 0x00000400
|
|
STATX_BASIC_STATS = 0x000007ff
|
|
STATX_BTIME = 0x00000800
|
|
STATX_ALL = 0x00000fff
|
|
STATX__RESERVED = 0x80000000
|
|
)
|
|
|
|
// Bitmasks for Statx.Attributes and Statx.AttributesMask, from
|
|
// include/uapi/linux/stat.h.
|
|
const (
|
|
STATX_ATTR_COMPRESSED = 0x00000004
|
|
STATX_ATTR_IMMUTABLE = 0x00000010
|
|
STATX_ATTR_APPEND = 0x00000020
|
|
STATX_ATTR_NODUMP = 0x00000040
|
|
STATX_ATTR_ENCRYPTED = 0x00000800
|
|
STATX_ATTR_AUTOMOUNT = 0x00001000
|
|
)
|
|
|
|
// Statx represents struct statx.
|
|
//
|
|
// +marshal
|
|
type Statx struct {
|
|
Mask uint32
|
|
Blksize uint32
|
|
Attributes uint64
|
|
Nlink uint32
|
|
UID uint32
|
|
GID uint32
|
|
Mode uint16
|
|
_ uint16
|
|
Ino uint64
|
|
Size uint64
|
|
Blocks uint64
|
|
AttributesMask uint64
|
|
Atime StatxTimestamp
|
|
Btime StatxTimestamp
|
|
Ctime StatxTimestamp
|
|
Mtime StatxTimestamp
|
|
RdevMajor uint32
|
|
RdevMinor uint32
|
|
DevMajor uint32
|
|
DevMinor uint32
|
|
}
|
|
|
|
// SizeOfStatx is the size of a Statx struct.
|
|
var SizeOfStatx = binary.Size(Statx{})
|
|
|
|
// FileMode represents a mode_t.
|
|
type FileMode uint16
|
|
|
|
// 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, "|")
|
|
}
|
|
|
|
// DirentType maps file types to dirent types appropriate for (struct
|
|
// dirent)::d_type.
|
|
func (m FileMode) DirentType() uint8 {
|
|
switch m.FileType() {
|
|
case ModeSocket:
|
|
return DT_SOCK
|
|
case ModeSymlink:
|
|
return DT_LNK
|
|
case ModeRegular:
|
|
return DT_REG
|
|
case ModeBlockDevice:
|
|
return DT_BLK
|
|
case ModeDirectory:
|
|
return DT_DIR
|
|
case ModeCharacterDevice:
|
|
return DT_CHR
|
|
case ModeNamedPipe:
|
|
return DT_FIFO
|
|
default:
|
|
return DT_UNKNOWN
|
|
}
|
|
}
|
|
|
|
var modeExtraBits = abi.FlagSet{
|
|
{
|
|
Flag: ModeSetUID,
|
|
Name: "S_ISUID",
|
|
},
|
|
{
|
|
Flag: ModeSetGID,
|
|
Name: "S_ISGID",
|
|
},
|
|
{
|
|
Flag: ModeSticky,
|
|
Name: "S_ISVTX",
|
|
},
|
|
}
|
|
|
|
var fileType = abi.ValueSet{
|
|
ModeSocket: "S_IFSOCK",
|
|
ModeSymlink: "S_IFLINK",
|
|
ModeRegular: "S_IFREG",
|
|
ModeBlockDevice: "S_IFBLK",
|
|
ModeDirectory: "S_IFDIR",
|
|
ModeCharacterDevice: "S_IFCHR",
|
|
ModeNamedPipe: "S_IFIFO",
|
|
}
|
|
|
|
// Constants for memfd_create(2). Source: include/uapi/linux/memfd.h
|
|
const (
|
|
MFD_CLOEXEC = 0x0001
|
|
MFD_ALLOW_SEALING = 0x0002
|
|
)
|
|
|
|
// Constants related to file seals. Source: include/uapi/{asm-generic,linux}/fcntl.h
|
|
const (
|
|
F_LINUX_SPECIFIC_BASE = 1024
|
|
F_ADD_SEALS = F_LINUX_SPECIFIC_BASE + 9
|
|
F_GET_SEALS = F_LINUX_SPECIFIC_BASE + 10
|
|
|
|
F_SEAL_SEAL = 0x0001 // Prevent further seals from being set.
|
|
F_SEAL_SHRINK = 0x0002 // Prevent file from shrinking.
|
|
F_SEAL_GROW = 0x0004 // Prevent file from growing.
|
|
F_SEAL_WRITE = 0x0008 // Prevent writes.
|
|
)
|
|
|
|
// Constants related to fallocate(2). Source: include/uapi/linux/falloc.h
|
|
const (
|
|
FALLOC_FL_KEEP_SIZE = 0x01
|
|
FALLOC_FL_PUNCH_HOLE = 0x02
|
|
FALLOC_FL_NO_HIDE_STALE = 0x04
|
|
FALLOC_FL_COLLAPSE_RANGE = 0x08
|
|
FALLOC_FL_ZERO_RANGE = 0x10
|
|
FALLOC_FL_INSERT_RANGE = 0x20
|
|
FALLOC_FL_UNSHARE_RANGE = 0x40
|
|
)
|