374 lines
8.4 KiB
Go
374 lines
8.4 KiB
Go
// Copyright 2018 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package linux
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import (
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"fmt"
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"strings"
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"gvisor.dev/gvisor/pkg/abi"
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"gvisor.dev/gvisor/pkg/binary"
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)
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// Constants for open(2).
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const (
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O_ACCMODE = 000000003
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O_RDONLY = 000000000
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O_WRONLY = 000000001
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O_RDWR = 000000002
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O_CREAT = 000000100
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O_EXCL = 000000200
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O_NOCTTY = 000000400
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O_TRUNC = 000001000
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O_APPEND = 000002000
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O_NONBLOCK = 000004000
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O_DSYNC = 000010000
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O_ASYNC = 000020000
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O_NOATIME = 001000000
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O_CLOEXEC = 002000000
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O_SYNC = 004000000 // __O_SYNC in Linux
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O_PATH = 010000000
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O_TMPFILE = 020000000 // __O_TMPFILE in Linux
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)
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// Constants for fstatat(2).
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const (
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AT_SYMLINK_NOFOLLOW = 0x100
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)
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// Constants for mount(2).
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const (
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MS_RDONLY = 0x1
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MS_NOSUID = 0x2
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MS_NODEV = 0x4
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MS_NOEXEC = 0x8
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MS_SYNCHRONOUS = 0x10
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MS_REMOUNT = 0x20
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MS_MANDLOCK = 0x40
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MS_DIRSYNC = 0x80
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MS_NOATIME = 0x400
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MS_NODIRATIME = 0x800
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MS_BIND = 0x1000
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MS_MOVE = 0x2000
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MS_REC = 0x4000
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MS_POSIXACL = 0x10000
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MS_UNBINDABLE = 0x20000
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MS_PRIVATE = 0x40000
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MS_SLAVE = 0x80000
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MS_SHARED = 0x100000
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MS_RELATIME = 0x200000
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MS_KERNMOUNT = 0x400000
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MS_I_VERSION = 0x800000
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MS_STRICTATIME = 0x1000000
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MS_MGC_VAL = 0xC0ED0000
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MS_MGC_MSK = 0xffff0000
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)
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// Constants for umount2(2).
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const (
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MNT_FORCE = 0x1
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MNT_DETACH = 0x2
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MNT_EXPIRE = 0x4
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UMOUNT_NOFOLLOW = 0x8
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)
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// Constants for unlinkat(2).
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const (
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AT_REMOVEDIR = 0x200
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)
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// Constants for linkat(2) and fchownat(2).
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const (
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AT_SYMLINK_FOLLOW = 0x400
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AT_EMPTY_PATH = 0x1000
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)
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// Constants for all file-related ...at(2) syscalls.
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const (
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AT_FDCWD = -100
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)
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// Special values for the ns field in utimensat(2).
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const (
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UTIME_NOW = ((1 << 30) - 1)
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UTIME_OMIT = ((1 << 30) - 2)
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)
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// MaxSymlinkTraversals is the maximum number of links that will be followed by
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// the kernel to resolve a symlink.
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const MaxSymlinkTraversals = 40
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// Constants for flock(2).
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const (
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LOCK_SH = 1 // shared lock
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LOCK_EX = 2 // exclusive lock
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LOCK_NB = 4 // or'd with one of the above to prevent blocking
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LOCK_UN = 8 // remove lock
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)
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// Values for mode_t.
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const (
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S_IFMT = 0170000
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S_IFSOCK = 0140000
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S_IFLNK = 0120000
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S_IFREG = 0100000
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S_IFBLK = 060000
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S_IFDIR = 040000
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S_IFCHR = 020000
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S_IFIFO = 010000
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FileTypeMask = S_IFMT
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ModeSocket = S_IFSOCK
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ModeSymlink = S_IFLNK
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ModeRegular = S_IFREG
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ModeBlockDevice = S_IFBLK
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ModeDirectory = S_IFDIR
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ModeCharacterDevice = S_IFCHR
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ModeNamedPipe = S_IFIFO
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S_ISUID = 04000
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S_ISGID = 02000
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S_ISVTX = 01000
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ModeSetUID = S_ISUID
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ModeSetGID = S_ISGID
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ModeSticky = S_ISVTX
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ModeUserAll = 0700
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ModeUserRead = 0400
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ModeUserWrite = 0200
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ModeUserExec = 0100
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ModeGroupAll = 0070
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ModeGroupRead = 0040
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ModeGroupWrite = 0020
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ModeGroupExec = 0010
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ModeOtherAll = 0007
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ModeOtherRead = 0004
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ModeOtherWrite = 0002
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ModeOtherExec = 0001
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PermissionsMask = 0777
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)
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// Values for linux_dirent64.d_type.
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const (
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DT_UNKNOWN = 0
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DT_FIFO = 1
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DT_CHR = 2
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DT_DIR = 4
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DT_BLK = 6
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DT_REG = 8
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DT_LNK = 10
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DT_SOCK = 12
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DT_WHT = 14
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)
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// DirentType are the friendly strings for linux_dirent64.d_type.
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var DirentType = abi.ValueSet{
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DT_UNKNOWN: "DT_UNKNOWN",
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DT_FIFO: "DT_FIFO",
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DT_CHR: "DT_CHR",
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DT_DIR: "DT_DIR",
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DT_BLK: "DT_BLK",
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DT_REG: "DT_REG",
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DT_LNK: "DT_LNK",
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DT_SOCK: "DT_SOCK",
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DT_WHT: "DT_WHT",
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}
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// Values for preadv2/pwritev2.
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const (
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// Note: gVisor does not implement the RWF_HIPRI feature, but the flag is
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// accepted as a valid flag argument for preadv2/pwritev2.
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RWF_HIPRI = 0x00000001
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RWF_DSYNC = 0x00000002
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RWF_SYNC = 0x00000004
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RWF_VALID = RWF_HIPRI | RWF_DSYNC | RWF_SYNC
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)
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// SizeOfStat is the size of a Stat struct.
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var SizeOfStat = binary.Size(Stat{})
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// Flags for statx.
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const (
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AT_STATX_SYNC_TYPE = 0x6000
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AT_STATX_SYNC_AS_STAT = 0x0000
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AT_STATX_FORCE_SYNC = 0x2000
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AT_STATX_DONT_SYNC = 0x4000
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)
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// Mask values for statx.
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const (
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STATX_TYPE = 0x00000001
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STATX_MODE = 0x00000002
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STATX_NLINK = 0x00000004
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STATX_UID = 0x00000008
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STATX_GID = 0x00000010
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STATX_ATIME = 0x00000020
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STATX_MTIME = 0x00000040
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STATX_CTIME = 0x00000080
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STATX_INO = 0x00000100
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STATX_SIZE = 0x00000200
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STATX_BLOCKS = 0x00000400
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STATX_BASIC_STATS = 0x000007ff
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STATX_BTIME = 0x00000800
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STATX_ALL = 0x00000fff
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STATX__RESERVED = 0x80000000
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)
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// Bitmasks for Statx.Attributes and Statx.AttributesMask, from
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// include/uapi/linux/stat.h.
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const (
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STATX_ATTR_COMPRESSED = 0x00000004
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STATX_ATTR_IMMUTABLE = 0x00000010
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STATX_ATTR_APPEND = 0x00000020
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STATX_ATTR_NODUMP = 0x00000040
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STATX_ATTR_ENCRYPTED = 0x00000800
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STATX_ATTR_AUTOMOUNT = 0x00001000
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)
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// Statx represents struct statx.
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type Statx struct {
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Mask uint32
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Blksize uint32
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Attributes uint64
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Nlink uint32
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UID uint32
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GID uint32
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Mode uint16
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_ uint16
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Ino uint64
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Size uint64
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Blocks uint64
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AttributesMask uint64
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Atime StatxTimestamp
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Btime StatxTimestamp
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Ctime StatxTimestamp
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Mtime StatxTimestamp
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RdevMajor uint32
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RdevMinor uint32
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DevMajor uint32
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DevMinor uint32
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}
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// FileMode represents a mode_t.
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type FileMode uint16
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// Permissions returns just the permission bits.
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func (m FileMode) Permissions() FileMode {
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return m & PermissionsMask
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}
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// FileType returns just the file type bits.
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func (m FileMode) FileType() FileMode {
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return m & FileTypeMask
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}
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// ExtraBits returns everything but the file type and permission bits.
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func (m FileMode) ExtraBits() FileMode {
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return m &^ (PermissionsMask | FileTypeMask)
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}
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// String returns a string representation of m.
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func (m FileMode) String() string {
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var s []string
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if ft := m.FileType(); ft != 0 {
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s = append(s, fileType.Parse(uint64(ft)))
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}
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if eb := m.ExtraBits(); eb != 0 {
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s = append(s, modeExtraBits.Parse(uint64(eb)))
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}
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s = append(s, fmt.Sprintf("0o%o", m.Permissions()))
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return strings.Join(s, "|")
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}
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// DirentType maps file types to dirent types appropriate for (struct
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// dirent)::d_type.
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func (m FileMode) DirentType() uint8 {
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switch m.FileType() {
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case ModeSocket:
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return DT_SOCK
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case ModeSymlink:
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return DT_LNK
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case ModeRegular:
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return DT_REG
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case ModeBlockDevice:
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return DT_BLK
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case ModeDirectory:
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return DT_DIR
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case ModeCharacterDevice:
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return DT_CHR
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case ModeNamedPipe:
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return DT_FIFO
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default:
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return DT_UNKNOWN
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}
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}
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var modeExtraBits = abi.FlagSet{
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{
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Flag: ModeSetUID,
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Name: "S_ISUID",
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},
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{
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Flag: ModeSetGID,
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Name: "S_ISGID",
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},
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{
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Flag: ModeSticky,
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Name: "S_ISVTX",
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},
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}
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var fileType = abi.ValueSet{
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ModeSocket: "S_IFSOCK",
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ModeSymlink: "S_IFLINK",
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ModeRegular: "S_IFREG",
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ModeBlockDevice: "S_IFBLK",
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ModeDirectory: "S_IFDIR",
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ModeCharacterDevice: "S_IFCHR",
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ModeNamedPipe: "S_IFIFO",
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}
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// Constants for memfd_create(2). Source: include/uapi/linux/memfd.h
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const (
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MFD_CLOEXEC = 0x0001
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MFD_ALLOW_SEALING = 0x0002
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)
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// Constants related to file seals. Source: include/uapi/{asm-generic,linux}/fcntl.h
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const (
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F_LINUX_SPECIFIC_BASE = 1024
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F_ADD_SEALS = F_LINUX_SPECIFIC_BASE + 9
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F_GET_SEALS = F_LINUX_SPECIFIC_BASE + 10
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F_SEAL_SEAL = 0x0001 // Prevent further seals from being set.
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F_SEAL_SHRINK = 0x0002 // Prevent file from shrinking.
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F_SEAL_GROW = 0x0004 // Prevent file from growing.
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F_SEAL_WRITE = 0x0008 // Prevent writes.
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)
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// Constants related to fallocate(2). Source: include/uapi/linux/falloc.h
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const (
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FALLOC_FL_KEEP_SIZE = 0x01
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FALLOC_FL_PUNCH_HOLE = 0x02
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FALLOC_FL_NO_HIDE_STALE = 0x04
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FALLOC_FL_COLLAPSE_RANGE = 0x08
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FALLOC_FL_ZERO_RANGE = 0x10
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FALLOC_FL_INSERT_RANGE = 0x20
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FALLOC_FL_UNSHARE_RANGE = 0x40
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)
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