138 lines
3.1 KiB
Go
138 lines
3.1 KiB
Go
// Copyright 2018 Google Inc.
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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 host
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import (
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"syscall"
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"unsafe"
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"gvisor.googlesource.com/gvisor/pkg/abi/linux"
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"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
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ktime "gvisor.googlesource.com/gvisor/pkg/sentry/kernel/time"
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)
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func createLink(fd int, name string, linkName string) error {
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namePtr, err := syscall.BytePtrFromString(name)
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if err != nil {
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return err
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}
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linkNamePtr, err := syscall.BytePtrFromString(linkName)
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if err != nil {
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return err
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}
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_, _, errno := syscall.Syscall(
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syscall.SYS_SYMLINKAT,
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uintptr(unsafe.Pointer(namePtr)),
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uintptr(fd),
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uintptr(unsafe.Pointer(linkNamePtr)))
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if errno != 0 {
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return errno
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}
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return nil
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}
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func readLink(fd int) (string, error) {
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// Buffer sizing copied from os.Readlink.
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for l := 128; ; l *= 2 {
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b := make([]byte, l)
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n, _, errno := syscall.Syscall6(
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syscall.SYS_READLINKAT,
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uintptr(fd),
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uintptr(unsafe.Pointer(syscall.StringBytePtr(""))),
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uintptr(unsafe.Pointer(&b[0])),
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uintptr(l),
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0, 0)
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if n < 0 {
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n = 0
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}
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if errno != 0 {
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return "", errno
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}
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if n < uintptr(l) {
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return string(b[:n]), nil
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}
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}
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}
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func unlinkAt(fd int, name string, dir bool) error {
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namePtr, err := syscall.BytePtrFromString(name)
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if err != nil {
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return err
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}
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var flags uintptr
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if dir {
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flags = linux.AT_REMOVEDIR
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}
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_, _, errno := syscall.Syscall(
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syscall.SYS_UNLINKAT,
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uintptr(fd),
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uintptr(unsafe.Pointer(namePtr)),
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flags,
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)
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if errno != 0 {
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return errno
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}
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return nil
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}
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func timespecFromTimestamp(t ktime.Time, omit, setSysTime bool) syscall.Timespec {
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if omit {
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return syscall.Timespec{0, linux.UTIME_OMIT}
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}
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if setSysTime {
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return syscall.Timespec{0, linux.UTIME_NOW}
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}
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return syscall.NsecToTimespec(t.Nanoseconds())
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}
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func setTimestamps(fd int, ts fs.TimeSpec) error {
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if ts.ATimeOmit && ts.MTimeOmit {
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return nil
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}
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var sts [2]syscall.Timespec
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sts[0] = timespecFromTimestamp(ts.ATime, ts.ATimeOmit, ts.ATimeSetSystemTime)
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sts[1] = timespecFromTimestamp(ts.MTime, ts.MTimeOmit, ts.MTimeSetSystemTime)
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_, _, errno := syscall.Syscall6(
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syscall.SYS_UTIMENSAT,
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uintptr(fd),
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0, /* path */
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uintptr(unsafe.Pointer(&sts)),
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0, /* flags */
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0, 0)
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if errno != 0 {
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return errno
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}
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return nil
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}
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func fstatat(fd int, name string, flags int) (syscall.Stat_t, error) {
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var stat syscall.Stat_t
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namePtr, err := syscall.BytePtrFromString(name)
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if err != nil {
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return stat, err
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}
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_, _, errno := syscall.Syscall6(
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syscall.SYS_NEWFSTATAT,
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uintptr(fd),
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uintptr(unsafe.Pointer(namePtr)),
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uintptr(unsafe.Pointer(&stat)),
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uintptr(flags),
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0, 0)
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if errno != 0 {
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return stat, errno
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}
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return stat, nil
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}
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