256 lines
8.3 KiB
Go
256 lines
8.3 KiB
Go
// Copyright 2018 Google LLC
|
|
//
|
|
// 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 (
|
|
"gvisor.googlesource.com/gvisor/pkg/abi/linux"
|
|
"gvisor.googlesource.com/gvisor/pkg/binary"
|
|
"gvisor.googlesource.com/gvisor/pkg/sentry/arch"
|
|
"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
|
|
"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
|
|
"gvisor.googlesource.com/gvisor/pkg/sentry/kernel/kdefs"
|
|
"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
|
|
"gvisor.googlesource.com/gvisor/pkg/syserror"
|
|
)
|
|
|
|
// Stat implements linux syscall stat(2).
|
|
func Stat(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
|
|
addr := args[0].Pointer()
|
|
statAddr := args[1].Pointer()
|
|
|
|
path, dirPath, err := copyInPath(t, addr, false /* allowEmpty */)
|
|
if err != nil {
|
|
return 0, nil, err
|
|
}
|
|
|
|
return 0, nil, fileOpOn(t, linux.AT_FDCWD, path, true /* resolve */, func(root *fs.Dirent, d *fs.Dirent) error {
|
|
return stat(t, d, dirPath, statAddr)
|
|
})
|
|
}
|
|
|
|
// Fstatat implements linux syscall newfstatat, i.e. fstatat(2).
|
|
func Fstatat(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
|
|
fd := kdefs.FD(args[0].Int())
|
|
addr := args[1].Pointer()
|
|
statAddr := args[2].Pointer()
|
|
flags := args[3].Int()
|
|
|
|
path, dirPath, err := copyInPath(t, addr, flags&linux.AT_EMPTY_PATH != 0)
|
|
if err != nil {
|
|
return 0, nil, err
|
|
}
|
|
|
|
if path == "" {
|
|
// Annoying. What's wrong with fstat?
|
|
file := t.FDMap().GetFile(fd)
|
|
if file == nil {
|
|
return 0, nil, syserror.EBADF
|
|
}
|
|
defer file.DecRef()
|
|
|
|
return 0, nil, fstat(t, file, statAddr)
|
|
}
|
|
|
|
return 0, nil, fileOpOn(t, fd, path, flags&linux.AT_SYMLINK_NOFOLLOW == 0, func(root *fs.Dirent, d *fs.Dirent) error {
|
|
return stat(t, d, dirPath, statAddr)
|
|
})
|
|
}
|
|
|
|
// Lstat implements linux syscall lstat(2).
|
|
func Lstat(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
|
|
addr := args[0].Pointer()
|
|
statAddr := args[1].Pointer()
|
|
|
|
path, dirPath, err := copyInPath(t, addr, false /* allowEmpty */)
|
|
if err != nil {
|
|
return 0, nil, err
|
|
}
|
|
|
|
// If the path ends in a slash (i.e. dirPath is true), then we *do*
|
|
// want to resolve the final component.
|
|
resolve := dirPath
|
|
|
|
return 0, nil, fileOpOn(t, linux.AT_FDCWD, path, resolve, func(root *fs.Dirent, d *fs.Dirent) error {
|
|
return stat(t, d, dirPath, statAddr)
|
|
})
|
|
}
|
|
|
|
// Fstat implements linux syscall fstat(2).
|
|
func Fstat(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
|
|
fd := kdefs.FD(args[0].Int())
|
|
statAddr := args[1].Pointer()
|
|
|
|
file := t.FDMap().GetFile(fd)
|
|
if file == nil {
|
|
return 0, nil, syserror.EBADF
|
|
}
|
|
defer file.DecRef()
|
|
|
|
return 0, nil, fstat(t, file, statAddr)
|
|
}
|
|
|
|
// stat implements stat from the given *fs.Dirent.
|
|
func stat(t *kernel.Task, d *fs.Dirent, dirPath bool, statAddr usermem.Addr) error {
|
|
if dirPath && !fs.IsDir(d.Inode.StableAttr) {
|
|
return syserror.ENOTDIR
|
|
}
|
|
uattr, err := d.Inode.UnstableAttr(t)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
return copyOutStat(t, statAddr, d.Inode.StableAttr, uattr)
|
|
}
|
|
|
|
// fstat implements fstat for the given *fs.File.
|
|
func fstat(t *kernel.Task, f *fs.File, statAddr usermem.Addr) error {
|
|
uattr, err := f.UnstableAttr(t)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
return copyOutStat(t, statAddr, f.Dirent.Inode.StableAttr, uattr)
|
|
}
|
|
|
|
// copyOutStat copies the attributes (sattr, uattr) to the struct stat at
|
|
// address dst in t's address space. It encodes the stat struct to bytes
|
|
// manually, as stat() is a very common syscall for many applications, and
|
|
// t.CopyObjectOut has noticeable performance impact due to its many slice
|
|
// allocations and use of reflection.
|
|
func copyOutStat(t *kernel.Task, dst usermem.Addr, sattr fs.StableAttr, uattr fs.UnstableAttr) error {
|
|
var mode uint32
|
|
switch sattr.Type {
|
|
case fs.RegularFile, fs.SpecialFile:
|
|
mode |= linux.ModeRegular
|
|
case fs.Symlink:
|
|
mode |= linux.ModeSymlink
|
|
case fs.Directory, fs.SpecialDirectory:
|
|
mode |= linux.ModeDirectory
|
|
case fs.Pipe:
|
|
mode |= linux.ModeNamedPipe
|
|
case fs.CharacterDevice:
|
|
mode |= linux.ModeCharacterDevice
|
|
case fs.BlockDevice:
|
|
mode |= linux.ModeBlockDevice
|
|
case fs.Socket:
|
|
mode |= linux.ModeSocket
|
|
}
|
|
|
|
b := t.CopyScratchBuffer(int(linux.SizeOfStat))[:0]
|
|
|
|
// Dev (uint64)
|
|
b = binary.AppendUint64(b, usermem.ByteOrder, uint64(sattr.DeviceID))
|
|
// Ino (uint64)
|
|
b = binary.AppendUint64(b, usermem.ByteOrder, uint64(sattr.InodeID))
|
|
// Nlink (uint64)
|
|
b = binary.AppendUint64(b, usermem.ByteOrder, uattr.Links)
|
|
// Mode (uint32)
|
|
b = binary.AppendUint32(b, usermem.ByteOrder, mode|uint32(uattr.Perms.LinuxMode()))
|
|
// UID (uint32)
|
|
b = binary.AppendUint32(b, usermem.ByteOrder, uint32(uattr.Owner.UID.In(t.UserNamespace()).OrOverflow()))
|
|
// GID (uint32)
|
|
b = binary.AppendUint32(b, usermem.ByteOrder, uint32(uattr.Owner.GID.In(t.UserNamespace()).OrOverflow()))
|
|
// Padding (uint32)
|
|
b = binary.AppendUint32(b, usermem.ByteOrder, 0)
|
|
// Rdev (uint64)
|
|
b = binary.AppendUint64(b, usermem.ByteOrder, uint64(linux.MakeDeviceID(sattr.DeviceFileMajor, sattr.DeviceFileMinor)))
|
|
// Size (uint64)
|
|
b = binary.AppendUint64(b, usermem.ByteOrder, uint64(uattr.Size))
|
|
// Blksize (uint64)
|
|
b = binary.AppendUint64(b, usermem.ByteOrder, uint64(sattr.BlockSize))
|
|
// Blocks (uint64)
|
|
b = binary.AppendUint64(b, usermem.ByteOrder, uint64(uattr.Usage/512))
|
|
|
|
// ATime
|
|
atime := uattr.AccessTime.Timespec()
|
|
b = binary.AppendUint64(b, usermem.ByteOrder, uint64(atime.Sec))
|
|
b = binary.AppendUint64(b, usermem.ByteOrder, uint64(atime.Nsec))
|
|
|
|
// MTime
|
|
mtime := uattr.ModificationTime.Timespec()
|
|
b = binary.AppendUint64(b, usermem.ByteOrder, uint64(mtime.Sec))
|
|
b = binary.AppendUint64(b, usermem.ByteOrder, uint64(mtime.Nsec))
|
|
|
|
// CTime
|
|
ctime := uattr.StatusChangeTime.Timespec()
|
|
b = binary.AppendUint64(b, usermem.ByteOrder, uint64(ctime.Sec))
|
|
b = binary.AppendUint64(b, usermem.ByteOrder, uint64(ctime.Nsec))
|
|
|
|
_, err := t.CopyOutBytes(dst, b)
|
|
return err
|
|
}
|
|
|
|
// Statfs implements linux syscall statfs(2).
|
|
func Statfs(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
|
|
addr := args[0].Pointer()
|
|
statfsAddr := args[1].Pointer()
|
|
|
|
path, _, err := copyInPath(t, addr, false /* allowEmpty */)
|
|
if err != nil {
|
|
return 0, nil, err
|
|
}
|
|
|
|
return 0, nil, fileOpOn(t, linux.AT_FDCWD, path, true /* resolve */, func(root *fs.Dirent, d *fs.Dirent) error {
|
|
return statfsImpl(t, d, statfsAddr)
|
|
})
|
|
}
|
|
|
|
// Fstatfs implements linux syscall fstatfs(2).
|
|
func Fstatfs(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
|
|
fd := kdefs.FD(args[0].Int())
|
|
statfsAddr := args[1].Pointer()
|
|
|
|
file := t.FDMap().GetFile(fd)
|
|
if file == nil {
|
|
return 0, nil, syserror.EBADF
|
|
}
|
|
defer file.DecRef()
|
|
|
|
return 0, nil, statfsImpl(t, file.Dirent, statfsAddr)
|
|
}
|
|
|
|
// statfsImpl implements the linux syscall statfs and fstatfs based on a Dirent,
|
|
// copying the statfs structure out to addr on success, otherwise an error is
|
|
// returned.
|
|
func statfsImpl(t *kernel.Task, d *fs.Dirent, addr usermem.Addr) error {
|
|
info, err := d.Inode.StatFS(t)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
// Construct the statfs structure and copy it out.
|
|
statfs := linux.Statfs{
|
|
Type: info.Type,
|
|
// Treat block size and fragment size as the same, as
|
|
// most consumers of this structure will expect one
|
|
// or the other to be filled in.
|
|
BlockSize: d.Inode.StableAttr.BlockSize,
|
|
Blocks: info.TotalBlocks,
|
|
// We don't have the concept of reserved blocks, so
|
|
// report blocks free the same as available blocks.
|
|
// This is a normal thing for filesystems, to do, see
|
|
// udf, hugetlbfs, tmpfs, among others.
|
|
BlocksFree: info.FreeBlocks,
|
|
BlocksAvailable: info.FreeBlocks,
|
|
Files: info.TotalFiles,
|
|
FilesFree: info.FreeFiles,
|
|
// Same as Linux for simple_statfs, see fs/libfs.c.
|
|
NameLength: linux.NAME_MAX,
|
|
FragmentSize: d.Inode.StableAttr.BlockSize,
|
|
// Leave other fields 0 like simple_statfs does.
|
|
}
|
|
if _, err := t.CopyOut(addr, &statfs); err != nil {
|
|
return err
|
|
}
|
|
return nil
|
|
}
|