132 lines
3.5 KiB
Go
132 lines
3.5 KiB
Go
// Copyright 2020 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 vfs2
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import (
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"gvisor.dev/gvisor/pkg/abi/linux"
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"gvisor.dev/gvisor/pkg/fspath"
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"gvisor.dev/gvisor/pkg/sentry/arch"
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"gvisor.dev/gvisor/pkg/sentry/kernel"
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"gvisor.dev/gvisor/pkg/sentry/vfs"
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"gvisor.dev/gvisor/pkg/syserror"
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)
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// Getcwd implements Linux syscall getcwd(2).
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func Getcwd(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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addr := args[0].Pointer()
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size := args[1].SizeT()
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root := t.FSContext().RootDirectoryVFS2()
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wd := t.FSContext().WorkingDirectoryVFS2()
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s, err := t.Kernel().VFS().PathnameForGetcwd(t, root, wd)
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root.DecRef()
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wd.DecRef()
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if err != nil {
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return 0, nil, err
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}
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// Note this is >= because we need a terminator.
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if uint(len(s)) >= size {
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return 0, nil, syserror.ERANGE
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}
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// Construct a byte slice containing a NUL terminator.
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buf := t.CopyScratchBuffer(len(s) + 1)
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copy(buf, s)
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buf[len(buf)-1] = 0
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// Write the pathname slice.
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n, err := t.CopyOutBytes(addr, buf)
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if err != nil {
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return 0, nil, err
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}
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return uintptr(n), nil, nil
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}
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// Chdir implements Linux syscall chdir(2).
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func Chdir(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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addr := args[0].Pointer()
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path, err := copyInPath(t, addr)
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if err != nil {
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return 0, nil, err
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}
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tpop, err := getTaskPathOperation(t, linux.AT_FDCWD, path, disallowEmptyPath, followFinalSymlink)
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if err != nil {
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return 0, nil, err
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}
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defer tpop.Release()
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vd, err := t.Kernel().VFS().GetDentryAt(t, t.Credentials(), &tpop.pop, &vfs.GetDentryOptions{
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CheckSearchable: true,
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})
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if err != nil {
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return 0, nil, err
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}
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t.FSContext().SetWorkingDirectoryVFS2(vd)
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vd.DecRef()
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return 0, nil, nil
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}
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// Fchdir implements Linux syscall fchdir(2).
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func Fchdir(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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fd := args[0].Int()
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tpop, err := getTaskPathOperation(t, fd, fspath.Path{}, allowEmptyPath, nofollowFinalSymlink)
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if err != nil {
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return 0, nil, err
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}
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defer tpop.Release()
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vd, err := t.Kernel().VFS().GetDentryAt(t, t.Credentials(), &tpop.pop, &vfs.GetDentryOptions{
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CheckSearchable: true,
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})
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if err != nil {
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return 0, nil, err
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}
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t.FSContext().SetWorkingDirectoryVFS2(vd)
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vd.DecRef()
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return 0, nil, nil
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}
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// Chroot implements Linux syscall chroot(2).
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func Chroot(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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addr := args[0].Pointer()
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if !t.HasCapability(linux.CAP_SYS_CHROOT) {
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return 0, nil, syserror.EPERM
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}
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path, err := copyInPath(t, addr)
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if err != nil {
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return 0, nil, err
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}
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tpop, err := getTaskPathOperation(t, linux.AT_FDCWD, path, disallowEmptyPath, followFinalSymlink)
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if err != nil {
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return 0, nil, err
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}
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defer tpop.Release()
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vd, err := t.Kernel().VFS().GetDentryAt(t, t.Credentials(), &tpop.pop, &vfs.GetDentryOptions{
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CheckSearchable: true,
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})
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if err != nil {
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return 0, nil, err
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}
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t.FSContext().SetRootDirectoryVFS2(vd)
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vd.DecRef()
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return 0, nil, nil
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}
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