357 lines
9.6 KiB
Go
357 lines
9.6 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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"bytes"
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"gvisor.dev/gvisor/pkg/abi/linux"
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"gvisor.dev/gvisor/pkg/gohacks"
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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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"gvisor.dev/gvisor/pkg/usermem"
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)
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// Listxattr implements Linux syscall listxattr(2).
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func Listxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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return listxattr(t, args, followFinalSymlink)
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}
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// Llistxattr implements Linux syscall llistxattr(2).
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func Llistxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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return listxattr(t, args, nofollowFinalSymlink)
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}
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func listxattr(t *kernel.Task, args arch.SyscallArguments, shouldFollowFinalSymlink shouldFollowFinalSymlink) (uintptr, *kernel.SyscallControl, error) {
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pathAddr := args[0].Pointer()
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listAddr := args[1].Pointer()
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size := args[2].SizeT()
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path, err := copyInPath(t, pathAddr)
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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, shouldFollowFinalSymlink)
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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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names, err := t.Kernel().VFS().ListxattrAt(t, t.Credentials(), &tpop.pop, uint64(size))
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if err != nil {
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return 0, nil, err
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}
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n, err := copyOutXattrNameList(t, listAddr, size, names)
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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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// Flistxattr implements Linux syscall flistxattr(2).
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func Flistxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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fd := args[0].Int()
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listAddr := args[1].Pointer()
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size := args[2].SizeT()
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file := t.GetFileVFS2(fd)
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if file == nil {
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return 0, nil, syserror.EBADF
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}
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defer file.DecRef()
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names, err := file.Listxattr(t, uint64(size))
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if err != nil {
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return 0, nil, err
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}
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n, err := copyOutXattrNameList(t, listAddr, size, names)
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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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// Getxattr implements Linux syscall getxattr(2).
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func Getxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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return getxattr(t, args, followFinalSymlink)
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}
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// Lgetxattr implements Linux syscall lgetxattr(2).
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func Lgetxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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return getxattr(t, args, nofollowFinalSymlink)
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}
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func getxattr(t *kernel.Task, args arch.SyscallArguments, shouldFollowFinalSymlink shouldFollowFinalSymlink) (uintptr, *kernel.SyscallControl, error) {
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pathAddr := args[0].Pointer()
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nameAddr := args[1].Pointer()
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valueAddr := args[2].Pointer()
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size := args[3].SizeT()
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path, err := copyInPath(t, pathAddr)
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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, shouldFollowFinalSymlink)
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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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name, err := copyInXattrName(t, nameAddr)
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if err != nil {
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return 0, nil, err
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}
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value, err := t.Kernel().VFS().GetxattrAt(t, t.Credentials(), &tpop.pop, &vfs.GetxattrOptions{
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Name: name,
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Size: uint64(size),
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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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n, err := copyOutXattrValue(t, valueAddr, size, value)
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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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// Fgetxattr implements Linux syscall fgetxattr(2).
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func Fgetxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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fd := args[0].Int()
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nameAddr := args[1].Pointer()
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valueAddr := args[2].Pointer()
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size := args[3].SizeT()
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file := t.GetFileVFS2(fd)
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if file == nil {
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return 0, nil, syserror.EBADF
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}
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defer file.DecRef()
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name, err := copyInXattrName(t, nameAddr)
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if err != nil {
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return 0, nil, err
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}
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value, err := file.Getxattr(t, &vfs.GetxattrOptions{Name: name, Size: uint64(size)})
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if err != nil {
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return 0, nil, err
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}
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n, err := copyOutXattrValue(t, valueAddr, size, value)
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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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// Setxattr implements Linux syscall setxattr(2).
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func Setxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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return 0, nil, setxattr(t, args, followFinalSymlink)
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}
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// Lsetxattr implements Linux syscall lsetxattr(2).
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func Lsetxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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return 0, nil, setxattr(t, args, nofollowFinalSymlink)
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}
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func setxattr(t *kernel.Task, args arch.SyscallArguments, shouldFollowFinalSymlink shouldFollowFinalSymlink) error {
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pathAddr := args[0].Pointer()
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nameAddr := args[1].Pointer()
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valueAddr := args[2].Pointer()
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size := args[3].SizeT()
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flags := args[4].Int()
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if flags&^(linux.XATTR_CREATE|linux.XATTR_REPLACE) != 0 {
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return syserror.EINVAL
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}
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path, err := copyInPath(t, pathAddr)
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if err != nil {
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return err
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}
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tpop, err := getTaskPathOperation(t, linux.AT_FDCWD, path, disallowEmptyPath, shouldFollowFinalSymlink)
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if err != nil {
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return err
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}
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defer tpop.Release()
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name, err := copyInXattrName(t, nameAddr)
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if err != nil {
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return err
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}
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value, err := copyInXattrValue(t, valueAddr, size)
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if err != nil {
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return err
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}
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return t.Kernel().VFS().SetxattrAt(t, t.Credentials(), &tpop.pop, &vfs.SetxattrOptions{
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Name: name,
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Value: value,
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Flags: uint32(flags),
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})
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}
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// Fsetxattr implements Linux syscall fsetxattr(2).
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func Fsetxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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fd := args[0].Int()
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nameAddr := args[1].Pointer()
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valueAddr := args[2].Pointer()
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size := args[3].SizeT()
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flags := args[4].Int()
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if flags&^(linux.XATTR_CREATE|linux.XATTR_REPLACE) != 0 {
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return 0, nil, syserror.EINVAL
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}
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file := t.GetFileVFS2(fd)
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if file == nil {
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return 0, nil, syserror.EBADF
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}
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defer file.DecRef()
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name, err := copyInXattrName(t, nameAddr)
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if err != nil {
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return 0, nil, err
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}
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value, err := copyInXattrValue(t, valueAddr, size)
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if err != nil {
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return 0, nil, err
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}
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return 0, nil, file.Setxattr(t, &vfs.SetxattrOptions{
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Name: name,
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Value: value,
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Flags: uint32(flags),
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})
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}
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// Removexattr implements Linux syscall removexattr(2).
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func Removexattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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return 0, nil, removexattr(t, args, followFinalSymlink)
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}
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// Lremovexattr implements Linux syscall lremovexattr(2).
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func Lremovexattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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return 0, nil, removexattr(t, args, nofollowFinalSymlink)
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}
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func removexattr(t *kernel.Task, args arch.SyscallArguments, shouldFollowFinalSymlink shouldFollowFinalSymlink) error {
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pathAddr := args[0].Pointer()
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nameAddr := args[1].Pointer()
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path, err := copyInPath(t, pathAddr)
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if err != nil {
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return err
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}
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tpop, err := getTaskPathOperation(t, linux.AT_FDCWD, path, disallowEmptyPath, shouldFollowFinalSymlink)
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if err != nil {
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return err
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}
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defer tpop.Release()
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name, err := copyInXattrName(t, nameAddr)
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if err != nil {
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return err
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}
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return t.Kernel().VFS().RemovexattrAt(t, t.Credentials(), &tpop.pop, name)
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}
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// Fremovexattr implements Linux syscall fremovexattr(2).
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func Fremovexattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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fd := args[0].Int()
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nameAddr := args[1].Pointer()
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file := t.GetFileVFS2(fd)
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if file == nil {
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return 0, nil, syserror.EBADF
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}
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defer file.DecRef()
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name, err := copyInXattrName(t, nameAddr)
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if err != nil {
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return 0, nil, err
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}
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return 0, nil, file.Removexattr(t, name)
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}
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func copyInXattrName(t *kernel.Task, nameAddr usermem.Addr) (string, error) {
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name, err := t.CopyInString(nameAddr, linux.XATTR_NAME_MAX+1)
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if err != nil {
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if err == syserror.ENAMETOOLONG {
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return "", syserror.ERANGE
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}
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return "", err
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}
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if len(name) == 0 {
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return "", syserror.ERANGE
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}
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return name, nil
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}
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func copyOutXattrNameList(t *kernel.Task, listAddr usermem.Addr, size uint, names []string) (int, error) {
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if size > linux.XATTR_LIST_MAX {
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size = linux.XATTR_LIST_MAX
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}
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var buf bytes.Buffer
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for _, name := range names {
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buf.WriteString(name)
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buf.WriteByte(0)
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}
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if size == 0 {
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// Return the size that would be required to accomodate the list.
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return buf.Len(), nil
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}
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if buf.Len() > int(size) {
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if size >= linux.XATTR_LIST_MAX {
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return 0, syserror.E2BIG
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}
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return 0, syserror.ERANGE
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}
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return t.CopyOutBytes(listAddr, buf.Bytes())
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}
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func copyInXattrValue(t *kernel.Task, valueAddr usermem.Addr, size uint) (string, error) {
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if size > linux.XATTR_SIZE_MAX {
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return "", syserror.E2BIG
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}
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buf := make([]byte, size)
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if _, err := t.CopyInBytes(valueAddr, buf); err != nil {
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return "", err
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}
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return gohacks.StringFromImmutableBytes(buf), nil
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}
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func copyOutXattrValue(t *kernel.Task, valueAddr usermem.Addr, size uint, value string) (int, error) {
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if size > linux.XATTR_SIZE_MAX {
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size = linux.XATTR_SIZE_MAX
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}
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if size == 0 {
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// Return the size that would be required to accomodate the value.
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return len(value), nil
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}
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if len(value) > int(size) {
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if size >= linux.XATTR_SIZE_MAX {
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return 0, syserror.E2BIG
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}
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return 0, syserror.ERANGE
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}
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return t.CopyOutBytes(valueAddr, gohacks.ImmutableBytesFromString(value))
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}
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