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// Copyright 2020 The gVisor Authors.
//
// 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 vfs2
import (
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sentry/kernel"
slinux "gvisor.dev/gvisor/pkg/sentry/syscalls/linux"
"gvisor.dev/gvisor/pkg/syserror"
)
// Close implements Linux syscall close(2).
func Close(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
fd := args[0].Int()
// Note that Remove provides a reference on the file that we may use to
// flush. It is still active until we drop the final reference below
// (and other reference-holding operations complete).
_, file := t.FDTable().Remove(fd)
if file == nil {
return 0, nil, syserror.EBADF
}
defer file.DecRef()
err := file.OnClose(t)
return 0, nil, slinux.HandleIOErrorVFS2(t, false /* partial */, err, syserror.EINTR, "close", file)
}
// Dup implements Linux syscall dup(2).
func Dup(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
fd := args[0].Int()
file := t.GetFileVFS2(fd)
if file == nil {
return 0, nil, syserror.EBADF
}
defer file.DecRef()
newFD, err := t.NewFDFromVFS2(0, file, kernel.FDFlags{})
if err != nil {
return 0, nil, syserror.EMFILE
}
return uintptr(newFD), nil, nil
}
// Dup2 implements Linux syscall dup2(2).
func Dup2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
oldfd := args[0].Int()
newfd := args[1].Int()
if oldfd == newfd {
// As long as oldfd is valid, dup2() does nothing and returns newfd.
file := t.GetFileVFS2(oldfd)
if file == nil {
return 0, nil, syserror.EBADF
}
file.DecRef()
return uintptr(newfd), nil, nil
}
return dup3(t, oldfd, newfd, 0)
}
// Dup3 implements Linux syscall dup3(2).
func Dup3(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
oldfd := args[0].Int()
newfd := args[1].Int()
flags := args[2].Uint()
if oldfd == newfd {
return 0, nil, syserror.EINVAL
}
return dup3(t, oldfd, newfd, flags)
}
func dup3(t *kernel.Task, oldfd, newfd int32, flags uint32) (uintptr, *kernel.SyscallControl, error) {
if flags&^linux.O_CLOEXEC != 0 {
return 0, nil, syserror.EINVAL
}
file := t.GetFileVFS2(oldfd)
if file == nil {
return 0, nil, syserror.EBADF
}
defer file.DecRef()
err := t.NewFDAtVFS2(newfd, file, kernel.FDFlags{
CloseOnExec: flags&linux.O_CLOEXEC != 0,
})
if err != nil {
return 0, nil, err
}
return uintptr(newfd), nil, nil
}
// Fcntl implements linux syscall fcntl(2).
func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
fd := args[0].Int()
cmd := args[1].Int()
file, flags := t.FDTable().GetVFS2(fd)
if file == nil {
return 0, nil, syserror.EBADF
}
defer file.DecRef()
switch cmd {
case linux.F_DUPFD, linux.F_DUPFD_CLOEXEC:
minfd := args[2].Int()
fd, err := t.NewFDFromVFS2(minfd, file, kernel.FDFlags{
CloseOnExec: cmd == linux.F_DUPFD_CLOEXEC,
})
if err != nil {
return 0, nil, err
}
return uintptr(fd), nil, nil
case linux.F_GETFD:
return uintptr(flags.ToLinuxFDFlags()), nil, nil
case linux.F_SETFD:
flags := args[2].Uint()
t.FDTable().SetFlags(fd, kernel.FDFlags{
CloseOnExec: flags&linux.FD_CLOEXEC != 0,
})
return 0, nil, nil
case linux.F_GETFL:
return uintptr(file.StatusFlags()), nil, nil
case linux.F_SETFL:
return 0, nil, file.SetStatusFlags(t, t.Credentials(), args[2].Uint())
default:
// TODO(gvisor.dev/issue/1623): Everything else is not yet supported.
return 0, nil, syserror.EINVAL
}
}
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