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// Copyright 2022 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 linux
import (
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/errors/linuxerr"
"gvisor.dev/gvisor/pkg/hostarch"
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sentry/fsimpl/iouringfs"
"gvisor.dev/gvisor/pkg/sentry/kernel"
)
// IOUringSetup implements linux syscall io_uring_setup(2).
func IOUringSetup(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
entries := uint32(args[0].Uint())
paramsAddr := args[1].Pointer()
var params linux.IOUringParams
if entries == 0 {
return 0, nil, linuxerr.EINVAL
}
if _, err := params.CopyIn(t, paramsAddr); err != nil {
return 0, nil, err
}
for i := int(0); i < len(params.Resv); i++ {
if params.Resv[i] != 0 {
return 0, nil, linuxerr.EINVAL
}
}
// List of currently supported flags in our IO_URING implementation.
const supportedFlags = 0 // Currently support none
// Since we don't implement everything, we fail explicitly on flags that are unimplemented.
if params.Flags|supportedFlags != supportedFlags {
return 0, nil, linuxerr.EINVAL
}
vfsObj := t.Kernel().VFS()
iouringfd, err := iouringfs.New(t, vfsObj, entries, ¶ms)
if err != nil {
// return 0, nil, err
return 0, nil, linuxerr.EPERM
}
defer iouringfd.DecRef(t)
fd, err := t.NewFDFrom(0, iouringfd, kernel.FDFlags{
// O_CLOEXEC is always set up. See io_uring/io_uring.c:io_uring_install_fd().
CloseOnExec: true,
})
if err != nil {
return 0, nil, err
}
if _, err := params.CopyOut(t, paramsAddr); err != nil {
return 0, nil, err
}
return uintptr(fd), nil, nil
}
// IOUringEnter implements linux syscall io_uring_enter(2).
func IOUringEnter(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
fd := int32(args[0].Int())
toSubmit := uint32(args[1].Uint())
minComplete := uint32(args[2].Uint())
flags := uint32(args[3].Uint())
sigSet := args[4].Pointer()
ret := -1
// List of currently supported flags for io_uring_enter(2).
const supportedFlags = linux.IORING_ENTER_GETEVENTS
// Since we don't implement everything, we fail explicitly on flags that are unimplemented.
if flags|supportedFlags != supportedFlags {
return uintptr(ret), nil, linuxerr.EINVAL
}
// Currently don't support replacing an existing signal mask.
if sigSet != hostarch.Addr(0) {
return uintptr(ret), nil, linuxerr.EFAULT
}
// If a user requested to submit zero SQEs, then we don't process any and return right away.
if toSubmit == 0 {
return uintptr(ret), nil, nil
}
file := t.GetFile(fd)
if file == nil {
return uintptr(ret), nil, linuxerr.EBADF
}
defer file.DecRef(t)
iouringfd, ok := file.Impl().(*iouringfs.FileDescription)
if !ok {
return uintptr(ret), nil, linuxerr.EBADF
}
ret, err := iouringfd.ProcessSubmissions(t, toSubmit, minComplete, flags)
if err != nil {
return uintptr(ret), nil, err
}
return uintptr(ret), nil, nil
}
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