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// Copyright 2018 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.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/syserror"
)
// Lseek implements linux syscall lseek(2).
func Lseek(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
fd := kdefs.FD(args[0].Int())
offset := args[1].Int64()
whence := args[2].Int()
file := t.FDMap().GetFile(fd)
if file == nil {
return 0, nil, syserror.EBADF
}
defer file.DecRef()
var sw fs.SeekWhence
switch whence {
case 0:
sw = fs.SeekSet
case 1:
sw = fs.SeekCurrent
case 2:
sw = fs.SeekEnd
default:
return 0, nil, syserror.EINVAL
}
offset, serr := file.Seek(t, sw, offset)
err := handleIOError(t, false /* partialResult */, serr, kernel.ERESTARTSYS, "lseek", file)
if err != nil {
return 0, nil, err
}
return uintptr(offset), nil, err
}
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