github.com/SagerNet/gvisor@v0.0.0-20210707092255-7731c139d75c/pkg/sentry/syscalls/linux/sys_pipe.go (about)

     1  // Copyright 2018 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package linux
    16  
    17  import (
    18  	"github.com/SagerNet/gvisor/pkg/abi/linux"
    19  	"github.com/SagerNet/gvisor/pkg/errors/linuxerr"
    20  	"github.com/SagerNet/gvisor/pkg/hostarch"
    21  	"github.com/SagerNet/gvisor/pkg/marshal/primitive"
    22  	"github.com/SagerNet/gvisor/pkg/sentry/arch"
    23  	"github.com/SagerNet/gvisor/pkg/sentry/fs"
    24  	"github.com/SagerNet/gvisor/pkg/sentry/kernel"
    25  	"github.com/SagerNet/gvisor/pkg/sentry/kernel/pipe"
    26  )
    27  
    28  // LINT.IfChange
    29  
    30  // pipe2 implements the actual system call with flags.
    31  func pipe2(t *kernel.Task, addr hostarch.Addr, flags uint) (uintptr, error) {
    32  	if flags&^(linux.O_NONBLOCK|linux.O_CLOEXEC) != 0 {
    33  		return 0, linuxerr.EINVAL
    34  	}
    35  	r, w := pipe.NewConnectedPipe(t, pipe.DefaultPipeSize)
    36  
    37  	r.SetFlags(linuxToFlags(flags).Settable())
    38  	defer r.DecRef(t)
    39  
    40  	w.SetFlags(linuxToFlags(flags).Settable())
    41  	defer w.DecRef(t)
    42  
    43  	fds, err := t.NewFDs(0, []*fs.File{r, w}, kernel.FDFlags{
    44  		CloseOnExec: flags&linux.O_CLOEXEC != 0,
    45  	})
    46  	if err != nil {
    47  		return 0, err
    48  	}
    49  
    50  	if _, err := primitive.CopyInt32SliceOut(t, addr, fds); err != nil {
    51  		for _, fd := range fds {
    52  			if file, _ := t.FDTable().Remove(t, fd); file != nil {
    53  				file.DecRef(t)
    54  			}
    55  		}
    56  		return 0, err
    57  	}
    58  	return 0, nil
    59  }
    60  
    61  // Pipe implements linux syscall pipe(2).
    62  func Pipe(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
    63  	addr := args[0].Pointer()
    64  
    65  	n, err := pipe2(t, addr, 0)
    66  	return n, nil, err
    67  }
    68  
    69  // Pipe2 implements linux syscall pipe2(2).
    70  func Pipe2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
    71  	addr := args[0].Pointer()
    72  	flags := uint(args[1].Uint())
    73  
    74  	n, err := pipe2(t, addr, flags)
    75  	return n, nil, err
    76  }
    77  
    78  // LINT.ThenChange(vfs2/pipe.go)