gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/pkg/sentry/syscalls/linux/sys_pipe.go (about)

     1  // Copyright 2020 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  	"gvisor.dev/gvisor/pkg/abi/linux"
    19  	"gvisor.dev/gvisor/pkg/errors/linuxerr"
    20  	"gvisor.dev/gvisor/pkg/hostarch"
    21  	"gvisor.dev/gvisor/pkg/marshal/primitive"
    22  	"gvisor.dev/gvisor/pkg/sentry/arch"
    23  	"gvisor.dev/gvisor/pkg/sentry/fsimpl/pipefs"
    24  	"gvisor.dev/gvisor/pkg/sentry/kernel"
    25  	"gvisor.dev/gvisor/pkg/sentry/vfs"
    26  )
    27  
    28  // Pipe implements Linux syscall pipe(2).
    29  func Pipe(t *kernel.Task, sysno uintptr, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
    30  	addr := args[0].Pointer()
    31  	return 0, nil, pipe2(t, addr, 0)
    32  }
    33  
    34  // Pipe2 implements Linux syscall pipe2(2).
    35  func Pipe2(t *kernel.Task, sysno uintptr, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
    36  	addr := args[0].Pointer()
    37  	flags := args[1].Int()
    38  	return 0, nil, pipe2(t, addr, flags)
    39  }
    40  
    41  func pipe2(t *kernel.Task, addr hostarch.Addr, flags int32) error {
    42  	if flags&^(linux.O_NONBLOCK|linux.O_CLOEXEC) != 0 {
    43  		return linuxerr.EINVAL
    44  	}
    45  	r, w, err := pipefs.NewConnectedPipeFDs(t, t.Kernel().PipeMount(), uint32(flags&linux.O_NONBLOCK))
    46  	if err != nil {
    47  		return err
    48  	}
    49  	defer r.DecRef(t)
    50  	defer w.DecRef(t)
    51  
    52  	fds, err := t.NewFDs(0, []*vfs.FileDescription{r, w}, kernel.FDFlags{
    53  		CloseOnExec: flags&linux.O_CLOEXEC != 0,
    54  	})
    55  	if err != nil {
    56  		return err
    57  	}
    58  	if _, err := primitive.CopyInt32SliceOut(t, addr, fds); err != nil {
    59  		for _, fd := range fds {
    60  			if file := t.FDTable().Remove(t, fd); file != nil {
    61  				file.DecRef(t)
    62  			}
    63  		}
    64  		return err
    65  	}
    66  	return nil
    67  }