diff options
| -rw-r--r-- | pkg/eventfd/BUILD | 1 | ||||
| -rw-r--r-- | pkg/eventfd/eventfd.go | 2 | ||||
| -rw-r--r-- | pkg/eventfd/eventfd_unsafe.go | 36 |
3 files changed, 38 insertions, 1 deletions
diff --git a/pkg/eventfd/BUILD b/pkg/eventfd/BUILD index 02407cb99..f0bed8e49 100644 --- a/pkg/eventfd/BUILD +++ b/pkg/eventfd/BUILD @@ -6,6 +6,7 @@ go_library( name = "eventfd", srcs = [ "eventfd.go", + "eventfd_unsafe.go", ], visibility = ["//:sandbox"], deps = [ diff --git a/pkg/eventfd/eventfd.go b/pkg/eventfd/eventfd.go index acdac01b8..99ebad34d 100644 --- a/pkg/eventfd/eventfd.go +++ b/pkg/eventfd/eventfd.go @@ -74,7 +74,7 @@ func (ev Eventfd) Write(val uint64) error { var buf [sizeofUint64]byte hostarch.ByteOrder.PutUint64(buf[:], val) for { - n, err := unix.Write(ev.fd, buf[:]) + n, err := nonBlockingWrite(ev.fd, buf[:]) if err == unix.EINTR { continue } diff --git a/pkg/eventfd/eventfd_unsafe.go b/pkg/eventfd/eventfd_unsafe.go new file mode 100644 index 000000000..bb9698f95 --- /dev/null +++ b/pkg/eventfd/eventfd_unsafe.go @@ -0,0 +1,36 @@ +// Copyright 2021 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 eventfd + +import ( + "unsafe" + + "golang.org/x/sys/unix" +) + +// nonBlockingWrite writes the given buffer to a file descriptor. It fails if +// partial data is written. +func nonBlockingWrite(fd int, buf []byte) (int, error) { + var ptr unsafe.Pointer + if len(buf) > 0 { + ptr = unsafe.Pointer(&buf[0]) + } + + nwritten, _, errno := unix.RawSyscall(unix.SYS_WRITE, uintptr(fd), uintptr(ptr), uintptr(len(buf))) + if errno != 0 { + return int(nwritten), errno + } + return int(nwritten), nil +} |