github.com/demonoid81/containerd@v1.3.4/sys/reaper_linux.go (about)

     1  /*
     2     Copyright The containerd Authors.
     3  
     4     Licensed under the Apache License, Version 2.0 (the "License");
     5     you may not use this file except in compliance with the License.
     6     You may obtain a copy of the License at
     7  
     8         http://www.apache.org/licenses/LICENSE-2.0
     9  
    10     Unless required by applicable law or agreed to in writing, software
    11     distributed under the License is distributed on an "AS IS" BASIS,
    12     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13     See the License for the specific language governing permissions and
    14     limitations under the License.
    15  */
    16  
    17  package sys
    18  
    19  import (
    20  	"unsafe"
    21  
    22  	"golang.org/x/sys/unix"
    23  )
    24  
    25  // If arg2 is nonzero, set the "child subreaper" attribute of the
    26  // calling process; if arg2 is zero, unset the attribute.  When a
    27  // process is marked as a child subreaper, all of the children
    28  // that it creates, and their descendants, will be marked as
    29  // having a subreaper.  In effect, a subreaper fulfills the role
    30  // of init(1) for its descendant processes.  Upon termination of
    31  // a process that is orphaned (i.e., its immediate parent has
    32  // already terminated) and marked as having a subreaper, the
    33  // nearest still living ancestor subreaper will receive a SIGCHLD
    34  // signal and be able to wait(2) on the process to discover its
    35  // termination status.
    36  const setChildSubreaper = 36
    37  
    38  // SetSubreaper sets the value i as the subreaper setting for the calling process
    39  func SetSubreaper(i int) error {
    40  	return unix.Prctl(setChildSubreaper, uintptr(i), 0, 0, 0)
    41  }
    42  
    43  // GetSubreaper returns the subreaper setting for the calling process
    44  func GetSubreaper() (int, error) {
    45  	var i uintptr
    46  
    47  	if err := unix.Prctl(unix.PR_GET_CHILD_SUBREAPER, uintptr(unsafe.Pointer(&i)), 0, 0, 0); err != nil {
    48  		return -1, err
    49  	}
    50  
    51  	return int(i), nil
    52  }