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Add prctl to utils package 

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
This commit is contained in:
Michael Crosby 2015-12-07 10:36:48 -08:00
parent 3fdc48eb01
commit 59093a22d0
2 changed files with 45 additions and 19 deletions
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21
containerd/reap_linux.go
View File

@ -9,24 +9,10 @@ import (
"github.com/Sirupsen/logrus"
"github.com/docker/containerd"
"github.com/docker/containerd/util"
"github.com/opencontainers/runc/libcontainer/utils"
)
// http://man7.org/linux/man-pages/man2/prctl.2.html
//
// If arg2 is nonzero, set the "child subreaper" attribute of the
// calling process; if arg2 is zero, unset the attribute. When a
// process is marked as a child subreaper, all of the children
// that it creates, and their descendants, will be marked as
// having a subreaper. In effect, a subreaper fulfills the role
// of init(1) for its descendant processes. Upon termination of
// a process that is orphaned (i.e., its immediate parent has
// already terminated) and marked as having a subreaper, the
// nearest still living ancestor subreaper will receive a SIGCHLD
// signal and be able to wait(2) on the process to discover its
// termination status.
const PR_SET_CHILD_SUBREAPER = 36
func startSignalHandler(supervisor *containerd.Supervisor, bufferSize int) {
logrus.Debug("containerd: starting signal handler")
signals := make(chan os.Signal, bufferSize)
@ -73,8 +59,5 @@ func reap() (exits []*containerd.Event, err error) {
}
func setSubReaper() error {
if _, _, err := syscall.RawSyscall(syscall.SYS_PRCTL, PR_SET_CHILD_SUBREAPER, 1, 0); err != 0 {
return err
}
return nil
return util.SetSubreaper(1)
}

43
util/prctl.go Normal file
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@ -0,0 +1,43 @@
// + build linux
// http://man7.org/linux/man-pages/man2/prctl.2.html
package util
import (
"syscall"
"unsafe"
)
// If arg2 is nonzero, set the "child subreaper" attribute of the
// calling process; if arg2 is zero, unset the attribute. When a
// process is marked as a child subreaper, all of the children
// that it creates, and their descendants, will be marked as
// having a subreaper. In effect, a subreaper fulfills the role
// of init(1) for its descendant processes. Upon termination of
// a process that is orphaned (i.e., its immediate parent has
// already terminated) and marked as having a subreaper, the
// nearest still living ancestor subreaper will receive a SIGCHLD
// signal and be able to wait(2) on the process to discover its
// termination status.
const PR_SET_CHILD_SUBREAPER = 36
// Return the "child subreaper" setting of the caller, in the
// location pointed to by (int *) arg2.
const PR_GET_CHILD_SUBREAPER = 37
// GetSubreaper returns the subreaper setting for the calling process
func GetSubreaper() (int, error) {
var i uintptr
if _, _, err := syscall.RawSyscall(syscall.SYS_PRCTL, PR_GET_CHILD_SUBREAPER, uintptr(unsafe.Pointer(&i)), 0); err != 0 {
return -1, err
}
return int(i), nil
}
// SetSubreaper sets the value i as the subreaper setting for the calling process
func SetSubreaper(i int) error {
if _, _, err := syscall.RawSyscall(syscall.SYS_PRCTL, PR_SET_CHILD_SUBREAPER, uintptr(i), 0); err != 0 {
return err
}
return nil
}