Move osutil to sys package

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

sys/prctl.go

@@ -0,0 +1,48 @@
+// +build linux
+
+// Package osutils provide access to the Get Child and Set Child prctl
+// flags.
+// See http://man7.org/linux/man-pages/man2/prctl.2.html
+package sys
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+// PR_SET_CHILD_SUBREAPER allows setting the child subreaper.
+// 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 prSetChildSubreaper = 36
+
+// PR_GET_CHILD_SUBREAPER allows retrieving the current child
+// subreaper.
+// Return the "child subreaper" setting of the caller, in the
+// location pointed to by (int *) arg2.
+const prGetChildSubreaper = 37
+
+// GetSubreaper returns the subreaper setting for the calling process
+func GetSubreaper() (int, error) {
+	var i uintptr
+	if _, _, err := syscall.RawSyscall(syscall.SYS_PRCTL, prGetChildSubreaper, 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, prSetChildSubreaper, uintptr(i), 0); err != 0 {
+		return err
+	}
+	return nil
+}