1 files changed, 51 insertions, 0 deletions
diff --git a/cap/oslocks.go b/cap/oslocks.go
new file mode 100644
index 0000000..9754020
--- /dev/null
+++ b/cap/oslocks.go
@@ -0,0 +1,51 @@
+// +build go1.10
+
+package cap
+
+import "syscall"
+
+// LaunchSupported indicates that is safe to return from a locked
+// OS Thread and have that OS Thread be terminated by the runtime. The
+// Launch functionality really needs to rely on the fact that an
+// excess of runtime.LockOSThread() vs. runtime.UnlockOSThread() calls
+// in a returning go routine will cause the underlying locked OSThread
+// to terminate. That feature was added to the Go runtime in version
+// 1.10.
+//
+// See these bugs for the discussion and feature assumed by the code
+// in this Launch() functionality:
+//
+//   https://github.com/golang/go/issues/20395
+//   https://github.com/golang/go/issues/20458
+//
+// A value of false for this constant causes the Launch functionality
+// to fail with an error: cap.ErrNoLaunch. If this value is false you
+// have two choices with respect to the Launch functionality:
+//
+//   1) don't use cap.(*Launcher).Launch()
+//   2) upgrade your Go toolchain to 1.10+ (ie., do this one).
+const LaunchSupported = true
+
+// validatePA confirms that the pa.Sys entry is not incompatible with
+// Launch and loads up the chroot value.
+func validatePA(pa *syscall.ProcAttr, chroot string) (bool, error) {
+	s := pa.Sys
+	if s == nil {
+		if chroot == "" {
+			return false, nil
+		}
+		s = &syscall.SysProcAttr{
+			Chroot: chroot,
+		}
+		pa.Sys = s
+	} else if s.Chroot != "" {
+		return false, ErrAmbiguousChroot
+	}
+	if s.Credential != nil {
+		return false, ErrAmbiguousIDs
+	}
+	if len(s.AmbientCaps) != 0 {
+		return false, ErrAmbiguousAmbient
+	}
+	return s != nil && s.Chroot != "", nil
+}