Add IsSandboxed() function to seatbelt wrapper.

sandbox/mac/seatbelt.h

Index: sandbox/mac/seatbelt.h
diff --git a/sandbox/mac/seatbelt.h b/sandbox/mac/seatbelt.h
index 2a5db08e4b6f3a38b9c19eac383fb62cab6a52b5..af935d7e3586d1689572cee9692ba18fd72a3897 100644
--- a/sandbox/mac/seatbelt.h
+++ b/sandbox/mac/seatbelt.h
@@ -5,11 +5,40 @@
 #ifndef SANDBOX_MAC_SEATBELT_H_
 #define SANDBOX_MAC_SEATBELT_H_
 
+#include <sys/types.h>
 #include <cstdint>
 
 #include "base/macros.h"
 #include "sandbox/mac/seatbelt_export.h"
 
+extern "C" {
+
+enum sandbox_filter_type {

[Robert Sesek, 2017/05/31 17:31:08]

Why is this extern C? I don't see this in /usr/include.

This could instead be:

enum class SandboxFilter {
  NONE,
  PATH,
  GLOBAL_NAME,
…
};

+  SANDBOX_FILTER_NONE,
+  SANDBOX_FILTER_PATH,
+  SANDBOX_FILTER_GLOBAL_NAME,
+  SANDBOX_FILTER_LOCAL_NAME,
+  SANDBOX_FILTER_APPLEEVENT_DESTINATION,
+  SANDBOX_FILTER_RIGHT_NAME,
+  SANDBOX_FILTER_PREFERENCE_DOMAIN,
+  SANDBOX_FILTER_KEXT_BUNDLE_ID,
+  SANDBOX_FILTER_INFO_TYPE,
+  SANDBOX_FILTER_NOTIFICATION
+};
+
+extern const enum sandbox_filter_type SANDBOX_CHECK_NO_REPORT;
+extern const enum sandbox_filter_type SANDBOX_CHECK_CANONICAL;
+
+// Not deprecated. The canonical usage to test if sandboxed is
+// sandbox_check(getpid(), NULL, SANDBOX_FILTER_NONE), which returns
+// 1 if sandboxed.
+int sandbox_check(pid_t pid,

[Robert Sesek, 2017/05/31 17:31:08]

Rather than exposing this as a C function, let's wrap it via a Seatbelt static
method.

[Greg K, 2017/05/31 17:36:25]

I wanted to do this, but I'm not sure how to pass along the "..." to the C
function. I can convert the `...` to a va_list, but I'm not aware of a version
of sandbox_check() that consumes a va_list. Are they the same thing?

[Robert Sesek, 2017/05/31 18:09:58]

Argh yeah the varargs is frustrating. Unless there were a variant that takes a
va_list (I don't see one...) you can't forward a varargs function. Do you intend
to use the varargs, because if not, then the Seatbelt method could simply not
take it. If you do, you could also overload it with non-varargs arguments, e.g.:

Seatbelt::Check(pid_t, const char* op, SandboxFilter)
Seatbelt::Check(pid_t, const char* op, SandboxFilter, const char* right)

[Greg K, 2017/05/31 18:14:37]

Right now I only plan to use it to check if it's sandboxed. Maybe I should just
add Seatbelt::IsSandboxed() and expose the generic function later if
appropriate.

[Robert Sesek, 2017/05/31 18:19:08]

That sounds good. Keeping APIs minimal is always the right call.

[Greg K, 2017/06/01 18:42:08]

Done.

+                  const char* operation,
+                  sandbox_filter_type type,
+                  ...);
+
+};  // extern "C"
+
 namespace sandbox {
 
 // This class exists because OS X deprecated the sandbox functions,