[resending with the right From:...]

Hi Luis,

@@ -556,20 +539,79 @@ capability::set_offset (uint64_t offset) ...

• - (2) - If the top 64 bits are non-zero and the representation is
  

•   COMPACT, the capability has the following format:
  

You're missing documentation for this format.

...

•  /* Handle attributes.  */
  

•  if (get_tag () == false)
  

• attr_str = "invalid ";

•  if (get_otype () == CAP_SEAL_TYPE_RB)
  

• attr_str = "sentry ";

•  if (is_sealed ())
  

• attr_str = "sealed ";

These are supposed to be comma-separated, with no trailing space.

Also sentries are not printed as sealed capabilities (but see below).

•  cap_str += "{";
  

There are no curly braces in the specification.

•  cap_str = val_str + " [" + perm_str + "," + range_str + "]";
  

•  if (!attr_str.empty ())
  

• cap_str += " ( " + attr_str + ")";

There should be no leading space.

I also couldn't help but notice you have the following:

inline bool is_sealed (void) { return check_permissions (CAP_PERM_SEAL); }

(in capability.h)

Whether a capability is sealed and whether a capability can be used to seal are not the same thing.

Jess