Allow the seccomp sandbox to be enabled, even if the suid sandbox has...

sandbox/linux/seccomp/munmap.cc

 #include "debug.h"
 #include "sandbox_impl.h"
 
 namespace playground {
 
 int Sandbox::sandbox_munmap(void* start, size_t length) {
   Debug::syscall(__NR_munmap, "Executing handler");
   struct {
     int       sysnum;
     long long cookie;
     MUnmap    munmap_req;
   } __attribute__((packed)) request;
   request.sysnum            = __NR_munmap;
   request.cookie            = cookie();
   request.munmap_req.start  = start;
   request.munmap_req.length = length;
 
   long rc;
   SysCalls sys;
   if (write(sys, processFdPub(), &request, sizeof(request)) !=
       sizeof(request) ||
       read(sys, threadFdPub(), &rc, sizeof(rc)) != sizeof(rc)) {
     die("Failed to forward munmap() request [sandbox]");
   }
   return static_cast<int>(rc);
 }
 
-bool Sandbox::process_munmap(int parentProc, int sandboxFd, int threadFdPub,
+bool Sandbox::process_munmap(int parentMapsFd, int sandboxFd, int threadFdPub,
                              int threadFd, SecureMem::Args* mem) {
   // Read request
   SysCalls sys;
   MUnmap munmap_req;
   if (read(sys, sandboxFd, &munmap_req, sizeof(munmap_req)) !=
       sizeof(munmap_req)) {
     die("Failed to read parameters for munmap() [process]");
   }
 
   // Cannot unmap any memory region that was part of the original memory
@@ skipping 16 matching lines @@
   }
 
   // Unmapping memory regions that were newly mapped inside of the sandbox
   // is OK.
   SecureMem::sendSystemCall(threadFdPub, false, -1, mem, __NR_munmap,
                             munmap_req.start, munmap_req.length);
   return true;
 }
 
 } // namespace