Add a get_random_bytes() syscall to replace the SRPC-based implementation

src/untrusted/irt/irt_random.c

Index: src/untrusted/irt/irt_random.c
diff --git a/src/untrusted/irt/irt_random.c b/src/untrusted/irt/irt_random.c
index 6f16dcf63a032678336089ef3fd6f92f30d03771..d1525afbcb1339c0d720a9694bd2babcd91125cd 100644
--- a/src/untrusted/irt/irt_random.c
+++ b/src/untrusted/irt/irt_random.c
@@ -7,46 +7,21 @@
 #include <errno.h>
 #include <fcntl.h>
 
-#include "native_client/src/public/name_service.h"
 #include "native_client/src/untrusted/nacl/nacl_random.h"
 #include "native_client/src/untrusted/irt/irt.h"
 #include "native_client/src/untrusted/irt/irt_private.h"
 #include "native_client/src/untrusted/nacl/syscall_bindings_trampoline.h"
 
-static int secure_random_fd = -1;
-
-static int prepare_secure_random(void) {
-  if (secure_random_fd == -1) {
-    int fd;
-    int status = irt_nameservice_lookup("SecureRandom", O_RDONLY, &fd);
-    if (status != NACL_NAME_SERVICE_SUCCESS) {
-      return EIO;
-    }
-    if (!__sync_bool_compare_and_swap(&secure_random_fd, -1, fd)) {
-      /*
-       * We raced with another thread.  It already installed an fd.
-       */
-      NACL_SYSCALL(close)(fd);
-    }
-  }
-  return 0;
-}
-
 int nacl_secure_random_init(void) {
   return 0;
 }
 
 int nacl_secure_random(void *buf, size_t count, size_t *nread) {
-  int error = prepare_secure_random();
-  if (error == 0) {
-    int rv = NACL_GC_WRAP_SYSCALL(NACL_SYSCALL(read)(secure_random_fd,
-                                                     buf, count));
-    if (rv < 0)
-      error = -rv;
-    else
-      *nread = rv;
-  }
-  return error;
+  int rv = NACL_GC_WRAP_SYSCALL(NACL_SYSCALL(get_random_bytes)(buf, count));
+  if (rv != 0)
+    return -rv;
+  *nread = count;
+  return 0;
 }
 
 const struct nacl_irt_random nacl_irt_random = {