mprotect system call exposed to the untrusted code.

src/untrusted/irt/irt_dev_mprotect.c

Index: src/untrusted/irt/irt_dev_mprotect.c
diff --git a/src/untrusted/irt/irt_dev_getpid.c b/src/untrusted/irt/irt_dev_mprotect.c
similarity index 62%
copy from src/untrusted/irt/irt_dev_getpid.c
copy to src/untrusted/irt/irt_dev_mprotect.c
index 8360fc8eecbf6015a38f4b39c545fa1028851e31..486667f86a35a2822685c43f202ae92fcb5d04bc 100644
--- a/src/untrusted/irt/irt_dev_getpid.c
+++ b/src/untrusted/irt/irt_dev_mprotect.c
@@ -8,14 +8,10 @@
 #include "native_client/src/untrusted/irt/irt_interfaces.h"
 #include "native_client/src/untrusted/nacl/syscall_bindings_trampoline.h"
 
-static int nacl_irt_dev_getpid_func(int *pid) {
-  int rv = NACL_SYSCALL(getpid)();
-  if (rv < 0)
-    return -rv;
-  *pid = rv;
-  return 0;
+static int nacl_irt_mprotect(void *addr, size_t len, int prot) {
+  return -NACL_SYSCALL(mprotect)(addr, len, prot);
 }
 
-const struct nacl_irt_dev_getpid nacl_irt_dev_getpid = {
-  nacl_irt_dev_getpid_func,
+const struct nacl_irt_dev_mprotect nacl_irt_dev_mprotect = {
+  nacl_irt_mprotect,
 };