mprotect system call exposed to the untrusted code.

src/untrusted/irt/irt.h

 /*
  * Copyright (c) 2012 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef NATIVE_CLIENT_SRC_UNTRUSTED_IRT_IRT_H_
 #define NATIVE_CLIENT_SRC_UNTRUSTED_IRT_IRT_H_
 
 #include <stddef.h>
 #include <sys/types.h>
@@ skipping 73 matching lines @@
 struct nacl_irt_filename {
   int (*open)(const char *pathname, int oflag, mode_t cmode, int *newfd);
   int (*stat)(const char *pathname, struct stat *);
 };
 
 #define NACL_IRT_MEMORY_v0_1    "nacl-irt-memory-0.1"
 struct nacl_irt_memory {
   int (*sysbrk)(void **newbrk);
   int (*mmap)(void **addr, size_t len, int prot, int flags, int fd, off_t off);
   int (*munmap)(void *addr, size_t len);
+  int (*mprotect)(void *addr, size_t len, int prot);

[Mark Seaborn, 2012/10/14 00:47:16]

You can't just add to "struct nacl_irt_memory".  You need to either change the
version number (but keep the old interface version) or introduce a new
interface.

[Petr Hosek, 2012/10/14 00:53:21]

Which one of these two is the preferred way?

[Mark Seaborn, 2012/10/14 00:59:49]

There's no precedent here.  We haven't extended any interfaces so far.  My
preference would be for a new interface containing only mprotect(), since it
avoids compatibility and testing problems.  Roland might disagree.

 };
 
 #define NACL_IRT_DYNCODE_v0_1   "nacl-irt-dyncode-0.1"
 struct nacl_irt_dyncode {
   int (*dyncode_create)(void *dest, const void *src, size_t size);
   int (*dyncode_modify)(void *dest, const void *src, size_t size);
   int (*dyncode_delete)(void *dest, size_t size);
 };
 
 #define NACL_IRT_THREAD_v0_1   "nacl-irt-thread-0.1"
@@ skipping 87 matching lines @@
                            NaClExceptionHandler *old_handler);
   int (*exception_stack)(void *stack, size_t size);
   int (*exception_clear_flag)(void);
 };
 
 #if defined(__cplusplus)
 }
 #endif
 
 #endif /* NATIVE_CLIENT_SRC_UNTRUSTED_IRT_IRT_H */