add restricted filesystem access to sel_ldr

src/trusted/service_runtime/nacl_syscall_common.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.
  */
 
 /*
  * NaCl service run-time, non-platform specific system call helper routines.
  */
 
@@ skipping 27 matching lines @@
 int32_t NaClSysExit(struct NaClAppThread  *natp,
                     int                   status);
 
 int32_t NaClSysThreadExit(struct NaClAppThread  *natp,
                           uint32_t              stack_flag_addr);
 
 extern int NaClAclBypassChecks;
 
 void NaClInsecurelyBypassAllAclChecks(void);
 
+extern char *NaClRootFolder;

[Mark Seaborn, 2015/06/25 23:55:09]

Nit: "Directory" or "Dir" would be preferred over "Folder" here, since the
former term is more commonly used in systems programming.

+extern size_t NaClRootFolderLen;
+
+void NaClMountRootFolder(char *root);
+
+/* bool */
+int NaClFileAccessEnabled(void);
+
 /* bool */
 int NaClSysCommonAddrRangeContainsExecutablePages(struct NaClApp *nap,
                                                   uintptr_t usraddr,
                                                   size_t length);
 
 /* bool */
 int NaClSysCommonAddrRangeInAllowedDynamicCodeSpace(struct NaClApp *nap,
                                                     uintptr_t usraddr,
                                                     size_t length);
 
@@ skipping 84 matching lines @@
                        int32_t              name,
                        uint32_t             result_addr);
 
 int32_t NaClSysTestInfoLeak(struct NaClAppThread *natp);
 
 int32_t NaClSysTestCrash(struct NaClAppThread *natp, int crash_type);
 
 EXTERN_C_END
 
 #endif  /* NATIVE_CLIENT_SERVICE_RUNTIME_NACL_SYSCALL_COMMON_H__ */