1                 : /*
       2                 :  * Copyright (c) 2008 The Native Client Authors. All rights reserved.
       3                 :  * Use of this source code is governed by a BSD-style license that can be
       4                 :  * found in the LICENSE file.
       5                 :  */
       6                 : 
       7                 : 
       8                 : /* TODO: add comment why this is needed */
       9                 : #ifndef _GNU_SOURCE
      10                 : #define _GNU_SOURCE
      11                 : #endif
      12                 : 
      13                 : #include <assert.h>
      14                 : #include <dlfcn.h>
      15                 : #include <libgen.h>
      16                 : #include <stdio.h>
      17                 : #include <stdint.h>
      18                 : #include <stdlib.h>
      19                 : #include <string.h>
      20                 : #include <unistd.h>
      21                 : 
      22                 : #include "native_client/src/include/portability.h"
      23                 : #include "native_client/src/trusted/nonnacl_util/sel_ldr_launcher.h"
      24                 : 
      25                 : namespace nacl {
      26                 : 
      27                 : // First, try looking a symbol up in the dynamic loader's records.
      28               0 : static void PathFromSymbol(char* buffer, size_t len, void* sym) {
      29                 : #if NACL_ANDROID
      30                 :   UNREFERENCED_PARAMETER(sym);
      31                 :   // We do not have dladdr() on Android.
      32                 :   if (len > 0)
      33                 :     buffer[0] = '\0';
      34                 : #else
      35                 :   Dl_info info;
      36                 : 
      37               0 :   if (0 != dladdr(sym, &info)) {
      38               0 :     strncpy(buffer, info.dli_fname, len - 1);
      39                 :   } else {
      40               0 :     buffer[0] = '\0';
      41                 :   }
      42                 : #endif
      43               0 : }
      44                 : 
      45                 : // Path of the current executable
      46               0 : static void PathFromExe(char* buffer, size_t len) {
      47               0 :   int bin_dir_size = readlink("/proc/self/exe", buffer, len - 1);
      48               0 :   if (bin_dir_size < 0 || (size_t) bin_dir_size >= len) {
      49               0 :     buffer[0] = '\0';
      50                 :   } else {
      51               0 :     buffer[len - 1] = '\0';
      52                 :   }
      53               0 : }
      54                 : 
      55                 : // This code tries to determine the plugin directory which contains
      56                 : // the sel_ldr and possibly other libraries
      57               0 : static void GetPluginDirectory(char* buffer, size_t len) {
      58                 :   // C++ really does not like to convert function pointer to regular pointers.
      59                 :   // This is apparently the only way to do it without compiler warnings
      60                 :   void* sym_addr = reinterpret_cast<void*>(
      61               0 :     reinterpret_cast<uintptr_t>(GetPluginDirectory));
      62                 : 
      63                 :   // We try 2 heuristics before giving up
      64               0 :   PathFromSymbol(buffer, len, sym_addr);
      65                 : 
      66               0 :   if (0 == strlen(buffer)) {
      67               0 :     PathFromExe(buffer, len);
      68                 :   }
      69                 : 
      70               0 :   if (0 == strlen(buffer)) {
      71                 :     // TOOD(robertm): maybe emit error message - but these file seem to not
      72                 :     //                use NaClLog
      73               0 :     return;
      74                 :   }
      75                 : 
      76               0 :   char* path_end = strrchr(buffer, '/');
      77               0 :   if (NULL != path_end) {
      78               0 :     *path_end = '\0';
      79                 :   }
      80                 : }
      81                 : 
      82               0 : void PluginSelLdrLocator::GetDirectory(char* buffer, size_t len) {
      83               0 :   GetPluginDirectory(buffer, len);
      84               0 : }
      85                 : 
      86                 : 
      87                 : }  // namespace nacl