libsanitizer/sanitizer_common/sanitizer_symbolizer_linux.cc

   1 //===-- sanitizer_symbolizer_linux.cc -------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is shared between AddressSanitizer and ThreadSanitizer
   9 // run-time libraries.
  10 // Linux-specific implementation of symbolizer parts.
  11 //===----------------------------------------------------------------------===//
  12 #ifdef __linux__
  13 #include "sanitizer_common.h"
  14 #include "sanitizer_internal_defs.h"
  15 #include "sanitizer_libc.h"
  16 #include "sanitizer_placement_new.h"
  17 #include "sanitizer_symbolizer.h"
  18
  19 #include <elf.h>
  20 #include <errno.h>
  21 #include <poll.h>
  22 #include <sys/socket.h>
  23 #include <sys/types.h>
  24 #include <unistd.h>
  25
  26 #if !defined(__ANDROID__) && !defined(ANDROID)
  27 #include <link.h>
  28 #endif
  29
  30 namespace __sanitizer {
  31
  32 bool StartSymbolizerSubprocess(const char *path_to_symbolizer,
  33                                int *input_fd, int *output_fd) {
  34   int *infd = NULL;
  35   int *outfd = NULL;
  36   // The client program may close its stdin and/or stdout and/or stderr
  37   // thus allowing socketpair to reuse file descriptors 0, 1 or 2.
  38   // In this case the communication between the forked processes may be
  39   // broken if either the parent or the child tries to close or duplicate
  40   // these descriptors. The loop below produces two pairs of file
  41   // descriptors, each greater than 2 (stderr).
  42   int sock_pair[5][2];
  43   for (int i = 0; i < 5; i++) {
  44     if (pipe(sock_pair[i]) == -1) {
  45       for (int j = 0; j < i; j++) {
  46         internal_close(sock_pair[j][0]);
  47         internal_close(sock_pair[j][1]);
  48       }
  49       Report("WARNING: Can't create a socket pair to start "
  50              "external symbolizer (errno: %d)\n", errno);
  51       return false;
  52     } else if (sock_pair[i][0] > 2 && sock_pair[i][1] > 2) {
  53       if (infd == NULL) {
  54         infd = sock_pair[i];
  55       } else {
  56         outfd = sock_pair[i];
  57         for (int j = 0; j < i; j++) {
  58           if (sock_pair[j] == infd) continue;
  59           internal_close(sock_pair[j][0]);
  60           internal_close(sock_pair[j][1]);
  61         }
  62         break;
  63       }
  64     }
  65   }
  66   CHECK(infd);
  67   CHECK(outfd);
  68
  69   int pid = fork();
  70   if (pid == -1) {
  71     // Fork() failed.
  72     internal_close(infd[0]);
  73     internal_close(infd[1]);
  74     internal_close(outfd[0]);
  75     internal_close(outfd[1]);
  76     Report("WARNING: failed to fork external symbolizer "
  77            " (errno: %d)\n", errno);
  78     return false;
  79   } else if (pid == 0) {
  80     // Child subprocess.
  81     internal_close(STDOUT_FILENO);
  82     internal_close(STDIN_FILENO);
  83     internal_dup2(outfd[0], STDIN_FILENO);
  84     internal_dup2(infd[1], STDOUT_FILENO);
  85     internal_close(outfd[0]);
  86     internal_close(outfd[1]);
  87     internal_close(infd[0]);
  88     internal_close(infd[1]);
  89     for (int fd = getdtablesize(); fd > 2; fd--)
  90       internal_close(fd);
  91     execl(path_to_symbolizer, path_to_symbolizer, (char*)0);
  92     Exit(1);
  93   }
  94
  95   // Continue execution in parent process.
  96   internal_close(outfd[0]);
  97   internal_close(infd[1]);
  98   *input_fd = infd[0];
  99   *output_fd = outfd[1];
 100   return true;
 101 }
 102
 103 #if defined(__ANDROID__) || defined(ANDROID)
 104 uptr GetListOfModules(LoadedModule *modules, uptr max_modules) {
 105   UNIMPLEMENTED();
 106   return 0;
 107 }
 108 #else  // ANDROID
 109 typedef ElfW(Phdr) Elf_Phdr;
 110
 111 struct DlIteratePhdrData {
 112   LoadedModule *modules;
 113   uptr current_n;
 114   uptr max_n;
 115 };
 116
 117 static const uptr kMaxPathLength = 512;
 118
 119 static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) {
 120   DlIteratePhdrData *data = (DlIteratePhdrData*)arg;
 121   if (data->current_n == data->max_n)
 122     return 0;
 123   InternalScopedBuffer<char> module_name(kMaxPathLength);
 124   module_name.data()[0] = '\0';
 125   if (data->current_n == 0) {
 126     // First module is the binary itself.
 127     uptr module_name_len = internal_readlink(
 128         "/proc/self/exe", module_name.data(), module_name.size());
 129     CHECK_NE(module_name_len, (uptr)-1);
 130     CHECK_LT(module_name_len, module_name.size());
 131     module_name[module_name_len] = '\0';
 132   } else if (info->dlpi_name) {
 133     internal_strncpy(module_name.data(), info->dlpi_name, module_name.size());
 134   }
 135   if (module_name.data()[0] == '\0')
 136     return 0;
 137   void *mem = &data->modules[data->current_n];
 138   LoadedModule *cur_module = new(mem) LoadedModule(module_name.data(),
 139                                                    info->dlpi_addr);
 140   data->current_n++;
 141   for (int i = 0; i < info->dlpi_phnum; i++) {
 142     const Elf_Phdr *phdr = &info->dlpi_phdr[i];
 143     if (phdr->p_type == PT_LOAD) {
 144       uptr cur_beg = info->dlpi_addr + phdr->p_vaddr;
 145       uptr cur_end = cur_beg + phdr->p_memsz;
 146       cur_module->addAddressRange(cur_beg, cur_end);
 147     }
 148   }
 149   return 0;
 150 }
 151
 152 uptr GetListOfModules(LoadedModule *modules, uptr max_modules) {
 153   CHECK(modules);
 154   DlIteratePhdrData data = {modules, 0, max_modules};
 155   dl_iterate_phdr(dl_iterate_phdr_cb, &data);
 156   return data.current_n;
 157 }
 158 #endif  // ANDROID
 159
 160 }  // namespace __sanitizer
 161
 162 #endif  // __linux__