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Commit 4843c186 authored by Josh Gao's avatar Josh Gao
Browse files

debuggerd_handler: receive abort messages via sigqueue(DEBUGGER_SIGNAL). 

Make it possible for code such as fdsan that generates debugging
tombstones via raise(DEBUGGER_SIGNAL) to pass an abort message as well.

Bug: http://b/112770187
Test: debuggerd_test
Change-Id: Idc34263241c18033573e466da3a45aa6f716ddb3
parent c86b01ba

debuggerd/handler/debuggerd_handler.cpp

+19 −9
Original line number Diff line number Diff line
@@ -457,14 +457,14 @@ static void debuggerd_signal_handler(int signal_number, siginfo_t* info, void* c 
    info = nullptr;

  }



  struct siginfo si = {};

  struct siginfo dummy_info = {};

  if (!info) {

    memset(&si, 0, sizeof(si));

    si.si_signo = signal_number;

    si.si_code = SI_USER;

    si.si_pid = __getpid();

    si.si_uid = getuid();

    info = &si;

    memset(&dummy_info, 0, sizeof(dummy_info));

    dummy_info.si_signo = signal_number;

    dummy_info.si_code = SI_USER;

    dummy_info.si_pid = __getpid();

    dummy_info.si_uid = getuid();

    info = &dummy_info;

  } else if (info->si_code >= 0 || info->si_code == SI_TKILL) {

    // rt_tgsigqueueinfo(2)'s documentation appears to be incorrect on kernels

    // that contain commit 66dd34a (3.9+). The manpage claims to only allow
@@ -473,9 +473,19 @@ static void debuggerd_signal_handler(int signal_number, siginfo_t* info, void* c 
  }



  void* abort_message = nullptr;

  if (signal_number != DEBUGGER_SIGNAL && g_callbacks.get_abort_message) {

  if (signal_number == DEBUGGER_SIGNAL) {

    if (info->si_code == SI_QUEUE && info->si_pid == __getpid()) {

      // Allow for the abort message to be explicitly specified via the sigqueue value.

      // Keep the bottom bit intact for representing whether we want a backtrace or a tombstone.

      uintptr_t value = reinterpret_cast<uintptr_t>(info->si_ptr);

      abort_message = reinterpret_cast<void*>(value & ~1);

      info->si_ptr = reinterpret_cast<void*>(value & 1);

    }

  } else {

    if (g_callbacks.get_abort_message) {

      abort_message = g_callbacks.get_abort_message();

    }

  }



  // If sival_int is ~0, it means that the fallback handler has been called

  // once before and this function is being called again to dump the stack