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Commit fe90276a authored by Josh Gao's avatar Josh Gao
Browse files

crash_dump: use /proc/<pid> fd to check tid process membership. 

Bug: http://b/34759490
Test: /data/nativetest/debuggerd_test/debuggerd_test32
Test: debuggerd -b `pidof system_server`
Test: debuggerd -b `pidof zygote`
Change-Id: I627692b44977335a9568cd765ad28205f0a61327
parent 7ae426c7

debuggerd/crash_dump.cpp

+12 −11
Original line number Original line Diff line number Diff line
@@ -51,24 +51,25 @@ 
using android::base::unique_fd;

using android::base::unique_fd;

using android::base::StringPrintf;

using android::base::StringPrintf;





static bool pid_contains_tid(pid_t pid, pid_t tid) {

static bool pid_contains_tid(int pid_proc_fd, pid_t tid) {

  std::string task_path = StringPrintf("/proc/%d/task/%d", pid, tid);

  struct stat st;

  return access(task_path.c_str(), F_OK) == 0;

  std::string task_path = StringPrintf("task/%d", tid);

  return fstatat(pid_proc_fd, task_path.c_str(), &st, 0) == 0;

}

}





// Attach to a thread, and verify that it's still a member of the given process

// Attach to a thread, and verify that it's still a member of the given process

static bool ptrace_seize_thread(pid_t pid, pid_t tid, std::string* error) {

static bool ptrace_seize_thread(int pid_proc_fd, pid_t tid, std::string* error) {

  if (ptrace(PTRACE_SEIZE, tid, 0, 0) != 0) {

  if (ptrace(PTRACE_SEIZE, tid, 0, 0) != 0) {

    *error = StringPrintf("failed to attach to thread %d: %s", tid, strerror(errno));

    *error = StringPrintf("failed to attach to thread %d: %s", tid, strerror(errno));

    return false;

    return false;

  }

  }





  // Make sure that the task we attached to is actually part of the pid we're dumping.

  // Make sure that the task we attached to is actually part of the pid we're dumping.

  if (!pid_contains_tid(pid, tid)) {

  if (!pid_contains_tid(pid_proc_fd, tid)) {

    if (ptrace(PTRACE_DETACH, tid, 0, 0) != 0) {

    if (ptrace(PTRACE_DETACH, tid, 0, 0) != 0) {

      PLOG(FATAL) << "failed to detach from thread " << tid;

      PLOG(FATAL) << "failed to detach from thread " << tid;

    }

    }

    *error = StringPrintf("thread %d is not in process %d", tid, pid);

    *error = StringPrintf("thread %d is not in process", tid);

    return false;

    return false;

  }

  }
@@ -263,7 +264,7 @@ int main(int argc, char** argv) { 
  check_process(target_proc_fd, target);

  check_process(target_proc_fd, target);





  std::string attach_error;

  std::string attach_error;

  if (!ptrace_seize_thread(target, main_tid, &attach_error)) {

  if (!ptrace_seize_thread(target_proc_fd, main_tid, &attach_error)) {

    LOG(FATAL) << attach_error;

    LOG(FATAL) << attach_error;

  }

  }
@@ -304,6 +305,7 @@ int main(int argc, char** argv) { 
  }

  }





  int signo = siginfo.si_signo;

  int signo = siginfo.si_signo;

  bool fatal_signal = signo != DEBUGGER_SIGNAL;

  bool backtrace = false;

  bool backtrace = false;

  uintptr_t abort_address = 0;

  uintptr_t abort_address = 0;
@@ -319,17 +321,16 @@ int main(int argc, char** argv) { 




  // Now that we have the signal that kicked things off, attach all of the

  // Now that we have the signal that kicked things off, attach all of the

  // sibling threads, and then proceed.

  // sibling threads, and then proceed.

  bool fatal_signal = signo != DEBUGGER_SIGNAL;

  std::set<pid_t> siblings;

  std::set<pid_t> attached_siblings;

  std::set<pid_t> attached_siblings;

  if (fatal_signal || backtrace) {

  {

    std::set<pid_t> siblings;

    if (!android::procinfo::GetProcessTids(target, &siblings)) {

    if (!android::procinfo::GetProcessTids(target, &siblings)) {

      PLOG(FATAL) << "failed to get process siblings";

      PLOG(FATAL) << "failed to get process siblings";

    }

    }

    siblings.erase(main_tid);

    siblings.erase(main_tid);





    for (pid_t sibling_tid : siblings) {

    for (pid_t sibling_tid : siblings) {

      if (!ptrace_seize_thread(target, sibling_tid, &attach_error)) {

      if (!ptrace_seize_thread(target_proc_fd, sibling_tid, &attach_error)) {

        LOG(WARNING) << attach_error;

        LOG(WARNING) << attach_error;

      } else {

      } else {

        attached_siblings.insert(sibling_tid);

        attached_siblings.insert(sibling_tid);