Refactor task OS-name setting

Task::copy_state sets the OS name of a task in the same fashion that
persistent checkpointing sets name. Refactored this functionality into
Task::set_name.

Also removed the unnecessary `update_prname` from Task::copy_state.

update_prname is not a "write to tracee"-operation but a "read from tracee"-operation; and since
we already know what name we want to set Task::prname to, we skip this reading from the tracee
in Task::copy_state and just set it to the parameter passed in to Task::set_name

src/ReplaySession.cc

@@ -2157,11 +2157,11 @@ void ReplaySession::load_checkpoint(
  Task* child = Task::os_clone(Task::SESSION_CLONE_LEADER, this, remote,
  taskInfo.getRecTid(), taskInfo.getSerial(),
  SIGCHLD, nullptr);
- cloned_leaders.push_back((ReplayTask*)child);
+ cloned_leaders.push_back(static_cast<ReplayTask*>(child));
  }
 
  auto clone_leader_index = 0;
-
+ LOG(debug) << "Restoring " << addr_spaces.size() << " clone leaders";
  for (const auto& as : addr_spaces) {
  ReplayTask* leader = cloned_leaders[clone_leader_index++];
  const auto proc_space = as.getProcessSpace();
@@ -2272,9 +2272,7 @@ void ReplaySession::load_checkpoint(
  auto index = original_exe_name.rfind('/');
  auto name = "rr:" + original_exe_name.substr(
  index == std::string::npos ? 0 : index + 1);
- AutoRestoreMem mem(remote, name.c_str());
- remote.infallible_syscall(syscall_number_for_prctl(leader->arch()),
- PR_SET_NAME, mem.get());
+ leader->set_name(remote, name);
  }
 
  ASSERT(leader, scratch_mem != nullptr)

src/Task.cc

@@ -2578,21 +2578,23 @@ Task::CapturedState Task::capture_state() {
  return state;
 }
 
+void Task::set_name(AutoRemoteSyscalls& remote, const std::string& name) {
+ char prname[17];
+ strncpy(prname, name.c_str(), sizeof(prname));
+ prname[16] = 0;
+ AutoRestoreMem remote_prname(remote, (const uint8_t*)prname, 16);
+ LOG(debug) << " setting name to " << prname;
+ remote.infallible_syscall(syscall_number_for_prctl(arch()), PR_SET_NAME,
+ remote_prname.get().as_int());
+ this->prname = name;
+}
+
 void Task::copy_state(const CapturedState& state) {
  set_regs(state.regs);
  set_extra_regs(state.extra_regs);
  {
  AutoRemoteSyscalls remote(this);
- {
- char prname[17];
- strncpy(prname, state.prname.c_str(), sizeof(prname));
- prname[16] = 0;
- AutoRestoreMem remote_prname(remote, (const uint8_t*)prname, 16);
- LOG(debug) << " setting name to " << prname;
- remote.infallible_syscall(syscall_number_for_prctl(arch()), PR_SET_NAME,
- remote_prname.get().as_int());
- update_prname(remote_prname.get());
- }
+ set_name(remote, state.prname);
 
  copy_tls(state, remote);
  thread_areas_ = state.thread_areas;

src/Task.h

@@ -1049,6 +1049,12 @@ class Task {
  */
  void forget();
 
+ /**
+ * Sets the OS-name of this task by injecting system call for PR_SET_NAME.
+ * Also updates |prname| to |name|.
+ */
+ void set_name(AutoRemoteSyscalls& remote_syscalls, const std::string& name);
+
  // Used on aarch64 to detect whether we've recorded x0 and x8 on syscall entry
  Ticks ticks_at_last_syscall_entry;
  remote_code_ptr ip_at_last_syscall_entry;