Android systrace: Optimize memory dumps.

systrace/atrace_helper/jni/process_info.cc

-// Copyright 2017 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "process_info.h"
-
-#include <ctype.h>
-#include <dirent.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <sys/types.h>
-
-#include "file_utils.h"
-#include "logging.h"
-
-ProcessInfo::ProcessInfo(int pid) : memory_(pid), pid_(pid) {}
-
-bool ProcessInfo::IsProcess(int pid) {
-  char buf[256];
-  ssize_t rsize = file_utils::ReadProcFile(pid, "status", buf, sizeof(buf));
-  if (rsize <= 0)
-    return false;
-  const char kTgid[] = "\nTgid:";
-  const char* tgid_line = strstr(buf, kTgid);
-  CHECK(tgid_line);
-  int tgid = 0;
-  if (sscanf(tgid_line + strlen(kTgid), "%d", &tgid) != 1)
-    CHECK(false);
-  return tgid == pid;
-}
-
-bool ProcessInfo::ReadProcessName() {
-  if (!file_utils::ReadProcFileTrimmed(pid_, "cmdline", name_, sizeof(name_)))
-    return false;
-
-  // Fallback on "comm" for kernel threads.
-  if (strlen(name_) == 0) {
-    if (!file_utils::ReadProcFileTrimmed(pid_, "comm", name_, sizeof(name_)))
-      return false;
-  }
-
-  // Get also the exe path, to distinguish system vs java apps and bitness.
-  char exe_path[64];
-  sprintf(exe_path, "/proc/%d/exe", pid_);
-  exe_[0] = '\0';
-  ssize_t res = readlink(exe_path, exe_, sizeof(exe_) - 1);
-  if (res >= 0)
-    exe_[res] = '\0';
-
-  return true;
-}
-
-bool ProcessInfo::ReadThreadNames() {
-  char tasks_path[64];
-  sprintf(tasks_path, "/proc/%d/task", pid_);
-  CHECK(threads_.empty());
-  ThreadInfoMap* threads = &threads_;
-  const int pid = pid_;
-  file_utils::ForEachPidInProcPath(tasks_path, [pid, threads](int tid) {
-    char comm[64];
-    std::unique_ptr<ThreadInfo> thread_info(new ThreadInfo());
-    sprintf(comm, "task/%d/comm", tid);
-    if (!file_utils::ReadProcFileTrimmed(pid, comm, thread_info->name,
-                                         sizeof(thread_info->name))) {
-      return;
-    }
-    (*threads)[tid] = std::move(thread_info);
-  });
-  return true;
-}
-
-bool ProcessInfo::ReadOOMStats() {
-  char buf[512];
-  if (file_utils::ReadProcFileTrimmed(pid_, "oom_adj", buf, sizeof(buf)))
-    oom_adj_ = atoi(buf);
-  else
-    return false;
-
-  if (file_utils::ReadProcFileTrimmed(pid_, "oom_score", buf, sizeof(buf)))
-    oom_score_ = atoi(buf);
-  else
-    return false;
-
-  if (file_utils::ReadProcFileTrimmed(pid_, "oom_score_adj", buf, sizeof(buf)))
-    oom_score_adj_ = atoi(buf);
-  else
-    return false;
-
-  return true;
-}
-
-bool ProcessInfo::ReadPageFaultsAndCPUTimeStats() {
-  char buf[512];
-  if (!file_utils::ReadProcFileTrimmed(pid_, "stat", buf, sizeof(buf)))
-    return false;
-  int ret = sscanf(buf,
-                   "%*d (%*[^)]) %*c %*d %*d %*d %*d %*d %*u %lu %*lu "
-                   "%lu %*lu %lu %lu %*ld %*ld %*ld %*ld %*ld %*ld %llu",
-                   &minflt_, &majflt_, &utime_, &stime_, &start_time_);
-  CHECK(ret == 5);
-  return true;
-}