/*
 * Copyright 2016, The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "util.h"

#include <time.h>

#include <functional>
#include <string>
#include <utility>

#include <android-base/file.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include "protocol.h"

constexpr const char kUnknown[] = "<unknown>";

std::vector<std::string> get_command_line(pid_t pid) {
  std::vector<std::string> result;

  std::string cmdline;
  android::base::ReadFileToString(android::base::StringPrintf("/proc/%d/cmdline", pid), &cmdline);

  auto it = cmdline.cbegin();
  while (it != cmdline.cend()) {
    // string::iterator is a wrapped type, not a raw char*.
    auto terminator = std::find(it, cmdline.cend(), '\0');
    result.emplace_back(it, terminator);
    it = std::find_if(terminator, cmdline.cend(), [](char c) { return c != '\0'; });
  }
  if (result.empty()) {
    return {kUnknown};
  }

  return result;
}

std::string get_process_name(pid_t pid) {
  std::string result(kUnknown);
  android::base::ReadFileToString(android::base::StringPrintf("/proc/%d/cmdline", pid), &result);
  // We only want the name, not the whole command line, so truncate at the first NUL.
  return result.c_str();
}

std::string get_thread_name(pid_t tid) {
  std::string result(kUnknown);
  android::base::ReadFileToString(android::base::StringPrintf("/proc/%d/comm", tid), &result);
  return android::base::Trim(result);
}

std::string get_executable_name(pid_t pid) {
  std::string result;
  if (!android::base::Readlink(android::base::StringPrintf("/proc/%d/exe", pid), &result)) {
    return kUnknown;
  }
  return result;
}

std::string get_timestamp() {
  timespec ts;
  clock_gettime(CLOCK_REALTIME, &ts);

  tm tm;
  localtime_r(&ts.tv_sec, &tm);

  char buf[strlen("1970-01-01 00:00:00.123456789+0830") + 1];
  char* s = buf;
  size_t sz = sizeof(buf), n;
  n = strftime(s, sz, "%F %H:%M", &tm), s += n, sz -= n;
  n = snprintf(s, sz, ":%02d.%09ld", tm.tm_sec, ts.tv_nsec), s += n, sz -= n;
  n = strftime(s, sz, "%z", &tm), s += n, sz -= n;
  return buf;
}

bool iterate_tids(pid_t pid, std::function<void(pid_t)> callback) {
  char buf[BUFSIZ];
  snprintf(buf, sizeof(buf), "/proc/%d/task", pid);
  std::unique_ptr<DIR, int (*)(DIR*)> dir(opendir(buf), closedir);
  if (dir == nullptr) {
    return false;
  }

  struct dirent* entry;
  while ((entry = readdir(dir.get())) != nullptr) {
    pid_t tid = atoi(entry->d_name);
    if (tid == 0) {
      continue;
    }
    callback(tid);
  }
  return true;
}

bool is_microdroid() {
  return android::base::GetProperty("ro.hardware", "") == "microdroid";
}
