// Copyright (c) 2011 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 "base/process_util.h"

#include <ctype.h>
#include <dirent.h>
#include <dlfcn.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/param.h>
#include <sys/sysctl.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/user.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

#include "base/file_util.h"
#include "base/logging.h"
#include "base/string_tokenizer.h"
#include "base/string_util.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_split.h"
#include "base/sys_info.h"
#include "base/threading/thread_restrictions.h"

namespace base {

ProcessId GetParentProcessId(ProcessHandle process) {
  struct kinfo_proc info;
  size_t length;
  int mib[] = { CTL_KERN, KERN_PROC, KERN_PROC_PID, process,
                sizeof(struct kinfo_proc), 0 };

  if (sysctl(mib, arraysize(mib), NULL, &length, NULL, 0) < 0)
    return -1;

  mib[5] = (length / sizeof(struct kinfo_proc));

  if (sysctl(mib, arraysize(mib), &info, &length, NULL, 0) < 0)
    return -1;

  return info.p_ppid;
}

FilePath GetProcessExecutablePath(ProcessHandle process) {
  struct kinfo_proc kp;
  size_t len;
  int mib[] = { CTL_KERN, KERN_PROC, KERN_PROC_PID, process,
                sizeof(struct kinfo_proc), 0 };

  if (sysctl(mib, arraysize(mib), NULL, &len, NULL, 0) == -1)
    return FilePath();
  mib[5] = (len / sizeof(struct kinfo_proc));
  if (sysctl(mib, arraysize(mib), &kp, &len, NULL, 0) < 0)
    return FilePath();
  if ((kp.p_flag & P_SYSTEM) != 0)
    return FilePath();
  if (strcmp(kp.p_comm, "chrome") == 0)
    return FilePath(kp.p_comm);

  return FilePath();
}

ProcessIterator::ProcessIterator(const ProcessFilter* filter)
    : index_of_kinfo_proc_(),
      filter_(filter) {

  int mib[] = { CTL_KERN, KERN_PROC, KERN_PROC_UID, getuid(),
                sizeof(struct kinfo_proc), 0 };

  bool done = false;
  int try_num = 1;
  const int max_tries = 10;

  do {
    size_t len = 0;
    if (sysctl(mib, arraysize(mib), NULL, &len, NULL, 0) < 0) {
      DLOG(ERROR) << "failed to get the size needed for the process list";
      kinfo_procs_.resize(0);
      done = true;
    } else {
      size_t num_of_kinfo_proc = len / sizeof(struct kinfo_proc);
      // Leave some spare room for process table growth (more could show up
      // between when we check and now)
      num_of_kinfo_proc += 16;
      kinfo_procs_.resize(num_of_kinfo_proc);
      len = num_of_kinfo_proc * sizeof(struct kinfo_proc);
      if (sysctl(mib, arraysize(mib), &kinfo_procs_[0], &len, NULL, 0) < 0) {
        // If we get a mem error, it just means we need a bigger buffer, so
        // loop around again.  Anything else is a real error and give up.
        if (errno != ENOMEM) {
          DLOG(ERROR) << "failed to get the process list";
          kinfo_procs_.resize(0);
          done = true;
        }
      } else {
        // Got the list, just make sure we're sized exactly right
        size_t num_of_kinfo_proc = len / sizeof(struct kinfo_proc);
        kinfo_procs_.resize(num_of_kinfo_proc);
        done = true;
      }
    }
  } while (!done && (try_num++ < max_tries));

  if (!done) {
    DLOG(ERROR) << "failed to collect the process list in a few tries";
    kinfo_procs_.resize(0);
  }
}

ProcessIterator::~ProcessIterator() {
}

bool ProcessIterator::CheckForNextProcess() {
  std::string data;
  for (; index_of_kinfo_proc_ < kinfo_procs_.size(); ++index_of_kinfo_proc_) {
    kinfo_proc& kinfo = kinfo_procs_[index_of_kinfo_proc_];

    // Skip processes just awaiting collection
    if ((kinfo.p_pid > 0) && (kinfo.p_stat == SZOMB))
      continue;

    int mib[] = { CTL_KERN, KERN_PROC_ARGS, kinfo.p_pid };

    // Find out what size buffer we need.
    size_t data_len = 0;
    if (sysctl(mib, arraysize(mib), NULL, &data_len, NULL, 0) < 0) {
      DVPLOG(1) << "failed to figure out the buffer size for a commandline";
      continue;
    }

    data.resize(data_len);
    if (sysctl(mib, arraysize(mib), &data[0], &data_len, NULL, 0) < 0) {
      DVPLOG(1) << "failed to fetch a commandline";
      continue;
    }

    // |data| contains all the command line parameters of the process, separated
    // by blocks of one or more null characters. We tokenize |data| into a
    // vector of strings using '\0' as a delimiter and populate
    // |entry_.cmd_line_args_|.
    std::string delimiters;
    delimiters.push_back('\0');
    Tokenize(data, delimiters, &entry_.cmd_line_args_);

    // |data| starts with the full executable path followed by a null character.
    // We search for the first instance of '\0' and extract everything before it
    // to populate |entry_.exe_file_|.
    size_t exec_name_end = data.find('\0');
    if (exec_name_end == std::string::npos) {
      DLOG(ERROR) << "command line data didn't match expected format";
      continue;
    }

    entry_.pid_ = kinfo.p_pid;
    entry_.ppid_ = kinfo.p_ppid;
    entry_.gid_ = kinfo.p__pgid;
    size_t last_slash = data.rfind('/', exec_name_end);
    if (last_slash == std::string::npos)
      entry_.exe_file_.assign(data, 0, exec_name_end);
    else
      entry_.exe_file_.assign(data, last_slash + 1,
                              exec_name_end - last_slash - 1);
    // Start w/ the next entry next time through
    ++index_of_kinfo_proc_;
    // Done
    return true;
  }
  return false;
}

bool NamedProcessIterator::IncludeEntry() {
  return (executable_name_ == entry().exe_file() &&
          ProcessIterator::IncludeEntry());
}


ProcessMetrics::ProcessMetrics(ProcessHandle process)
    : process_(process),
      last_time_(0),
      last_system_time_(0),
      last_cpu_(0) {

  processor_count_ = base::SysInfo::NumberOfProcessors();
}

// static
ProcessMetrics* ProcessMetrics::CreateProcessMetrics(ProcessHandle process) {
  return new ProcessMetrics(process);
}

size_t ProcessMetrics::GetPagefileUsage() const {
  struct kinfo_proc info;
  size_t length;
  int mib[] = { CTL_KERN, KERN_PROC, KERN_PROC_PID, process_,
                sizeof(struct kinfo_proc), 0 };

  if (sysctl(mib, arraysize(mib), NULL, &length, NULL, 0) < 0)
    return -1;

  mib[5] = (length / sizeof(struct kinfo_proc));

  if (sysctl(mib, arraysize(mib), &info, &length, NULL, 0) < 0)
    return -1;

  return (info.p_vm_tsize + info.p_vm_dsize + info.p_vm_ssize);
}

size_t ProcessMetrics::GetPeakPagefileUsage() const {

  return 0;
}

size_t ProcessMetrics::GetWorkingSetSize() const {
  struct kinfo_proc info;
  size_t length;
  int mib[] = { CTL_KERN, KERN_PROC, KERN_PROC_PID, process_,
                sizeof(struct kinfo_proc), 0 };

  if (sysctl(mib, arraysize(mib), NULL, &length, NULL, 0) < 0)
    return -1;

  mib[5] = (length / sizeof(struct kinfo_proc));

  if (sysctl(mib, arraysize(mib), &info, &length, NULL, 0) < 0)
    return -1;

  return info.p_vm_rssize * getpagesize();
}

size_t ProcessMetrics::GetPeakWorkingSetSize() const {

  return 0;
}

bool ProcessMetrics::GetMemoryBytes(size_t* private_bytes,
                                    size_t* shared_bytes) {
  WorkingSetKBytes ws_usage;

  if (!GetWorkingSetKBytes(&ws_usage))
    return false;

  if (private_bytes)
    *private_bytes = ws_usage.priv << 10;

  if (shared_bytes)
    *shared_bytes = ws_usage.shared * 1024;

  return true;
}

bool ProcessMetrics::GetWorkingSetKBytes(WorkingSetKBytes* ws_usage) const {
// TODO(bapt) be sure we can't be precise
  size_t priv = GetWorkingSetSize();
  if (!priv)
    return false;
  ws_usage->priv = priv / 1024;
  ws_usage->shareable = 0;
  ws_usage->shared = 0;

  return true;
}

bool ProcessMetrics::GetIOCounters(IoCounters* io_counters) const {
  return false;
}

static int GetProcessCPU(pid_t pid) {
  struct kinfo_proc info;
  size_t length;
  int mib[] = { CTL_KERN, KERN_PROC, KERN_PROC_PID, pid,
                sizeof(struct kinfo_proc), 0 };

  if (sysctl(mib, arraysize(mib), NULL, &length, NULL, 0) < 0)
    return -1;

  mib[5] = (length / sizeof(struct kinfo_proc));

  if (sysctl(mib, arraysize(mib), &info, &length, NULL, 0) < 0)
    return 0;

  return info.p_pctcpu;
}

double ProcessMetrics::GetCPUUsage() {
  struct timeval now;

  int retval = gettimeofday(&now, NULL);
  if (retval)
    return 0;

  int64 time = TimeValToMicroseconds(now);

  if (last_time_ == 0) {
    // First call, just set the last values.
    last_time_ = time;
    last_cpu_ = GetProcessCPU(process_);
    return 0;
  }

  int64 time_delta = time - last_time_;
  DCHECK_NE(time_delta, 0);

  if (time_delta == 0)
    return 0;

  int cpu = GetProcessCPU(process_);

  last_time_ = time;
  last_cpu_ = cpu;

  double percentage = static_cast<double>((cpu * 100.0) / FSCALE);

  return percentage;
}

size_t GetSystemCommitCharge() {
  int mib[] = { CTL_VM, VM_METER };
  int pagesize;
  struct vmtotal vmtotal;
  unsigned long mem_total, mem_free, mem_inactive;
  size_t len = sizeof(vmtotal);

  if (sysctl(mib, arraysize(mib), &vmtotal, &len, NULL, 0) < 0)
    return 0;

  mem_total = vmtotal.t_vm;
  mem_free = vmtotal.t_free;
  mem_inactive = vmtotal.t_vm - vmtotal.t_avm;

  pagesize = getpagesize();

  return mem_total - (mem_free*pagesize) - (mem_inactive*pagesize);
}

void EnableTerminationOnOutOfMemory() {
}

void EnableTerminationOnHeapCorruption() {
}

}  // namespace base