// Copyright 2017 The Fuchsia 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 "encoder/system_data.h"

#include <cstring>
#include <map>
#include <string>
#include <utility>

#include "./logging.h"

namespace cobalt {
namespace encoder {

namespace {

#if defined(__x86_64__)

// This identifies board names for x86 Systems.
// If the signature of the CPU matches a known signature, then we use the name,
// otherwise we encode the signature as a string so we can easily identify when
// new signatures start to become popular.
std::string getBoardName(int signature) {
  // This function will only be run once per system boot, so this map will only
  // be created once.
  std::map<int, std::string> knownCPUSignatures = {
      {0x806e9, "Eve"},
  };

  auto name = knownCPUSignatures.find(signature);
  if (name == knownCPUSignatures.end()) {
    char sigstr[20];
    snprintf(sigstr, sizeof(sigstr), "unknown:0x%X", signature);
    return sigstr;
  } else {
    return name->second;
  }
}

// Invokes the cpuid instruction on X86. |info_type| specifies which query
// we are performing. This is written into register EAX prior to invoking
// cpuid. (The sub-type specifier in register ECX is alwyas set to zero.)  The
// results from registers EAX, EBX, ECX, EDX respectively are writtent into the
// four entries of |cpu_info|. See for example the wikipedia article on
// cpuid for more info.
void Cpuid(int info_type, int cpu_info[4]) {
  __asm__ volatile("cpuid\n"
                   : "=a"(cpu_info[0]), "=b"(cpu_info[1]), "=c"(cpu_info[2]),
                     "=d"(cpu_info[3])
                   : "a"(info_type), "c"(0));
}

// Invokes Cpuid() to determine the board_name.
void PopulateBoardName(SystemProfile* profile) {
  // "": means that the calling system has no idea.
  // "pc": is the current placeholder value that fuchsia reports for x86
  //       devices, so we think we can do better.
  // Anything else is considered to be "better" than just raw Cpuid or a lookup
  // table.
  if (profile->board_name() == "" || profile->board_name() == "pc") {
    // First we invoke Cpuid with info_type = 0 in order to obtain num_ids
    // and vendor_name.
    int cpu_info[4] = {-1};
    Cpuid(0, cpu_info);
    int num_ids = cpu_info[0];

    if (num_ids > 0) {
      // Then invoke Cpuid again with info_type = 1 in order to obtain
      // |signature|.
      Cpuid(1, cpu_info);
      profile->set_board_name(getBoardName(cpu_info[0]));
    }
  }
}

#elif defined(__aarch64__)

void PopulateBoardName(SystemProfile* profile) {
  if (profile->board_name() == "") {
    profile->set_board_name("Generic ARM");
  }
}

#else

void PopulateBoardName(SystemProfile* profile) {}

#endif

}  // namespace

SystemData::SystemData(const std::string& product_name,
                       const std::string& board_name_suggestion,
                       const std::string& version) {
  system_profile_.set_product_name(product_name);
  system_profile_.set_board_name(board_name_suggestion);
  system_profile_.set_system_version(version);
  PopulateSystemProfile();
}

void SystemData::OverrideSystemProfile(const SystemProfile& profile) {
  system_profile_ = profile;
}

void SystemData::PopulateSystemProfile() {
#if defined(__linux__)

  system_profile_.set_os(SystemProfile::LINUX);

#elif defined(__Fuchsia__)

  system_profile_.set_os(SystemProfile::FUCHSIA);

#else

  system_profile_.set_os(SystemProfile::UNKNOWN_OS);

#endif

#if defined(__x86_64__)

  system_profile_.set_arch(SystemProfile::X86_64);

#elif defined(__aarch64__)

  system_profile_.set_arch(SystemProfile::ARM_64);

#else

  system_profile_.set_arch(SystemProfile::UNKNOWN_ARCH);

#endif

  PopulateBoardName(&system_profile_);
}

}  // namespace encoder
}  // namespace cobalt