include/dbus_monitor.hpp

#ifndef THIRD_PARTY_GBMCWEB_INCLUDE_DBUS_MONITOR_H_
#define THIRD_PARTY_GBMCWEB_INCLUDE_DBUS_MONITOR_H_
#include <systemd/sd-bus.h>

#include <cstring>
#include <functional>
#include <memory>
#include <regex>  // NOLINT
#include <string>
#include <vector>

#include "boost/container/flat_map.hpp"  // NOLINT
#include "boost/container/flat_set.hpp"  // NOLINT
#include "app.hpp"
#include "logging.hpp"
#include "websocket.hpp"
#include "openbmc_dbus_rest.hpp"
#include <nlohmann/json.hpp>
#include "managed_store.hpp"
#include "sdbusplus/bus/match.hpp"
#include "sdbusplus/message.hpp"

#ifdef UNIT_TEST_BUILD
#include "test/g3/mock_managed_store.hpp"  // NOLINT
#endif

namespace crow {
namespace dbus_monitor {

struct DbusWebsocketSession {
  std::vector<std::unique_ptr<sdbusplus::bus::match_t>> matches;
  boost::container::flat_set<std::string, std::less<>, std::vector<std::string>>
      interfaces;
};

using SessionMap = boost::container::flat_map<crow::websocket::Connection*,
                                              DbusWebsocketSession>;

// NOLINTNEXTLINE(cppcoreguidelines-avoid-non-const-global-variables)
static SessionMap sessions;

inline int onPropertyUpdate(sd_bus_message* m, void* userdata,
                            sd_bus_error* retError) {
  if (retError == nullptr || (sd_bus_error_is_set(retError) != 0)) {
    BMCWEB_LOG_ERROR << "Got sdbus error on match";
    return 0;
  }
  crow::websocket::Connection* connection =
      static_cast<crow::websocket::Connection*>(userdata);
  auto thisSession = sessions.find(connection);
  if (thisSession == sessions.end()) {
    BMCWEB_LOG_ERROR << "Couldn't find dbus connection " << connection;
    return 0;
  }
  sdbusplus::message_t message(m);
  nlohmann::json json;
  json["event"] = message.get_member();
  json["path"] = message.get_path();
  if (strcmp(message.get_member(), "PropertiesChanged") == 0) {
    nlohmann::json data;
    int r = openbmc_mapper::convertDBusToJSON("sa{sv}as", message, data);
    if (r < 0) {
      BMCWEB_LOG_ERROR << "convertDBusToJSON failed with " << r;
      return 0;
    }
    if (!data.is_array()) {
      BMCWEB_LOG_ERROR << "No data in PropertiesChanged signal";
      return 0;
    }

    // data is type sa{sv}as and is an array[3] of string, object, array
    json["interface"] = data[0];
    json["properties"] = data[1];
  } else if (strcmp(message.get_member(), "InterfacesAdded") == 0) {
    nlohmann::json data;
    int r = openbmc_mapper::convertDBusToJSON("oa{sa{sv}}", message, data);
    if (r < 0) {
      BMCWEB_LOG_ERROR << "convertDBusToJSON failed with " << r;
      return 0;
    }

    if (!data.is_array()) {
      BMCWEB_LOG_ERROR << "No data in InterfacesAdded signal";
      return 0;
    }

    // data is type oa{sa{sv}} which is an array[2] of string, object
    for (const auto& entry : data[1].items()) {
      auto it = thisSession->second.interfaces.find(entry.key());
      if (it != thisSession->second.interfaces.end()) {
        json["interfaces"][entry.key()] = entry.value();
      }
    }
  } else {
    BMCWEB_LOG_CRITICAL << "message " << message.get_member()
                        << " was unexpected";
    return 0;
  }

  connection->sendText(
      json.dump(2, ' ', true, nlohmann::json::error_handler_t::replace));
  return 0;
}

inline void requestRoutes(App& app) {
  BMCWEB_ROUTE(app, "/subscribe")
      .privileges({{"Login"}})
      .websocket()
      .onopen([&](crow::websocket::Connection& conn) {
        BMCWEB_LOG_DEBUG << "Connection " << &conn << " opened";
        sessions.try_emplace(&conn);
      })
      .onclose([&](crow::websocket::Connection& conn, const std::string&) {
        sessions.erase(&conn);
      })
      .onmessage([&](crow::websocket::Connection& conn, const std::string& data,
                     bool) {
        const auto sessionPair = sessions.find(&conn);
        if (sessionPair == sessions.end()) {
          conn.close("Internal error");
        }
        DbusWebsocketSession& thisSession = sessionPair->second;
        BMCWEB_LOG_DEBUG << "Connection " << &conn << " received " << data;
        nlohmann::json j = nlohmann::json::parse(data, nullptr, false);
        if (j.is_discarded()) {
          BMCWEB_LOG_ERROR << "Unable to parse json data for monitor";
          conn.close("Unable to parse json request");
          return;
        }
        nlohmann::json::iterator interfaces = j.find("interfaces");
        if (interfaces != j.end()) {
          thisSession.interfaces.reserve(interfaces->size());
          for (auto& interface : *interfaces) {
            const std::string* str = interface.get_ptr<const std::string*>();
            if (str != nullptr) {
              thisSession.interfaces.insert(*str);
            }
          }
        }

        nlohmann::json::iterator paths = j.find("paths");
        if (paths == j.end()) {
          BMCWEB_LOG_ERROR << "Unable to find paths in json data";
          conn.close("Unable to find paths in json data");
          return;
        }

        size_t interfaceCount = thisSession.interfaces.size();
        if (interfaceCount == 0) {
          interfaceCount = 1;
        }
        // Reserve our matches upfront.  For each path there is 1 for
        // interfacesAdded, and InterfaceCount number for
        // PropertiesChanged
        thisSession.matches.reserve(thisSession.matches.size() +
                                    paths->size() * (1U + interfaceCount));

        // These regexes derived on the rules here:
        // https://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names
        static const std::regex validPath("^/([A-Za-z0-9_]+/?)*$");
        static const std::regex validInterface(
            "^[A-Za-z_][A-Za-z0-9_]*(\\.[A-Za-z_][A-Za-z0-9_]*)+$");

        for (const auto& thisPath : *paths) {
          const std::string* thisPathString =
              thisPath.get_ptr<const std::string*>();
          if (thisPathString == nullptr) {
            BMCWEB_LOG_ERROR << "subscribe path isn't a string?";
            conn.close("quit");
            return;
          }
          if (!std::regex_match(*thisPathString, validPath)) {
            BMCWEB_LOG_ERROR << "Invalid path name " << *thisPathString;
            conn.close("quit");
            return;
          }
          std::string propertiesMatchString =
              ("type='signal',"
               "interface='org.freedesktop.DBus.Properties',"
               "path_namespace='" +
               *thisPathString +
               "',"
               "member='PropertiesChanged'");
          // If interfaces weren't specified, add a single match for all
          // interfaces
          if (thisSession.interfaces.empty()) {
            BMCWEB_LOG_DEBUG << "Creating match " << propertiesMatchString;

            thisSession.matches.emplace_back(
                std::make_unique<sdbusplus::bus::match_t>(
                    *(managedStore::GetManagedObjectStore()
                          ->GetDeprecatedThreadUnsafeSystemBus()),
                    propertiesMatchString, onPropertyUpdate, &conn));
          } else {
            // If interfaces were specified, add a match for each
            // interface
            for (const std::string& interface : thisSession.interfaces) {
              if (!std::regex_match(interface, validInterface)) {
                BMCWEB_LOG_ERROR << "Invalid interface name " << interface;
                conn.close("quit");
                return;
              }
              std::string ifaceMatchString = propertiesMatchString;
              ifaceMatchString += ",arg0='";
              ifaceMatchString += interface;
              ifaceMatchString += "'";
              BMCWEB_LOG_DEBUG << "Creating match " << ifaceMatchString;
              thisSession.matches.emplace_back(
                  std::make_unique<sdbusplus::bus::match_t>(
                      *(managedStore::GetManagedObjectStore()
                            ->GetDeprecatedThreadUnsafeSystemBus()),
                      ifaceMatchString, onPropertyUpdate, &conn));
            }
          }
          std::string objectManagerMatchString =
              ("type='signal',"
               "interface='org.freedesktop.DBus.ObjectManager',"
               "path_namespace='" +
               *thisPathString +
               "',"
               "member='InterfacesAdded'");
          BMCWEB_LOG_DEBUG << "Creating match " << objectManagerMatchString;
          thisSession.matches.emplace_back(
              std::make_unique<sdbusplus::bus::match_t>(
                  *(managedStore::GetManagedObjectStore()
                        ->GetDeprecatedThreadUnsafeSystemBus()),
                  objectManagerMatchString, onPropertyUpdate, &conn));
        }
      });
}
}  // namespace dbus_monitor
}  // namespace crow

#endif  // THIRD_PARTY_GBMCWEB_INCLUDE_DBUS_MONITOR_H_