log_manager.cpp - openbmc/phosphor-logging - Gitiles

 #include "config.h"

 #include "log_manager.hpp"

 #include "elog_entry.hpp"
 #include "elog_meta.hpp"
 #include "elog_serialize.hpp"
 #include "extensions.hpp"
 #include "util.hpp"

 #include <poll.h>
 #include <sys/inotify.h>
 #include <systemd/sd-bus.h>
 #include <systemd/sd-journal.h>
 #include <unistd.h>

 #include <cassert>
 #include <chrono>
 #include <cstdio>
 #include <cstring>
 #include <fstream>
 #include <functional>
 #include <future>
 #include <iostream>
 #include <map>
 #include <phosphor-logging/log.hpp>
 #include <sdbusplus/vtable.hpp>
 #include <set>
 #include <string>
 #include <vector>
 #include <xyz/openbmc_project/State/Host/server.hpp>

 using namespace phosphor::logging;
 using namespace std::chrono;
 using sdbusplus::exception::SdBusError;
 extern const std::map<metadata::Metadata,
                       std::function<metadata::associations::Type>>
     meta;

 namespace phosphor
 {
 namespace logging
 {
 namespace internal
 {
 inline auto getLevel(const std::string& errMsg)
 {
     auto reqLevel = Entry::Level::Error; // Default to Error

     auto levelmap = g_errLevelMap.find(errMsg);
     if (levelmap != g_errLevelMap.end())
     {
         reqLevel = static_cast<Entry::Level>(levelmap->second);
     }

     return reqLevel;
 }

 int Manager::getRealErrSize()
 {
     return realErrors.size();
 }

 int Manager::getInfoErrSize()
 {
     return infoErrors.size();
 }

 void Manager::commit(uint64_t transactionId, std::string errMsg)
 {
     auto level = getLevel(errMsg);
     _commit(transactionId, std::move(errMsg), level);
 }

 void Manager::commitWithLvl(uint64_t transactionId, std::string errMsg,
                             uint32_t errLvl)
 {
     _commit(transactionId, std::move(errMsg),
             static_cast<Entry::Level>(errLvl));
 }

 void Manager::_commit(uint64_t transactionId, std::string&& errMsg,
                       Entry::Level errLvl)
 {
     constexpr const auto transactionIdVar = "TRANSACTION_ID";
     // Length of 'TRANSACTION_ID' string.
     constexpr const auto transactionIdVarSize = std::strlen(transactionIdVar);
     // Length of 'TRANSACTION_ID=' string.
     constexpr const auto transactionIdVarOffset = transactionIdVarSize + 1;

     // Flush all the pending log messages into the journal
     journalSync();

     sd_journal* j = nullptr;
     int rc = sd_journal_open(&j, SD_JOURNAL_LOCAL_ONLY);
     if (rc < 0)
     {
         logging::log<logging::level::ERR>(
             "Failed to open journal",
             logging::entry("DESCRIPTION=%s", strerror(-rc)));
         return;
     }

     std::string transactionIdStr = std::to_string(transactionId);
     std::set<std::string> metalist;
     auto metamap = g_errMetaMap.find(errMsg);
     if (metamap != g_errMetaMap.end())
     {
         metalist.insert(metamap->second.begin(), metamap->second.end());
     }

     // Add _PID field information in AdditionalData.
     metalist.insert("_PID");

     std::vector<std::string> additionalData;

     // Read the journal from the end to get the most recent entry first.
     // The result from the sd_journal_get_data() is of the form VARIABLE=value.
     SD_JOURNAL_FOREACH_BACKWARDS(j)
     {
         const char* data = nullptr;
         size_t length = 0;

         // Look for the transaction id metadata variable
         rc = sd_journal_get_data(j, transactionIdVar, (const void**)&data,
                                  &length);
         if (rc < 0)
         {
             // This journal entry does not have the TRANSACTION_ID
             // metadata variable.
             continue;
         }

         // journald does not guarantee that sd_journal_get_data() returns NULL
         // terminated strings, so need to specify the size to use to compare,
         // use the returned length instead of anything that relies on NULL
         // terminators like strlen().
         // The data variable is in the form of 'TRANSACTION_ID=1234'. Remove
         // the TRANSACTION_ID characters plus the (=) sign to do the comparison.
         // 'data + transactionIdVarOffset' will be in the form of '1234'.
         // 'length - transactionIdVarOffset' will be the length of '1234'.
         if ((length <= (transactionIdVarOffset)) ||
             (transactionIdStr.compare(0, transactionIdStr.size(),
                                       data + transactionIdVarOffset,
                                       length - transactionIdVarOffset) != 0))
         {
             // The value of the TRANSACTION_ID metadata is not the requested
             // transaction id number.
             continue;
         }

         // Search for all metadata variables in the current journal entry.
         for (auto i = metalist.cbegin(); i != metalist.cend();)
         {
             rc = sd_journal_get_data(j, (*i).c_str(), (const void**)&data,
                                      &length);
             if (rc < 0)
             {
                 // Metadata variable not found, check next metadata variable.
                 i++;
                 continue;
             }

             // Metadata variable found, save it and remove it from the set.
             additionalData.emplace_back(data, length);
             i = metalist.erase(i);
         }
         if (metalist.empty())
         {
             // All metadata variables found, break out of journal loop.
             break;
         }
     }
     if (!metalist.empty())
     {
         // Not all the metadata variables were found in the journal.
         for (auto& metaVarStr : metalist)
         {
             logging::log<logging::level::INFO>(
                 "Failed to find metadata",
                 logging::entry("META_FIELD=%s", metaVarStr.c_str()));
         }
     }

     sd_journal_close(j);

     createEntry(errMsg, errLvl, additionalData);
 }

 void Manager::createEntry(std::string errMsg, Entry::Level errLvl,
                           std::vector<std::string> additionalData,
                           const FFDCEntries& ffdc)
 {
     if (!Extensions::disableDefaultLogCaps())
     {
         if (errLvl < Entry::sevLowerLimit)
         {
             if (realErrors.size() >= ERROR_CAP)
             {
                 erase(realErrors.front());
             }
         }
         else
         {
             if (infoErrors.size() >= ERROR_INFO_CAP)
             {
                 erase(infoErrors.front());
             }
         }
     }

     entryId++;
     if (errLvl >= Entry::sevLowerLimit)
     {
         infoErrors.push_back(entryId);
     }
     else
     {
         realErrors.push_back(entryId);
     }
     auto ms = std::chrono::duration_cast<std::chrono::milliseconds>(
                   std::chrono::system_clock::now().time_since_epoch())
                   .count();
     auto objPath = std::string(OBJ_ENTRY) + '/' + std::to_string(entryId);

     AssociationList objects{};
     processMetadata(errMsg, additionalData, objects);

     auto e = std::make_unique<Entry>(busLog, objPath, entryId,
                                      ms, // Milliseconds since 1970
                                      errLvl, std::move(errMsg),
                                      std::move(additionalData),
                                      std::move(objects), fwVersion, *this);
     serialize(*e);

     if (isQuiesceOnErrorEnabled() && isCalloutPresent(*e))
     {
         quiesceOnError(entryId);
     }

     doExtensionLogCreate(*e, ffdc);

     // Note: No need to close the file descriptors in the FFDC.

     entries.insert(std::make_pair(entryId, std::move(e)));
 }

 bool Manager::isQuiesceOnErrorEnabled()
 {
     std::variant<bool> property;

     auto method = this->busLog.new_method_call(
         "xyz.openbmc_project.Settings", "/xyz/openbmc_project/logging/settings",
         "org.freedesktop.DBus.Properties", "Get");

     method.append("xyz.openbmc_project.Logging.Settings", "QuiesceOnHwError");

     try
     {
         auto reply = this->busLog.call(method);
         reply.read(property);
     }
     catch (const SdBusError& e)
     {
         log<level::ERR>("Error reading QuiesceOnHwError property",
                         entry("ERROR=%s", e.what()));
         throw;
     }

     return std::get<bool>(property);
 }

 bool Manager::isCalloutPresent(const Entry& entry)
 {
     for (const auto& c : entry.additionalData())
     {
         if (c.find("CALLOUT_") != std::string::npos)
         {
             return true;
         }
     }

     return false;
 }

 void Manager::findAndRemoveResolvedBlocks()
 {
     for (auto& entry : entries)
     {
         if (entry.second->resolved())
         {
             checkAndRemoveBlockingError(entry.first);
         }
     }
 }

 void Manager::onEntryResolve(sdbusplus::message::message& msg)
 {
     using Interface = std::string;
     using Property = std::string;
     using Value = std::string;
     using Properties = std::map<Property, std::variant<Value>>;

     Interface interface;
     Properties properties;

     msg.read(interface, properties);

     for (const auto& p : properties)
     {
         if (p.first == "Resolved")
         {
             findAndRemoveResolvedBlocks();
             return;
         }
     }
 }

 void Manager::checkAndQuiesceHost()
 {
     // First check host state
     std::variant<std::string> property;

     auto method = this->busLog.new_method_call(
         "xyz.openbmc_project.State.Host", "/xyz/openbmc_project/state/host0",
         "org.freedesktop.DBus.Properties", "Get");

     method.append("xyz.openbmc_project.State.Host", "CurrentHostState");

     try
     {
         auto reply = this->busLog.call(method);
         reply.read(property);
     }
     catch (const SdBusError& e)
     {
         // Quiescing the host is a "best effort" type function. If unable to
         // read the host state or it comes back empty, just return.
         // The boot block object will still be created and the associations to
         // find the log will be present. Don't want a dependency with
         // phosphor-state-manager service
         log<level::INFO>("Error reading QuiesceOnHwError property",
                          entry("ERROR=%s", e.what()));
         return;
     }

     std::string hostState = std::get<std::string>(property);

     // If host state is empty, do nothing
     if (hostState.empty())
     {
         return;
     }

     using Host = sdbusplus::xyz::openbmc_project::State::server::Host;
     auto state = Host::convertHostStateFromString(hostState);
     if (state != Host::HostState::Running)
     {
         return;
     }

     auto quiesce = this->busLog.new_method_call(
         "org.freedesktop.systemd1", "/org/freedesktop/systemd1",
         "org.freedesktop.systemd1.Manager", "StartUnit");

     quiesce.append("obmc-host-quiesce@0.target");
     quiesce.append("replace");

     this->busLog.call_noreply(quiesce);
 }

 void Manager::quiesceOnError(const uint32_t entryId)
 {

     logging::log<logging::level::INFO>(
         "QuiesceOnError set and callout present");

     auto blockPath =
         std::string(OBJ_LOGGING) + "/block" + std::to_string(entryId);
     auto blockObj = std::make_unique<Block>(this->busLog, blockPath, entryId);
     this->blockingErrors.push_back(std::move(blockObj));

     // Register call back if log is resolved
     using namespace sdbusplus::bus::match::rules;
     auto entryPath = std::string(OBJ_ENTRY) + '/' + std::to_string(entryId);
     auto callback = std::make_unique<sdbusplus::bus::match::match>(
         this->busLog,
         propertiesChanged(entryPath, "xyz.openbmc_project.Logging.Entry"),
         std::bind(std::mem_fn(&Manager::onEntryResolve), this,
                   std::placeholders::_1));

     propChangedEntryCallback.insert(
         std::make_pair(entryId, std::move(callback)));

     checkAndQuiesceHost();
 }

 void Manager::doExtensionLogCreate(const Entry& entry, const FFDCEntries& ffdc)
 {
     // Make the association <endpointpath>/<endpointtype> paths
     std::vector<std::string> assocs;
     for (const auto& [forwardType, reverseType, endpoint] :
          entry.associations())
     {
         std::string e{endpoint};
         e += '/' + reverseType;
         assocs.push_back(e);
     }

     for (auto& create : Extensions::getCreateFunctions())
     {
         try
         {
             create(entry.message(), entry.id(), entry.timestamp(),
                    entry.severity(), entry.additionalData(), assocs, ffdc);
         }
         catch (std::exception& e)
         {
             log<level::ERR>("An extension's create function threw an exception",
                             phosphor::logging::entry("ERROR=%s", e.what()));
         }
     }
 }

 void Manager::processMetadata(const std::string& errorName,
                               const std::vector<std::string>& additionalData,
                               AssociationList& objects) const
 {
     // additionalData is a list of "metadata=value"
     constexpr auto separator = '=';
     for (const auto& entryItem : additionalData)
     {
         auto found = entryItem.find(separator);
         if (std::string::npos != found)
         {
             auto metadata = entryItem.substr(0, found);
             auto iter = meta.find(metadata);
             if (meta.end() != iter)
             {
                 (iter->second)(metadata, additionalData, objects);
             }
         }
     }
 }

 void Manager::checkAndRemoveBlockingError(uint32_t entryId)
 {
     // First look for blocking object and remove
     auto it = find_if(
         blockingErrors.begin(), blockingErrors.end(),
         [&](std::unique_ptr<Block>& obj) { return obj->entryId == entryId; });
     if (it != blockingErrors.end())
     {
         blockingErrors.erase(it);
     }

     // Now remove the callback looking for the error to be resolved
     auto resolveFind = propChangedEntryCallback.find(entryId);
     if (resolveFind != propChangedEntryCallback.end())
     {
         propChangedEntryCallback.erase(resolveFind);
     }

     return;
 }

 void Manager::erase(uint32_t entryId)
 {
     auto entryFound = entries.find(entryId);
     if (entries.end() != entryFound)
     {
         for (auto& func : Extensions::getDeleteProhibitedFunctions())
         {
             try
             {
                 bool prohibited = false;
                 func(entryId, prohibited);
                 if (prohibited)
                 {
                     // Future work remains to throw an error here.
                     return;
                 }
             }
             catch (std::exception& e)
             {
                 log<level::ERR>(
                     "An extension's deleteProhibited function threw "
                     "an exception",
                     entry("ERROR=%s", e.what()));
             }
         }

         // Delete the persistent representation of this error.
         fs::path errorPath(ERRLOG_PERSIST_PATH);
         errorPath /= std::to_string(entryId);
         fs::remove(errorPath);

         auto removeId = [](std::list<uint32_t>& ids, uint32_t id) {
             auto it = std::find(ids.begin(), ids.end(), id);
             if (it != ids.end())
             {
                 ids.erase(it);
             }
         };
         if (entryFound->second->severity() >= Entry::sevLowerLimit)
         {
             removeId(infoErrors, entryId);
         }
         else
         {
             removeId(realErrors, entryId);
         }
         entries.erase(entryFound);

         checkAndRemoveBlockingError(entryId);

         for (auto& remove : Extensions::getDeleteFunctions())
         {
             try
             {
                 remove(entryId);
             }
             catch (std::exception& e)
             {
                 log<level::ERR>("An extension's delete function threw an "
                                 "exception",
                                 entry("ERROR=%s", e.what()));
             }
         }
     }
     else
     {
         logging::log<level::ERR>("Invalid entry ID to delete",
                                  logging::entry("ID=%d", entryId));
     }
 }

 void Manager::restore()
 {
     auto sanity = [](const auto& id, const auto& restoredId) {
         return id == restoredId;
     };
     std::vector<uint32_t> errorIds;

     fs::path dir(ERRLOG_PERSIST_PATH);
     if (!fs::exists(dir) || fs::is_empty(dir))
     {
         return;
     }

     for (auto& file : fs::directory_iterator(dir))
     {
         auto id = file.path().filename().c_str();
         auto idNum = std::stol(id);
         auto e = std::make_unique<Entry>(
             busLog, std::string(OBJ_ENTRY) + '/' + id, idNum, *this);
         if (deserialize(file.path(), *e))
         {
             // validate the restored error entry id
             if (sanity(static_cast<uint32_t>(idNum), e->id()))
             {
                 e->emit_object_added();
                 if (e->severity() >= Entry::sevLowerLimit)
                 {
                     infoErrors.push_back(idNum);
                 }
                 else
                 {
                     realErrors.push_back(idNum);
                 }

                 entries.insert(std::make_pair(idNum, std::move(e)));
                 errorIds.push_back(idNum);
             }
             else
             {
                 logging::log<logging::level::ERR>(
                     "Failed in sanity check while restoring error entry. "
                     "Ignoring error entry",
                     logging::entry("ID_NUM=%d", idNum),
                     logging::entry("ENTRY_ID=%d", e->id()));
             }
         }
     }

     if (!errorIds.empty())
     {
         entryId = *(std::max_element(errorIds.begin(), errorIds.end()));
     }
 }

 void Manager::journalSync()
 {
     bool syncRequested = false;
     auto fd = -1;
     auto rc = -1;
     auto wd = -1;
     auto bus = sdbusplus::bus::new_default();

     auto start =
         duration_cast<microseconds>(steady_clock::now().time_since_epoch())
             .count();

     // Each time an error log is committed, a request to sync the journal
     // must occur and block that error log commit until it completes. A 5sec
     // block is done to allow sufficient time for the journal to be synced.
     //
     // Number of loop iterations = 3 for the following reasons:
     // Iteration #1: Requests a journal sync by killing the journald service.
     // Iteration #2: Setup an inotify watch to monitor the synced file that
     //               journald updates with the timestamp the last time the
     //               journal was flushed.
     // Iteration #3: Poll to wait until inotify reports an event which blocks
     //               the error log from being commited until the sync completes.
     constexpr auto maxRetry = 3;
     for (int i = 0; i < maxRetry; i++)
     {
         // Read timestamp from synced file
         constexpr auto syncedPath = "/run/systemd/journal/synced";
         std::ifstream syncedFile(syncedPath);
         if (syncedFile.fail())
         {
             // If the synced file doesn't exist, a sync request will create it.
             if (errno != ENOENT)
             {
                 log<level::ERR>("Failed to open journal synced file",
                                 entry("FILENAME=%s", syncedPath),
                                 entry("ERRNO=%d", errno));
                 return;
             }
         }
         else
         {
             // Only read the synced file if it exists.
             // See if a sync happened by now
             std::string timestampStr;
             std::getline(syncedFile, timestampStr);
             auto timestamp = std::stoll(timestampStr);
             if (timestamp >= start)
             {
                 break;
             }
         }

         // Let's ask for a sync, but only once
         if (!syncRequested)
         {
             syncRequested = true;

             constexpr auto JOURNAL_UNIT = "systemd-journald.service";
             auto signal = SIGRTMIN + 1;

             auto method = bus.new_method_call(SYSTEMD_BUSNAME, SYSTEMD_PATH,
                                               SYSTEMD_INTERFACE, "KillUnit");
             method.append(JOURNAL_UNIT, "main", signal);
             bus.call(method);
             if (method.is_method_error())
             {
                 log<level::ERR>("Failed to kill journal service");
                 break;
             }
             continue;
         }

         // Let's install the inotify watch, if we didn't do that yet. This watch
         // monitors the syncedFile for when journald updates it with a newer
         // timestamp. This means the journal has been flushed.
         if (fd < 0)
         {
             fd = inotify_init1(IN_NONBLOCK | IN_CLOEXEC);
             if (fd < 0)
             {
                 log<level::ERR>("Failed to create inotify watch",
                                 entry("ERRNO=%d", errno));
                 return;
             }

             constexpr auto JOURNAL_RUN_PATH = "/run/systemd/journal";
             wd = inotify_add_watch(fd, JOURNAL_RUN_PATH,
                                    IN_MOVED_TO | IN_DONT_FOLLOW | IN_ONLYDIR);
             if (wd < 0)
             {
                 log<level::ERR>("Failed to watch journal directory",
                                 entry("PATH=%s", JOURNAL_RUN_PATH),
                                 entry("ERRNO=%d", errno));
                 close(fd);
                 return;
             }
             continue;
         }

         // Let's wait until inotify reports an event
         struct pollfd fds = {
             .fd = fd,
             .events = POLLIN,
         };
         constexpr auto pollTimeout = 5; // 5 seconds
         rc = poll(&fds, 1, pollTimeout * 1000);
         if (rc < 0)
         {
             log<level::ERR>("Failed to add event", entry("ERRNO=%d", errno),
                             entry("ERR=%s", strerror(-rc)));
             inotify_rm_watch(fd, wd);
             close(fd);
             return;
         }
         else if (rc == 0)
         {
             log<level::INFO>("Poll timeout, no new journal synced data",
                              entry("TIMEOUT=%d", pollTimeout));
             break;
         }

         // Read from the specified file descriptor until there is no new data,
         // throwing away everything read since the timestamp will be read at the
         // beginning of the loop.
         constexpr auto maxBytes = 64;
         uint8_t buffer[maxBytes];
         while (read(fd, buffer, maxBytes) > 0)
             ;
     }

     if (fd != -1)
     {
         if (wd != -1)
         {
             inotify_rm_watch(fd, wd);
         }
         close(fd);
     }

     return;
 }

 std::string Manager::readFWVersion()
 {
     auto version = util::getOSReleaseValue("VERSION_ID");

     if (!version)
     {
         log<level::ERR>("Unable to read BMC firmware version");
     }

     return version.value_or("");
 }

 void Manager::create(const std::string& message, Entry::Level severity,
                      const std::map<std::string, std::string>& additionalData)
 {
     // Convert the map into a vector of "key=value" strings
     std::vector<std::string> ad;
     metadata::associations::combine(additionalData, ad);

     createEntry(message, severity, ad);
 }

 void Manager::createWithFFDC(
     const std::string& message, Entry::Level severity,
     const std::map<std::string, std::string>& additionalData,
     const FFDCEntries& ffdc)
 {
     // Convert the map into a vector of "key=value" strings
     std::vector<std::string> ad;
     metadata::associations::combine(additionalData, ad);

     createEntry(message, severity, ad, ffdc);
 }

 } // namespace internal
 } // namespace logging
 } // namespace phosphor
	#include "config.h"

	#include "log_manager.hpp"

	#include "elog_entry.hpp"
	#include "elog_meta.hpp"
	#include "elog_serialize.hpp"
	#include "extensions.hpp"
	#include "util.hpp"

	#include <poll.h>
	#include <sys/inotify.h>
	#include <systemd/sd-bus.h>
	#include <systemd/sd-journal.h>
	#include <unistd.h>

	#include <cassert>
	#include <chrono>
	#include <cstdio>
	#include <cstring>
	#include <fstream>
	#include <functional>
	#include <future>
	#include <iostream>
	#include <map>
	#include <phosphor-logging/log.hpp>
	#include <sdbusplus/vtable.hpp>
	#include <set>
	#include <string>
	#include <vector>
	#include <xyz/openbmc_project/State/Host/server.hpp>

	using namespace phosphor::logging;
	using namespace std::chrono;
	using sdbusplus::exception::SdBusError;
	extern const std::map<metadata::Metadata,
	std::function<metadata::associations::Type>>
	meta;

	namespace phosphor
	{
	namespace logging
	{
	namespace internal
	{
	inline auto getLevel(const std::string& errMsg)
	{
	auto reqLevel = Entry::Level::Error; // Default to Error

	auto levelmap = g_errLevelMap.find(errMsg);
	if (levelmap != g_errLevelMap.end())
	{
	reqLevel = static_cast<Entry::Level>(levelmap->second);
	}

	return reqLevel;
	}

	int Manager::getRealErrSize()
	{
	return realErrors.size();
	}

	int Manager::getInfoErrSize()
	{
	return infoErrors.size();
	}

	void Manager::commit(uint64_t transactionId, std::string errMsg)
	{
	auto level = getLevel(errMsg);
	_commit(transactionId, std::move(errMsg), level);
	}

	void Manager::commitWithLvl(uint64_t transactionId, std::string errMsg,
	uint32_t errLvl)
	{
	_commit(transactionId, std::move(errMsg),
	static_cast<Entry::Level>(errLvl));
	}

	void Manager::_commit(uint64_t transactionId, std::string&& errMsg,
	Entry::Level errLvl)
	{
	constexpr const auto transactionIdVar = "TRANSACTION_ID";
	// Length of 'TRANSACTION_ID' string.
	constexpr const auto transactionIdVarSize = std::strlen(transactionIdVar);
	// Length of 'TRANSACTION_ID=' string.
	constexpr const auto transactionIdVarOffset = transactionIdVarSize + 1;

	// Flush all the pending log messages into the journal
	journalSync();

	sd_journal* j = nullptr;
	int rc = sd_journal_open(&j, SD_JOURNAL_LOCAL_ONLY);
	if (rc < 0)
	{
	logging::log<logging::level::ERR>(
	"Failed to open journal",
	logging::entry("DESCRIPTION=%s", strerror(-rc)));
	return;
	}

	std::string transactionIdStr = std::to_string(transactionId);
	std::set<std::string> metalist;
	auto metamap = g_errMetaMap.find(errMsg);
	if (metamap != g_errMetaMap.end())
	{
	metalist.insert(metamap->second.begin(), metamap->second.end());
	}

	// Add _PID field information in AdditionalData.
	metalist.insert("_PID");

	std::vector<std::string> additionalData;

	// Read the journal from the end to get the most recent entry first.
	// The result from the sd_journal_get_data() is of the form VARIABLE=value.
	SD_JOURNAL_FOREACH_BACKWARDS(j)
	{
	const char* data = nullptr;
	size_t length = 0;

	// Look for the transaction id metadata variable
	rc = sd_journal_get_data(j, transactionIdVar, (const void**)&data,
	&length);
	if (rc < 0)
	{
	// This journal entry does not have the TRANSACTION_ID
	// metadata variable.
	continue;
	}

	// journald does not guarantee that sd_journal_get_data() returns NULL
	// terminated strings, so need to specify the size to use to compare,
	// use the returned length instead of anything that relies on NULL
	// terminators like strlen().
	// The data variable is in the form of 'TRANSACTION_ID=1234'. Remove
	// the TRANSACTION_ID characters plus the (=) sign to do the comparison.
	// 'data + transactionIdVarOffset' will be in the form of '1234'.
	// 'length - transactionIdVarOffset' will be the length of '1234'.
	if ((length <= (transactionIdVarOffset)) \|\|
	(transactionIdStr.compare(0, transactionIdStr.size(),
	data + transactionIdVarOffset,
	length - transactionIdVarOffset) != 0))
	{
	// The value of the TRANSACTION_ID metadata is not the requested
	// transaction id number.
	continue;
	}

	// Search for all metadata variables in the current journal entry.
	for (auto i = metalist.cbegin(); i != metalist.cend();)
	{
	rc = sd_journal_get_data(j, (i).c_str(), (const void*)&data,
	&length);
	if (rc < 0)
	{
	// Metadata variable not found, check next metadata variable.
	i++;
	continue;
	}

	// Metadata variable found, save it and remove it from the set.
	additionalData.emplace_back(data, length);
	i = metalist.erase(i);
	}
	if (metalist.empty())
	{
	// All metadata variables found, break out of journal loop.
	break;
	}
	}
	if (!metalist.empty())
	{
	// Not all the metadata variables were found in the journal.
	for (auto& metaVarStr : metalist)
	{
	logging::log<logging::level::INFO>(
	"Failed to find metadata",
	logging::entry("META_FIELD=%s", metaVarStr.c_str()));
	}
	}

	sd_journal_close(j);

	createEntry(errMsg, errLvl, additionalData);
	}

	void Manager::createEntry(std::string errMsg, Entry::Level errLvl,
	std::vector<std::string> additionalData,
	const FFDCEntries& ffdc)
	{
	if (!Extensions::disableDefaultLogCaps())
	{
	if (errLvl < Entry::sevLowerLimit)
	{
	if (realErrors.size() >= ERROR_CAP)
	{
	erase(realErrors.front());
	}
	}
	else
	{
	if (infoErrors.size() >= ERROR_INFO_CAP)
	{
	erase(infoErrors.front());
	}
	}
	}

	entryId++;
	if (errLvl >= Entry::sevLowerLimit)
	{
	infoErrors.push_back(entryId);
	}
	else
	{
	realErrors.push_back(entryId);
	}
	auto ms = std::chrono::duration_cast<std::chrono::milliseconds>(
	std::chrono::system_clock::now().time_since_epoch())
	.count();
	auto objPath = std::string(OBJ_ENTRY) + '/' + std::to_string(entryId);

	AssociationList objects{};
	processMetadata(errMsg, additionalData, objects);

	auto e = std::make_unique<Entry>(busLog, objPath, entryId,
	ms, // Milliseconds since 1970
	errLvl, std::move(errMsg),
	std::move(additionalData),
	std::move(objects), fwVersion, *this);
	serialize(*e);

	if (isQuiesceOnErrorEnabled() && isCalloutPresent(*e))
	{
	quiesceOnError(entryId);
	}

	doExtensionLogCreate(*e, ffdc);

	// Note: No need to close the file descriptors in the FFDC.

	entries.insert(std::make_pair(entryId, std::move(e)));
	}

	bool Manager::isQuiesceOnErrorEnabled()
	{
	std::variant<bool> property;

	auto method = this->busLog.new_method_call(
	"xyz.openbmc_project.Settings", "/xyz/openbmc_project/logging/settings",
	"org.freedesktop.DBus.Properties", "Get");

	method.append("xyz.openbmc_project.Logging.Settings", "QuiesceOnHwError");

	try
	{
	auto reply = this->busLog.call(method);
	reply.read(property);
	}
	catch (const SdBusError& e)
	{
	log<level::ERR>("Error reading QuiesceOnHwError property",
	entry("ERROR=%s", e.what()));
	throw;
	}

	return std::get<bool>(property);
	}

	bool Manager::isCalloutPresent(const Entry& entry)
	{
	for (const auto& c : entry.additionalData())
	{
	if (c.find("CALLOUT_") != std::string::npos)
	{
	return true;
	}
	}

	return false;
	}

	void Manager::findAndRemoveResolvedBlocks()
	{
	for (auto& entry : entries)
	{
	if (entry.second->resolved())
	{
	checkAndRemoveBlockingError(entry.first);
	}
	}
	}

	void Manager::onEntryResolve(sdbusplus::message::message& msg)
	{
	using Interface = std::string;
	using Property = std::string;
	using Value = std::string;
	using Properties = std::map<Property, std::variant<Value>>;

	Interface interface;
	Properties properties;

	msg.read(interface, properties);

	for (const auto& p : properties)
	{
	if (p.first == "Resolved")
	{
	findAndRemoveResolvedBlocks();
	return;
	}
	}
	}

	void Manager::checkAndQuiesceHost()
	{
	// First check host state
	std::variant<std::string> property;

	auto method = this->busLog.new_method_call(
	"xyz.openbmc_project.State.Host", "/xyz/openbmc_project/state/host0",
	"org.freedesktop.DBus.Properties", "Get");

	method.append("xyz.openbmc_project.State.Host", "CurrentHostState");

	try
	{
	auto reply = this->busLog.call(method);
	reply.read(property);
	}
	catch (const SdBusError& e)
	{
	// Quiescing the host is a "best effort" type function. If unable to
	// read the host state or it comes back empty, just return.
	// The boot block object will still be created and the associations to
	// find the log will be present. Don't want a dependency with
	// phosphor-state-manager service
	log<level::INFO>("Error reading QuiesceOnHwError property",
	entry("ERROR=%s", e.what()));
	return;
	}

	std::string hostState = std::get<std::string>(property);

	// If host state is empty, do nothing
	if (hostState.empty())
	{
	return;
	}

	using Host = sdbusplus::xyz::openbmc_project::State::server::Host;
	auto state = Host::convertHostStateFromString(hostState);
	if (state != Host::HostState::Running)
	{
	return;
	}

	auto quiesce = this->busLog.new_method_call(
	"org.freedesktop.systemd1", "/org/freedesktop/systemd1",
	"org.freedesktop.systemd1.Manager", "StartUnit");

	quiesce.append("obmc-host-quiesce@0.target");
	quiesce.append("replace");

	this->busLog.call_noreply(quiesce);
	}

	void Manager::quiesceOnError(const uint32_t entryId)
	{

	logging::log<logging::level::INFO>(
	"QuiesceOnError set and callout present");

	auto blockPath =
	std::string(OBJ_LOGGING) + "/block" + std::to_string(entryId);
	auto blockObj = std::make_unique<Block>(this->busLog, blockPath, entryId);
	this->blockingErrors.push_back(std::move(blockObj));

	// Register call back if log is resolved
	using namespace sdbusplus::bus::match::rules;
	auto entryPath = std::string(OBJ_ENTRY) + '/' + std::to_string(entryId);
	auto callback = std::make_unique<sdbusplus::bus::match::match>(
	this->busLog,
	propertiesChanged(entryPath, "xyz.openbmc_project.Logging.Entry"),
	std::bind(std::mem_fn(&Manager::onEntryResolve), this,
	std::placeholders::_1));

	propChangedEntryCallback.insert(
	std::make_pair(entryId, std::move(callback)));

	checkAndQuiesceHost();
	}

	void Manager::doExtensionLogCreate(const Entry& entry, const FFDCEntries& ffdc)
	{
	// Make the association <endpointpath>/<endpointtype> paths
	std::vector<std::string> assocs;
	for (const auto& [forwardType, reverseType, endpoint] :
	entry.associations())
	{
	std::string e{endpoint};
	e += '/' + reverseType;
	assocs.push_back(e);
	}

	for (auto& create : Extensions::getCreateFunctions())
	{
	try
	{
	create(entry.message(), entry.id(), entry.timestamp(),
	entry.severity(), entry.additionalData(), assocs, ffdc);
	}
	catch (std::exception& e)
	{
	log<level::ERR>("An extension's create function threw an exception",
	phosphor::logging::entry("ERROR=%s", e.what()));
	}
	}
	}

	void Manager::processMetadata(const std::string& errorName,
	const std::vector<std::string>& additionalData,
	AssociationList& objects) const
	{
	// additionalData is a list of "metadata=value"
	constexpr auto separator = '=';
	for (const auto& entryItem : additionalData)
	{
	auto found = entryItem.find(separator);
	if (std::string::npos != found)
	{
	auto metadata = entryItem.substr(0, found);
	auto iter = meta.find(metadata);
	if (meta.end() != iter)
	{
	(iter->second)(metadata, additionalData, objects);
	}
	}
	}
	}

	void Manager::checkAndRemoveBlockingError(uint32_t entryId)
	{
	// First look for blocking object and remove
	auto it = find_if(
	blockingErrors.begin(), blockingErrors.end(),
	[&](std::unique_ptr<Block>& obj) { return obj->entryId == entryId; });
	if (it != blockingErrors.end())
	{
	blockingErrors.erase(it);
	}

	// Now remove the callback looking for the error to be resolved
	auto resolveFind = propChangedEntryCallback.find(entryId);
	if (resolveFind != propChangedEntryCallback.end())
	{
	propChangedEntryCallback.erase(resolveFind);
	}

	return;
	}

	void Manager::erase(uint32_t entryId)
	{
	auto entryFound = entries.find(entryId);
	if (entries.end() != entryFound)
	{
	for (auto& func : Extensions::getDeleteProhibitedFunctions())
	{
	try
	{
	bool prohibited = false;
	func(entryId, prohibited);
	if (prohibited)
	{
	// Future work remains to throw an error here.
	return;
	}
	}
	catch (std::exception& e)
	{
	log<level::ERR>(
	"An extension's deleteProhibited function threw "
	"an exception",
	entry("ERROR=%s", e.what()));
	}
	}

	// Delete the persistent representation of this error.
	fs::path errorPath(ERRLOG_PERSIST_PATH);
	errorPath /= std::to_string(entryId);
	fs::remove(errorPath);

	auto removeId = [](std::list<uint32_t>& ids, uint32_t id) {
	auto it = std::find(ids.begin(), ids.end(), id);
	if (it != ids.end())
	{
	ids.erase(it);
	}
	};
	if (entryFound->second->severity() >= Entry::sevLowerLimit)
	{
	removeId(infoErrors, entryId);
	}
	else
	{
	removeId(realErrors, entryId);
	}
	entries.erase(entryFound);

	checkAndRemoveBlockingError(entryId);

	for (auto& remove : Extensions::getDeleteFunctions())
	{
	try
	{
	remove(entryId);
	}
	catch (std::exception& e)
	{
	log<level::ERR>("An extension's delete function threw an "
	"exception",
	entry("ERROR=%s", e.what()));
	}
	}
	}
	else
	{
	logging::log<level::ERR>("Invalid entry ID to delete",
	logging::entry("ID=%d", entryId));
	}
	}

	void Manager::restore()
	{
	auto sanity = [](const auto& id, const auto& restoredId) {
	return id == restoredId;
	};
	std::vector<uint32_t> errorIds;

	fs::path dir(ERRLOG_PERSIST_PATH);
	if (!fs::exists(dir) \|\| fs::is_empty(dir))
	{
	return;
	}

	for (auto& file : fs::directory_iterator(dir))
	{
	auto id = file.path().filename().c_str();
	auto idNum = std::stol(id);
	auto e = std::make_unique<Entry>(
	busLog, std::string(OBJ_ENTRY) + '/' + id, idNum, *this);
	if (deserialize(file.path(), *e))
	{
	// validate the restored error entry id
	if (sanity(static_cast<uint32_t>(idNum), e->id()))
	{
	e->emit_object_added();
	if (e->severity() >= Entry::sevLowerLimit)
	{
	infoErrors.push_back(idNum);
	}
	else
	{
	realErrors.push_back(idNum);
	}

	entries.insert(std::make_pair(idNum, std::move(e)));
	errorIds.push_back(idNum);
	}
	else
	{
	logging::log<logging::level::ERR>(
	"Failed in sanity check while restoring error entry. "
	"Ignoring error entry",
	logging::entry("ID_NUM=%d", idNum),
	logging::entry("ENTRY_ID=%d", e->id()));
	}
	}
	}

	if (!errorIds.empty())
	{
	entryId = *(std::max_element(errorIds.begin(), errorIds.end()));
	}
	}

	void Manager::journalSync()
	{
	bool syncRequested = false;
	auto fd = -1;
	auto rc = -1;
	auto wd = -1;
	auto bus = sdbusplus::bus::new_default();

	auto start =
	duration_cast<microseconds>(steady_clock::now().time_since_epoch())
	.count();

	// Each time an error log is committed, a request to sync the journal
	// must occur and block that error log commit until it completes. A 5sec
	// block is done to allow sufficient time for the journal to be synced.
	//
	// Number of loop iterations = 3 for the following reasons:
	// Iteration #1: Requests a journal sync by killing the journald service.
	// Iteration #2: Setup an inotify watch to monitor the synced file that
	// journald updates with the timestamp the last time the
	// journal was flushed.
	// Iteration #3: Poll to wait until inotify reports an event which blocks
	// the error log from being commited until the sync completes.
	constexpr auto maxRetry = 3;
	for (int i = 0; i < maxRetry; i++)
	{
	// Read timestamp from synced file
	constexpr auto syncedPath = "/run/systemd/journal/synced";
	std::ifstream syncedFile(syncedPath);
	if (syncedFile.fail())
	{
	// If the synced file doesn't exist, a sync request will create it.
	if (errno != ENOENT)
	{
	log<level::ERR>("Failed to open journal synced file",
	entry("FILENAME=%s", syncedPath),
	entry("ERRNO=%d", errno));
	return;
	}
	}
	else
	{
	// Only read the synced file if it exists.
	// See if a sync happened by now
	std::string timestampStr;
	std::getline(syncedFile, timestampStr);
	auto timestamp = std::stoll(timestampStr);
	if (timestamp >= start)
	{
	break;
	}
	}

	// Let's ask for a sync, but only once
	if (!syncRequested)
	{
	syncRequested = true;

	constexpr auto JOURNAL_UNIT = "systemd-journald.service";
	auto signal = SIGRTMIN + 1;

	auto method = bus.new_method_call(SYSTEMD_BUSNAME, SYSTEMD_PATH,
	SYSTEMD_INTERFACE, "KillUnit");
	method.append(JOURNAL_UNIT, "main", signal);
	bus.call(method);
	if (method.is_method_error())
	{
	log<level::ERR>("Failed to kill journal service");
	break;
	}
	continue;
	}

	// Let's install the inotify watch, if we didn't do that yet. This watch
	// monitors the syncedFile for when journald updates it with a newer
	// timestamp. This means the journal has been flushed.
	if (fd < 0)
	{
	fd = inotify_init1(IN_NONBLOCK \| IN_CLOEXEC);
	if (fd < 0)
	{
	log<level::ERR>("Failed to create inotify watch",
	entry("ERRNO=%d", errno));
	return;
	}

	constexpr auto JOURNAL_RUN_PATH = "/run/systemd/journal";
	wd = inotify_add_watch(fd, JOURNAL_RUN_PATH,
	IN_MOVED_TO \| IN_DONT_FOLLOW \| IN_ONLYDIR);
	if (wd < 0)
	{
	log<level::ERR>("Failed to watch journal directory",
	entry("PATH=%s", JOURNAL_RUN_PATH),
	entry("ERRNO=%d", errno));
	close(fd);
	return;
	}
	continue;
	}

	// Let's wait until inotify reports an event
	struct pollfd fds = {
	.fd = fd,
	.events = POLLIN,
	};
	constexpr auto pollTimeout = 5; // 5 seconds
	rc = poll(&fds, 1, pollTimeout * 1000);
	if (rc < 0)
	{
	log<level::ERR>("Failed to add event", entry("ERRNO=%d", errno),
	entry("ERR=%s", strerror(-rc)));
	inotify_rm_watch(fd, wd);
	close(fd);
	return;
	}
	else if (rc == 0)
	{
	log<level::INFO>("Poll timeout, no new journal synced data",
	entry("TIMEOUT=%d", pollTimeout));
	break;
	}

	// Read from the specified file descriptor until there is no new data,
	// throwing away everything read since the timestamp will be read at the
	// beginning of the loop.
	constexpr auto maxBytes = 64;
	uint8_t buffer[maxBytes];
	while (read(fd, buffer, maxBytes) > 0)
	;
	}

	if (fd != -1)
	{
	if (wd != -1)
	{
	inotify_rm_watch(fd, wd);
	}
	close(fd);
	}

	return;
	}

	std::string Manager::readFWVersion()
	{
	auto version = util::getOSReleaseValue("VERSION_ID");

	if (!version)
	{
	log<level::ERR>("Unable to read BMC firmware version");
	}

	return version.value_or("");
	}

	void Manager::create(const std::string& message, Entry::Level severity,
	const std::map<std::string, std::string>& additionalData)
	{
	// Convert the map into a vector of "key=value" strings
	std::vector<std::string> ad;
	metadata::associations::combine(additionalData, ad);

	createEntry(message, severity, ad);
	}

	void Manager::createWithFFDC(
	const std::string& message, Entry::Level severity,
	const std::map<std::string, std::string>& additionalData,
	const FFDCEntries& ffdc)
	{
	// Convert the map into a vector of "key=value" strings
	std::vector<std::string> ad;
	metadata::associations::combine(additionalData, ad);

	createEntry(message, severity, ad, ffdc);
	}

	} // namespace internal
	} // namespace logging
	} // namespace phosphor