PEL: Create class to read from the journal
Create a Journal class that can extract messages out of the journal and
return them as a vector of strings that look like:
"Dec 14 15:58:17 systemd[1]: systemd-tmpfiles-clean.service: Deactivated
successfully."
It can either grab the previous N entries, or the previous N entries
that match a specific SYSLOG_IDENTIFIER value.
The class follows the same strategy as the DataInterface class where a
base class pointer is passed into the PEL Manager class so that during
unit test it can be mocked.
Future commits will capture the journal into PEL UserData sections.
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I9f4bb304c4b213165049fa00de2e62f962ae67f1
diff --git a/extensions/openpower-pels/journal.cpp b/extensions/openpower-pels/journal.cpp
new file mode 100644
index 0000000..0a728f0
--- /dev/null
+++ b/extensions/openpower-pels/journal.cpp
@@ -0,0 +1,176 @@
+/**
+ * Copyright © 2023 IBM Corporation
+ *
+ * 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 "journal.hpp"
+
+#include <phosphor-logging/log.hpp>
+
+#include <stdexcept>
+#include <thread>
+
+namespace openpower::pels
+{
+
+using namespace phosphor::logging;
+
+/**
+ * @class JournalCloser
+ *
+ * Closes the journal on destruction
+ */
+class JournalCloser
+{
+ public:
+ JournalCloser() = delete;
+ JournalCloser(const JournalCloser&) = delete;
+ JournalCloser(JournalCloser&&) = delete;
+ JournalCloser& operator=(const JournalCloser&) = delete;
+ JournalCloser& operator=(JournalCloser&&) = delete;
+
+ explicit JournalCloser(sd_journal* journal) : journal{journal} {}
+
+ ~JournalCloser()
+ {
+ sd_journal_close(journal);
+ }
+
+ private:
+ sd_journal* journal{nullptr};
+};
+
+std::vector<std::string> Journal::getMessages(const std::string& syslogID,
+ size_t maxMessages) const
+{
+ // The message registry JSON schema will also fail if a zero is in the JSON
+ if (0 == maxMessages)
+ {
+ log<level::ERR>(
+ "maxMessages value of zero passed into Journal::getMessages");
+ return std::vector<std::string>{};
+ }
+
+ sd_journal* journal;
+ int rc = sd_journal_open(&journal, SD_JOURNAL_LOCAL_ONLY);
+ if (rc < 0)
+ {
+ throw std::runtime_error{std::string{"Failed to open journal: "} +
+ strerror(-rc)};
+ }
+
+ JournalCloser closer{journal};
+
+ if (!syslogID.empty())
+ {
+ std::string match{"SYSLOG_IDENTIFIER=" + syslogID};
+
+ rc = sd_journal_add_match(journal, match.c_str(), 0);
+ if (rc < 0)
+ {
+ throw std::runtime_error{
+ std::string{"Failed to add journal match: "} + strerror(-rc)};
+ }
+ }
+
+ // Loop through matching entries from newest to oldest
+ std::vector<std::string> messages;
+ messages.reserve(maxMessages);
+ std::string sID, pid, message, timeStamp, line;
+
+ SD_JOURNAL_FOREACH_BACKWARDS(journal)
+ {
+ timeStamp = getTimeStamp(journal);
+ sID = getFieldValue(journal, "SYSLOG_IDENTIFIER");
+ pid = getFieldValue(journal, "_PID");
+ message = getFieldValue(journal, "MESSAGE");
+
+ line = timeStamp + " " + sID + "[" + pid + "]: " + message;
+ messages.emplace(messages.begin(), line);
+
+ if (messages.size() >= maxMessages)
+ {
+ break;
+ }
+ }
+
+ return messages;
+}
+
+std::string Journal::getFieldValue(sd_journal* journal,
+ const std::string& field) const
+{
+ std::string value{};
+
+ const void* data{nullptr};
+ size_t length{0};
+ int rc = sd_journal_get_data(journal, field.c_str(), &data, &length);
+ if (rc < 0)
+ {
+ if (-rc == ENOENT)
+ {
+ // Current entry does not include this field; return empty value
+ return value;
+ }
+ else
+ {
+ throw std::runtime_error{
+ std::string{"Failed to read journal entry field: "} +
+ strerror(-rc)};
+ }
+ }
+
+ // Get value from field data. Field data in format "FIELD=value".
+ std::string dataString{static_cast<const char*>(data), length};
+ std::string::size_type pos = dataString.find('=');
+ if ((pos != std::string::npos) && ((pos + 1) < dataString.size()))
+ {
+ // Value is substring after the '='
+ value = dataString.substr(pos + 1);
+ }
+
+ return value;
+}
+
+std::string Journal::getTimeStamp(sd_journal* journal) const
+{
+ // Get realtime (wallclock) timestamp of current journal entry. The
+ // timestamp is in microseconds since the epoch.
+ uint64_t usec{0};
+ int rc = sd_journal_get_realtime_usec(journal, &usec);
+ if (rc < 0)
+ {
+ throw std::runtime_error{
+ std::string{"Failed to get journal entry timestamp: "} +
+ strerror(-rc)};
+ }
+
+ // Convert to number of seconds since the epoch
+ time_t secs = usec / 1000000;
+
+ // Convert seconds to tm struct required by strftime()
+ struct tm* timeStruct = localtime(&secs);
+ if (timeStruct == nullptr)
+ {
+ throw std::runtime_error{
+ std::string{"Invalid journal entry timestamp: "} + strerror(errno)};
+ }
+
+ // Convert tm struct into a date/time string
+ char timeStamp[80];
+ strftime(timeStamp, sizeof(timeStamp), "%b %d %H:%M:%S", timeStruct);
+
+ return timeStamp;
+}
+
+} // namespace openpower::pels