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package jdk.jfr.internal.dcmd;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.InvalidPathException;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.text.ParseException;
import java.time.Duration;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

import jdk.jfr.FlightRecorder;
import jdk.jfr.Recording;
import jdk.jfr.internal.JVM;
import jdk.jfr.internal.LogLevel;
import jdk.jfr.internal.LogTag;
import jdk.jfr.internal.Logger;
import jdk.jfr.internal.OldObjectSample;
import jdk.jfr.internal.PrivateAccess;
import jdk.jfr.internal.SecuritySupport.SafePath;
import jdk.jfr.internal.Type;
import jdk.jfr.internal.jfc.JFC;

JFR.start
/** * JFR.start * */
//Instantiated by native final class DCmdStart extends AbstractDCmd {
Execute JFR.start.
Params:
  • name – optional name that can be used to identify recording.
  • settings – names of settings files to use, i.e. "default" or "default.jfc".
  • delay – delay before recording is started, in nanoseconds. Must be at least 1 second.
  • duration – duration of the recording, in nanoseconds. Must be at least 1 second.
  • disk – if recording should be persisted to disk
  • path – file path where recording data should be written
  • maxAge – how long recording data should be kept in the disk repository, or 0 if no limit should be set.
  • maxSize – the minimum amount data to keep in the disk repository before it is discarded, or 0 if no limit should be set.
  • dumpOnExit – if recording should dump on exit
Throws:
Returns:result output
/** * Execute JFR.start. * * @param name optional name that can be used to identify recording. * @param settings names of settings files to use, i.e. "default" or * "default.jfc". * @param delay delay before recording is started, in nanoseconds. Must be * at least 1 second. * @param duration duration of the recording, in nanoseconds. Must be at * least 1 second. * @param disk if recording should be persisted to disk * @param path file path where recording data should be written * @param maxAge how long recording data should be kept in the disk * repository, or <code>0</code> if no limit should be set. * * @param maxSize the minimum amount data to keep in the disk repository * before it is discarded, or <code>0</code> if no limit should be * set. * * @param dumpOnExit if recording should dump on exit * * @return result output * * @throws DCmdException if recording could not be started */
@SuppressWarnings("resource") public String execute(String name, String[] settings, Long delay, Long duration, Boolean disk, String path, Long maxAge, Long maxSize, Boolean dumpOnExit, Boolean pathToGcRoots) throws DCmdException { if (Logger.shouldLog(LogTag.JFR_DCMD, LogLevel.DEBUG)) { Logger.log(LogTag.JFR_DCMD, LogLevel.DEBUG, "Executing DCmdStart: name=" + name + ", settings=" + (settings != null ? Arrays.asList(settings) : "(none)") + ", delay=" + delay + ", duration=" + duration + ", disk=" + disk+ ", filename=" + path + ", maxage=" + maxAge + ", maxsize=" + maxSize + ", dumponexit =" + dumpOnExit + ", path-to-gc-roots=" + pathToGcRoots); } if (name != null) { try { Integer.parseInt(name); throw new DCmdException("Name of recording can't be numeric"); } catch (NumberFormatException nfe) { // ok, can't be mixed up with name } } if (duration == null && Boolean.FALSE.equals(dumpOnExit) && path != null) { throw new DCmdException("Filename can only be set for a time bound recording or if dumponexit=true. Set duration/dumponexit or omit filename."); } if (settings.length == 1 && settings[0].length() == 0) { throw new DCmdException("No settings specified. Use settings=none to start without any settings"); } Map<String, String> s = new HashMap<>(); for (String configName : settings) { try { s.putAll(JFC.createKnown(configName).getSettings()); } catch(FileNotFoundException e) { throw new DCmdException("Could not find settings file'" + configName + "'", e); } catch (IOException | ParseException e) { throw new DCmdException("Could not parse settings file '" + settings[0] + "'", e); } } OldObjectSample.updateSettingPathToGcRoots(s, pathToGcRoots); if (duration != null) { if (duration < 1000L * 1000L * 1000L) { // to avoid typo, duration below 1s makes no sense throw new DCmdException("Could not start recording, duration must be at least 1 second."); } } if (delay != null) { if (delay < 1000L * 1000L * 1000) { // to avoid typo, delay shorter than 1s makes no sense. throw new DCmdException("Could not start recording, delay must be at least 1 second."); } } if (!FlightRecorder.isInitialized() && delay == null) { initializeWithForcedInstrumentation(s); } Recording recording = new Recording(); if (name != null) { recording.setName(name); } if (disk != null) { recording.setToDisk(disk.booleanValue()); } recording.setSettings(s); SafePath safePath = null; if (path != null) { try { if (dumpOnExit == null) { // default to dumponexit=true if user specified filename dumpOnExit = Boolean.TRUE; } Path p = Paths.get(path); if (Files.isDirectory(p) && Boolean.TRUE.equals(dumpOnExit)) { // Decide destination filename at dump time // Purposely avoid generating filename in Recording#setDestination due to // security concerns PrivateAccess.getInstance().getPlatformRecording(recording).setDumpOnExitDirectory(new SafePath(p)); } else { safePath = resolvePath(recording, path); recording.setDestination(safePath.toPath()); } } catch (IOException | InvalidPathException e) { recording.close(); throw new DCmdException("Could not start recording, not able to write to file %s. %s ", path, e.getMessage()); } } if (maxAge != null) { recording.setMaxAge(Duration.ofNanos(maxAge)); } if (maxSize != null) { recording.setMaxSize(maxSize); } if (duration != null) { recording.setDuration(Duration.ofNanos(duration)); } if (dumpOnExit != null) { recording.setDumpOnExit(dumpOnExit); } if (delay != null) { Duration dDelay = Duration.ofNanos(delay); recording.scheduleStart(dDelay); print("Recording " + recording.getId() + " scheduled to start in "); printTimespan(dDelay, " "); print("."); } else { recording.start(); print("Started recording " + recording.getId() + "."); } if (recording.isToDisk() && duration == null && maxAge == null && maxSize == null) { print(" No limit specified, using maxsize=250MB as default."); recording.setMaxSize(250*1024L*1024L); } if (safePath != null && duration != null) { println(" The result will be written to:"); println(); printPath(safePath); } else { println(); println(); String cmd = duration == null ? "dump" : "stop"; String fileOption = path == null ? "filename=FILEPATH " : ""; String recordingspecifier = "name=" + recording.getId(); // if user supplied a name, use it. if (name != null) { recordingspecifier = "name=" + quoteIfNeeded(name); } print("Use jcmd " + getPid() + " JFR." + cmd + " " + recordingspecifier + " " + fileOption + "to copy recording data to file."); println(); } return getResult(); } // Instruments JDK-events on class load to reduce startup time private void initializeWithForcedInstrumentation(Map<String, String> settings) { if (!hasJDKEvents(settings)) { return; } JVM jvm = JVM.getJVM(); try { jvm.setForceInstrumentation(true); FlightRecorder.getFlightRecorder(); } finally { jvm.setForceInstrumentation(false); } } private boolean hasJDKEvents(Map<String, String> settings) { String[] eventNames = new String[7]; eventNames[0] = "FileRead"; eventNames[1] = "FileWrite"; eventNames[2] = "SocketRead"; eventNames[3] = "SocketWrite"; eventNames[4] = "JavaErrorThrow"; eventNames[5] = "JavaExceptionThrow"; eventNames[6] = "FileForce"; for (String eventName : eventNames) { if ("true".equals(settings.get(Type.EVENT_NAME_PREFIX + eventName + "#enabled"))) { return true; } } return false; } }