1 /*
   2  * Copyright (c) 2020, Red Hat Inc.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package jdk.internal.platform;
  27 
  28 import java.io.IOException;
  29 import java.lang.System.Logger;
  30 import java.lang.System.Logger.Level;
  31 import java.nio.file.Paths;
  32 import java.util.HashMap;
  33 import java.util.List;
  34 import java.util.Map;
  35 import java.util.stream.Collectors;
  36 import java.util.stream.Stream;
  37 
  38 import jdk.internal.platform.cgroupv1.CgroupV1Subsystem;
  39 import jdk.internal.platform.cgroupv2.CgroupV2Subsystem;
  40 import jdk.internal.platform.cgroupv2.CgroupV2SubsystemController;
  41 
  42 class CgroupSubsystemFactory {
  43 
  44     private static final String CPU_CTRL = "cpu";
  45     private static final String CPUACCT_CTRL = "cpuacct";
  46     private static final String CPUSET_CTRL = "cpuset";
  47     private static final String BLKIO_CTRL = "blkio";
  48     private static final String MEMORY_CTRL = "memory";
  49 
  50     static CgroupMetrics create() {
  51         Map<String, CgroupInfo> infos = new HashMap<>();
  52         try {
  53             List<String> lines = CgroupUtil.readAllLinesPrivileged(Paths.get("/proc/cgroups"));
  54             for (String line : lines) {
  55                 if (line.startsWith("#")) {
  56                     continue;
  57                 }
  58                 CgroupInfo info = CgroupInfo.fromCgroupsLine(line);
  59                 switch (info.getName()) {
  60                 case CPU_CTRL:      infos.put(CPU_CTRL, info); break;
  61                 case CPUACCT_CTRL:  infos.put(CPUACCT_CTRL, info); break;
  62                 case CPUSET_CTRL:   infos.put(CPUSET_CTRL, info); break;
  63                 case MEMORY_CTRL:   infos.put(MEMORY_CTRL, info); break;
  64                 case BLKIO_CTRL:    infos.put(BLKIO_CTRL, info); break;
  65                 }
  66             }
  67         } catch (IOException e) {
  68             return null;
  69         }
  70 
  71         // For cgroups v1 all controllers need to have non-zero hierarchy id
  72         boolean isCgroupsV2 = true;
  73         boolean anyControllersEnabled = false;
  74         boolean anyCgroupsV2Controller = false;
  75         boolean anyCgroupsV1Controller = false;
  76         for (CgroupInfo info: infos.values()) {
  77             anyCgroupsV1Controller = anyCgroupsV1Controller || info.getHierarchyId() != 0;
  78             anyCgroupsV2Controller = anyCgroupsV2Controller || info.getHierarchyId() == 0;
  79             isCgroupsV2 = isCgroupsV2 && info.getHierarchyId() == 0;
  80             anyControllersEnabled = anyControllersEnabled || info.isEnabled();
  81         }
  82 
  83         // If no controller is enabled, return no metrics.
  84         if (!anyControllersEnabled) {
  85             return null;
  86         }
  87         // Warn about mixed cgroups v1 and cgroups v2 controllers. The code is
  88         // not ready to deal with that on a per-controller basis. Return no metrics
  89         // in that case
  90         if (anyCgroupsV1Controller && anyCgroupsV2Controller) {
  91             Logger logger = System.getLogger("jdk.internal.platform");
  92             logger.log(Level.WARNING, "Mixed cgroupv1 and cgroupv2 not supported. Metrics disabled.");
  93             return null;
  94         }
  95 
  96         if (isCgroupsV2) {
  97             // read mountinfo so as to determine root mount path
  98             String mountPath = null;
  99             try (Stream<String> lines =
 100                     CgroupUtil.readFilePrivileged(Paths.get("/proc/self/mountinfo"))) {
 101 
 102                 String l = lines.filter(line -> line.contains(" - cgroup2 "))
 103                                 .collect(Collectors.joining());
 104                 String[] tokens = l.split(" ");
 105                 mountPath = tokens[4];
 106             } catch (IOException e) {
 107                 return null;
 108             }
 109             String cgroupPath = null;
 110             try {
 111                 List<String> lines = CgroupUtil.readAllLinesPrivileged(Paths.get("/proc/self/cgroup"));
 112                 for (String line: lines) {
 113                     String[] tokens = line.split(":");
 114                     if (tokens.length != 3) {
 115                         return null; // something is not right.
 116                     }
 117                     if (!"0".equals(tokens[0])) {
 118                         // hierarchy must be zero for cgroups v2
 119                         return null;
 120                     }
 121                     cgroupPath = tokens[2];
 122                     break;
 123                 }
 124             } catch (IOException e) {
 125                 return null;
 126             }
 127             CgroupSubsystemController unified = new CgroupV2SubsystemController(
 128                     mountPath,
 129                     cgroupPath);
 130             return new CgroupMetrics(new CgroupV2Subsystem(unified));
 131         } else {
 132             return new CgroupV1Metrics(CgroupV1Subsystem.getInstance());
 133         }
 134     }
 135 }