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.nio.file.Paths;
  30 import java.util.HashMap;
  31 import java.util.List;
  32 import java.util.Map;
  33 import java.util.stream.Collectors;
  34 import java.util.stream.Stream;
  35 
  36 import jdk.internal.platform.cgroupv1.CgroupV1Subsystem;
  37 import jdk.internal.platform.cgroupv2.CgroupV2Subsystem;
  38 import jdk.internal.platform.cgroupv2.CgroupV2SubsystemController;
  39 
  40 class CgroupSubsystemFactory {
  41 
  42     private static final String CPU_CTRL = "cpu";
  43     private static final String CPUACCT_CTRL = "cpuacct";
  44     private static final String CPUSET_CTRL = "cpuset";
  45     private static final String BLKIO_CTRL = "blkio";
  46     private static final String MEMORY_CTRL = "memory";
  47 
  48     static CgroupSubsystem create() {
  49         Map<String, CgroupInfo> infos = new HashMap<>();
  50         try {
  51             List<String> lines = CgroupUtil.readAllLinesPrivileged(Paths.get("/proc/cgroups"));
  52             for (String line : lines) {
  53                 if (line.startsWith("#")) {
  54                     continue;
  55                 }
  56                 CgroupInfo info = CgroupInfo.fromCgroupsLine(line);
  57                 switch (info.getName()) {
  58                 case CPU_CTRL:      infos.put(CPU_CTRL, info); break;
  59                 case CPUACCT_CTRL:  infos.put(CPUACCT_CTRL, info); break;
  60                 case CPUSET_CTRL:   infos.put(CPUSET_CTRL, info); break;
  61                 case MEMORY_CTRL:   infos.put(MEMORY_CTRL, info); break;
  62                 case BLKIO_CTRL:    infos.put(BLKIO_CTRL, info); break;
  63                 }
  64             }
  65         } catch (IOException e) {
  66             return null;
  67         }
  68 
  69         // For cgroups v1 all controllers need to have non-zero hierarchy id
  70         boolean isCgroupsV2 = true;
  71         boolean anyControllersEnabled = false;
  72         boolean anyCgroupsV2Controller = false;
  73         boolean anyCgroupsV1Controller = false;
  74         for (CgroupInfo info: infos.values()) {
  75             anyCgroupsV1Controller = anyCgroupsV1Controller || info.getHierarchyId() != 0;
  76             anyCgroupsV2Controller = anyCgroupsV2Controller || info.getHierarchyId() == 0;
  77             isCgroupsV2 = isCgroupsV2 && info.getHierarchyId() == 0;
  78             anyControllersEnabled = anyControllersEnabled || info.isEnabled();
  79         }
  80 
  81         // If no controller is enabled, return no metrics.
  82         if (!anyControllersEnabled) {
  83             return null;
  84         }
  85         // Warn about mixed cgroups v1 and cgroups v2 controllers. The code is
  86         // not ready to deal with that on a per-controller basis. Return no metrics
  87         // in that case
  88         if (anyCgroupsV1Controller && anyCgroupsV2Controller) {
  89             System.err.println("Warning: Mixed cgroupv1 and cgroupv2 not supported. Metrics disabled.");
  90             return null;
  91         }
  92 
  93         if (isCgroupsV2) {
  94             // read mountinfo so as to determine root mount path
  95             String mountPath = null;
  96             try (Stream<String> lines =
  97                     CgroupUtil.readFilePrivileged(Paths.get("/proc/self/mountinfo"))) {
  98 
  99                 String l = lines.filter(line -> line.contains(" - cgroup2 "))
 100                                 .collect(Collectors.joining());
 101                 String[] tokens = l.split(" ");
 102                 mountPath = tokens[4];
 103             } catch (IOException e) {
 104                 return null;
 105             }
 106             String cgroupPath = null;
 107             try {
 108                 List<String> lines = CgroupUtil.readAllLinesPrivileged(Paths.get("/proc/self/cgroup"));
 109                 for (String line: lines) {
 110                     String[] tokens = line.split(":");
 111                     if (tokens.length != 3) {
 112                         return null; // something is not right.
 113                     }
 114                     if (!Integer.valueOf(0).toString().equals(tokens[0])) {
 115                         // hierarchy must be zero for cgroups v2
 116                         return null;
 117                     }
 118                     cgroupPath = tokens[2];
 119                     break;
 120                 }
 121             } catch (IOException e) {
 122                 return null;
 123             }
 124             CgroupSubsystemController unified = new CgroupV2SubsystemController(
 125                     mountPath,
 126                     cgroupPath);
 127             return new CgroupV2Subsystem(unified);
 128         } else {
 129             return CgroupV1Subsystem.getInstance();
 130         }
 131     }
 132 }