1/*
2 * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
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.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25#ifndef SHARE_VM_SERVICES_ATTACHLISTENER_HPP
26#define SHARE_VM_SERVICES_ATTACHLISTENER_HPP
27
28#include "memory/allocation.hpp"
29#include "utilities/debug.hpp"
30#include "utilities/ostream.hpp"
31#include "utilities/macros.hpp"
32#include "utilities/globalDefinitions.hpp"
33
34// The AttachListener thread services a queue of operations that are enqueued
35// by client tools. Each operation is identified by a name and has up to 3
36// arguments. The operation name is mapped to a function which performs the
37// operation. The function is called with an outputStream which is can use to
38// write any result data (for examples the properties command serializes
39// properties names and values to the output stream). When the function
40// complets the result value and any result data is returned to the client
41// tool.
42
43class AttachOperation;
44
45typedef jint (*AttachOperationFunction)(AttachOperation* op, outputStream* out);
46
47struct AttachOperationFunctionInfo {
48  const char* name;
49  AttachOperationFunction func;
50};
51
52class AttachListener: AllStatic {
53 public:
54  static void vm_start() NOT_SERVICES_RETURN;
55  static void init()  NOT_SERVICES_RETURN;
56  static void abort() NOT_SERVICES_RETURN;
57
58  // invoke to perform clean-up tasks when all clients detach
59  static void detachall() NOT_SERVICES_RETURN;
60
61  // indicates if the Attach Listener needs to be created at startup
62  static bool init_at_startup() NOT_SERVICES_RETURN_(false);
63
64  // indicates if we have a trigger to start the Attach Listener
65  static bool is_init_trigger() NOT_SERVICES_RETURN_(false);
66
67#if !INCLUDE_SERVICES
68  static bool is_attach_supported()             { return false; }
69#else
70 private:
71  static volatile bool _initialized;
72
73 public:
74  static bool is_initialized()                  { return _initialized; }
75  static void set_initialized()                 { _initialized = true; }
76
77  // indicates if this VM supports attach-on-demand
78  static bool is_attach_supported()             { return !DisableAttachMechanism; }
79
80  // platform specific initialization
81  static int pd_init();
82
83  // platform specific operation
84  static AttachOperationFunctionInfo* pd_find_operation(const char* name);
85
86  // platform specific flag change
87  static jint pd_set_flag(AttachOperation* op, outputStream* out);
88
89  // platform specific detachall
90  static void pd_detachall();
91
92  // platform specific data dump
93  static void pd_data_dump();
94
95  // dequeue the next operation
96  static AttachOperation* dequeue();
97#endif // !INCLUDE_SERVICES
98
99 private:
100  static bool has_init_error(TRAPS);
101};
102
103#if INCLUDE_SERVICES
104class AttachOperation: public CHeapObj<mtInternal> {
105 public:
106  enum {
107    name_length_max = 16,       // maximum length of  name
108    arg_length_max = 1024,      // maximum length of argument
109    arg_count_max = 3           // maximum number of arguments
110  };
111
112  // name of special operation that can be enqueued when all
113  // clients detach
114  static char* detachall_operation_name() { return (char*)"detachall"; }
115
116 private:
117  char _name[name_length_max+1];
118  char _arg[arg_count_max][arg_length_max+1];
119
120 public:
121  const char* name() const                      { return _name; }
122
123  // set the operation name
124  void set_name(char* name) {
125    size_t len = strlen(name);
126    assert(len <= name_length_max, "exceeds maximum name length");
127    memcpy(_name, name, MIN2(len + 1, (size_t)name_length_max));
128  }
129
130  // get an argument value
131  const char* arg(int i) const {
132    assert(i>=0 && i<arg_count_max, "invalid argument index");
133    return _arg[i];
134  }
135
136  // set an argument value
137  void set_arg(int i, char* arg) {
138    assert(i>=0 && i<arg_count_max, "invalid argument index");
139    if (arg == NULL) {
140      _arg[i][0] = '\0';
141    } else {
142      size_t len = strlen(arg);
143      assert(len <= arg_length_max, "exceeds maximum argument length");
144      memcpy(_arg[i], arg, MIN2(len + 1, (size_t)arg_length_max));
145    }
146  }
147
148  // create an operation of a given name
149  AttachOperation(char* name) {
150    set_name(name);
151    for (int i=0; i<arg_count_max; i++) {
152      set_arg(i, NULL);
153    }
154  }
155
156  // complete operation by sending result code and any result data to the client
157  virtual void complete(jint result, bufferedStream* result_stream) = 0;
158};
159#endif // INCLUDE_SERVICES
160
161#endif // SHARE_VM_SERVICES_ATTACHLISTENER_HPP
162