1/*
2 * Copyright (c) 2005, 2019, 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
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23 */
24
25#ifndef SHARE_SERVICES_ATTACHLISTENER_HPP
26#define SHARE_SERVICES_ATTACHLISTENER_HPP
27
28#include "memory/allocation.hpp"
29#include "utilities/debug.hpp"
30#include "utilities/globalDefinitions.hpp"
31#include "utilities/macros.hpp"
32#include "utilities/ostream.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(const char* name) {
125 assert(strlen(name) <= name_length_max, "exceeds maximum name length");
126 size_t len = MIN2(strlen(name), (size_t)name_length_max);
127 memcpy(_name, name, len);
128 _name[len] = '\0';
129 }
130
131 // get an argument value
132 const char* arg(int i) const {
133 assert(i>=0 && i<arg_count_max, "invalid argument index");
134 return _arg[i];
135 }
136
137 // set an argument value
138 void set_arg(int i, char* arg) {
139 assert(i>=0 && i<arg_count_max, "invalid argument index");
140 if (arg == NULL) {
141 _arg[i][0] = '\0';
142 } else {
143 assert(strlen(arg) <= arg_length_max, "exceeds maximum argument length");
144 size_t len = MIN2(strlen(arg), (size_t)arg_length_max);
145 memcpy(_arg[i], arg, len);
146 _arg[i][len] = '\0';
147 }
148 }
149
150 // create an operation of a given name
151 AttachOperation(const char* name) {
152 set_name(name);
153 for (int i=0; i<arg_count_max; i++) {
154 set_arg(i, NULL);
155 }
156 }
157
158 // complete operation by sending result code and any result data to the client
159 virtual void complete(jint result, bufferedStream* result_stream) = 0;
160};
161#endif // INCLUDE_SERVICES
162
163#endif // SHARE_SERVICES_ATTACHLISTENER_HPP
164