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
33 // The AttachListener thread services a queue of operations that are enqueued
34 // by client tools. Each operation is identified by a name and has up to 3
35 // arguments. The operation name is mapped to a function which performs the
36 // operation. The function is called with an outputStream which is can use to
37 // write any result data (for examples the properties command serializes
38 // properties names and values to the output stream). When the function
39 // complets the result value and any result data is returned to the client
40 // tool.
41
42 class AttachOperation;
43
44 typedef jint (*AttachOperationFunction)(AttachOperation* op, outputStream* out);
45
46 struct AttachOperationFunctionInfo {
47 const char* name;
48 AttachOperationFunction func;
49 };
50
51 class AttachListener: AllStatic {
52 public:
53 static void init() NOT_SERVICES_RETURN;
54 static void abort() NOT_SERVICES_RETURN;
55
56 // invoke to perform clean-up tasks when all clients detach
57 static void detachall() NOT_SERVICES_RETURN;
58
59 // indicates if the Attach Listener needs to be created at startup
60 static bool init_at_startup() NOT_SERVICES_RETURN_(false);
61
62 // indicates if we have a trigger to start the Attach Listener
63 static bool is_init_trigger() NOT_SERVICES_RETURN_(false);
64
65 #if !INCLUDE_SERVICES
66 static bool is_attach_supported() { return false; }
67 #else
68 private:
69 static volatile bool _initialized;
70
71 public:
72 static bool is_initialized() { return _initialized; }
73 static void set_initialized() { _initialized = true; }
74
75 // indicates if this VM supports attach-on-demand
76 static bool is_attach_supported() { return !DisableAttachMechanism; }
77
78 // platform specific initialization
79 static int pd_init();
80
81 // platform specific operation
82 static AttachOperationFunctionInfo* pd_find_operation(const char* name);
83
84 // platform specific flag change
85 static jint pd_set_flag(AttachOperation* op, outputStream* out);
86
87 // platform specific detachall
88 static void pd_detachall();
89
90 // platform specific data dump
91 static void pd_data_dump();
92
93 // dequeue the next operation
94 static AttachOperation* dequeue();
95 #endif // !INCLUDE_SERVICES
96 };
97
98 #if INCLUDE_SERVICES
99 class AttachOperation: public CHeapObj<mtInternal> {
100 public:
101 enum {
102 name_length_max = 16, // maximum length of name
103 arg_length_max = 1024, // maximum length of argument
104 arg_count_max = 3 // maximum number of arguments
105 };
106
107 // name of special operation that can be enqueued when all
108 // clients detach
109 static char* detachall_operation_name() { return (char*)"detachall"; }
110
111 private:
112 char _name[name_length_max+1];
113 char _arg[arg_count_max][arg_length_max+1];
114
115 public:
116 const char* name() const { return _name; }
117
118 // set the operation name
119 void set_name(char* name) {
120 assert(strlen(name) <= name_length_max, "exceeds maximum name length");
121 strcpy(_name, name);
122 }
123
124 // get an argument value
125 const char* arg(int i) const {
126 assert(i>=0 && i<arg_count_max, "invalid argument index");
127 return _arg[i];
128 }
129
130 // set an argument value
131 void set_arg(int i, char* arg) {
132 assert(i>=0 && i<arg_count_max, "invalid argument index");
133 if (arg == NULL) {
134 _arg[i][0] = '\0';
135 } else {
136 assert(strlen(arg) <= arg_length_max, "exceeds maximum argument length");
137 strcpy(_arg[i], arg);
138 }
139 }
140
141 // create an operation of a given name
142 AttachOperation(char* name) {
143 set_name(name);
144 for (int i=0; i<arg_count_max; i++) {
145 set_arg(i, NULL);
146 }
147 }
148
149 // complete operation by sending result code and any result data to the client
150 virtual void complete(jint result, bufferedStream* result_stream) = 0;
151 };
152 #endif // INCLUDE_SERVICES
153
154 #endif // SHARE_VM_SERVICES_ATTACHLISTENER_HPP