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 vm_start() NOT_SERVICES_RETURN;
54 static void init() NOT_SERVICES_RETURN;
55 static void abort() NOT_SERVICES_RETURN;
56
57 // invoke to perform clean-up tasks when all clients detach
58 static void detachall() NOT_SERVICES_RETURN;
59
60 // indicates if the Attach Listener needs to be created at startup
61 static bool init_at_startup() NOT_SERVICES_RETURN_(false);
62
63 // indicates if we have a trigger to start the Attach Listener
64 static bool is_init_trigger() NOT_SERVICES_RETURN_(false);
65
66 #if !INCLUDE_SERVICES
67 static bool is_attach_supported() { return false; }
68 #else
69 private:
70 static volatile bool _initialized;
71
72 public:
73 static bool is_initialized() { return _initialized; }
74 static void set_initialized() { _initialized = true; }
75
76 // indicates if this VM supports attach-on-demand
77 static bool is_attach_supported() { return !DisableAttachMechanism; }
78
79 // platform specific initialization
80 static int pd_init();
81
82 // platform specific operation
83 static AttachOperationFunctionInfo* pd_find_operation(const char* name);
84
85 // platform specific flag change
86 static jint pd_set_flag(AttachOperation* op, outputStream* out);
87
88 // platform specific detachall
89 static void pd_detachall();
90
91 // platform specific data dump
92 static void pd_data_dump();
93
94 // dequeue the next operation
95 static AttachOperation* dequeue();
96 #endif // !INCLUDE_SERVICES
97
98 private:
99 static bool init_error(TRAPS);
100 };
101
102 #if INCLUDE_SERVICES
103 class AttachOperation: public CHeapObj<mtInternal> {
104 public:
105 enum {
106 name_length_max = 16, // maximum length of name
107 arg_length_max = 1024, // maximum length of argument
108 arg_count_max = 3 // maximum number of arguments
109 };
110
111 // name of special operation that can be enqueued when all
112 // clients detach
113 static char* detachall_operation_name() { return (char*)"detachall"; }
114
115 private:
116 char _name[name_length_max+1];
117 char _arg[arg_count_max][arg_length_max+1];
118
119 public:
120 const char* name() const { return _name; }
121
122 // set the operation name
123 void set_name(char* name) {
124 assert(strlen(name) <= name_length_max, "exceeds maximum name length");
125 strcpy(_name, name);
126 }
127
128 // get an argument value
129 const char* arg(int i) const {
130 assert(i>=0 && i<arg_count_max, "invalid argument index");
131 return _arg[i];
132 }
133
134 // set an argument value
135 void set_arg(int i, char* arg) {
136 assert(i>=0 && i<arg_count_max, "invalid argument index");
137 if (arg == NULL) {
138 _arg[i][0] = '\0';
139 } else {
140 assert(strlen(arg) <= arg_length_max, "exceeds maximum argument length");
141 strcpy(_arg[i], arg);
142 }
143 }
144
145 // create an operation of a given name
146 AttachOperation(char* name) {
147 set_name(name);
148 for (int i=0; i<arg_count_max; i++) {
149 set_arg(i, NULL);
150 }
151 }
152
153 // complete operation by sending result code and any result data to the client
154 virtual void complete(jint result, bufferedStream* result_stream) = 0;
155 };
156 #endif // INCLUDE_SERVICES
157
158 #endif // SHARE_VM_SERVICES_ATTACHLISTENER_HPP