1 /*
2 * Copyright (c) 2005, 2006, 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 // The AttachListener thread services a queue of operations that are enqueued
26 // by client tools. Each operation is identified by a name and has up to 3
27 // arguments. The operation name is mapped to a function which performs the
28 // operation. The function is called with an outputStream which is can use to
29 // write any result data (for examples the properties command serializes
30 // properties names and values to the output stream). When the function
31 // complets the result value and any result data is returned to the client
32 // tool.
33
34 #ifndef SERVICES_KERNEL
35
36 class AttachOperation;
37
38 typedef jint (*AttachOperationFunction)(AttachOperation* op, outputStream* out);
39
40 struct AttachOperationFunctionInfo {
41 const char* name;
42 AttachOperationFunction func;
43 };
44 #endif // SERVICES_KERNEL
45
46 class AttachListener: AllStatic {
47 public:
48 static void init() KERNEL_RETURN;
49 static void abort() KERNEL_RETURN;
50
51 // invoke to perform clean-up tasks when all clients detach
52 static void detachall() KERNEL_RETURN;
53
54 // indicates if the Attach Listener needs to be created at startup
55 static bool init_at_startup() KERNEL_RETURN_(return false;);
56
57 // indicates if we have a trigger to start the Attach Listener
58 static bool is_init_trigger() KERNEL_RETURN_(return false;);
59
60 #ifdef SERVICES_KERNEL
61 static bool is_attach_supported() { return false; }
62 #else // SERVICES_KERNEL
63 private:
64 static volatile bool _initialized;
65
66 public:
67 static bool is_initialized() { return _initialized; }
68 static void set_initialized() { _initialized = true; }
69
70 // indicates if this VM supports attach-on-demand
71 static bool is_attach_supported() { return !DisableAttachMechanism; }
72
73 // platform specific initialization
74 static int pd_init();
75
76 // platform specific operation
77 static AttachOperationFunctionInfo* pd_find_operation(const char* name);
78
79 // platform specific flag change
80 static jint pd_set_flag(AttachOperation* op, outputStream* out);
81
82 // platform specific detachall
83 static void pd_detachall();
84
85 // platform specific data dump
86 static void pd_data_dump();
87
88 // dequeue the next operation
89 static AttachOperation* dequeue();
90 #endif // SERVICES_KERNEL
91 };
92
93 #ifndef SERVICES_KERNEL
94 class AttachOperation: public CHeapObj {
95 public:
96 enum {
97 name_length_max = 16, // maximum length of name
98 arg_length_max = 1024, // maximum length of argument
99 arg_count_max = 3 // maximum number of arguments
100 };
101
102 // name of special operation that can be enqueued when all
103 // clients detach
104 static char* detachall_operation_name() { return (char*)"detachall"; }
105
106 private:
107 char _name[name_length_max+1];
108 char _arg[arg_count_max][arg_length_max+1];
109
110 public:
111 const char* name() const { return _name; }
112
113 // set the operation name
114 void set_name(char* name) {
115 assert(strlen(name) <= name_length_max, "exceeds maximum name length");
116 strcpy(_name, name);
117 }
118
119 // get an argument value
120 const char* arg(int i) const {
121 assert(i>=0 && i<arg_count_max, "invalid argument index");
122 return _arg[i];
123 }
124
125 // set an argument value
126 void set_arg(int i, char* arg) {
127 assert(i>=0 && i<arg_count_max, "invalid argument index");
128 if (arg == NULL) {
129 _arg[i][0] = '\0';
130 } else {
131 assert(strlen(arg) <= arg_length_max, "exceeds maximum argument length");
132 strcpy(_arg[i], arg);
133 }
134 }
135
136 // create an operation of a given name
137 AttachOperation(char* name) {
138 set_name(name);
139 for (int i=0; i<arg_count_max; i++) {
140 set_arg(i, NULL);
141 }
142 }
143
144 // complete operation by sending result code and any result data to the client
145 virtual void complete(jint result, bufferedStream* result_stream) = 0;
146 };
147 #endif // SERVICES_KERNEL