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 21 * questions. 22 * 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 43 class AttachOperation; 44 45 typedef jint (*AttachOperationFunction)(AttachOperation* op, outputStream* out); 46 47 struct AttachOperationFunctionInfo { 48 const char* name; 49 AttachOperationFunction func; 50 }; 51 52 class 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 104 class 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