source: Evidence/Evidence.cc@ 152

Last change on this file since 152 was 152, checked in by ogrimm, 12 years ago
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File size: 6.6 KB
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1/********************************************************************\
2
3 General code to start a server of the Evidence Control System
4
5 - The server is started with the given name.
6 - DIM exit and error handlers are implemented.
7 - The Status service is published (special format, see below).
8 It can be updated with the State() method. The text will also be logged.
9 - If the severity of a State() call is FATAL, exit() will be called (with
10 this severity, the call to State() is guranteed not to return).
11 - Configuration data can be requested by GetConfig().
12 - Signal handlers to ignore common signals are installed.
13 These signals will then cause pause() to return which can be used
14 by the application to terminate gracefully.
15 - The static method ToString() converts the contents of a
16 DIMInfo service into text
17
18 All memory allocated by the non-static methods will be freed by the
19 class destructor.
20
21 Oliver Grimm, December 2009
22
23\********************************************************************/
24
25#include "Evidence.h"
26
27bool EvidenceServer::ExitRequest = false;
28string __StatusName;
29
30// Constructor starts server with given name
31EvidenceServer::EvidenceServer(const char *Name) {
32
33 // Initialize
34 Status = NULL;
35 ConfigList = NULL;
36 ConfigNum = 0;
37 __StatusName = string(Name) + "/Status";
38
39 // Catch some signals
40 signal(SIGQUIT, &SignalHandler); // CTRL-Backspace
41 signal(SIGTERM, &SignalHandler); // Termination signal
42 signal(SIGINT, &SignalHandler); // CTRL-C
43 signal(SIGHUP, &SignalHandler); // Terminal closed
44
45 // Catch C++ unhandled exceptions
46 set_terminate(Terminate);
47
48 // Start server
49 Status = new DimService(__StatusName.c_str(), (char *) "Server started");
50
51 start(Name);
52 addExitHandler(this);
53}
54
55// Destructor: Free memory
56EvidenceServer::~EvidenceServer() {
57
58 for (unsigned int i=0; i<ConfigNum; i++) {
59 delete[] ConfigList[i].Name;
60 delete[] ConfigList[i].Value;
61 }
62 free(ConfigList);
63}
64
65// DIM exit handler
66void EvidenceServer::exitHandler(int Code) {
67 State(INFO, "Server stopped (DIM exit code %d)", Code);
68 exit(EXIT_SUCCESS);
69}
70
71// DIM error handler
72void EvidenceServer::errorHandler(int Severity, int Code, char *Message) {
73 State(ERROR, "%s (DIM error code %d, severity %d)\n", Message, Code, Severity);
74}
75
76// Set status of server
77//
78// The message format is special: after the string-terminating '\0' the Severity
79// is given, terminated by another '\0' The buffer for the DIM service must have
80// the same lifetime as the DIM service. If Severity is FATAL, exit() will be invoked.
81void EvidenceServer::State(StateType Severity, const char *Format, ...) {
82
83 static const char* StateString[] = {"Info", "Warn", "Error", "Fatal"};
84 static char ErrorString[] = "vasprintf() failed in State()";
85 static char SBuf[STATUS_SIZE];
86 char TBuf[STATUS_SIZE];
87 char *Tmp;
88
89 // Assemble message from application
90 va_list ArgumentPointer;
91 va_start(ArgumentPointer, Format);
92 if (vasprintf(&Tmp, Format, ArgumentPointer) == -1) Tmp = ErrorString;
93 va_end(ArgumentPointer);
94
95 snprintf(TBuf, sizeof(TBuf), "%s (%s): %s", __StatusName.c_str(), StateString[Severity], Tmp); // Normal string
96 snprintf(SBuf, sizeof(SBuf), "%s*%c", Tmp, (char) Severity);
97 *(strrchr(SBuf, '*')) = '\0'; // String with severity encoding
98 if (Tmp != ErrorString) free(Tmp);
99
100 // Send message to console and log file
101 printf("%s\n", TBuf);
102 if (Severity != INFO) DimClient::sendCommand("DColl/Log", TBuf);
103
104 // Update DIM status service (including severity encoding)
105 if (Status != NULL) Status->updateService(SBuf, strlen(SBuf)+2);
106
107 // Terminate if message type is fatal
108 if (Severity == FATAL) exit(EXIT_FAILURE);
109}
110
111// Get configuration data (program terminates if data is missing)
112//
113// The memory allocated by all calls to this function will be freed by
114// the destructor.
115char* EvidenceServer::GetConfig(const char *Item, const char *Default) {
116
117 // Determine configuration file update time
118 DimCurrentInfo ModifyTime("Config/ModifyTime", 0);
119 int Time = ModifyTime.getInt(), ItemNo = -1;
120
121 // Check if configuration request already in list
122 for (unsigned int i=0; i<ConfigNum; i++) {
123 if (strcmp(ConfigList[i].Name, Item) == 0) {
124 // Return original value if still up to date
125 if (ConfigList[i].Time >= Time) return ConfigList[i].Value;
126
127 // Otherwise, free memory of old value
128 delete[] ConfigList[i].Name;
129 delete[] ConfigList[i].Value;
130 ItemNo = i;
131 break;
132 }
133 }
134
135 // Make configuration request
136 DimRpcInfo Config((char *) "ConfigRequest", (char *) "");
137 Config.setData((char *) Item);
138 char *Result = Config.getString();
139
140 // Terminate if not successful
141 if (strlen(Result) == 0) {
142 if (Default == NULL) State(FATAL, "Missing configuration data '%s'", Item);
143 Result = (char *) Default;
144 }
145
146 // Enlarge memory to hold new pointer if necessary
147 if (ItemNo == -1) {
148 void *N = realloc(ConfigList, sizeof(struct ConfigItem)*(++ConfigNum));
149 if (N == NULL) {
150 State(WARN, "Could not realloc() memory for configuration, will lose memory (%s)", strerror(errno));
151 ConfigNum--;
152 }
153 else ConfigList = (struct ConfigItem *) N;
154
155 ItemNo = ConfigNum-1;
156 }
157
158 // Allocate memory for strings, and copy data to this memory
159 ConfigList[ItemNo].Value = new char [strlen(Result)+1];
160 ConfigList[ItemNo].Name = new char [strlen(Item)+1];
161 strcpy(ConfigList[ItemNo].Name, Item);
162 strcpy(ConfigList[ItemNo].Value, Result);
163
164 ConfigList[ItemNo].Time = Time;
165
166 // Return address to configuration value
167 return ConfigList[ItemNo].Value;
168}
169
170
171// ====== Static methods ======
172
173// Signal handler (causes pause() and other syscalls to return)
174void EvidenceServer::SignalHandler(int) {
175
176 EvidenceServer::ExitRequest = true;
177}
178
179// C++ exception handler
180void EvidenceServer::Terminate() {
181
182 string Msg = __StatusName + ": Caught unhandled exception";
183 printf("%s\n", Msg.c_str());
184 DimClient::sendCommand("DColl/Log", Msg.c_str());
185
186 abort();
187}
188
189// Translates DIMInfo to string (memory has to be freed by caller)
190// No DIM structures are supported (only a single number or string is converted)
191char *EvidenceServer::ToString(DimInfo *Item) {
192
193 char *Text;
194 int R;
195
196 if (strlen(Item->getFormat()) != 1) return NULL;
197
198 switch (*(Item->getFormat())) {
199 case 'I': R = asprintf(&Text, "%d", Item->getInt()); break;
200 case 'C': R = asprintf(&Text, "%s", Item->getString()); break;
201 case 'S': R = asprintf(&Text, "%hd", Item->getShort()); break;
202 case 'F': R = asprintf(&Text, "%.5f", Item->getFloat()); break;
203 case 'D': R = asprintf(&Text, "%.5f", Item->getDouble()); break;
204 case 'X': R = asprintf(&Text, "%lld", Item->getLonglong()); break;
205 default: return NULL;
206 }
207
208 return (R == -1) ? NULL : Text;
209}
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