source: Evidence/Evidence.cc@ 144

Last change on this file since 144 was 144, checked in by ogrimm, 12 years ago
Core system updates
File size: 6.9 KB
Line 
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;
28
29// Constructor starts server with given name
30EvidenceServer::EvidenceServer(const char *Name) {
31
32 // Initialize
33 Status = NULL;
34 ConfigList = NULL;
35 ConfigNum = 0;
36
37 // Catch some signals
38 signal(SIGQUIT, &SignalHandler); // CTRL-Backspace
39 signal(SIGTERM, &SignalHandler); // Termination signal
40 signal(SIGINT, &SignalHandler); // CTRL-C
41 signal(SIGHUP, &SignalHandler); // Terminal closed
42
43 // Create server name
44 if (MakeString(&StatusName, "%s/Status", Name) == -1) {
45 State(FATAL, "Could not generate service name, asprintf() failed");
46 }
47
48 // Start server
49 Status = new DimService(StatusName, (char *) "Server started");
50
51 start(Name);
52 addExitHandler(this);
53}
54
55// Destructor: Free memory
56EvidenceServer::~EvidenceServer() {
57
58 free(StatusName);
59
60 for (unsigned int i=0; i<ConfigNum; i++) {
61 delete[] ConfigList[i].Name;
62 delete[] ConfigList[i].Value;
63 }
64 free(ConfigList);
65}
66
67// DIM exit handler
68void EvidenceServer::exitHandler(int Code) {
69 State(INFO, "Server stopped (DIM exit code %d)", Code);
70 exit(EXIT_SUCCESS);
71}
72
73// DIM error handler
74void EvidenceServer::errorHandler(int Severity, int Code, char *Message) {
75 State(ERROR, "%s (DIM error code %d, severity %d)\n", Message, Code, Severity);
76}
77
78// Set status of server
79//
80// The message format is special: after the string-terminating '\0' the Severity
81// is given, terminated by another '\0' The buffer for the DIM service must have
82// the same lifetime as the DIM service. If Severity is FATAL, exit() will be invoked.
83void EvidenceServer::State(StateType Severity, const char *Format, ...) {
84
85 static const char* StateString[] = {"Info", "Warn", "Error", "Fatal"};
86 static char ErrorString[] = "vasprintf() failed in State()";
87 static char SBuf[STATUS_SIZE];
88 char TBuf[STATUS_SIZE];
89 char *Tmp;
90
91 // Assemble message from application
92 va_list ArgumentPointer;
93 va_start(ArgumentPointer, Format);
94 if (vasprintf(&Tmp, Format, ArgumentPointer) == -1) Tmp = ErrorString;
95 va_end(ArgumentPointer);
96
97 snprintf(TBuf, sizeof(TBuf), "%s (%s): %s", StatusName, StateString[Severity], Tmp); // Normal string
98 snprintf(SBuf, sizeof(SBuf), "%s*%c", Tmp, (char) Severity);
99 *(strrchr(SBuf, '*')) = '\0'; // String with severity encoding
100 if (Tmp != ErrorString) free(Tmp);
101
102 // Send message to console and log file
103 printf("%s\n", TBuf);
104 if (Severity != INFO) DimClient::sendCommand("DColl/Log", TBuf);
105
106 // Update DIM status service (including severity encoding)
107 if (Status != NULL) Status->updateService(SBuf, strlen(SBuf)+2);
108
109 // Terminate if message type is fatal
110 if (Severity == FATAL) exit(EXIT_FAILURE);
111}
112
113// Get configuration data (program terminates if data is missing)
114//
115// The memory allocated by all calls to this function will be freed by
116// the destructor.
117char* EvidenceServer::GetConfig(const char *Item) {
118
119 // Determine configuration file update time
120 DimCurrentInfo ModifyTime("Config/ModifyTime", 0);
121 int Time = ModifyTime.getInt(), ItemNo = -1;
122
123 // Check if configuration request already in list
124 for (unsigned int i=0; i<ConfigNum; i++) {
125 if (strcmp(ConfigList[i].Name, Item) == 0) {
126 // Return original value if still up to date
127 if (ConfigList[i].Time >= Time) return ConfigList[i].Value;
128
129 // Otherwise, free memory of old value
130 delete[] ConfigList[i].Name;
131 delete[] ConfigList[i].Value;
132 ItemNo = i;
133 break;
134 }
135 }
136
137 // Make configuration request
138 DimRpcInfo Config((char *) "ConfigRequest", (char *) "");
139 Config.setData((char *) Item);
140
141 // Terminate if not successful
142 if (strlen(Config.getString()) == 0) {
143 State(FATAL, "Missing configuration data '%s'", Item);
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(Config.getString())+1];
160 ConfigList[ItemNo].Name = new char [strlen(Item)+1];
161 strcpy(ConfigList[ItemNo].Name, Item);
162 strcpy(ConfigList[ItemNo].Value, Config.getString());
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// Translates DIMInfo to string (memory has to be freed by caller)
180// No DIM structures are supported (only a single number or string is converted)
181char *EvidenceServer::ToString(DimInfo *Item) {
182
183 char *Text;
184
185 if (strlen(Item->getFormat()) != 1) return NULL;
186
187 switch (*(Item->getFormat())) {
188 case 'I': MakeString(&Text, "%d", Item->getInt()); break;
189 case 'C': MakeString(&Text, "%s", Item->getString()); break;
190 case 'S': MakeString(&Text, "%hd", Item->getShort()); break;
191 case 'F': MakeString(&Text, "%.5f", Item->getFloat()); break;
192 case 'D': MakeString(&Text, "%.5f", Item->getDouble()); break;
193 case 'X': MakeString(&Text, "%lld", Item->getLonglong()); break;
194 default: return NULL;
195 }
196
197 return Text;
198}
199
200//
201// Generate string with vasprintf()
202//
203// The pointer will be set to NULL in case of error, so can always safely passed to free().
204// In case vasprintf() is not available on a particular system, the functionality can
205// be manually implemented in this routine.
206//
207int EvidenceServer::MakeString(char **Pointer, const char *Format, ...) {
208
209 int Ret;
210 va_list ArgumentPointer;
211
212 va_start(ArgumentPointer, Format);
213 if ((Ret = vasprintf(Pointer, Format, ArgumentPointer)) == -1) Pointer = NULL;
214 va_end(ArgumentPointer);
215
216 return Ret;
217}
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