source: Evidence/Evidence.cc @ 154

Last change on this file since 154 was 154, checked in by ogrimm, 11 years ago
Updates to status service
File size: 6.6 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
27EvidenceServer *ThisServer;
28
29// Constructor starts server with given name
30EvidenceServer::EvidenceServer(const char *Name) {
31
32  // Initialize
33  Status = NULL;
34  ExitRequest = false;
35  ThisServer = this;
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  // Catch C++ unhandled exceptions
44  set_terminate(Terminate);
45 
46  // Start server
47  static char Init[] = "Server started";
48  Status = new DimService((string(Name) + "/Status").c_str(), (char *) "C", Init, sizeof(Init));
49
50  start(Name);
51  addExitHandler(this);
52
53}
54
55// Destructor: Free memory
56EvidenceServer::~EvidenceServer() {
57
58  for (unsigned int i=0; i<ConfigList.size(); i++) {
59        delete[] ConfigList[i].Name;
60        delete[] ConfigList[i].Value;
61  }
62}
63
64// DIM exit handler
65void EvidenceServer::exitHandler(int Code) {
66  State(INFO, "Server stopped (DIM exit code %d)", Code);
67  exit(EXIT_SUCCESS);
68}
69
70// DIM error handler
71void EvidenceServer::errorHandler(int Severity, int Code, char *Message) {   
72  State(ERROR, "%s (DIM error code %d, severity %d)\n", Message, Code, Severity);
73}
74
75// Set status of server
76//
77// The message format is special: after the string-terminating '\0' the Severity
78// is given, terminated by another '\0'  The buffer for the DIM service must have
79// the same lifetime as the DIM service. If Severity is FATAL, exit() will be invoked.
80void EvidenceServer::State(StateType Severity, const char *Format, ...) {
81
82  static const char* StateString[] = {"Info", "Warn", "Error", "Fatal"};
83  static char ErrorString[] = "vasprintf() failed in State()";
84  static char SBuf[STATUS_SIZE];
85  char TBuf[STATUS_SIZE];
86  char *Tmp;
87 
88  // Assemble message from application
89  va_list ArgumentPointer;
90  va_start(ArgumentPointer, Format);
91  if (vasprintf(&Tmp, Format, ArgumentPointer) == -1) Tmp = ErrorString;
92  va_end(ArgumentPointer);
93
94  // Create normal string
95  snprintf(TBuf, sizeof(TBuf), "%s (%s): %s", Status->getName(), StateString[Severity], Tmp);
96
97  // Create string with severity encoding
98  snprintf(SBuf, sizeof(SBuf), "%s**", Tmp);
99  SBuf[strlen(SBuf)-2] = '\0';
100  SBuf[strlen(SBuf)+1] = Severity;
101
102  if (Tmp != ErrorString) free(Tmp);
103 
104  // Send message to console and log file
105  printf("%s\n", TBuf);
106  if (Severity != INFO) DimClient::sendCommand("DColl/Log", TBuf);
107
108  // Update DIM status service (including severity encoding)
109  if (Status != NULL) Status->updateService(SBuf, strlen(SBuf)+2);
110
111  // Terminate if message type is fatal
112  if (Severity == FATAL) exit(EXIT_FAILURE);
113}
114
115// Get configuration data (program terminates if data is missing)
116//
117// The memory allocated by all calls to this function will be freed by
118// the destructor.
119char* EvidenceServer::GetConfig(const char *Item, const char *Default) {
120 
121  // Determine configuration file update time
122  DimCurrentInfo ModifyTime("Config/ModifyTime", 0);
123  int Time = ModifyTime.getInt(), ItemNo = -1;
124 
125  // Check if configuration request already in list
126  for (unsigned int i=0; i<ConfigList.size(); i++) {
127    if (strcmp(ConfigList[i].Name, Item) == 0) {
128          // Return original value if still up to date
129          if (ConfigList[i].Time >= Time) return ConfigList[i].Value;
130
131          // Otherwise, free memory of old value
132          delete[] ConfigList[i].Name;
133          delete[] ConfigList[i].Value;   
134          ItemNo = i;
135          break;
136        }
137  } 
138 
139  // Make configuration request
140  DimRpcInfo Config((char *) "ConfigRequest", (char *) "");
141  Config.setData((char *) Item);
142  char *Result = Config.getString();
143 
144  // Terminate if not successful
145  if (strlen(Result) == 0) {
146    if (Default == NULL) State(FATAL, "Missing configuration data '%s'", Item);
147        Result = (char *) Default;
148  }
149
150  // Enlarge list if necessary
151  if (ItemNo == -1) {
152    struct ConfigItem New;
153    ConfigList.push_back(New);
154        ItemNo = ConfigList.size()-1;
155  }
156
157  // Create new entry in item list, allocate memory and copy data to this memory
158  ConfigList[ItemNo].Value = new char [strlen(Result)+1];
159  ConfigList[ItemNo].Name = new char [strlen(Item)+1];
160  strcpy(ConfigList[ItemNo].Name, Item);
161  strcpy(ConfigList[ItemNo].Value, Result);
162  ConfigList[ItemNo].Time = Time;
163   
164  // Return address to configuration value 
165  return ConfigList[ItemNo].Value;
166}
167
168
169// ====== Static methods ======
170
171// Signal handler (causes pause() and other syscalls to return)
172void EvidenceServer::SignalHandler(int) {
173
174  ThisServer->ExitRequest = true;
175}
176
177// C++ exception handler
178void EvidenceServer::Terminate() {
179
180  string Msg = string(ThisServer->Status->getName()) + ": Caught unhandled exception";
181
182  printf("%s\n", Msg.c_str());
183  DimClient::sendCommand("DColl/Log", Msg.c_str());
184 
185  abort();
186}
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)
191// For string conversion, a terminating \0 is enforced.
192char *EvidenceServer::ToString(DimInfo *Item) {
193
194  char *Text;
195  int R;
196 
197  if (strlen(Item->getFormat()) != 1) return NULL;
198 
199  switch (*(Item->getFormat())) {
200    case 'I':  R = asprintf(&Text, "%d", Item->getInt());   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    case 'C':  *(Item->getString() + Item->getSize()) = '\0'; 
206                           R = asprintf(&Text, "%s", Item->getString());
207                           break;
208    default: return NULL;
209  }
210
211  return (R == -1) ? NULL : Text;
212}
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