source: Evidence/Evidence.cc @ 142

Last change on this file since 142 was 142, checked in by ogrimm, 11 years ago
Various updates
File size: 6.8 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);
98  snprintf(SBuf, sizeof(SBuf), "%s\0%d", Tmp);
99
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 (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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