1 | /********************************************************************\ |
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2 | |
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3 | Interface to the sky quality monitor (essentially a socket interface) |
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4 | |
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5 | Terminate with CTRL-c. Note that socket is closed automatically by exit(). |
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6 | |
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7 | Oliver Grimm, September 2009 |
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8 | |
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9 | \********************************************************************/ |
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10 | |
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11 | #include <iostream> |
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12 | #include <sys/socket.h> |
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13 | #include <netdb.h> |
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14 | #include <signal.h> |
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15 | #include <errno.h> |
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16 | #include <stdarg.h> |
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17 | |
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18 | #define SERVER_NAME "SQM" // Name to use in DIM |
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19 | #include "Evidence.h" |
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20 | |
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21 | #define READ_CMD "rx" // Command to read from device |
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22 | #define BUF_SIZE 1000 // Read and text buffer size |
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23 | |
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24 | |
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25 | // Main program |
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26 | int main() { |
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27 | |
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28 | int SocketDescriptor; |
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29 | struct sockaddr_in SocketAddress; |
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30 | fd_set ReadFileDescriptor; |
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31 | time_t Time; |
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32 | unsigned int Period; |
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33 | |
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34 | // Start server and request configuration data |
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35 | EvidenceServer Srv(SERVER_NAME); |
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36 | char *Address = Srv.GetConfig(SERVER_NAME " address"); |
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37 | unsigned int Port = atoi(Srv.GetConfig(SERVER_NAME " port")); |
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38 | |
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39 | // Open socket descriptor |
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40 | if ((SocketDescriptor = socket(PF_INET, SOCK_STREAM, 0)) == -1) { |
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41 | Srv.State(Srv.FATAL, "Could not open socket (%s)", strerror(errno)); |
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42 | } |
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43 | |
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44 | // Resolve hostname |
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45 | struct hostent *hostent = gethostbyname(Address); |
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46 | if (hostent==0) { |
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47 | Srv.State(Srv.FATAL, "Could not resolve host name '%s' (%s)", Address, hstrerror(h_errno)); |
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48 | } |
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49 | |
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50 | // Connect to server |
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51 | SocketAddress.sin_family = PF_INET; |
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52 | SocketAddress.sin_port = htons((unsigned short) Port); |
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53 | SocketAddress.sin_addr = *(struct in_addr*) hostent->h_addr; |
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54 | |
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55 | if (connect(SocketDescriptor, (struct sockaddr *) &SocketAddress, sizeof(SocketAddress))==-1) { |
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56 | Srv.State(Srv.FATAL, "Could not connect to server '%s' on port %d (%s)", Address, Port, strerror(errno)); |
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57 | } |
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58 | |
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59 | Srv.State(Srv.INFO, "Connected to server '%s' on port %d", Address, Port); |
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60 | signal(SIGPIPE,SIG_IGN); // Do not kill process if writing to closed socket |
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61 | |
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62 | // Create DIM services |
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63 | double sqm_reading=0.0; |
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64 | char Buffer[BUF_SIZE]; |
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65 | |
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66 | DimService SQM_Brightness(SERVER_NAME"/NSB", sqm_reading); |
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67 | DimService SQM_Response(SERVER_NAME"/Response", NO_LINK); |
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68 | |
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69 | while(!EvidenceServer::ExitRequest) { |
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70 | // Request measurement period |
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71 | Period = atoi(Srv.GetConfig(SERVER_NAME " period")); |
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72 | |
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73 | // Write read command to socket |
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74 | if ((write(SocketDescriptor, READ_CMD, strlen(READ_CMD)))<1) { |
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75 | Srv.State(Srv.ERROR, "Could not write read command '%s' to socket.", READ_CMD); |
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76 | } |
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77 | |
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78 | // Wait for response (minimum 100 ms) |
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79 | usleep(100000); |
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80 | FD_ZERO(&ReadFileDescriptor); |
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81 | FD_SET(SocketDescriptor, &ReadFileDescriptor); |
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82 | struct timeval WaitTime = {Period, 0}; |
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83 | if (select(((int) SocketDescriptor)+1, &ReadFileDescriptor, NULL, NULL, &WaitTime)==-1) { |
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84 | Srv.State(Srv.FATAL, "Error with select() (%s)", strerror(errno)); |
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85 | } |
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86 | |
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87 | if (!FD_ISSET(SocketDescriptor, &ReadFileDescriptor)) { |
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88 | Srv.State(Srv.WARN, "Time-out of %d seconds expired before receiving response from socket", Period); |
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89 | continue; |
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90 | } |
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91 | |
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92 | memset(Buffer, 0, BUF_SIZE); |
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93 | if(read(SocketDescriptor, Buffer, BUF_SIZE) == 0) { |
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94 | Srv.State(Srv.FATAL, "Server not existing anymore, exiting...\n"); |
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95 | } |
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96 | |
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97 | // Update full textual response and brightness reading |
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98 | for (int i=0; i<strlen(Buffer); i++) if (Buffer[i] == '\n') Buffer[i] = '\0'; |
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99 | sqm_reading = strtod(Buffer+2 ,NULL); |
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100 | |
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101 | SQM_Brightness.updateService(sqm_reading); |
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102 | SQM_Response.updateService(Buffer); |
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103 | |
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104 | Time = time(NULL); |
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105 | printf("%s\n %s CTRL-c to exit.\r", Buffer, asctime(localtime(&Time))); |
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106 | fflush(stdout); |
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107 | |
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108 | sleep(Period); |
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109 | } // while() |
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110 | |
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111 | } |
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