| 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("address");
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| 37 | unsigned int Port = atoi(Srv.GetConfig("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(!Srv.ExitRequest) {
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| 70 | // Request measurement period
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| 71 | Period = atoi(Srv.GetConfig("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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