client server program between two programs to talk with arduino interfaced with serve

This is a discussion on client server program between two programs to talk with arduino interfaced with serve within the Networking/Device Communication forums, part of the General Programming Boards category; hello every body i am recently working over a mobile robot project. here i need to send an instruction to ...

  1. #1
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    Oct 2011
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    3

    client server program to talk with arduino which is interfaced to server

    hello every body

    i am recently working over a mobile robot project. here i need to send an instruction to arduino microcontroller over network. for this i had choosed client server architecture. i modified the server program to read the buffer to device file descriptor ("/dev/ttyACM0" in this case.

    i was able to compile the programs and run them. when i send a request from client to server . the server simply closes with out receiving the message.

    my working environment is
    Linux 10.10

    in order to execute the client

    $ <ur path> ./client <ip address of server > <port number of server>


    for serial_server

    $ <ur path > ./serial_server <specify a port number >

    below is the code of the programs
    client code
    Code:
    #include <stdio.h>
    #include <stdlib.h>
    #include <unistd.h>
    #include <string.h>
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <netinet/in.h>
    #include <netdb.h> 
    
    void error(const char *msg)
    {
        perror(msg);
        exit(0);
    }
    
    int main(int argc, char *argv[])
    {
        int sockfd, portno, n;
        struct sockaddr_in serv_addr;
        struct hostent *server;
    
        char buffer[256];
        if (argc < 3) {
           fprintf(stderr,"usage %s hostname port\n", argv[0]);
           exit(0);
        }
        portno = atoi(argv[2]);
        sockfd = socket(AF_INET, SOCK_STREAM, 0);
        if (sockfd < 0) 
            error("ERROR opening socket");
        server = gethostbyname(argv[1]);
        if (server == NULL) {
            fprintf(stderr,"ERROR, no such host\n");
            exit(0);
        }
        bzero((char *) &serv_addr, sizeof(serv_addr));
        serv_addr.sin_family = AF_INET;
        bcopy((char *)server->h_addr, 
             (char *)&serv_addr.sin_addr.s_addr,
             server->h_length);
        serv_addr.sin_port = htons(portno);
        if (connect(sockfd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0) 
            error("ERROR connecting");
        printf("Please enter the message: ");
        bzero(buffer,256);
        fgets(buffer,255,stdin);
        n = write(sockfd,buffer,strlen(buffer));
        if (n < 0) 
             error("ERROR writing to socket");
        bzero(buffer,256);
        n = read(sockfd,buffer,255);
        if (n < 0) 
             error("ERROR reading from socket");
        printf("%s\n",buffer);
        close(sockfd);
        return 0;
    }


    serial_server code
    Code:
    /* A simple server in the internet domain using TCP
       The port number is passed as an argument */
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <unistd.h>
    #include <sys/types.h> 
    #include <sys/socket.h>
    #include <netinet/in.h>
    #include<errno.h>
    #include<sys/ioctl.h>
    #include<termios.h>
    #include<fcntl.h>
    #include<getopt.h>
    void error(const char *msg)
    {
        perror(msg);
        exit(1);
    }
    
    int main(int argc, char *argv[])
    {
         int sockfd, newsockfd, portno;
         socklen_t clilen;
         char buffer[256];
         struct sockaddr_in serv_addr, cli_addr;
         int n,k;
    // serial data 
         int fd;
         int baudrate = B9600;
         int rc;
         
    
         if (argc < 2) {
             fprintf(stderr,"ERROR, no port provided\n");
             exit(1);
         }
         sockfd = socket(AF_INET, SOCK_STREAM, 0);
         if (sockfd < 0) 
            error("ERROR opening socket");
         bzero((char *) &serv_addr, sizeof(serv_addr));
         portno = atoi(argv[1]);
         serv_addr.sin_family = AF_INET;
         serv_addr.sin_addr.s_addr = INADDR_ANY;
         serv_addr.sin_port = htons(portno);
         if (bind(sockfd, (struct sockaddr *) &serv_addr,
                  sizeof(serv_addr)) < 0) 
                  error("ERROR on binding");
         listen(sockfd,5);
         clilen = sizeof(cli_addr);
         newsockfd = accept(sockfd, 
                     (struct sockaddr *) &cli_addr, 
                     &clilen);
         if (newsockfd < 0) 
              error("ERROR on accept");
         bzero(buffer,256);
     // serial filedescriptor initializing ;
          fd = open("/dev/ttyACM0", O_RDWR | O_NOCTTY | O_NDELAY);
        if (fd == -1)  {
            perror("init_serialport: Unable to open port ");
            return -1;
    
         n = read(newsockfd,buffer,255);
         if (n < 0) error("ERROR reading from socket");
     
        k= write(fd,buffer,255);
        if(k<0)error("Unable to open the arduino ");
    
        
         
         printf("Here is the message: %s\n",buffer);
         n = write(newsockfd,"I got your message",18);
         if (n < 0) error("ERROR writing to socket");
         k= write(fd,buffer,255);
        if(k<0)error("Unable to send to the arduino ");
         close(newsockfd);
         close(sockfd);
         return 0; 
    }}
    Attached Files Attached Files
    Last edited by bha123; 11-19-2011 at 03:34 AM.

  2. #2
    spurious conceit MK27's Avatar
    Join Date
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    segmentation fault
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    Quote Originally Posted by bha123 View Post
    my working environment is
    Linux 10.10
    There's no such thing. Perhaps you mean Ubuntu 10.10, which is a specific pre-compiled distribution of the GNU/linux OS?

    i was able to compile the programs and run them. when i send a request from client to server . the server simply closes with out receiving the message.
    Because:

    Code:
    // serial filedescriptor initializing ;
          fd = open("/dev/ttyACM0", O_RDWR | O_NOCTTY | O_NDELAY);
        if (fd == -1)  {
            perror("init_serialport: Unable to open port ");
            return -1;
     
         n = read(newsockfd,buffer,255);
         if (n < 0) error("ERROR reading from socket");
    You left a closing brace off the error handling if (fd == -1). This would cause a compiler error, unless there was a stray closing brace later -- which perhaps you just stuck one on the end to get rid of the error?

    line 77
    Code:
    }}
    Meaning if the serial device opened successfully, that is the last thing this program does. You should compile with warnings enabled:

    gcc -Wall

    This will give you a bit of clue:

    test.c:77: warning: control reaches end of non-void function

    When there is a return statement on line 76?!? Except...hmmm. It's inside the if() block from 20 lines earlier.
    C programming resources:
    GNU C Function and Macro Index -- glibc reference manual
    The C Book -- nice online learner guide
    Current ISO draft standard
    CCAN -- new CPAN like open source library repository
    3 (different) GNU debugger tutorials: #1 -- #2 -- #3
    cpwiki -- our wiki on sourceforge

  3. #3
    Registered User
    Join Date
    Oct 2011
    Posts
    3
    thnks
    sry for the late replay

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