Sample C SIP Server

sipserver.c

#include  <stdio.h>
#include  <stdlib.h>
#include  <unistd.h>
#include  <errno.h>
#include  <string.h>
#include  <sys/types.h>
#include  <sys/socket.h>
#include  <netinet/in.h>
#include  <arpa/inet.h>
#include  <sys/wait.h> 
#include  <signal.h>
#include <netinet/tcp.h>

#define MYPORT 3490 // the port users will be connecting to
#define BACKLOG 10    // how many pending connections queue will hold
#define MAXDATASIZE 100

void str_server(int); 

void sigchld_handler(int s)
{
 while(waitpid(-1, NULL, WNOHANG) > 0);
}
int main(void)
{
 int sockfd, numbytes,new_fd, optlen; // listen on sock_fd, new connection on new_fd
 struct sockaddr_in my_addr; // my address information
 struct sockaddr_in their_addr; // connector's address information
 struct tcp_info info;
 socklen_t sin_size;
 struct sigaction sa;
 char buf[MAXDATASIZE];
 int yes=1;
 if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
     perror("socket");
     exit(1);
 }
 if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1) {
     perror("setsockopt");
     exit(1);
 }
 my_addr.sin_family = AF_INET;         // host byte order
 my_addr.sin_port = htons(MYPORT);     // short, network byte order
 my_addr.sin_addr.s_addr = INADDR_ANY; // automatically fill with my IP
 memset(my_addr.sin_zero, '\0', sizeof my_addr.sin_zero);
 if (bind(sockfd, (struct sockaddr *)&my_addr, sizeof my_addr) == -1) {
     perror("bind");
     exit(1);
 }
 if (listen(sockfd, BACKLOG) == -1) {
     perror("listen");
     exit(1);
 }
 sa.sa_handler = sigchld_handler; // reap all dead processes
 sigemptyset(&sa.sa_mask);
 sa.sa_flags = SA_RESTART;
 if (sigaction(SIGCHLD, &sa, NULL) == -1) {
     perror("sigaction");
     exit(1);
 }
 while(1) { // main accept() loop
     sin_size = sizeof their_addr;
     getchar();
     if ((new_fd = accept(sockfd, (struct sockaddr *)&their_addr, \
             &sin_size)) == -1) {
         perror("accept");
         continue;
     }
     printf("server: got connection from %s\n", \
         inet_ntoa(their_addr.sin_addr));

     if (!fork()) { // this is the child process
         close(sockfd); // child doesn't need the listener
         if ((numbytes=recv(new_fd, buf, MAXDATASIZE-1, 0)) == -1) {
            perror("recv");
            exit(1);
        }
        buf[numbytes] = '\0';
        printf("Received From Client: %s\n",buf);

 str_server(sockfd);
 FILE *fp = fopen( "adventure.mpg", "rb" );
 //if(!fork())
 // execlp("gedit", "gedit", "SIPFILE.txt", NULL);
            //system("popen /home/umair/Documents/CurrentData/SIPFILE.txt");
     //ShellExecute(GetDesktopWindow(), "open","ls /home/umair/Documents 

            /CurrentData/SIPFILE.txt",NULL, NULL, SW_SHOW);
         if (send(new_fd, "Hello, world!\n", 14, 0) == -1)
             perror("send");
         close(new_fd);
         exit(0);
     }
     close(new_fd); // parent doesn't need this

 }
 return 0;
 }

void str_server(int sock) 
{ 
 char buf[1025]; 
 const char* filename = "test.text"; 
 FILE *file = fopen(filename, "rb"); 
 if (!file)
{
    printf("Can't open file for reading"); 
    return;
}
while (!feof(file)) 
{ 
    int rval = fread(buf, 1, sizeof(buf), file); 
    if (rval < 1)
    {
        printf("Can't read from file");
        fclose(file);
        return;
    }

    int off = 0;
    do
    {
        int sent = send(sock, &buf[off], rval - off, 0);
        if (sent < 1)
        {
            // if the socket is non-blocking, then check
            // the socket error for WSAEWOULDBLOCK/EAGAIN
            // (depending on platform) and if true then
            // use select() to wait for a small period of
            // time to see if the socket becomes writable
            // again before failing the transfer...

            printf("Can't write to socket");
            fclose(file);
            return;
        }

        off += sent;
    }
    while (off < rval);
} 

fclose(file);
}