Example: Use accept_and_recv() and send_file() APIs to send contents of a file

/*************************************************/
/* Server example send file data to client       */
/*************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define SERVER_PORT 12345

main (int argc, char *argv[])
{
   int    i, num, rc, flag = 1;
   int    fd, listen_sd, accept_sd = -1;

   size_t local_addr_length;
   size_t remote_addr_length;
   size_t total_sent;

   struct sockaddr_in   addr;
   struct sockaddr_in   local_addr;
   struct sockaddr_in   remote_addr;
   struct sf_parms      parms;

   char   buffer[255];

   /*************************************************/
   /* If an argument is specified, use it to       */
   /* control the number of incoming connections    */
   /*************************************************/
   if (argc >= 2)
      num = atoi(argv[1]);
   else
      num = 1;

   /*************************************************/
   /* Create an AF_INET stream socket to receive    */
   /* incoming connections on                       */
   /*************************************************/
   listen_sd = socket(AF_INET, SOCK_STREAM, 0);
   if (listen_sd < 0)
   {
      perror("socket() failed");
      exit(-1);
   }

   /*************************************************/
   /* Set the SO_REUSEADDR bit so that you do not   */
   /* need to wait 2 minutes before restarting      */
   /* the server                                    */
   /*************************************************/
   rc = setsockopt(listen_sd,
                   SOL_SOCKET,
                   SO_REUSEADDR,
                   (char *)&flag,
                   sizeof(flag));
   if (rc < 0)
   {
      perror("setsockop() failed");
      close(listen_sd);
      exit(-1);
   }

   /*************************************************/
   /* Bind the socket                               */
   /*************************************************/
   memset(&addr, 0, sizeof(addr));
   addr.sin_family      = AF_INET;
   addr.sin_addr.s_addr = htonl(INADDR_ANY);
   addr.sin_port        = htons(SERVER_PORT);
   rc = bind(listen_sd,
             (struct sockaddr *)&addr, sizeof(addr));
   if (rc < 0)
   {
      perror("bind() failed");
      close(listen_sd);
      exit(-1);
   }

   /*************************************************/
   /* Set the listen backlog                        */
   /*************************************************/
   rc = listen(listen_sd, 5);
   if (rc < 0)
   {
      perror("listen() failed");
      close(listen_sd);
      exit(-1);
   }

   /*************************************************/
   /* Initialize the local and remote addr lengths  */
   /*************************************************/
   local_addr_length  = sizeof(local_addr);
   remote_addr_length = sizeof(remote_addr);

   /*************************************************/
   /* Inform the user that the server is ready      */
   /*************************************************/
   printf("The server is ready\n");

   /*************************************************/
   /* Go through the loop once for each connection  */
   /*************************************************/
   for (i=0; i < num; i++)
   {
      /**********************************************/
      /* Wait for an incoming connection            */
      /**********************************************/
      printf("Iteration: %d\n", i+1);
      printf("  waiting on accept_and_recv()\n");

      rc = accept_and_recv(listen_sd,
                           &accept_sd,
                           (struct sockaddr *)&remote_addr,
                           &remote_addr_length,
                           (struct sockaddr *)&local_addr,
                           &local_addr_length,
                           &buffer,
                           sizeof(buffer));
      if (rc < 0)
      {
         perror("accept_and_recv() failed");
         close(listen_sd);
         close(accept_sd);
         exit(-1);
      }
      printf("  Request for file: %s\n", buffer);

      /**********************************************/
      /* Open the file to retrieve                  */
      /**********************************************/
      fd = open(buffer, O_RDONLY);
      if (fd < 0)
      {
         perror("open() failed");
         close(listen_sd);
         close(accept_sd);
         exit(-1);
      }

      /**********************************************/
      /* Initialize the sf_parms structure          */
      /**********************************************/
      memset(&parms, 0, sizeof(parms));
      parms.file_descriptor = fd;
      parms.file_bytes      = -1;

      /**********************************************/
      /* Initialize the counter of the total number */
      /* of bytes sent                              */
      /**********************************************/
      total_sent = 0;

      /**********************************************/
      /* Loop until the entire file has been sent   */
      /**********************************************/
      do
      {
         rc = send_file(&accept_sd, &parms, SF_CLOSE);
         if (rc < 0)
         {
            perror("send_file() failed");
            close(fd);
            close(listen_sd);
            close(accept_sd);
            exit(-1);
         }
         total_sent += parms.bytes_sent;

      } while (rc == 1);

      printf("  Total number of bytes sent: %d\n", total_sent);

      /**********************************************/
      /* Close the file that is sent out           */
      /**********************************************/
      close(fd);
   }

   /*************************************************/
   /* Close the listen socket                       */
   /*************************************************/
   close(listen_sd);

   /*************************************************/
   /* Close the accept socket                       */
   /*************************************************/
   if (accept_sd != -1)
      close(accept_sd);
}