sddslogclient.c File Reference

Detailed Description

A simple TCP client for sending commands to a server.

This program establishes a TCP connection to a specified server and port, sends commands either from the command-line arguments or interactively from the user, and processes the server's responses. The client supports persistent connections, allowing multiple commands to be sent over a single socket until a "disconnect" command is issued.

Usage

sddslogclient <hostname> <port> [<command> ...]

Options

Required	Description
hostname	The server's hostname or IP address.
port	The port number on which the server is listening.

Optional	Description
<command>	One or more commands to send to the server initially.

Copyright

• (c) 2002 The University of Chicago, as Operator of Argonne National Laboratory.
• (c) 2002 The Regents of the University of California, as Operator of Los Alamos National Laboratory.

License

This file is distributed under the terms of the Software License Agreement found in the file LICENSE included with this distribution.

Author

M. Borland, R. Soliday

Definition in file sddslogclient.c.

#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>

Go to the source code of this file.

Functions
void	error_exit (const char *msg)
int	process_command (char *buffer, int sockfd)
int	main (int argc, char *argv[])

Function Documentation

error_exit()

void error_exit

(

const char *

msg

)

Definition at line 51 of file sddslogclient.c.

                                 {
  perror(msg);
  exit(EXIT_FAILURE);
}

main()

int main	(	int	argc,
		char *	argv[] )

Definition at line 74 of file sddslogclient.c.

                                 {
  int sockfd, portno, arg_index;
  struct sockaddr_in serv_addr;
  struct hostent *server;
  int persist = 1;
 
  char buffer[BUFLEN];
 
  if (argc < 3) {
    fprintf(stderr, "Usage: %s <hostname> <port> [<command> [<command> ...]]\n", argv[0]);
    exit(EXIT_FAILURE);
  }
 
  portno = atoi(argv[2]);
  sockfd = socket(AF_INET, SOCK_STREAM, 0);
  if (sockfd < 0)
    error_exit("ERROR opening socket");
 
  server = gethostbyname(argv[1]);
  if (server == NULL) {
    fprintf(stderr, "ERROR, no such host\n");
    exit(EXIT_FAILURE);
  }
 
  memset(&serv_addr, 0, sizeof(serv_addr));
  serv_addr.sin_family = AF_INET;
  memcpy(&serv_addr.sin_addr.s_addr, server->h_addr, server->h_length);
  serv_addr.sin_port = htons(portno);
 
  if (connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0)
    error_exit("ERROR connecting");
 
  for (arg_index = 3; persist && arg_index < argc; arg_index++) {
    if (snprintf(buffer, BUFLEN, "%s\n", argv[arg_index]) >= BUFLEN) {
      fprintf(stderr, "ERROR: Command too long\n");
      continue;
    }
 
    if (strcmp(buffer, "disconnect\n") == 0)
      persist = 0;
 
    printf("Processing command: %s", buffer);
    fflush(stdout);
 
    process_command(buffer, sockfd);
  }
 
  while (persist) {
    printf("Please enter the message: ");
    fflush(stdout);
 
    memset(buffer, 0, BUFLEN);
    if (fgets(buffer, BUFLEN - 1, stdin) == NULL)
      break;
 
    if (strcmp(buffer, "disconnect\n") == 0)
      persist = 0;
 
    process_command(buffer, sockfd);
  }
 
  close(sockfd);
  return EXIT_SUCCESS;
}

process_command()

int process_command	(	char *	buffer,
		int	sockfd )

Definition at line 57 of file sddslogclient.c.

                                              {
  ssize_t n;
 
  n = write(sockfd, buffer, strlen(buffer));
  if (n < 0)
    error_exit("ERROR writing to socket");
 
  memset(buffer, 0, BUFLEN);
  n = read(sockfd, buffer, BUFLEN - 1);
  if (n < 0)
    error_exit("ERROR reading from socket");
 
  printf("%s\n", buffer);
  return n;
}