c - Prob with binary files using sockets -

this not total code.

this working fine normal files text files, not working tar.gz , binary files transfer please me.

and how send chunks of memory using sockets.

server.c

void main() { int sockfd, new_fd;  // listen on sock_fd, new connection on new_fd struct sockaddr_in my_addr; // address information struct sockaddr_in their_addr; // connector's address information socklen_t sin_size; struct sigaction sa; int yes=1; char buf[16384]; char remotefile[maxdatasize]; 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 ip memset(my_addr.sin_zero, '\0', sizeof my_addr.sin_zero);  printf("call binding\n"); 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 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;     if ((new_fd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size)) == -1)      {         perror("accept");         exit(1);         continue;     }     printf("server: got connection %s\n",inet_ntoa(their_addr.sin_addr));     if (!fork())      { // child process if ((byt=recv(new_fd, remotefile, maxdatasize-1, 0)) == -1)              {                 perror("server recv");                 exit(1);             }         int serverfile_fd;         size_t result;         printf("\nremotefile in val1 %s\n",remotefile);          if((serverfile_fd = open(remotefile,o_rdonly)) < 0)         {             printf("error @ remotefile\n");             exit(1);         }          else          {               read(serverfile_fd, &buf[0], sizeof(buf));          }         //printf("file is\n%s", buf);         /* 3. sending  buf in val 0*/         if (send(new_fd, buf, 16384, 0) == -1)             perror("send");         close(new_fd);         exit(0);     } 

client.c

int remote_to_local(const  char *remotehost,const  char *remotefile,const  char *localfile) {  int sockfd, numbytes,i = 0,j = 0;   char buf[16384]; struct hostent *he; struct sockaddr_in s_addr; // connector's address information  printf("\n"); printf("remotehost %s\n", remotehost); if ((he=gethostbyname(remotehost)) == null)  {  // host info      perror("gethostbyname");     exit(1); }  if ((sockfd = socket(af_inet, sock_stream, 0)) == -1)  {     perror("socket");     exit(1); }  s_addr.sin_family = af_inet;    // host byte order  s_addr.sin_port = htons(port);  // short, network byte order  s_addr.sin_addr = *((struct in_addr *)he->h_addr); //inet_aton(he->h_addr, &s_addr.sin_addr); memset(s_addr.sin_zero, '\0', sizeof s_addr.sin_zero);  if (connect(sockfd, (struct sockaddr *)&s_addr, sizeof s_addr) == -1)  {     perror("connect");     exit(1); }  //send(sockfd, remotefile, maxdatasize-1, 0); val[0] = 1; printf("val 0 %d\n", val[0]); printf("val 1 %d\n", val[1]);         /*1 sending val in r l*/ if (send(sockfd, val, maxdatasize-1, 0) == -1)             perror("send");  printf("remotefile %s\n",remotefile);  /* 2 sending remotefile in r l*/ if (send(sockfd, remotefile, maxdatasize-1, 0) == -1)             perror("send"); /* 3. recieve buf in r l */   if ((numbytes=recv(sockfd, buf, 16384, 0)) == -1)  {     perror("recv");     exit(1); }  buf[numbytes] = '\0';  //printf("received: \n%s",buf);   int clientfile_fd; printf("local file %s\n",localfile); if((clientfile_fd = open(localfile,o_creat|o_wronly,0777)) < 0)     {        printf("error @ remotefile\n");         exit(1);     }    else    {             //read(clientfile_fd, &buf[0], sizeof(buf));          int  result = strlen(buf);           //printf("result size %d\n",result);          open(localfile,o_trunc);          write(clientfile_fd, &buf[0], result);    }  close(sockfd);   return 0;   } 

go through code , fix/change places you:

• don't correctly handle results returned system calls recv(). if positive value returned, value safe way of finding out how data has been read buffer.
• get rid of strlen(), printf("%s...) etc. either useless, (the binary data may contain nulls , action complete early), or dangerous, (binary data contains no nulls @ , calls ub).