Server Source Code

00001 /* tcpserv.c */
00002 /* linked with wrapsock */
00003 /* Client module */
00004 /* Author: Michèle Garoche */
00005 /* Date: February 26th 2003
00006 /* Feel free to do what you want with it */
00007 
00032 /* Includes */
00033 #include "wrapsock.h"
00034 
00041 int main(int argc, char *argv[])
00042 {
00043         /* Variables */
00047         int listenfd;   /* passive sockets' file descriptors */
00051         int connfd;     /* active sockets' file descriptors */
00055         int chopt;      /* dummy variable for options test */
00059         int port_served = 0;    /* port to connect */
00063         pid_t childpid;                 /* pid of the child process */
00067         socklen_t clilen;               /* size of the client's address structure */
00071         char progname[MAXLINE];         /* program's name */
00075         struct sockaddr_in cliaddr; /* client address structure */
00079         struct sockaddr_in servaddr; /* server's address structure */
00080 
00081         /* Functions */
00086         void sig_chld(int signo);       /* function to catch the end of child process */
00087 
00088         /* Retrieve the program's name */
00090         strcpy(progname, argv[0]);
00091 
00092         /* The user should supplied an option for port.
00093         As the first argument is the program name, we should have
00094         2 arguments */
00096         if (argc != 2)
00097         {
00098                 /* Display the help and quit */
00099                 servusage(progname);
00100         }
00101 
00102         /* Check for a valid option */
00104         while ((chopt = getopt(argc, argv, "abch")) != -1)
00105         {
00106                 switch (chopt)
00107                 {
00108                         case 'a':
00109                         {
00110                                 port_served = 1;
00111                                 break;
00112                         }
00113                         case 'b':
00114                         {
00115                                 port_served = 2;
00116                                 break;
00117                         }
00118                         case 'c':
00119                         {
00120                                 port_served = 3;
00121                                 break;
00122                         }
00123                         case 'h':
00124                         default:
00125                         {
00126                                 /* Display help and quit */
00127                                 servusage(progname);
00128                         }
00129                 }
00130         }
00131 
00132         /* Compute the real port number */
00133         port_served = port_served +  SERV_PORT1 - 1;
00134 
00135         /* Display help and quit if the argument for port is supplied without a dash before it */
00137         if (port_served < SERV_PORT1 || port_served > SERV_PORT3)
00138         {
00139                 servusage(progname);
00140         }
00141 
00142         /* Help message for the user */
00144         fprintf(stdout, "\nThe server %s will be attached to port %d.\n"
00145                  "Its pid is %d.\n\nIf you have launched the server as a "
00146                  "background process,\nreturn to continue and launch clients."
00147                  "\nYou will have to kill the server with:\n   kill -9 %d\n"
00148                  "when finishing with it.\n\nIf you have launched the server"
00149                  "as a foreground process,\nopen a new terminal to launch a "
00150                  "client.\nYou will have to type:\n   ctrl-C\nto quit the "
00151                  "server when finishing with it."
00152                  "\n\n", progname, port_served, (int)getpid(), (int)getpid());
00153 
00154         /* Create the socket */
00156         listenfd = Socket(AF_INET, SOCK_STREAM, 0);
00157 
00158         /* Fill in the address structure */
00160         bzero(&servaddr, sizeof(servaddr));
00161         servaddr.sin_family      = AF_INET;
00162         servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
00163         servaddr.sin_port        = htons(port_served);
00164 
00165         /* Attach the socket to the address */
00167         Bind(listenfd, (SA *) &servaddr, sizeof(servaddr));
00168 
00169         /* Convert the active socket into passive socket */
00171         Listen(listenfd, LISTENQ);
00172 
00173         /* Set the signal to catch the end of child's process */
00175         Signal(SIGCHLD, sig_chld);
00176 
00178         for ( ; ; )
00179         {
00180                 clilen = sizeof(cliaddr);       /* retrieve the size of address structure */
00181 
00182                 /* Duplicates the listening socket */
00183                 if ( (connfd = accept(listenfd, (SA *) &cliaddr, &clilen)) < 0)
00184                 {
00185                         /* Accept was interrupted by system call - so restart it manually if needed */
00186                         if (errno == EINTR)
00187                         {
00188                                 continue;
00189                         }
00190                         /* Any other error */
00191                         else
00192                         {
00193                                 err_sys("accept error");
00194                         }
00195                 }
00196 
00197                 /* Fork a process for answering each client's request */
00198                 if ( (childpid = Fork()) == 0)
00199                 {
00200                         /* Process Pi */
00201 
00202                         /* Close the listening socket on child side */
00203                         Close(listenfd);
00204 
00205                         /* Perform the requested job */
00206                         switch (port_served)
00207                         {
00208                                 case SERV_PORT1:
00209                                 {
00210                                         str_serv1(connfd);
00211                                         break;
00212                                 }
00213                                 case SERV_PORT2:
00214                                 {
00215                                         str_serv2(connfd);
00216                                         break;
00217                                 }
00218                                 case SERV_PORT3:
00219                                 {
00220                                         str_serv3(connfd);
00221                                         break;
00222                                 }
00223                         }
00224 
00225                         exit(EXIT_SUCCESS);
00226                 }
00227                 
00228                 /* Parent closes connected socket */
00229                 /* End of child is handled by Signal function */
00230                 Close(connfd);                  
00231         }
00232 
00233         /* Never goes here, just to be consistent with main's declaration */
00234         return 0;
00235 }