initial import

manual/examples/inetsrv.c

@@ -0,0 +1,103 @@
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netdb.h>
+
+#define PORT	5555
+#define MAXMSG	512
+
+int
+read_from_client (int filedes)
+{
+  char buffer[MAXMSG];
+  int nbytes;
+
+  nbytes = read (filedes, buffer, MAXMSG);
+  if (nbytes < 0)
+    {
+      /* Read error. */
+      perror ("read");
+      exit (EXIT_FAILURE);
+    }
+  else if (nbytes == 0)
+    /* End-of-file. */
+    return -1;
+  else
+    {
+      /* Data read. */
+      fprintf (stderr, "Server: got message: `%s'\n", buffer);
+      return 0;
+    }
+}
+
+int
+main (void)
+{
+  extern int make_socket (unsigned short int port);
+  int sock;
+  fd_set active_fd_set, read_fd_set;
+  int i;
+  struct sockaddr_in clientname;
+  size_t size;
+
+  /* Create the socket and set it up to accept connections. */
+  sock = make_socket (PORT);
+  if (listen (sock, 1) < 0)
+    {
+      perror ("listen");
+      exit (EXIT_FAILURE);
+    }
+
+  /* Initialize the set of active sockets. */
+  FD_ZERO (&active_fd_set);
+  FD_SET (sock, &active_fd_set);
+
+  while (1)
+    {
+      /* Block until input arrives on one or more active sockets. */
+      read_fd_set = active_fd_set;
+      if (select (FD_SETSIZE, &read_fd_set, NULL, NULL, NULL) < 0)
+	{
+	  perror ("select");
+	  exit (EXIT_FAILURE);
+	}
+
+      /* Service all the sockets with input pending. */
+      for (i = 0; i < FD_SETSIZE; ++i)
+	if (FD_ISSET (i, &read_fd_set))
+	  {
+	    if (i == sock)
+	      {
+		/* Connection request on original socket. */
+		int new;
+		size = sizeof (clientname);
+		new = accept (sock,
+			      (struct sockaddr *) &clientname,
+			      &size);
+		if (new < 0)
+		  {
+		    perror ("accept");
+		    exit (EXIT_FAILURE);
+		  }
+		fprintf (stderr,
+			 "Server: connect from host %s, port %hd.\n",
+			 inet_ntoa (clientname.sin_addr),
+			 ntohs (clientname.sin_port));
+		FD_SET (new, &active_fd_set);
+	      }
+	    else
+	      {
+		/* Data arriving on an already-connected socket. */
+		if (read_from_client (i) < 0)
+		  {
+		    close (i);
+		    FD_CLR (i, &active_fd_set);
+		  }
+	      }
+	  }
+    }
+}