Materiale dimenticato e la versione preliminare del server echo implementato

[gapil.git] / listati / select_echod.c

diff --git a/listati/select_echod.c b/listati/select_echod.c
new file mode 100644 (file)
index 0000000..d06b14e
--- /dev/null
+++ b/listati/select_echod.c
@@ -0,0 +1,57 @@
+    ...
+    memset(fd_open, 0, FD_SETSIZE);   /* clear array of open files */
+    max_fd = list_fd;                 /* maximum now is listening socket */
+    fd_open[max_fd] = 1;
+    /* main loop, wait for connection and data inside a select */
+    while (1) {  
+       FD_ZERO(&fset);               /* clear fd_set */
+       for (i = list_fd; i <= max_fd; i++) { /* initialize fd_set */
+           if (fd_open[i] != 0) FD_SET(i, &fset); 
+       }
+       while ( ((n = select(max_fd + 1, &fset, NULL, NULL, NULL)) < 0) 
+               && (errno == EINTR));         /* wait for data or connection */
+       if (n < 0) {                          /* on real error exit */
+           PrintErr("select error");
+           exit(1);
+       }
+       if (FD_ISSET(list_fd, &fset)) {       /* if new connection */
+           n--;                              /* decrement active */
+           len = sizeof(c_addr);             /* and call accept */         
+           if ((fd = accept(list_fd, (struct sockaddr *)&c_addr, &len)) < 0) {
+               PrintErr("accept error");
+               exit(1);
+           }
+           fd_open[fd] = 1;                  /* set new connection socket */
+           if (max_fd < fd) max_fd = fd;     /* if needed set new maximum */
+       }
+       /* loop on open connections */
+       i = list_fd;                  /* first socket to look */
+       while (n != 0) {              /* loop until active */
+           i++;                      /* start after listening socket */
+           if (fd_open[i] == 0) continue;   /* closed, go next */
+           if (FD_ISSET(i, &fset)) {        /* if active process it*/
+               n--;                         /* decrease active */
+               nread = read(i, buffer, MAXLINE);     /* read operations */
+               if (nread < 0) {
+                   PrintErr("Errore in lettura");
+                   exit(1);
+               }
+               if (nread == 0) {            /* if closed connection */
+                   close(i);                /* close file */
+                   fd_open[i] = 0;          /* mark as closed in table */
+                   if (max_fd == i) {       /* if was the maximum */
+                       while (fd_open[--i] == 0);  /* loop down */
+                       max_fd = i;          /* set new maximum */
+                       break;               /* and go back to select */
+                   }
+                   continue;                /* continue loop on open */
+               }
+               nwrite = FullWrite(i, buffer, nread); /* write data */
+               if (nwrite) {
+                   PrintErr("Errore in scrittura");
+                   exit(1);
+               }
+           }
+       }
+    }
+    ...