Added basic server functionality from ex 2 lesson 11

lib/utils/conn.h

@@ -0,0 +1,68 @@
+#ifndef CONN_H
+#define CONN_H
+
+#include <sys/types.h> 
+#include <sys/socket.h>
+#include <sys/uio.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#if !defined(BUFSIZE)
+#define BUFSIZE 256
+#endif
+#if !defined(SOCKNAME)
+#define SOCKNAME     "./cs_sock"
+#endif
+#if !defined(MAXBACKLOG)
+#define MAXBACKLOG   32
+#endif
+
+/** Evita letture parziali
+ *
+ *   \retval -1   errore (errno settato)
+ *   \retval  0   se durante la lettura da fd leggo EOF
+ *   \retval size se termina con successo
+ */
+static inline int readn(long fd, void *buf, size_t size) {
+    size_t left = size;
+    int r;
+    char *bufptr = (char*)buf;
+    while(left>0) {
+	if ((r=read((int)fd ,bufptr,left)) == -1) {
+	    if (errno == EINTR) continue;
+	    return -1;
+	}
+	if (r == 0) return 0;   // EOF
+        left    -= r;
+	bufptr  += r;
+    }
+    return size;
+}
+
+/** Evita scritture parziali
+ *
+ *   \retval -1   errore (errno settato)
+ *   \retval  0   se durante la scrittura la write ritorna 0
+ *   \retval  1   se la scrittura termina con successo
+ */
+static inline int writen(long fd, void *buf, size_t size) {
+    size_t left = size;
+    int r;
+    char *bufptr = (char*)buf;
+    while(left>0) {
+	if ((r=write((int)fd ,bufptr,left)) == -1) {
+	    if (errno == EINTR) continue;
+	    return -1;
+	}
+	if (r == 0) return 0;  
+        left    -= r;
+	bufptr  += r;
+    }
+    return 1;
+}
+
+
+#endif /* CONN_H */