lib/network.c

   1 /*
   2  * Network library.
   3  * Copyright (C) 1997 Kunihiro Ishiguro
   4  *
   5  * This file is part of GNU Zebra.
   6  *
   7  * GNU Zebra is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the
   9  * Free Software Foundation; either version 2, or (at your option) any
  10  * later version.
  11  *
  12  * GNU Zebra is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with GNU Zebra; see the file COPYING.  If not, write to the Free
  19  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  20  * 02111-1307, USA.
  21  */
  22
  23 #include <zebra.h>
  24 #include "log.h"
  25 #include "network.h"
  26
  27 /* Read nbytes from fd and store into ptr. */
  28 int
  29 readn (int fd, u_char *ptr, int nbytes)
  30 {
  31   int nleft;
  32   int nread;
  33
  34   nleft = nbytes;
  35
  36   while (nleft > 0)
  37     {
  38       nread = read (fd, ptr, nleft);
  39
  40       if (nread < 0)
  41         return (nread);
  42       else
  43         if (nread == 0)
  44           break;
  45
  46       nleft -= nread;
  47       ptr += nread;
  48     }
  49
  50   return nbytes - nleft;
  51 }
  52
  53 /* Write nbytes from ptr to fd. */
  54 int
  55 writen(int fd, const u_char *ptr, int nbytes)
  56 {
  57   int nleft;
  58   int nwritten;
  59
  60   nleft = nbytes;
  61
  62   while (nleft > 0)
  63     {
  64       nwritten = write(fd, ptr, nleft);
  65
  66       if (nwritten <= 0)
  67         return (nwritten);
  68
  69       nleft -= nwritten;
  70       ptr += nwritten;
  71     }
  72   return nbytes - nleft;
  73 }
  74
  75 int
  76 set_nonblocking(int fd)
  77 {
  78   int flags;
  79
  80   /* According to the Single UNIX Spec, the return value for F_GETFL should
  81      never be negative. */
  82   if ((flags = fcntl(fd, F_GETFL)) < 0)
  83     {
  84       zlog_warn("fcntl(F_GETFL) failed for fd %d: %s",
  85                 fd, safe_strerror(errno));
  86       return -1;
  87     }
  88   if (fcntl(fd, F_SETFL, (flags | O_NONBLOCK)) < 0)
  89     {
  90       zlog_warn("fcntl failed setting fd %d non-blocking: %s",
  91                 fd, safe_strerror(errno));
  92       return -1;
  93     }
  94   return 0;
  95 }