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/*
* Network library.
* Copyright (C) 1997 Kunihiro Ishiguro
*
* This file is part of GNU Zebra.
*
* GNU Zebra is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2, or (at your option) any
* later version.
*
* GNU Zebra is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU Zebra; see the file COPYING. If not, write to the Free
* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
* 02111-1307, USA.
*/
#include <zebra.h>
#include "log.h"
#include "network.h"
/*------------------------------------------------------------------------------
* Read nbytes from fd and store into ptr -- BLOCKING
*
* Loops internally if gets EINTR.
*
* Returns: >= 0 -- number of bytes read
* < 0 => error
*
* NB: if applied to a NON-BLOCKING fd, may return EAGAIN or EWOULDBLOCK
*/
int
readn (int fd, u_char *ptr, int nbytes)
{
int nleft;
int nread;
nleft = nbytes;
while (nleft > 0)
{
nread = read (fd, ptr, nleft);
if (nread > 0)
{
nleft -= nread;
ptr += nread;
}
else if (nread == 0)
break;
else
{
if (errno != EINTR)
return (nread);
}
}
return nbytes - nleft;
}
/*------------------------------------------------------------------------------
* Read up to nbyte bytes into buf -- assuming NON-BLOCKING.
*
* Loops internally if gets EINTR -- so if does not read everything asked for,
* that must be because the read would otherwise block.
*
* Returns: 0..n -- number of bytes read
* -1 => failed -- see errno
* -2 => EOF met immediately
*
* NB: if asked to write zero bytes, does nothing and will return 0.
*
* Reading zero bytes is defined for all types of files, and may be used
* to probe for error state.
*/
int
read_nb(int fd, void* buf, size_t nbyte)
{
size_t nleft = nbyte ;
do
{
int ret = read(fd, buf, nleft);
if (ret > 0)
{
buf = (char*)buf + ret ;
nleft -= ret ;
}
else if (ret == 0)
{
if (nleft < nbyte)
break ; /* if read something before EOF */
return -2 ; /* hit EOF immediately */
}
else
{
int err = errno ;
if ((err == EAGAIN) || (err == EWOULDBLOCK))
break ;
if (err != EINTR)
return -1 ; /* failed */
} ;
} while (nleft > 0) ;
return (nbyte - nleft) ;
} ;
/*------------------------------------------------------------------------------
* Write nbytes to fd from ptr -- BLOCKING
*
* Loops internally if gets EINTR.
*
* Returns: >= 0 -- number of bytes written
* < 0 => error
*
* NB: if applied to a NON-BLOCKING fd, may return EAGAIN or EWOULDBLOCK
*/
int
writen(int fd, const u_char *ptr, int nbytes)
{
int nleft;
int nwritten;
nleft = nbytes;
while (nleft > 0)
{
nwritten = write(fd, ptr, nleft);
if (nwritten > 0)
{
nleft -= nwritten;
ptr += nwritten;
}
else if (nwritten == 0)
break ;
else
{
if (errno != EINTR)
return (nwritten);
}
}
return nbytes - nleft;
}
/*------------------------------------------------------------------------------
* Write up to nbyte bytes from buf -- assuming NON-BLOCKING.
*
* Loops internally if gets EINTR.
*
* Returns: 0..n -- number of bytes written
* -1 => failed -- see errno
*
* NB: if asked to write zero bytes, does nothing and will return 0.
*
* Writing zero bytes is defined for "regular files", but not for anything
* else.
*/
int
write_nb(int fd, void* buf, size_t nbyte)
{
size_t nleft = nbyte ;
while (nleft > 0)
{
int ret = write(fd, buf, nleft);
if (ret > 0)
{
buf = (char*)buf + ret ;
nleft -= ret ;
}
else if (ret == 0)
break ; /* not sure can happen... but
cannot assume will go away */
else
{
int err = errno ;
if ((err == EAGAIN) || (err == EWOULDBLOCK))
break ;
if (err != EINTR)
return -1 ; /* failed */
} ;
} ;
return (nbyte - nleft) ;
} ;
/*------------------------------------------------------------------------------
* Set fd to non-blocking
*
* Returns: 0 => OK
* -1 => failed
*/
int
set_nonblocking(int fd)
{
int flags;
/* According to the Single UNIX Spec, the return value for F_GETFL should
never be negative. */
if ((flags = fcntl(fd, F_GETFL)) < 0)
{
zlog_warn("fcntl(F_GETFL) failed for fd %d: %s",
fd, errtoa(errno, 0).str);
return -1;
}
if (fcntl(fd, F_SETFL, (flags | O_NONBLOCK)) < 0)
{
zlog_warn("fcntl failed setting fd %d non-blocking: %s",
fd, errtoa(errno, 0).str);
return -1;
}
return 0;
}
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