Dogcows Code - chaz/tar/blob - lib/full-write.c

   1 /* full-write.c -- an interface to write that retries after interrupts
   2    Copyright 1993,94,97,98,99,2000, 2001 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17
  18    Copied largely from GNU C's cccp.c.
  19    */
  20
  21 #if HAVE_CONFIG_H
  22 # include <config.h>
  23 #endif
  24
  25 #include <sys/types.h>
  26
  27 #include "full-write.h"
  28
  29 #if HAVE_UNISTD_H
  30 # include <unistd.h>
  31 #endif
  32
  33 #include <errno.h>
  34 #ifndef errno
  35 extern int errno;
  36 #endif
  37
  38 /* Write LEN bytes at PTR to descriptor DESC, retrying if interrupted
  39    or if partial writes occur.  Return the number of bytes successfully
  40    written, setting errno if that is less than LEN.  */
  41
  42 size_t
  43 full_write (int desc, const char *ptr, size_t len)
  44 {
  45   size_t total_written = 0;
  46
  47   while (len > 0)
  48     {
  49       ssize_t written = write (desc, ptr, len);
  50       if (written <= 0)
  51         {
  52           /* Some buggy drivers return 0 when you fall off a device's end.  */
  53           if (written == 0)
  54             errno = ENOSPC;
  55 #ifdef EINTR
  56           if (errno == EINTR)
  57             continue;
  58 #endif
  59           break;
  60         }
  61       total_written += written;
  62       ptr += written;
  63       len -= written;
  64     }
  65   return total_written;
  66 }