lib/sh/zwrite.c

   1 /* Copyright (C) 1999 Free Software Foundation, Inc.
   2
   3    This file is part of GNU Bash, the Bourne Again SHell.
   4
   5    Bash is free software; you can redistribute it and/or modify it under
   6    the terms of the GNU General Public License as published by the Free
   7    Software Foundation; either version 2, or (at your option) any later
   8    version.
   9
  10    Bash is distributed in the hope that it will be useful, but WITHOUT ANY
  11    WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13    for more details.
  14
  15    You should have received a copy of the GNU General Public License along
  16    with Bash; see the file COPYING.  If not, write to the Free Software
  17    Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. */
  18
  19 #include <config.h>
  20
  21 #include <sys/types.h>
  22
  23 #if defined (HAVE_UNISTD_H)
  24 #  include <unistd.h>
  25 #endif
  26
  27 #include <errno.h>
  28
  29 #if !defined (errno)
  30 extern int errno;
  31 #endif
  32
  33 /* Write NB bytes from BUF to file descriptor FD, retrying the write if
  34    it is interrupted.  We retry three times if we get a zero-length
  35    write.  Any other signal causes this function to return prematurely. */
  36 int
  37 zwrite (fd, buf, nb)
  38      int fd;
  39      unsigned char *buf;
  40      size_t nb;
  41 {
  42   int n, i, nt;
  43
  44   for (n = nb, nt = 0;;)
  45     {
  46       i = write (fd, buf, n);
  47       if (i > 0)
  48         {
  49           n -= i;
  50           if (n <= 0)
  51             return nb;
  52           buf += i;
  53         }
  54       else if (i == 0)
  55         {
  56           if (++nt > 3)
  57             return (nb - n);
  58         }
  59       else if (errno != EINTR)
  60         return -1;
  61     }
  62 }