1: /* Copyright (C) 1993, 1995, 1996, 1997, 1998, 1999, 2002, 2003, 2005
    2:    Free Software Foundation, Inc.
    3:    This file is part of the GNU C Library.
    4: 
    5:    The GNU C Library is free software; you can redistribute it and/or
    6:    modify it under the terms of the GNU Lesser General Public
    7:    License as published by the Free Software Foundation; either
    8:    version 2.1 of the License, or (at your option) any later version.
    9: 
   10:    The GNU C Library is distributed in the hope that it will be useful,
   11:    but WITHOUT ANY WARRANTY; without even the implied warranty of
   12:    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   13:    Lesser General Public License for more details.
   14: 
   15:    You should have received a copy of the GNU Lesser General Public
   16:    License along with the GNU C Library; if not, write to the Free
   17:    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   18:    02111-1307 USA.
   19: 
   20:    As a special exception, if you link the code in this file with
   21:    files compiled with a GNU compiler to produce an executable,
   22:    that does not cause the resulting executable to be covered by
   23:    the GNU Lesser General Public License.  This exception does not
   24:    however invalidate any other reasons why the executable file
   25:    might be covered by the GNU Lesser General Public License.
   26:    This exception applies to code released by its copyright holders
   27:    in files containing the exception.  */
   28: 
   29: #include "libioP.h"
   30: #include <stdio.h>
   31: #include <sys/param.h>
   32: 
   33: char *
   34: __fgets_chk (buf, size, n, fp)
   35:      char *buf;
   36:      size_t size;
   37:      int n;
   38:      _IO_FILE *fp;
   39: {
   40:   _IO_size_t count;
   41:   char *result;
   42:   CHECK_FILE (fp, NULL);
   43:   if (n <= 0)
   44:     return NULL;
   45:   _IO_acquire_lock (fp);
   46:   /* This is very tricky since a file descriptor may be in the
   47:      non-blocking mode. The error flag doesn't mean much in this
   48:      case. We return an error only when there is a new error. */
   49:   int old_error = fp->_IO_file_flags & _IO_ERR_SEEN;
   50:   fp->_IO_file_flags &= ~_IO_ERR_SEEN;
   51:   count = INTUSE(_IO_getline) (fp, buf, MIN ((size_t) n - 1, size), '\n', 1);
   52:   /* If we read in some bytes and errno is EAGAIN, that error will
   53:      be reported for next read. */
   54:   if (count == 0 || ((fp->_IO_file_flags & _IO_ERR_SEEN)
   55:                      && errno != EAGAIN))
   56:     result = NULL;
   57:   else if (count >= size)
   58:     __chk_fail ();
   59:   else
   60:     {
   61:       buf[count] = '\0';
   62:       result = buf;
   63:     }
   64:   fp->_IO_file_flags |= old_error;
   65:   _IO_release_lock (fp);
   66:   return result;
   67: }