lib/libc/stdio/fflush.c

   1 /*-
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Chris Torek.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * @(#)fflush.c 8.1 (Berkeley) 6/4/93
  37  * $FreeBSD: src/lib/libc/stdio/fflush.c,v 1.7 1999/08/28 00:00:58 peter Exp $
  38  * $DragonFly: src/lib/libc/stdio/fflush.c,v 1.6 2005/07/23 20:23:05 joerg Exp $
  39  */
  40
  41 #include "namespace.h"
  42 #include <errno.h>
  43 #include <stdio.h>
  44 #include "un-namespace.h"
  45 #include "libc_private.h"
  46
  47 #include "local.h"
  48 #include "priv_stdio.h"
  49
  50 /*
  51  * Flush a single file, or (if fp is NULL) all files.
  52  * MT-safe version
  53  */
  54 int
  55 fflush(FILE *fp)
  56 {
  57         int retval;
  58
  59         if (fp == NULL)
  60                 return (_fwalk(__sflush));
  61         FLOCKFILE(fp);
  62         if ((fp->pub._flags & (__SWR | __SRW)) == 0) {
  63                 errno = EBADF;
  64                 retval = EOF;
  65         } else
  66                 retval = __sflush(fp);
  67
  68         FUNLOCKFILE(fp);
  69         return (retval);
  70 }
  71
  72 /*
  73  * Flush a single file, or (if fp is NULL) all files.
  74  * Non-MT-safe version
  75  */
  76 int
  77 __fflush(FILE *fp)
  78 {
  79         int retval;
  80
  81         if (fp == NULL)
  82                 return (_fwalk(__sflush));
  83         if ((fp->pub._flags & (__SWR | __SRW)) == 0) {
  84                 errno = EBADF;
  85                 retval = EOF;
  86         } else
  87                 retval = __sflush(fp);
  88         return (retval);
  89 }
  90
  91 int
  92 __sflush(FILE *fp)
  93 {
  94         unsigned char *p;
  95         int n, t;
  96
  97         t = fp->pub._flags;
  98         if ((t & __SWR) == 0)
  99                 return (0);
 100
 101         if ((p = fp->_bf._base) == NULL)
 102                 return (0);
 103
 104         n = fp->pub._p - p;             /* write this much */
 105
 106         /*
 107          * Set these immediately to avoid problems with longjmp and to allow
 108          * exchange buffering (via setvbuf) in user write function.
 109          */
 110         fp->pub._p = p;
 111         fp->pub._w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
 112
 113         for (; n > 0; n -= t, p += t) {
 114                 t = (*fp->_write)(fp->_cookie, (char *)p, n);
 115                 if (t <= 0) {
 116                         fp->pub._flags |= __SERR;
 117                         return (EOF);
 118                 }
 119         }
 120         return (0);
 121 }