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      1 /*
      2     Copyright (c) 2010 - 2012, Intel Corporation. All rights reserved.<BR>
      3     This program and the accompanying materials are licensed and made available
      4     under the terms and conditions of the BSD License that accompanies this
      5     distribution.  The full text of the license may be found at
      6     http://opensource.org/licenses/bsd-license.
      7 
      8     THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
      9     WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
     10 
     11  * Copyright (c) 1990, 1993
     12  *  The Regents of the University of California.  All rights reserved.
     13  *
     14  * This code is derived from software contributed to Berkeley by
     15  * Chris Torek.
     16  *
     17  * Redistribution and use in source and binary forms, with or without
     18  * modification, are permitted provided that the following conditions
     19  * are met:
     20  * 1. Redistributions of source code must retain the above copyright
     21  *    notice, this list of conditions and the following disclaimer.
     22  * 2. Redistributions in binary form must reproduce the above copyright
     23  *    notice, this list of conditions and the following disclaimer in the
     24  *    documentation and/or other materials provided with the distribution.
     25  * 3. Neither the name of the University nor the names of its contributors
     26  *    may be used to endorse or promote products derived from this software
     27  *    without specific prior written permission.
     28  *
     29  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     39  * SUCH DAMAGE.
     40 
     41     NetBSD: refill.c,v 1.13 2003/08/07 16:43:30 agc Exp
     42     refill.c  8.1 (Berkeley) 6/4/93
     43 */
     44 #include  <LibConfig.h>
     45 #include <sys/EfiCdefs.h>
     46 
     47 #include <assert.h>
     48 #include <errno.h>
     49 #include <stdio.h>
     50 #include <stdlib.h>
     51 #include "reentrant.h"
     52 #include "local.h"
     53 
     54 #ifdef _REENTRANT
     55 extern rwlock_t __sfp_lock;
     56 #endif
     57 
     58 static int lflush(FILE *);
     59 
     60 static int
     61 lflush(FILE *fp)
     62 {
     63 
     64   _DIAGASSERT(fp != NULL);
     65   if(fp == NULL) {
     66     errno = EINVAL;
     67     return (EOF);
     68   }
     69 
     70   if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR))
     71     return (__sflush(fp));
     72   return (0);
     73 }
     74 
     75 /*
     76  * Refill a stdio buffer.
     77  * Return EOF on eof or error, 0 otherwise.
     78  */
     79 int
     80 __srefill(FILE *fp)
     81 {
     82 
     83   _DIAGASSERT(fp != NULL);
     84   if(fp == NULL) {
     85     errno = EINVAL;
     86     return (EOF);
     87   }
     88 
     89   /* make sure stdio is set up */
     90   if (!__sdidinit)
     91     __sinit();
     92 
     93   fp->_r = 0;   /* largely a convenience for callers */
     94 
     95   /* SysV does not make this test; take it out for compatibility */
     96   if (fp->_flags & __SEOF) {
     97     return (EOF);
     98   }
     99 
    100   /* if not already reading, have to be reading and writing */
    101   if ((fp->_flags & __SRD) == 0) {
    102     if ((fp->_flags & __SRW) == 0) {
    103       errno = EBADF;
    104       fp->_flags |= __SERR;   //<dvm> Allows differentiation between errors and EOF
    105       return (EOF);
    106     }
    107     /* switch to reading */
    108     if (fp->_flags & __SWR) {
    109       if (__sflush(fp)) {
    110         return (EOF);
    111       }
    112       fp->_flags &= ~__SWR;
    113       fp->_w = 0;
    114       fp->_lbfsize = 0;
    115     }
    116     fp->_flags |= __SRD;
    117   } else {
    118     /*
    119      * We were reading.  If there is an ungetc buffer,
    120      * we must have been reading from that.  Drop it,
    121      * restoring the previous buffer (if any).  If there
    122      * is anything in that buffer, return.
    123      */
    124     if (HASUB(fp)) {
    125       FREEUB(fp);
    126       if ((fp->_r = fp->_ur) != 0) {
    127         fp->_p = fp->_up;
    128         return (0);
    129       }
    130     }
    131   }
    132 
    133   if (fp->_bf._base == NULL)
    134     __smakebuf(fp);
    135 
    136   /*
    137    * Before reading from a line buffered or unbuffered file,
    138    * flush all line buffered output files, per the ANSI C
    139    * standard.
    140    */
    141   if (fp->_flags & (__SLBF|__SNBF)) {
    142     rwlock_rdlock(&__sfp_lock);
    143     (void) _fwalk(lflush);
    144     rwlock_unlock(&__sfp_lock);
    145   }
    146   fp->_p = fp->_bf._base;
    147   fp->_r = (*fp->_read)(fp->_cookie, (char *)fp->_p, fp->_bf._size);
    148   fp->_flags &= ~__SMOD;  /* buffer contents are again pristine */
    149   if (fp->_r <= 0) {
    150     if (fp->_r == 0)
    151       fp->_flags |= __SEOF;
    152     else {
    153       fp->_r = 0;
    154       fp->_flags |= __SERR;
    155     }
    156     return (EOF);
    157   }
    158   return (0);
    159 }
    160