StdLib/LibC/Stdio/refill.c

   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 }