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. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)refill.c 8.1 (Berkeley) 6/4/93 33 * $FreeBSD: src/lib/libc/stdio/refill.c,v 1.20 2008/04/17 22:17:54 jhb Exp $ 34 */ 35 36 #include "namespace.h" 37 #include <errno.h> 38 #include <stdio.h> 39 #include <stdlib.h> 40 #include "un-namespace.h" 41 42 #include "libc_private.h" 43 #include "local.h" 44 45 static int lflush(FILE *); 46 47 static int 48 lflush(FILE *fp) 49 { 50 int ret = 0; 51 52 if ((fp->pub._flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) { 53 FLOCKFILE(fp); 54 ret = __sflush(fp); 55 FUNLOCKFILE(fp); 56 } 57 return (ret); 58 } 59 60 /* 61 * Refill a stdio buffer. 62 * Return EOF on eof or error, 0 otherwise. 63 */ 64 int 65 __srefill(FILE *fp) 66 { 67 68 /* make sure stdio is set up */ 69 if (!__sdidinit) 70 __sinit(); 71 72 ORIENT(fp, -1); 73 74 fp->pub._r = 0; /* largely a convenience for callers */ 75 76 /* SysV does not make this test; take it out for compatibility */ 77 if (fp->pub._flags & __SEOF) 78 return (EOF); 79 80 /* if not already reading, have to be reading and writing */ 81 if ((fp->pub._flags & __SRD) == 0) { 82 if ((fp->pub._flags & __SRW) == 0) { 83 errno = EBADF; 84 fp->pub._flags |= __SERR; 85 return (EOF); 86 } 87 /* switch to reading */ 88 if (fp->pub._flags & __SWR) { 89 if (__sflush(fp)) 90 return (EOF); 91 fp->pub._flags &= ~__SWR; 92 fp->pub._w = 0; 93 fp->pub._lbfsize = 0; 94 } 95 fp->pub._flags |= __SRD; 96 } else { 97 /* 98 * We were reading. If there is an ungetc buffer, 99 * we must have been reading from that. Drop it, 100 * restoring the previous buffer (if any). If there 101 * is anything in that buffer, return. 102 */ 103 if (HASUB(fp)) { 104 FREEUB(fp); 105 if ((fp->pub._r = fp->_ur) != 0) { 106 fp->pub._p = fp->_up; 107 return (0); 108 } 109 } 110 } 111 112 if (fp->_bf._base == NULL) 113 __smakebuf(fp); 114 115 /* 116 * Before reading from a line buffered or unbuffered file, 117 * flush all line buffered output files, per the ANSI C 118 * standard. 119 */ 120 if (fp->pub._flags & (__SLBF|__SNBF)) { 121 /* Ignore this file in _fwalk to avoid potential deadlock. */ 122 fp->pub._flags |= __SIGN; 123 _fwalk(lflush); 124 fp->pub._flags &= ~__SIGN; 125 126 /* Now flush this file without locking it. */ 127 if ((fp->pub._flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) 128 __sflush(fp); 129 } 130 fp->pub._p = fp->_bf._base; 131 fp->pub._r = _sread(fp, (char *)fp->pub._p, fp->_bf._size); 132 fp->pub._flags &= ~__SMOD; /* buffer contents are again pristine */ 133 if (fp->pub._r <= 0) { 134 if (fp->pub._r == 0) 135 fp->pub._flags |= __SEOF; 136 else { 137 fp->pub._r = 0; 138 fp->pub._flags |= __SERR; 139 } 140 return (EOF); 141 } 142 return (0); 143 } 144