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 * @(#)refill.c 8.1 (Berkeley) 6/4/93 37 * $FreeBSD: src/lib/libc/stdio/refill.c,v 1.8.2.1 2001/03/05 11:27:49 obrien Exp $ 38 * $DragonFly: src/lib/libc/stdio/refill.c,v 1.10 2005/11/20 11:07:30 swildner Exp $ 39 */ 40 41 #include <errno.h> 42 #include <stdio.h> 43 #include <stdlib.h> 44 45 #include "local.h" 46 #include "priv_stdio.h" 47 48 static int lflush (FILE *); 49 50 static int 51 lflush(FILE *fp) 52 { 53 54 if ((fp->pub._flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) 55 return (__sflush(fp)); 56 return (0); 57 } 58 59 /* 60 * Refill a stdio buffer. 61 * Return EOF on eof or error, 0 otherwise. 62 */ 63 int 64 __srefill(FILE *fp) 65 { 66 67 /* make sure stdio is set up */ 68 if (!__sdidinit) 69 __sinit(); 70 71 fp->pub._r = 0; /* largely a convenience for callers */ 72 73 /* SysV does not make this test; take it out for compatibility */ 74 if (fp->pub._flags & __SEOF) 75 return (EOF); 76 77 /* if not already reading, have to be reading and writing */ 78 if ((fp->pub._flags & __SRD) == 0) { 79 if ((fp->pub._flags & __SRW) == 0) { 80 errno = EBADF; 81 fp->pub._flags |= __SERR; 82 return (EOF); 83 } 84 /* switch to reading */ 85 if (fp->pub._flags & __SWR) { 86 if (__sflush(fp)) 87 return (EOF); 88 fp->pub._flags &= ~__SWR; 89 fp->pub._w = 0; 90 fp->pub._lbfsize = 0; 91 } 92 fp->pub._flags |= __SRD; 93 } else { 94 /* 95 * We were reading. If there is an ungetc buffer, 96 * we must have been reading from that. Drop it, 97 * restoring the previous buffer (if any). If there 98 * is anything in that buffer, return. 99 */ 100 if (HASUB(fp)) { 101 FREEUB(fp); 102 if ((fp->pub._r = fp->_ur) != 0) { 103 fp->pub._p = fp->_up; 104 return (0); 105 } 106 } 107 } 108 109 if (fp->_bf._base == NULL) 110 __smakebuf(fp); 111 112 /* 113 * Before reading from a line buffered or unbuffered file, 114 * flush all line buffered output files, per the ANSI C 115 * standard. 116 */ 117 if (fp->pub._flags & (__SLBF|__SNBF)) 118 _fwalk(lflush); 119 fp->pub._p = fp->_bf._base; 120 fp->pub._r = (*fp->_read)(fp->_cookie, (char *)fp->pub._p, fp->_bf._size); 121 fp->pub._flags &= ~__SMOD; /* buffer contents are again pristine */ 122 if (fp->pub._r <= 0) { 123 if (fp->pub._r == 0) 124 fp->pub._flags |= __SEOF; 125 else { 126 fp->pub._r = 0; 127 fp->pub._flags |= __SERR; 128 } 129 return (EOF); 130 } 131 return (0); 132 } 133