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 1.5 2004/06/07 20:35:41 hmp Exp $ 39 */ 40 41 #include <errno.h> 42 #include <stdio.h> 43 #include <stdlib.h> 44 #include "local.h" 45 46 static int lflush (FILE *); 47 48 static int 49 lflush(FILE *fp) 50 { 51 52 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) 53 return (__sflush(fp)); 54 return (0); 55 } 56 57 /* 58 * Refill a stdio buffer. 59 * Return EOF on eof or error, 0 otherwise. 60 */ 61 int 62 __srefill(FILE *fp) 63 { 64 65 /* make sure stdio is set up */ 66 if (!__sdidinit) 67 __sinit(); 68 69 fp->_r = 0; /* largely a convenience for callers */ 70 71 /* SysV does not make this test; take it out for compatibility */ 72 if (fp->_flags & __SEOF) 73 return (EOF); 74 75 /* if not already reading, have to be reading and writing */ 76 if ((fp->_flags & __SRD) == 0) { 77 if ((fp->_flags & __SRW) == 0) { 78 errno = EBADF; 79 fp->_flags |= __SERR; 80 return (EOF); 81 } 82 /* switch to reading */ 83 if (fp->_flags & __SWR) { 84 if (__sflush(fp)) 85 return (EOF); 86 fp->_flags &= ~__SWR; 87 fp->_w = 0; 88 fp->_lbfsize = 0; 89 } 90 fp->_flags |= __SRD; 91 } else { 92 /* 93 * We were reading. If there is an ungetc buffer, 94 * we must have been reading from that. Drop it, 95 * restoring the previous buffer (if any). If there 96 * is anything in that buffer, return. 97 */ 98 if (HASUB(fp)) { 99 FREEUB(fp); 100 if ((fp->_r = fp->_ur) != 0) { 101 fp->_p = fp->_up; 102 return (0); 103 } 104 } 105 } 106 107 if (fp->_bf._base == NULL) 108 __smakebuf(fp); 109 110 /* 111 * Before reading from a line buffered or unbuffered file, 112 * flush all line buffered output files, per the ANSI C 113 * standard. 114 */ 115 if (fp->_flags & (__SLBF|__SNBF)) 116 (void) _fwalk(lflush); 117 fp->_p = fp->_bf._base; 118 fp->_r = (*fp->_read)(fp->_cookie, (char *)fp->_p, fp->_bf._size); 119 fp->_flags &= ~__SMOD; /* buffer contents are again pristine */ 120 if (fp->_r <= 0) { 121 if (fp->_r == 0) 122 fp->_flags |= __SEOF; 123 else { 124 fp->_r = 0; 125 fp->_flags |= __SERR; 126 } 127 return (EOF); 128 } 129 return (0); 130 } 131