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 1.3 2003/11/12 20:21:25 eirikn 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(fp) 63 register FILE *fp; 64 { 65 66 /* make sure stdio is set up */ 67 if (!__sdidinit) 68 __sinit(); 69 70 fp->_r = 0; /* largely a convenience for callers */ 71 72 /* SysV does not make this test; take it out for compatibility */ 73 if (fp->_flags & __SEOF) 74 return (EOF); 75 76 /* if not already reading, have to be reading and writing */ 77 if ((fp->_flags & __SRD) == 0) { 78 if ((fp->_flags & __SRW) == 0) { 79 errno = EBADF; 80 fp->_flags |= __SERR; 81 return (EOF); 82 } 83 /* switch to reading */ 84 if (fp->_flags & __SWR) { 85 if (__sflush(fp)) 86 return (EOF); 87 fp->_flags &= ~__SWR; 88 fp->_w = 0; 89 fp->_lbfsize = 0; 90 } 91 fp->_flags |= __SRD; 92 } else { 93 /* 94 * We were reading. If there is an ungetc buffer, 95 * we must have been reading from that. Drop it, 96 * restoring the previous buffer (if any). If there 97 * is anything in that buffer, return. 98 */ 99 if (HASUB(fp)) { 100 FREEUB(fp); 101 if ((fp->_r = fp->_ur) != 0) { 102 fp->_p = fp->_up; 103 return (0); 104 } 105 } 106 } 107 108 if (fp->_bf._base == NULL) 109 __smakebuf(fp); 110 111 /* 112 * Before reading from a line buffered or unbuffered file, 113 * flush all line buffered output files, per the ANSI C 114 * standard. 115 */ 116 if (fp->_flags & (__SLBF|__SNBF)) 117 (void) _fwalk(lflush); 118 fp->_p = fp->_bf._base; 119 fp->_r = (*fp->_read)(fp->_cookie, (char *)fp->_p, fp->_bf._size); 120 fp->_flags &= ~__SMOD; /* buffer contents are again pristine */ 121 if (fp->_r <= 0) { 122 if (fp->_r == 0) 123 fp->_flags |= __SEOF; 124 else { 125 fp->_r = 0; 126 fp->_flags |= __SERR; 127 } 128 return (EOF); 129 } 130 return (0); 131 } 132