1 /* $OpenBSD: refill.c,v 1.8 2005/08/08 08:05:36 espie Exp $ */ 2 /*- 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Chris Torek. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #include <errno.h> 35 #include <stdio.h> 36 #include <stdlib.h> 37 #include "local.h" 38 39 static int 40 lflush(FILE *fp) 41 { 42 43 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) 44 return (__sflush(fp)); 45 return (0); 46 } 47 48 /* 49 * Refill a stdio buffer. 50 * Return EOF on eof or error, 0 otherwise. 51 */ 52 int 53 __srefill(FILE *fp) 54 { 55 56 /* make sure stdio is set up */ 57 if (!__sdidinit) 58 __sinit(); 59 60 fp->_r = 0; /* largely a convenience for callers */ 61 62 /* SysV does not make this test; take it out for compatibility */ 63 if (fp->_flags & __SEOF) 64 return (EOF); 65 66 /* if not already reading, have to be reading and writing */ 67 if ((fp->_flags & __SRD) == 0) { 68 if ((fp->_flags & __SRW) == 0) { 69 errno = EBADF; 70 fp->_flags |= __SERR; 71 return (EOF); 72 } 73 /* switch to reading */ 74 if (fp->_flags & __SWR) { 75 if (__sflush(fp)) 76 return (EOF); 77 fp->_flags &= ~__SWR; 78 fp->_w = 0; 79 fp->_lbfsize = 0; 80 } 81 fp->_flags |= __SRD; 82 } else { 83 /* 84 * We were reading. If there is an ungetc buffer, 85 * we must have been reading from that. Drop it, 86 * restoring the previous buffer (if any). If there 87 * is anything in that buffer, return. 88 */ 89 if (HASUB(fp)) { 90 FREEUB(fp); 91 if ((fp->_r = fp->_ur) != 0) { 92 fp->_p = fp->_up; 93 return (0); 94 } 95 } 96 } 97 98 if (fp->_bf._base == NULL) 99 __smakebuf(fp); 100 101 /* 102 * Before reading from a line buffered or unbuffered file, 103 * flush all line buffered output files, per the ANSI C 104 * standard. 105 */ 106 if (fp->_flags & (__SLBF|__SNBF)) 107 (void) _fwalk(lflush); 108 fp->_p = fp->_bf._base; 109 fp->_r = (*fp->_read)(fp->_cookie, (char *)fp->_p, fp->_bf._size); 110 fp->_flags &= ~__SMOD; /* buffer contents are again pristine */ 111 if (fp->_r <= 0) { 112 if (fp->_r == 0) 113 fp->_flags |= __SEOF; 114 else { 115 fp->_r = 0; 116 fp->_flags |= __SERR; 117 } 118 return (EOF); 119 } 120 return (0); 121 } 122