1 /* $OpenBSD: refill.c,v 1.11 2009/11/09 00:18:27 kurt 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 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) 43 return (__sflush_locked(fp)); /* ignored... */ 44 return (0); 45 } 46 47 /* 48 * Refill a stdio buffer. 49 * Return EOF on eof or error, 0 otherwise. 50 */ 51 int 52 __srefill(FILE *fp) 53 { 54 fp->_r = 0; /* largely a convenience for callers */ 55 56 #if !defined(__ANDROID__) 57 /* SysV does not make this test; take it out for compatibility */ 58 if (fp->_flags & __SEOF) 59 return (EOF); 60 #endif 61 62 /* if not already reading, have to be reading and writing */ 63 if ((fp->_flags & __SRD) == 0) { 64 if ((fp->_flags & __SRW) == 0) { 65 errno = EBADF; 66 fp->_flags |= __SERR; 67 return (EOF); 68 } 69 /* switch to reading */ 70 if (fp->_flags & __SWR) { 71 if (__sflush(fp)) 72 return (EOF); 73 fp->_flags &= ~__SWR; 74 fp->_w = 0; 75 fp->_lbfsize = 0; 76 } 77 fp->_flags |= __SRD; 78 } else { 79 /* 80 * We were reading. If there is an ungetc buffer, 81 * we must have been reading from that. Drop it, 82 * restoring the previous buffer (if any). If there 83 * is anything in that buffer, return. 84 */ 85 if (HASUB(fp)) { 86 FREEUB(fp); 87 if ((fp->_r = fp->_ur) != 0) { 88 fp->_p = fp->_up; 89 return (0); 90 } 91 } 92 } 93 94 if (fp->_bf._base == NULL) 95 __smakebuf(fp); 96 97 /* 98 * Before reading from a line buffered or unbuffered file, 99 * flush all line buffered output files, per the ANSI C 100 * standard. 101 */ 102 if (fp->_flags & (__SLBF|__SNBF)) { 103 /* Ignore this file in _fwalk to avoid potential deadlock. */ 104 fp->_flags |= __SIGN; 105 (void) _fwalk(lflush); 106 fp->_flags &= ~__SIGN; 107 108 /* Now flush this file without locking it. */ 109 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) 110 __sflush(fp); 111 } 112 fp->_p = fp->_bf._base; 113 fp->_r = (*fp->_read)(fp->_cookie, (char *)fp->_p, fp->_bf._size); 114 fp->_flags &= ~__SMOD; /* buffer contents are again pristine */ 115 if (fp->_r <= 0) { 116 if (fp->_r == 0) 117 fp->_flags |= __SEOF; 118 else { 119 fp->_r = 0; 120 fp->_flags |= __SERR; 121 } 122 return (EOF); 123 } 124 return (0); 125 } 126
