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. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #if defined(LIBC_SCCS) && !defined(lint) 34 static char rcsid[] = "$OpenBSD: refill.c,v 1.7 2004/09/28 18:12:44 otto Exp $"; 35 #endif /* LIBC_SCCS and not lint */ 36 37 #include <errno.h> 38 #include <stdio.h> 39 #include <stdlib.h> 40 #include "local.h" 41 42 static int 43 lflush(FILE *fp) 44 { 45 46 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) 47 return (__sflush(fp)); 48 return (0); 49 } 50 51 /* 52 * Refill a stdio buffer. 53 * Return EOF on eof or error, 0 otherwise. 54 */ 55 int 56 __srefill(FILE *fp) 57 { 58 59 /* make sure stdio is set up */ 60 if (!__sdidinit) 61 __sinit(); 62 63 fp->_r = 0; /* largely a convenience for callers */ 64 65 /* SysV does not make this test; take it out for compatibility */ 66 if (fp->_flags & __SEOF) 67 return (EOF); 68 69 /* if not already reading, have to be reading and writing */ 70 if ((fp->_flags & __SRD) == 0) { 71 if ((fp->_flags & __SRW) == 0) { 72 errno = EBADF; 73 fp->_flags |= __SERR; 74 return (EOF); 75 } 76 /* switch to reading */ 77 if (fp->_flags & __SWR) { 78 if (__sflush(fp)) 79 return (EOF); 80 fp->_flags &= ~__SWR; 81 fp->_w = 0; 82 fp->_lbfsize = 0; 83 } 84 fp->_flags |= __SRD; 85 } else { 86 /* 87 * We were reading. If there is an ungetc buffer, 88 * we must have been reading from that. Drop it, 89 * restoring the previous buffer (if any). If there 90 * is anything in that buffer, return. 91 */ 92 if (HASUB(fp)) { 93 FREEUB(fp); 94 if ((fp->_r = fp->_ur) != 0) { 95 fp->_p = fp->_up; 96 return (0); 97 } 98 } 99 } 100 101 if (fp->_bf._base == NULL) 102 __smakebuf(fp); 103 104 /* 105 * Before reading from a line buffered or unbuffered file, 106 * flush all line buffered output files, per the ANSI C 107 * standard. 108 */ 109 if (fp->_flags & (__SLBF|__SNBF)) 110 (void) _fwalk(lflush); 111 fp->_p = fp->_bf._base; 112 fp->_r = (*fp->_read)(fp->_cookie, (char *)fp->_p, fp->_bf._size); 113 fp->_flags &= ~__SMOD; /* buffer contents are again pristine */ 114 if (fp->_r <= 0) { 115 if (fp->_r == 0) 116 fp->_flags |= __SEOF; 117 else { 118 fp->_r = 0; 119 fp->_flags |= __SERR; 120 } 121 return (EOF); 122 } 123 return (0); 124 } 125