1 /* $NetBSD: refill.c,v 1.11 1999/09/20 04:39:32 lukem Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #if defined(LIBC_SCCS) && !defined(lint) 41 #if 0 42 static char sccsid[] = "@(#)refill.c 8.1 (Berkeley) 6/4/93"; 43 #else 44 __RCSID("$NetBSD: refill.c,v 1.11 1999/09/20 04:39:32 lukem Exp $"); 45 #endif 46 #endif /* LIBC_SCCS and not lint */ 47 48 #include <assert.h> 49 #include <errno.h> 50 #include <stdio.h> 51 #include <stdlib.h> 52 #include "local.h" 53 #include "reentrant.h" 54 55 #ifdef _REENT 56 extern rwlock_t __sfp_lock; 57 #endif 58 59 static int lflush __P((FILE *)); 60 61 static int 62 lflush(fp) 63 FILE *fp; 64 { 65 66 _DIAGASSERT(fp != NULL); 67 68 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) 69 return (__sflush(fp)); 70 return (0); 71 } 72 73 /* 74 * Refill a stdio buffer. 75 * Return EOF on eof or error, 0 otherwise. 76 */ 77 int 78 __srefill(fp) 79 FILE *fp; 80 { 81 82 _DIAGASSERT(fp != NULL); 83 84 /* make sure stdio is set up */ 85 if (!__sdidinit) 86 __sinit(); 87 88 fp->_r = 0; /* largely a convenience for callers */ 89 90 /* SysV does not make this test; take it out for compatibility */ 91 if (fp->_flags & __SEOF) 92 return (EOF); 93 94 /* if not already reading, have to be reading and writing */ 95 if ((fp->_flags & __SRD) == 0) { 96 if ((fp->_flags & __SRW) == 0) { 97 errno = EBADF; 98 return (EOF); 99 } 100 /* switch to reading */ 101 if (fp->_flags & __SWR) { 102 if (__sflush(fp)) 103 return (EOF); 104 fp->_flags &= ~__SWR; 105 fp->_w = 0; 106 fp->_lbfsize = 0; 107 } 108 fp->_flags |= __SRD; 109 } else { 110 /* 111 * We were reading. If there is an ungetc buffer, 112 * we must have been reading from that. Drop it, 113 * restoring the previous buffer (if any). If there 114 * is anything in that buffer, return. 115 */ 116 if (HASUB(fp)) { 117 FREEUB(fp); 118 if ((fp->_r = fp->_ur) != 0) { 119 fp->_p = fp->_up; 120 return (0); 121 } 122 } 123 } 124 125 if (fp->_bf._base == NULL) 126 __smakebuf(fp); 127 128 /* 129 * Before reading from a line buffered or unbuffered file, 130 * flush all line buffered output files, per the ANSI C 131 * standard. 132 */ 133 if (fp->_flags & (__SLBF|__SNBF)) { 134 rwlock_rdlock(&__sfp_lock); 135 (void) _fwalk(lflush); 136 rwlock_unlock(&__sfp_lock); 137 } 138 fp->_p = fp->_bf._base; 139 fp->_r = (*fp->_read)(fp->_cookie, (char *)fp->_p, fp->_bf._size); 140 fp->_flags &= ~__SMOD; /* buffer contents are again pristine */ 141 if (fp->_r <= 0) { 142 if (fp->_r == 0) 143 fp->_flags |= __SEOF; 144 else { 145 fp->_r = 0; 146 fp->_flags |= __SERR; 147 } 148 return (EOF); 149 } 150 return (0); 151 } 152