1 /* $NetBSD: refill.c,v 1.13 2003/08/07 16:43:30 agc 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. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)refill.c 8.1 (Berkeley) 6/4/93"; 39 #else 40 __RCSID("$NetBSD: refill.c,v 1.13 2003/08/07 16:43:30 agc Exp $"); 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include <assert.h> 45 #include <errno.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include "reentrant.h" 49 #include "local.h" 50 51 #ifdef _REENTRANT 52 extern rwlock_t __sfp_lock; 53 #endif 54 55 static int lflush __P((FILE *)); 56 57 static int 58 lflush(fp) 59 FILE *fp; 60 { 61 62 _DIAGASSERT(fp != NULL); 63 64 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) 65 return (__sflush(fp)); 66 return (0); 67 } 68 69 /* 70 * Refill a stdio buffer. 71 * Return EOF on eof or error, 0 otherwise. 72 */ 73 int 74 __srefill(fp) 75 FILE *fp; 76 { 77 78 _DIAGASSERT(fp != NULL); 79 80 /* make sure stdio is set up */ 81 if (!__sdidinit) 82 __sinit(); 83 84 fp->_r = 0; /* largely a convenience for callers */ 85 86 /* SysV does not make this test; take it out for compatibility */ 87 if (fp->_flags & __SEOF) 88 return (EOF); 89 90 /* if not already reading, have to be reading and writing */ 91 if ((fp->_flags & __SRD) == 0) { 92 if ((fp->_flags & __SRW) == 0) { 93 errno = EBADF; 94 return (EOF); 95 } 96 /* switch to reading */ 97 if (fp->_flags & __SWR) { 98 if (__sflush(fp)) 99 return (EOF); 100 fp->_flags &= ~__SWR; 101 fp->_w = 0; 102 fp->_lbfsize = 0; 103 } 104 fp->_flags |= __SRD; 105 } else { 106 /* 107 * We were reading. If there is an ungetc buffer, 108 * we must have been reading from that. Drop it, 109 * restoring the previous buffer (if any). If there 110 * is anything in that buffer, return. 111 */ 112 if (HASUB(fp)) { 113 FREEUB(fp); 114 if ((fp->_r = fp->_ur) != 0) { 115 fp->_p = fp->_up; 116 return (0); 117 } 118 } 119 } 120 121 if (fp->_bf._base == NULL) 122 __smakebuf(fp); 123 124 /* 125 * Before reading from a line buffered or unbuffered file, 126 * flush all line buffered output files, per the ANSI C 127 * standard. 128 */ 129 if (fp->_flags & (__SLBF|__SNBF)) { 130 rwlock_rdlock(&__sfp_lock); 131 (void) _fwalk(lflush); 132 rwlock_unlock(&__sfp_lock); 133 } 134 fp->_p = fp->_bf._base; 135 fp->_r = (*fp->_read)(fp->_cookie, (char *)fp->_p, fp->_bf._size); 136 fp->_flags &= ~__SMOD; /* buffer contents are again pristine */ 137 if (fp->_r <= 0) { 138 if (fp->_r == 0) 139 fp->_flags |= __SEOF; 140 else { 141 fp->_r = 0; 142 fp->_flags |= __SERR; 143 } 144 return (EOF); 145 } 146 return (0); 147 } 148