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 1.6 2003/06/02 20:18:37 millert 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(fp) 44 FILE *fp; 45 { 46 47 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) 48 return (__sflush(fp)); 49 return (0); 50 } 51 52 /* 53 * Refill a stdio buffer. 54 * Return EOF on eof or error, 0 otherwise. 55 */ 56 int 57 __srefill(fp) 58 register FILE *fp; 59 { 60 61 /* make sure stdio is set up */ 62 if (!__sdidinit) 63 __sinit(); 64 65 fp->_r = 0; /* largely a convenience for callers */ 66 67 /* SysV does not make this test; take it out for compatibility */ 68 if (fp->_flags & __SEOF) 69 return (EOF); 70 71 /* if not already reading, have to be reading and writing */ 72 if ((fp->_flags & __SRD) == 0) { 73 if ((fp->_flags & __SRW) == 0) { 74 errno = EBADF; 75 fp->_flags |= __SERR; 76 return (EOF); 77 } 78 /* switch to reading */ 79 if (fp->_flags & __SWR) { 80 if (__sflush(fp)) 81 return (EOF); 82 fp->_flags &= ~__SWR; 83 fp->_w = 0; 84 fp->_lbfsize = 0; 85 } 86 fp->_flags |= __SRD; 87 } else { 88 /* 89 * We were reading. If there is an ungetc buffer, 90 * we must have been reading from that. Drop it, 91 * restoring the previous buffer (if any). If there 92 * is anything in that buffer, return. 93 */ 94 if (HASUB(fp)) { 95 FREEUB(fp); 96 if ((fp->_r = fp->_ur) != 0) { 97 fp->_p = fp->_up; 98 return (0); 99 } 100 } 101 } 102 103 if (fp->_bf._base == NULL) 104 __smakebuf(fp); 105 106 /* 107 * Before reading from a line buffered or unbuffered file, 108 * flush all line buffered output files, per the ANSI C 109 * standard. 110 */ 111 if (fp->_flags & (__SLBF|__SNBF)) 112 (void) _fwalk(lflush); 113 fp->_p = fp->_bf._base; 114 fp->_r = (*fp->_read)(fp->_cookie, (char *)fp->_p, fp->_bf._size); 115 fp->_flags &= ~__SMOD; /* buffer contents are again pristine */ 116 if (fp->_r <= 0) { 117 if (fp->_r == 0) 118 fp->_flags |= __SEOF; 119 else { 120 fp->_r = 0; 121 fp->_flags |= __SERR; 122 } 123 return (EOF); 124 } 125 return (0); 126 } 127