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