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 "namespace.h" 46 #include <errno.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include "un-namespace.h" 50 51 #include "libc_private.h" 52 #include "local.h" 53 54 static int lflush __P((FILE *)); 55 56 static int 57 lflush(FILE *fp) 58 { 59 int ret = 0; 60 61 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) { 62 FLOCKFILE(fp); 63 ret = __sflush(fp); 64 FUNLOCKFILE(fp); 65 } 66 return (ret); 67 } 68 69 /* 70 * Refill a stdio buffer. 71 * Return EOF on eof or error, 0 otherwise. 72 */ 73 int 74 __srefill(FILE *fp) 75 { 76 /* make sure stdio is set up */ 77 if (!__sdidinit) 78 __sinit(); 79 80 fp->_r = 0; /* largely a convenience for callers */ 81 82 /* SysV does not make this test; take it out for compatibility */ 83 if (fp->_flags & __SEOF) 84 return (EOF); 85 86 /* if not already reading, have to be reading and writing */ 87 if ((fp->_flags & __SRD) == 0) { 88 if ((fp->_flags & __SRW) == 0) { 89 errno = EBADF; 90 fp->_flags |= __SERR; 91 return (EOF); 92 } 93 /* switch to reading */ 94 if (fp->_flags & __SWR) { 95 if (__sflush(fp)) 96 return (EOF); 97 fp->_flags &= ~__SWR; 98 fp->_w = 0; 99 fp->_lbfsize = 0; 100 } 101 fp->_flags |= __SRD; 102 } else { 103 /* 104 * We were reading. If there is an ungetc buffer, 105 * we must have been reading from that. Drop it, 106 * restoring the previous buffer (if any). If there 107 * is anything in that buffer, return. 108 */ 109 if (HASUB(fp)) { 110 FREEUB(fp); 111 if ((fp->_r = fp->_ur) != 0) { 112 fp->_p = fp->_extra->_up; 113 return (0); 114 } 115 } 116 } 117 118 if (fp->_bf._base == NULL) 119 __smakebuf(fp); 120 121 /* 122 * Before reading from a line buffered or unbuffered file, 123 * flush all line buffered output files, per the ANSI C 124 * standard. 125 */ 126 if (fp->_flags & (__SLBF|__SNBF)) { 127 /* Ignore this file in _fwalk to avoid potential deadlock. */ 128 fp->_flags |= __SIGN; 129 (void) _fwalk(lflush); 130 fp->_flags &= ~__SIGN; 131 132 /* Now flush this file without locking it. */ 133 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) 134 __sflush(fp); 135 } 136 fp->_p = fp->_bf._base; 137 fp->_r = (*fp->_read)(fp->_cookie, (char *)fp->_p, fp->_bf._size); 138 fp->_flags &= ~__SMOD; /* buffer contents are again pristine */ 139 if (fp->_r <= 0) { 140 if (fp->_r == 0) 141 fp->_flags |= __SEOF; 142 else { 143 fp->_r = 0; 144 fp->_flags |= __SERR; 145 } 146 return (EOF); 147 } 148 return (0); 149 } 150