1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 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 #if defined(LIBC_SCCS) && !defined(lint) 36 static char sccsid[] = "@(#)refill.c 8.1 (Berkeley) 6/4/93"; 37 #endif /* LIBC_SCCS and not lint */ 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 40 41 #include "namespace.h" 42 #include <errno.h> 43 #include <stdio.h> 44 #include <stdlib.h> 45 #include "un-namespace.h" 46 47 #include "libc_private.h" 48 #include "local.h" 49 50 static int lflush(FILE *); 51 52 static int 53 lflush(FILE *fp) 54 { 55 int ret = 0; 56 57 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) { 58 FLOCKFILE_CANCELSAFE(fp); 59 ret = __sflush(fp); 60 FUNLOCKFILE_CANCELSAFE(); 61 } 62 return (ret); 63 } 64 65 /* 66 * Refill a stdio buffer. 67 * Return EOF on eof or error, 0 otherwise. 68 */ 69 int 70 __srefill(FILE *fp) 71 { 72 73 /* make sure stdio is set up */ 74 if (!__sdidinit) 75 __sinit(); 76 77 ORIENT(fp, -1); 78 79 fp->_r = 0; /* largely a convenience for callers */ 80 81 /* SysV does not make this test; take it out for compatibility */ 82 if (fp->_flags & __SEOF) 83 return (EOF); 84 85 /* if not already reading, have to be reading and writing */ 86 if ((fp->_flags & __SRD) == 0) { 87 if ((fp->_flags & __SRW) == 0) { 88 errno = EBADF; 89 fp->_flags |= __SERR; 90 return (EOF); 91 } 92 /* switch to reading */ 93 if (fp->_flags & __SWR) { 94 if (__sflush(fp)) 95 return (EOF); 96 fp->_flags &= ~__SWR; 97 fp->_w = 0; 98 fp->_lbfsize = 0; 99 } 100 fp->_flags |= __SRD; 101 } else { 102 /* 103 * We were reading. If there is an ungetc buffer, 104 * we must have been reading from that. Drop it, 105 * restoring the previous buffer (if any). If there 106 * is anything in that buffer, return. 107 */ 108 if (HASUB(fp)) { 109 FREEUB(fp); 110 if ((fp->_r = fp->_ur) != 0) { 111 fp->_p = fp->_up; 112 return (0); 113 } 114 } 115 } 116 117 if (fp->_bf._base == NULL) 118 __smakebuf(fp); 119 120 /* 121 * Before reading from a line buffered or unbuffered file, 122 * flush all line buffered output files, per the ANSI C 123 * standard. 124 */ 125 if (fp->_flags & (__SLBF|__SNBF)) { 126 /* Ignore this file in _fwalk to avoid potential deadlock. */ 127 fp->_flags |= __SIGN; 128 (void) _fwalk(lflush); 129 fp->_flags &= ~__SIGN; 130 131 /* Now flush this file without locking it. */ 132 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) 133 __sflush(fp); 134 } 135 fp->_p = fp->_bf._base; 136 fp->_r = _sread(fp, (char *)fp->_p, fp->_bf._size); 137 fp->_flags &= ~__SMOD; /* buffer contents are again pristine */ 138 if (fp->_r <= 0) { 139 if (fp->_r == 0) 140 fp->_flags |= __SEOF; 141 else { 142 fp->_r = 0; 143 fp->_flags |= __SERR; 144 } 145 return (EOF); 146 } 147 return (0); 148 } 149