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 "namespace.h" 39 #include <errno.h> 40 #include <stdio.h> 41 #include <stdlib.h> 42 #include "un-namespace.h" 43 44 #include "libc_private.h" 45 #include "local.h" 46 47 static int lflush(FILE *); 48 49 static int 50 lflush(FILE *fp) 51 { 52 int ret = 0; 53 54 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) { 55 FLOCKFILE_CANCELSAFE(fp); 56 ret = __sflush(fp); 57 FUNLOCKFILE_CANCELSAFE(); 58 } 59 return (ret); 60 } 61 62 /* 63 * Refill a stdio buffer. 64 * Return EOF on eof or error, 0 otherwise. 65 */ 66 int 67 __srefill(FILE *fp) 68 { 69 70 /* make sure stdio is set up */ 71 if (!__sdidinit) 72 __sinit(); 73 74 ORIENT(fp, -1); 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 /* Ignore this file in _fwalk to avoid potential deadlock. */ 124 fp->_flags |= __SIGN; 125 (void) _fwalk(lflush); 126 fp->_flags &= ~__SIGN; 127 128 /* Now flush this file without locking it. */ 129 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) 130 __sflush(fp); 131 } 132 fp->_p = fp->_bf._base; 133 fp->_r = _sread(fp, (char *)fp->_p, fp->_bf._size); 134 fp->_flags &= ~__SMOD; /* buffer contents are again pristine */ 135 if (fp->_r <= 0) { 136 if (fp->_r == 0) 137 fp->_flags |= __SEOF; 138 else { 139 fp->_r = 0; 140 fp->_flags |= __SERR; 141 } 142 return (EOF); 143 } 144 return (0); 145 } 146