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