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 <limits.h> 48 #include <stdio.h> 49 #include <stdlib.h> 50 #include "un-namespace.h" 51 52 #include "libc_private.h" 53 #include "local.h" 54 55 static int lflush __P((FILE *)); 56 57 static int 58 lflush(FILE *fp) 59 { 60 int ret = 0; 61 62 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) { 63 FLOCKFILE(fp); 64 ret = __sflush(fp); 65 FUNLOCKFILE(fp); 66 } 67 return (ret); 68 } 69 70 /* 71 * Refill a stdio buffer. 72 * Return EOF on eof or error, 0 otherwise. 73 */ 74 int 75 __srefill(FILE *fp) 76 { 77 78 /* make sure stdio is set up */ 79 if (!__sdidinit) 80 __sinit(); 81 82 fp->_r = 0; /* largely a convenience for callers */ 83 84 /* SysV does not make this test; take it out for compatibility */ 85 if (fp->_flags & __SEOF) 86 return (EOF); 87 88 /* if not already reading, have to be reading and writing */ 89 if ((fp->_flags & __SRD) == 0) { 90 if ((fp->_flags & __SRW) == 0) { 91 errno = EBADF; 92 fp->_flags |= __SERR; 93 return (EOF); 94 } 95 /* switch to reading */ 96 if (fp->_flags & __SWR) { 97 if (__sflush(fp)) 98 return (EOF); 99 fp->_flags &= ~__SWR; 100 fp->_w = 0; 101 fp->_lbfsize = 0; 102 } 103 fp->_flags |= __SRD; 104 } else { 105 /* 106 * We were reading. If there is an ungetc buffer, 107 * we must have been reading from that. Drop it, 108 * restoring the previous buffer (if any). If there 109 * is anything in that buffer, return. 110 */ 111 if (HASUB(fp)) { 112 FREEUB(fp); 113 if ((fp->_r = fp->_ur) != 0) { 114 fp->_p = fp->_extra->_up; 115 return (0); 116 } 117 } 118 } 119 120 if (fp->_bf._base == NULL) 121 __smakebuf(fp); 122 123 /* 124 * Before reading from a line buffered or unbuffered file, 125 * flush all line buffered output files, per the ANSI C 126 * standard. 127 */ 128 if (fp->_flags & (__SLBF|__SNBF)) { 129 /* Ignore this file in _fwalk to avoid potential deadlock. */ 130 fp->_flags |= __SIGN; 131 (void) _fwalk(lflush); 132 fp->_flags &= ~__SIGN; 133 134 /* Now flush this file without locking it. */ 135 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) 136 __sflush(fp); 137 } 138 fp->_p = fp->_bf._base; 139 fp->_r = (*fp->_read)(fp->_cookie, (char *)fp->_p, fp->_bf._size); 140 fp->_flags &= ~__SMOD; /* buffer contents are again pristine */ 141 if (fp->_r <= 0) { 142 if (fp->_r == 0) 143 fp->_flags |= __SEOF; 144 else { 145 err: 146 fp->_r = 0; 147 fp->_flags |= __SERR; 148 fp->_flags &= ~__SOFF; 149 } 150 return (EOF); 151 } else if (fp->_flags & __SOFF) { 152 if (fp->_offset > OFF_MAX - fp->_r) { 153 errno = EOVERFLOW; 154 goto err; 155 } else 156 fp->_offset += fp->_r; 157 } 158 return (0); 159 } 160