| | 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 | static char sccsid[] = "@(#)refill.c 8.1 (Berkeley) 6/4/93"; |
| | 39 | #endif /* LIBC_SCCS and not lint */ |
| | 40 | #include <sys/cdefs.h> |
| | 41 | __FBSDID("$FreeBSD: src/lib/libc/stdio/refill.c,v 1.18 2002/08/13 09:30:41 tjr Exp $"); |
| | 42 | |
| | 43 | #include "namespace.h" |
| | 44 | #include <errno.h> |
| | 45 | #include <stdio.h> |
| | 46 | #include <stdlib.h> |
| | 47 | #include "un-namespace.h" |
| | 48 | |
| | 49 | #include "libc_private.h" |
| | 50 | #include "local.h" |
| | 51 | |
| | 52 | static int lflush(FILE *); |
| | 53 | |
| | 54 | static int |
| | 55 | lflush(FILE *fp) |
| | 56 | { |
| | 57 | int ret = 0; |
| | 58 | |
| | 59 | if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) { |
| | 60 | FLOCKFILE(fp); |
| | 61 | ret = __sflush(fp); |
| | 62 | FUNLOCKFILE(fp); |
| | 63 | } |
| | 64 | return (ret); |
| | 65 | } |
| | 66 | |
| | 67 | /* |
| | 68 | * Refill a stdio buffer. |
| | 69 | * Return EOF on eof or error, 0 otherwise. |
| | 70 | */ |
| | 71 | int |
| | 72 | __srefill(FILE *fp) |
| | 73 | { |
| | 74 | |
| | 75 | /* make sure stdio is set up */ |
| | 76 | if (!__sdidinit) |
| | 77 | __sinit(); |
| | 78 | |
| | 79 | ORIENT(fp, -1); |
| | 80 | |
| | 81 | fp->_r = 0; /* largely a convenience for callers */ |
| | 82 | |
| | 83 | /* SysV does not make this test; take it out for compatibility */ |
| | 84 | if (fp->_flags & __SEOF) |
| | 85 | return (EOF); |
| | 86 | |
| | 87 | /* if not already reading, have to be reading and writing */ |
| | 88 | if ((fp->_flags & __SRD) == 0) { |
| | 89 | if ((fp->_flags & __SRW) == 0) { |
| | 90 | errno = EBADF; |
| | 91 | fp->_flags |= __SERR; |
| | 92 | return (EOF); |
| | 93 | } |
| | 94 | /* switch to reading */ |
| | 95 | if (fp->_flags & __SWR) { |
| | 96 | if (__sflush(fp)) |
| | 97 | return (EOF); |
| | 98 | fp->_flags &= ~__SWR; |
| | 99 | fp->_w = 0; |
| | 100 | fp->_lbfsize = 0; |
| | 101 | } |
| | 102 | fp->_flags |= __SRD; |
| | 103 | } else { |
| | 104 | /* |
| | 105 | * We were reading. If there is an ungetc buffer, |
| | 106 | * we must have been reading from that. Drop it, |
| | 107 | * restoring the previous buffer (if any). If there |
| | 108 | * is anything in that buffer, return. |
| | 109 | */ |
| | 110 | if (HASUB(fp)) { |
| | 111 | FREEUB(fp); |
| | 112 | if ((fp->_r = fp->_ur) != 0) { |
| | 113 | fp->_p = fp->_extra->_up; |
| | 114 | return (0); |
| | 115 | } |
| | 116 | } |
| | 117 | } |
| | 118 | |
| | 119 | if (fp->_bf._base == NULL) |
| | 120 | __smakebuf(fp); |
| | 121 | |
| | 122 | /* |
| | 123 | * Before reading from a line buffered or unbuffered file, |
| | 124 | * flush all line buffered output files, per the ANSI C |
| | 125 | * standard. |
| | 126 | */ |
| | 127 | if (fp->_flags & (__SLBF|__SNBF)) { |
| | 128 | /* Ignore this file in _fwalk to avoid potential deadlock. */ |
| | 129 | fp->_flags |= __SIGN; |
| | 130 | (void) _fwalk(lflush); |
| | 131 | fp->_flags &= ~__SIGN; |
| | 132 | |
| | 133 | /* Now flush this file without locking it. */ |
| | 134 | if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) |
| | 135 | __sflush(fp); |
| | 136 | } |
| | 137 | fp->_p = fp->_bf._base; |
| | 138 | fp->_r = _sread(fp, (char *)fp->_p, fp->_bf._size); |
| | 139 | fp->_flags &= ~__SMOD; /* buffer contents are again pristine */ |
| | 140 | if (fp->_r <= 0) { |
| | 141 | if (fp->_r == 0) |
| | 142 | fp->_flags |= __SEOF; |
| | 143 | else { |
| | 144 | fp->_r = 0; |
| | 145 | fp->_flags |= __SERR; |
| | 146 | } |
| | 147 | return (EOF); |
| | 148 | } |
| | 149 | return (0); |
| | 150 | } |
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