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| Rev | Author | Line No. | Line |
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| 2 | pj | 1 | /*- |
| 2 | * Copyright (c) 1990, 1993 |
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| 3 | * The Regents of the University of California. All rights reserved. |
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| 4 | * |
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| 5 | * This code is derived from software contributed to Berkeley by |
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| 6 | * Chris Torek. |
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| 7 | * |
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| 8 | * Redistribution and use in source and binary forms, with or without |
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| 9 | * modification, are permitted provided that the following conditions |
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| 10 | * are met: |
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| 11 | * 1. Redistributions of source code must retain the above copyright |
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| 12 | * notice, this list of conditions and the following disclaimer. |
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| 13 | * 2. Redistributions in binary form must reproduce the above copyright |
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| 14 | * notice, this list of conditions and the following disclaimer in the |
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| 15 | * documentation and/or other materials provided with the distribution. |
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| 16 | * 3. All advertising materials mentioning features or use of this software |
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| 17 | * must display the following acknowledgement: |
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| 18 | * This product includes software developed by the University of |
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| 19 | * California, Berkeley and its contributors. |
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| 20 | * 4. Neither the name of the University nor the names of its contributors |
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| 21 | * may be used to endorse or promote products derived from this software |
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| 22 | * without specific prior written permission. |
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| 23 | * |
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| 24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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| 25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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| 26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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| 27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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| 28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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| 29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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| 30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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| 31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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| 32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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| 33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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| 34 | * SUCH DAMAGE. |
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| 35 | */ |
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| 36 | |||
| 37 | #if defined(LIBC_SCCS) && !defined(lint) |
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| 38 | static char sccsid[] = "@(#)makebuf.c 8.1 (Berkeley) 6/4/93"; |
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| 39 | #endif /* LIBC_SCCS and not lint */ |
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| 40 | |||
| 41 | #include <sys/types.h> |
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| 42 | #include <sys/stat.h> |
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| 43 | #include <unistd.h> |
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| 44 | #include <stdio.h> |
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| 45 | #include <stdlib.h> |
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| 46 | #include "local.h" |
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| 47 | |||
| 48 | /* |
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| 49 | * Allocate a file buffer, or switch to unbuffered I/O. |
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| 50 | * Per the ANSI C standard, ALL tty devices default to line buffered. |
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| 51 | * |
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| 52 | * As a side effect, we set __SOPT or __SNPT (en/dis-able fseek |
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| 53 | * optimisation) right after the fstat() that finds the buffer size. |
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| 54 | */ |
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| 55 | void |
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| 56 | __smakebuf(fp) |
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| 57 | register FILE *fp; |
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| 58 | { |
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| 59 | register void *p; |
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| 60 | register int flags; |
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| 61 | size_t size; |
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| 62 | int couldbetty; |
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| 63 | |||
| 64 | if (fp->_flags & __SNBF) { |
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| 65 | fp->_bf._base = fp->_p = fp->_nbuf; |
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| 66 | fp->_bf._size = 1; |
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| 67 | return; |
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| 68 | } |
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| 69 | flags = __swhatbuf(fp, &size, &couldbetty); |
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| 70 | if ((p = malloc(size)) == NULL) { |
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| 71 | fp->_flags |= __SNBF; |
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| 72 | fp->_bf._base = fp->_p = fp->_nbuf; |
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| 73 | fp->_bf._size = 1; |
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| 74 | return; |
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| 75 | } |
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| 76 | __cleanup = _cleanup; |
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| 77 | flags |= __SMBF; |
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| 78 | fp->_bf._base = fp->_p = p; |
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| 79 | fp->_bf._size = size; |
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| 80 | if (couldbetty && isatty(fp->_file)) |
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| 81 | flags |= __SLBF; |
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| 82 | fp->_flags |= flags; |
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| 83 | } |
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| 84 | |||
| 85 | /* |
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| 86 | * Internal routine to determine `proper' buffering for a file. |
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| 87 | */ |
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| 88 | int |
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| 89 | __swhatbuf(fp, bufsize, couldbetty) |
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| 90 | register FILE *fp; |
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| 91 | size_t *bufsize; |
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| 92 | int *couldbetty; |
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| 93 | { |
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| 94 | struct stat st; |
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| 95 | |||
| 96 | if (fp->_file < 0 || fstat(fp->_file, &st) < 0) { |
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| 97 | *couldbetty = 0; |
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| 98 | *bufsize = BUFSIZ; |
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| 99 | return (__SNPT); |
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| 100 | } |
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| 101 | |||
| 102 | /* could be a tty iff it is a character device */ |
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| 103 | *couldbetty = (st.st_mode & S_IFMT) == S_IFCHR; |
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| 104 | if (st.st_blksize <= 0) { |
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| 105 | *bufsize = BUFSIZ; |
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| 106 | return (__SNPT); |
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| 107 | } |
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| 108 | |||
| 109 | /* |
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| 110 | * Optimise fseek() only if it is a regular file. (The test for |
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| 111 | * __sseek is mainly paranoia.) It is safe to set _blksize |
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| 112 | * unconditionally; it will only be used if __SOPT is also set. |
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| 113 | */ |
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| 114 | *bufsize = st.st_blksize; |
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| 115 | fp->_blksize = st.st_blksize; |
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| 116 | return ((st.st_mode & S_IFMT) == S_IFREG && fp->_seek == __sseek ? |
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| 117 | __SOPT : __SNPT); |
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| 118 | } |