| 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 | * 4. Neither the name of the University nor the names of its contributors␊ |
| 17 | * may be used to endorse or promote products derived from this software␊ |
| 18 | * without specific prior written permission.␊ |
| 19 | *␊ |
| 20 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND␊ |
| 21 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE␊ |
| 22 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE␊ |
| 23 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE␊ |
| 24 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL␊ |
| 25 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS␊ |
| 26 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)␊ |
| 27 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT␊ |
| 28 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY␊ |
| 29 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF␊ |
| 30 | * SUCH DAMAGE.␊ |
| 31 | */␊ |
| 32 | ␊ |
| 33 | #if defined(LIBC_SCCS) && !defined(lint)␊ |
| 34 | static char sccsid[] = "@(#)makebuf.c␉8.1 (Berkeley) 6/4/93";␊ |
| 35 | #endif /* LIBC_SCCS and not lint */␊ |
| 36 | #include <sys/cdefs.h>␊ |
| 37 | //__FBSDID("$FreeBSD: src/lib/libc/stdio/makebuf.c,v 1.6 2007/01/09 00:28:07 imp Exp $");␊ |
| 38 | ␊ |
| 39 | #include "namespace.h"␊ |
| 40 | #include <sys/types.h>␊ |
| 41 | #include "stdio.h"␊ |
| 42 | #include "un-namespace.h"␊ |
| 43 | #include "stat.h"␊ |
| 44 | ␊ |
| 45 | #include "local.h"␊ |
| 46 | ␊ |
| 47 | #define MAXBUFSIZE␉(1 << 16)␊ |
| 48 | #define TTYBUFSIZE␉4096␊ |
| 49 | ␊ |
| 50 | /*␊ |
| 51 | * Allocate a file buffer, or switch to unbuffered I/O.␊ |
| 52 | * Per the ANSI C standard, ALL tty devices default to line buffered.␊ |
| 53 | *␊ |
| 54 | * As a side effect, we set __SOPT or __SNPT (en/dis-able fseek␊ |
| 55 | * optimisation) right after the _fstat() that finds the buffer size.␊ |
| 56 | */␊ |
| 57 | void␊ |
| 58 | __smakebuf(fp)␊ |
| 59 | ␉FILE *fp;␊ |
| 60 | {␊ |
| 61 | ␉void *p;␊ |
| 62 | ␉int flags;␊ |
| 63 | ␉size_t size;␊ |
| 64 | ␉int couldbetty;␊ |
| 65 | ␊ |
| 66 | ␉if (fp->_flags & __SNBF) {␊ |
| 67 | ␉␉fp->_bf._base = fp->_p = fp->_nbuf;␊ |
| 68 | ␉␉fp->_bf._size = 1;␊ |
| 69 | ␉␉return;␊ |
| 70 | ␉}␊ |
| 71 | ␉flags = __swhatbuf(fp, &size, &couldbetty);␊ |
| 72 | ␉␊ |
| 73 | ␊ |
| 74 | ␉if ((p = malloc(size)) == NULL) {␊ |
| 75 | ␉␉fp->_flags |= __SNBF;␊ |
| 76 | ␉␉fp->_bf._base = fp->_p = fp->_nbuf;␊ |
| 77 | ␉␉fp->_bf._size = 1;␊ |
| 78 | ␉␉return;␊ |
| 79 | ␉}␊ |
| 80 | ␉__cleanup = _cleanup;␊ |
| 81 | ␉flags |= __SMBF;␊ |
| 82 | ␉fp->_bf._base = fp->_p = p;␊ |
| 83 | ␉fp->_bf._size = size;␊ |
| 84 | ␉fp->_flags |= flags;␊ |
| 85 | }␊ |
| 86 | ␊ |
| 87 | /*␊ |
| 88 | * Internal routine to determine `proper' buffering for a file.␊ |
| 89 | */␊ |
| 90 | int␊ |
| 91 | __swhatbuf(fp, bufsize, couldbetty)␊ |
| 92 | ␉FILE *fp;␊ |
| 93 | ␉size_t *bufsize;␊ |
| 94 | ␉int *couldbetty;␊ |
| 95 | {␊ |
| 96 | ␉//struct stat st;␊ |
| 97 | *couldbetty = 0;␊ |
| 98 | ␊ |
| 99 | ␉if (fp->_file < 0 /*|| _fstat(fp->_file, &st) < 0*/) {␊ |
| 100 | ␉␉//*couldbetty = 0;␊ |
| 101 | ␉␉*bufsize = BUFSIZ;␊ |
| 102 | ␉␉return (__SNPT);␊ |
| 103 | ␉}␊ |
| 104 | ␊ |
| 105 | ␉/* could be a tty iff it is a character device */␊ |
| 106 | /*␊ |
| 107 | ␉*couldbetty = (st.st_mode & S_IFMT) == S_IFCHR;␊ |
| 108 | ␉if (st.st_blksize <= 0) {␊ |
| 109 | ␉␉*bufsize = BUFSIZ;␊ |
| 110 | ␉␉return (__SNPT);␊ |
| 111 | ␉}␊ |
| 112 | */␊ |
| 113 | ␉/*␊ |
| 114 | ␉ * Optimise fseek() only if it is a regular file. (The test for␊ |
| 115 | ␉ * __sseek is mainly paranoia.) It is safe to set _blksize␊ |
| 116 | ␉ * unconditionally; it will only be used if __SOPT is also set.␊ |
| 117 | ␉ */␊ |
| 118 | ␉//fp->_blksize = *bufsize = st.st_blksize > MAXBUFSIZE ? MAXBUFSIZE : st.st_blksize;␊ |
| 119 | fp->_blksize = *bufsize = MAXBUFSIZE ;␊ |
| 120 | ␉return (/*(st.st_mode & S_IFMT) == S_IFREG &&*/ fp->_seek == __sseek ?␊ |
| 121 | ␉ __SOPT : __SNPT);␊ |
| 122 | }␊ |
| 123 | |
