1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1988 AT&T */ 28 /* All Rights Reserved */ 29 30 /* 31 * Copyright 2020 Robert Mustacchi 32 */ 33 34 35 #define _LARGEFILE64_SOURCE 1 36 37 #include "lint.h" 38 #include "file64.h" 39 #include <stdlib.h> 40 #include <stdio.h> 41 #include <sys/types.h> 42 #include <sys/stat.h> 43 #include "stdiom.h" 44 45 /* 46 * If buffer space has been pre-allocated use it otherwise malloc space. 47 * PUSHBACK causes the base pointer to be bumped forward. At least 4 bytes 48 * of pushback are required to meet international specifications. 49 * Extra space at the end of the buffer allows for synchronization problems. 50 * If malloc() fails stdio bails out; assumption being the system is in trouble. 51 * Associate a buffer with stream; return NULL on error. 52 */ 53 Uchar * 54 _findbuf(FILE *iop) 55 { 56 int fd = _get_fd(iop); 57 Uchar *buf; 58 int size = BUFSIZ; 59 Uchar *endbuf; 60 int tty = -1; 61 62 if (iop->_flag & _IONBF) { /* need a small buffer, at least */ 63 trysmall: 64 size = _SMBFSZ - PUSHBACK; 65 if (fd >= 0 && fd < _NFILE) { 66 buf = _smbuf[fd]; 67 } else if ((buf = (Uchar *)malloc(_SMBFSZ * sizeof (Uchar))) != 68 NULL) { 69 iop->_flag |= _IOMYBUF; 70 } 71 } else if (fd >= 0 && fd < 2 && (tty = isatty(fd))) { 72 /* Use special buffers for standard in and standard out */ 73 buf = (fd == 0) ? _sibuf : _sobuf; 74 } else { 75 76 /* 77 * The operating system can tell us the right size for a buffer; 78 * avoid 0-size buffers as returned for some special files 79 * (doors). Use the default buffer size for memory streams. 80 */ 81 struct stat64 stbuf; 82 83 if (fd != -1 && fstat64(fd, &stbuf) == 0 && stbuf.st_blksize > 84 0) { 85 size = stbuf.st_blksize; 86 } 87 88 if ((buf = (Uchar *)malloc(sizeof (Uchar)*(size+_SMBFSZ))) != 89 NULL) { 90 iop->_flag |= _IOMYBUF; 91 } else { 92 goto trysmall; 93 } 94 } 95 if (buf == NULL) 96 return (NULL); /* malloc() failed */ 97 iop->_base = buf + PUSHBACK; /* bytes for pushback */ 98 iop->_ptr = buf + PUSHBACK; 99 endbuf = iop->_base + size; 100 _setbufend(iop, endbuf); 101 if (!(iop->_flag & _IONBF) && ((tty != -1) ? tty : isatty(fd))) 102 iop->_flag |= _IOLBF; 103 return (endbuf); 104 } 105