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 * Copyright 2022 OmniOS Community Edition (OmniOSce) Association. 33 */ 34 35 36 #define _LARGEFILE64_SOURCE 1 37 38 #include "lint.h" 39 #include "file64.h" 40 #include <errno.h> 41 #include <stdlib.h> 42 #include <stdio.h> 43 #include <sys/types.h> 44 #include <sys/stat.h> 45 #include "stdiom.h" 46 47 /* 48 * If buffer space has been pre-allocated use it otherwise malloc space. 49 * PUSHBACK causes the base pointer to be bumped forward. At least 4 bytes 50 * of pushback are required to meet international specifications. 51 * Extra space at the end of the buffer allows for synchronization problems. 52 * If malloc() fails stdio bails out; assumption being the system is in trouble. 53 * Associate a buffer with stream; return NULL on error. 54 */ 55 Uchar * 56 _findbuf(FILE *iop) 57 { 58 int fd = _get_fd(iop); 59 Uchar *buf; 60 int size = BUFSIZ; 61 Uchar *endbuf; 62 int tty, err; 63 64 /* 65 * isatty(3C) will set errno as a side-effect of returning 0. Hide this 66 * from callers so that they do not see errno changing for no apparent 67 * reason. 68 */ 69 err = errno; 70 tty = isatty(fd); 71 errno = err; 72 73 if (iop->_flag & _IONBF) { /* need a small buffer, at least */ 74 trysmall: 75 size = _SMBFSZ - PUSHBACK; 76 if (fd >= 0 && fd < _NFILE) { 77 buf = _smbuf[fd]; 78 } else if ((buf = (Uchar *)malloc(_SMBFSZ * sizeof (Uchar))) != 79 NULL) { 80 iop->_flag |= _IOMYBUF; 81 } 82 } else if (fd >= 0 && fd < 2 && tty != 0) { 83 /* Use special buffers for standard in and standard out */ 84 buf = (fd == 0) ? _sibuf : _sobuf; 85 } else { 86 87 /* 88 * The operating system can tell us the right size for a buffer; 89 * avoid 0-size buffers as returned for some special files 90 * (doors). Use the default buffer size for memory streams. 91 */ 92 struct stat64 stbuf; 93 94 if (fd != -1 && fstat64(fd, &stbuf) == 0 && stbuf.st_blksize > 95 0) { 96 size = stbuf.st_blksize; 97 } 98 99 if ((buf = (Uchar *)malloc(sizeof (Uchar)*(size+_SMBFSZ))) != 100 NULL) { 101 iop->_flag |= _IOMYBUF; 102 } else { 103 goto trysmall; 104 } 105 } 106 if (buf == NULL) 107 return (NULL); /* malloc() failed */ 108 iop->_base = buf + PUSHBACK; /* bytes for pushback */ 109 iop->_ptr = buf + PUSHBACK; 110 endbuf = iop->_base + size; 111 _setbufend(iop, endbuf); 112 if (!(iop->_flag & _IONBF) && tty != 0) 113 iop->_flag |= _IOLBF; 114 return (endbuf); 115 } 116