fdopen.c revision 176628
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) 34static char sccsid[] = "@(#)fdopen.c 8.1 (Berkeley) 6/4/93"; 35#endif /* LIBC_SCCS and not lint */ 36#include <sys/cdefs.h> 37__FBSDID("$FreeBSD: head/lib/libc/stdio/fdopen.c 176628 2008-02-27 19:02:02Z jhb $"); 38 39#include "namespace.h" 40#include <sys/types.h> 41#include <fcntl.h> 42#include <unistd.h> 43#include <stdio.h> 44#include <errno.h> 45#include "un-namespace.h" 46#include "local.h" 47 48FILE * 49fdopen(fd, mode) 50 int fd; 51 const char *mode; 52{ 53 FILE *fp; 54 static int nofile; 55 int flags, oflags, fdflags, tmp; 56 57 if (nofile == 0) 58 nofile = getdtablesize(); 59 60 /* 61 * File descriptors are a full int, but _file is only a short. 62 * If we get a valid file descriptor that is greater than 63 * SHRT_MAX, then the fd will get sign-extended into an 64 * invalid file descriptor. Handle this case by failing the 65 * open. 66 */ 67 if (fd > SHRT_MAX) { 68 errno = EMFILE; 69 return (NULL); 70 } 71 72 if ((flags = __sflags(mode, &oflags)) == 0) 73 return (NULL); 74 75 /* Make sure the mode the user wants is a subset of the actual mode. */ 76 if ((fdflags = _fcntl(fd, F_GETFL, 0)) < 0) 77 return (NULL); 78 tmp = fdflags & O_ACCMODE; 79 if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE))) { 80 errno = EINVAL; 81 return (NULL); 82 } 83 84 if ((fp = __sfp()) == NULL) 85 return (NULL); 86 fp->_flags = flags; 87 /* 88 * If opened for appending, but underlying descriptor does not have 89 * O_APPEND bit set, assert __SAPP so that __swrite() caller 90 * will _sseek() to the end before write. 91 */ 92 if ((oflags & O_APPEND) && !(fdflags & O_APPEND)) 93 fp->_flags |= __SAPP; 94 fp->_file = fd; 95 fp->_cookie = fp; 96 fp->_read = __sread; 97 fp->_write = __swrite; 98 fp->_seek = __sseek; 99 fp->_close = __sclose; 100 return (fp); 101} 102