1 /* $OpenBSD: fdopen.c,v 1.11 2025年08月08日 15:58:53 yasuoka Exp $ */ 2 /*- 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Chris Torek. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34#include <sys/types.h> 35#include <fcntl.h> 36#include <limits.h> 37#include <unistd.h> 38#include <stdio.h> 39#include <errno.h> 40#include "local.h" 41 42 FILE * 43 fdopen(int fd, const char *mode) 44{ 45 FILE *fp; 46 int flags, oflags, fdflags, tmp; 47 48 if ((flags = __sflags(mode, &oflags)) == 0) 49 return (NULL); 50 51 /* Make sure the mode the user wants is a subset of the actual mode. */ 52 if ((fdflags = fcntl(fd, F_GETFL)) == -1) 53 return (NULL); 54 tmp = fdflags & O_ACCMODE; 55 if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE))) { 56 errno = EINVAL; 57 return (NULL); 58 } 59 60 if ((fp = __sfp()) == NULL) 61 return (NULL); 62 fp->_flags = flags; 63 64 /* 65 * If opened for appending, but underlying descriptor does not have 66 * O_APPEND bit set, assert __SAPP so that __swrite() will lseek to 67 * end before each write. 68 */ 69 if ((oflags & O_APPEND) && !(fdflags & O_APPEND)) 70 fp->_flags |= __SAPP; 71 72 /* 73 * If close-on-exec was requested, then turn it on if not already 74 */ 75 if ((oflags & O_CLOEXEC) && !((tmp = fcntl(fd, F_GETFD)) & FD_CLOEXEC)) 76 fcntl(fd, F_SETFD, tmp | FD_CLOEXEC); 77 78 fp->_file = fd; 79 fp->_cookie = fp; 80 fp->_read = __sread; 81 fp->_write = __swrite; 82 fp->_seek = __sseek; 83 fp->_close = __sclose; 84 return (fp); 85} 86 DEF_WEAK(fdopen); 87