1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #if defined(LIBC_SCCS) && !defined(lint) 36 static char sccsid[] = "@(#)fdopen.c 8.1 (Berkeley) 6/4/93"; 37 #endif /* LIBC_SCCS and not lint */ 38 #include <sys/cdefs.h> 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 <limits.h> 46 #include "un-namespace.h" 47 #include "local.h" 48 49 FILE * 50 fdopen(int fd, const char *mode) 51 { 52 FILE *fp; 53 int flags, oflags, fdflags, tmp; 54 55 /* 56 * File descriptors are a full int, but _file is only a short. 57 * If we get a valid file descriptor that is greater than 58 * SHRT_MAX, then the fd will get sign-extended into an 59 * invalid file descriptor. Handle this case by failing the 60 * open. 61 */ 62 if (fd > SHRT_MAX) { 63 errno = EMFILE; 64 return (NULL); 65 } 66 67 if ((flags = __sflags(mode, &oflags)) == 0) 68 return (NULL); 69 70 /* Make sure the mode the user wants is a subset of the actual mode. */ 71 if ((fdflags = _fcntl(fd, F_GETFL, 0)) < 0) 72 return (NULL); 73 /* Work around incorrect O_ACCMODE. */ 74 tmp = fdflags & (O_ACCMODE | O_EXEC); 75 if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE))) { 76 errno = EINVAL; 77 return (NULL); 78 } 79 80 if ((fp = __sfp()) == NULL) 81 return (NULL); 82 83 if ((oflags & O_CLOEXEC) && _fcntl(fd, F_SETFD, FD_CLOEXEC) == -1) { 84 fp->_flags = 0; 85 return (NULL); 86 } 87 88 fp->_flags = flags; 89 /* 90 * If opened for appending, but underlying descriptor does not have 91 * O_APPEND bit set, assert __SAPP so that __swrite() caller 92 * will _sseek() to the end before write. 93 */ 94 if (fdflags & O_APPEND) 95 fp->_flags2 |= __S2OAP; 96 else if (oflags & O_APPEND) 97 fp->_flags |= __SAPP; 98 fp->_file = fd; 99 fp->_cookie = fp; 100 fp->_read = __sread; 101 fp->_write = __swrite; 102 fp->_seek = __sseek; 103 fp->_close = __sclose; 104 return (fp); 105 } 106