1 /* $OpenBSD: fdopen.c,v 1.10 2019/06/28 13:32:42 deraadt 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 /* _file is only a short */ 49 if (fd > SHRT_MAX) { 50 errno = EMFILE; 51 return (NULL); 52 } 53 54 if ((flags = __sflags(mode, &oflags)) == 0) 55 return (NULL); 56 57 /* Make sure the mode the user wants is a subset of the actual mode. */ 58 if ((fdflags = fcntl(fd, F_GETFL)) == -1) 59 return (NULL); 60 tmp = fdflags & O_ACCMODE; 61 if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE))) { 62 errno = EINVAL; 63 return (NULL); 64 } 65 66 if ((fp = __sfp()) == NULL) 67 return (NULL); 68 fp->_flags = flags; 69 70 /* 71 * If opened for appending, but underlying descriptor does not have 72 * O_APPEND bit set, assert __SAPP so that __swrite() will lseek to 73 * end before each write. 74 */ 75 if ((oflags & O_APPEND) && !(fdflags & O_APPEND)) 76 fp->_flags |= __SAPP; 77 78 /* 79 * If close-on-exec was requested, then turn it on if not already 80 */ 81 if ((oflags & O_CLOEXEC) && !((tmp = fcntl(fd, F_GETFD)) & FD_CLOEXEC)) 82 fcntl(fd, F_SETFD, tmp | FD_CLOEXEC); 83 84 fp->_file = fd; 85 fp->_cookie = fp; 86 fp->_read = __sread; 87 fp->_write = __swrite; 88 fp->_seek = __sseek; 89 fp->_close = __sclose; 90 return (fp); 91 } 92 DEF_WEAK(fdopen); 93