1 /* $NetBSD: fdopen.c,v 1.16 2012/03/15 18:22:30 christos Exp $ */ 2 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 #include <sys/cdefs.h> 36 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)fdopen.c 8.1 (Berkeley) 6/4/93"; 39 #else 40 __RCSID("$NetBSD: fdopen.c,v 1.16 2012/03/15 18:22:30 christos Exp $"); 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include "namespace.h" 45 #include <sys/types.h> 46 47 #include <assert.h> 48 #include <errno.h> 49 #include <fcntl.h> 50 #include <unistd.h> 51 #include <stdio.h> 52 #include <limits.h> 53 54 #include "reentrant.h" 55 #include "local.h" 56 57 #ifdef __weak_alias __weak_alias(fdopen,_fdopen)58 __weak_alias(fdopen,_fdopen) 59 #endif 60 61 FILE * 62 fdopen(int fd, const char *mode) 63 { 64 FILE *fp; 65 int flags, oflags, fdflags, tmp; 66 67 _DIAGASSERT(fd != -1); 68 69 /* 70 * File descriptors are a full int, but _file is only a short. 71 * If we get a valid file descriptor that is greater or equal to 72 * USHRT_MAX, then the fd will get sign-extended into an 73 * invalid file descriptor. Handle this case by failing the 74 * open. (We treat the short as unsigned, and special-case -1). 75 */ 76 if (fd >= USHRT_MAX) { 77 errno = EMFILE; 78 return NULL; 79 } 80 81 if ((flags = __sflags(mode, &oflags)) == 0) 82 return NULL; 83 84 /* Make sure the mode the user wants is a subset of the actual mode. */ 85 if ((fdflags = fcntl(fd, F_GETFL, 0)) < 0) 86 return NULL; 87 tmp = fdflags & O_ACCMODE; 88 if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE))) { 89 errno = EINVAL; 90 return NULL; 91 } 92 93 if (oflags & O_NONBLOCK) { 94 struct stat st; 95 if (fstat(fd, &st) == -1) { 96 return NULL; 97 } 98 if (!S_ISREG(st.st_mode)) { 99 errno = EFTYPE; 100 return NULL; 101 } 102 } 103 104 if ((fp = __sfp()) == NULL) 105 return NULL; 106 fp->_flags = flags; 107 /* 108 * If opened for appending, but underlying descriptor does not have 109 * O_APPEND bit set, assert __SAPP so that __swrite() will lseek to 110 * end before each write. 111 */ 112 if ((oflags & O_APPEND) && !(fdflags & O_APPEND)) 113 fp->_flags |= __SAPP; 114 fp->_file = fd; 115 fp->_cookie = fp; 116 fp->_read = __sread; 117 fp->_write = __swrite; 118 fp->_seek = __sseek; 119 fp->_close = __sclose; 120 return fp; 121 } 122