1 /* $NetBSD: fdopen.c,v 1.15 2008/03/13 15:40:00 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 1.15 2008/03/13 15:40:00 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 58 __weak_alias(fdopen,_fdopen) 59 #endif 60 61 FILE * 62 fdopen(fd, mode) 63 int fd; 64 const char *mode; 65 { 66 FILE *fp; 67 int flags, oflags, fdflags, tmp; 68 69 _DIAGASSERT(fd != -1); 70 71 /* 72 * File descriptors are a full int, but _file is only a short. 73 * If we get a valid file descriptor that is greater or equal to 74 * USHRT_MAX, then the fd will get sign-extended into an 75 * invalid file descriptor. Handle this case by failing the 76 * open. (We treat the short as unsigned, and special-case -1). 77 */ 78 if (fd >= USHRT_MAX) { 79 errno = EMFILE; 80 return NULL; 81 } 82 83 if ((flags = __sflags(mode, &oflags)) == 0) 84 return (NULL); 85 86 /* Make sure the mode the user wants is a subset of the actual mode. */ 87 if ((fdflags = fcntl(fd, F_GETFL, 0)) < 0) 88 return (NULL); 89 tmp = fdflags & O_ACCMODE; 90 if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE))) { 91 errno = EINVAL; 92 return (NULL); 93 } 94 95 if (oflags & O_NONBLOCK) { 96 struct stat st; 97 if (fstat(fd, &st) == -1) { 98 return (NULL); 99 } 100 if (!S_ISREG(st.st_mode)) { 101 errno = EFTYPE; 102 return (NULL); 103 } 104 } 105 106 if ((fp = __sfp()) == NULL) 107 return (NULL); 108 fp->_flags = flags; 109 /* 110 * If opened for appending, but underlying descriptor does not have 111 * O_APPEND bit set, assert __SAPP so that __swrite() will lseek to 112 * end before each write. 113 */ 114 if ((oflags & O_APPEND) && !(fdflags & O_APPEND)) 115 fp->_flags |= __SAPP; 116 fp->_file = fd; 117 fp->_cookie = fp; 118 fp->_read = __sread; 119 fp->_write = __swrite; 120 fp->_seek = __sseek; 121 fp->_close = __sclose; 122 return (fp); 123 } 124