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[] = "@(#)fopen.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 <sys/stat.h> 42 #include <fcntl.h> 43 #include <unistd.h> 44 #include <stdio.h> 45 #include <errno.h> 46 #include <limits.h> 47 #include "un-namespace.h" 48 49 #include "local.h" 50 51 FILE * 52 fopen(const char * __restrict file, const char * __restrict mode) 53 { 54 FILE *fp; 55 int f; 56 int flags, oflags; 57 58 if ((flags = __sflags(mode, &oflags)) == 0) 59 return (NULL); 60 if ((fp = __sfp()) == NULL) 61 return (NULL); 62 if ((f = _open(file, oflags, DEFFILEMODE)) < 0) { 63 fp->_flags = 0; /* release */ 64 return (NULL); 65 } 66 /* 67 * File descriptors are a full int, but _file is only a short. 68 * If we get a valid file descriptor that is greater than 69 * SHRT_MAX, then the fd will get sign-extended into an 70 * invalid file descriptor. Handle this case by failing the 71 * open. 72 */ 73 if (f > SHRT_MAX) { 74 fp->_flags = 0; /* release */ 75 _close(f); 76 errno = EMFILE; 77 return (NULL); 78 } 79 fp->_file = f; 80 fp->_flags = flags; 81 fp->_cookie = fp; 82 fp->_read = __sread; 83 fp->_write = __swrite; 84 fp->_seek = __sseek; 85 fp->_close = __sclose; 86 /* 87 * When opening in append mode, even though we use O_APPEND, 88 * we need to seek to the end so that ftell() gets the right 89 * answer. If the user then alters the seek pointer, or 90 * the file extends, this will fail, but there is not much 91 * we can do about this. (We could set __SAPP and check in 92 * fseek and ftell.) 93 */ 94 if (oflags & O_APPEND) { 95 fp->_flags2 |= __S2OAP; 96 (void)_sseek(fp, (fpos_t)0, SEEK_END); 97 } 98 return (fp); 99 } 100