c55d7e868a
them. Thus, any fd whose value is greater than SHRT_MAX is handled incorrectly (the short value is sign-extended when converted to an int). An unpleasant side effect is that if fopen() opens a file and gets a backing fd that is greater than SHRT_MAX, fclose() will fail and the file descriptor will be leaked. Better handle this by fixing fopen(), fdopen(), and freopen() to fail attempts to use a fd greater than SHRT_MAX with EMFILE. At some point in the future we should look at expanding the file descriptor in FILE to an int, but that is a bit complicated due to ABI issues. MFC after: 1 week Discussed on: arch Reviewed by: wollman
102 lines
3.2 KiB
C
102 lines
3.2 KiB
C
/*-
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Chris Torek.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)fdopen.c 8.1 (Berkeley) 6/4/93";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "namespace.h"
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#include <sys/types.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <errno.h>
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#include "un-namespace.h"
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#include "local.h"
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FILE *
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fdopen(fd, mode)
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int fd;
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const char *mode;
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{
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FILE *fp;
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static int nofile;
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int flags, oflags, fdflags, tmp;
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if (nofile == 0)
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nofile = getdtablesize();
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/*
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* File descriptors are a full int, but _file is only a short.
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* If we get a valid file descriptor that is greater than
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* SHRT_MAX, then the fd will get sign-extended into an
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* invalid file descriptor. Handle this case by failing the
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* open.
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*/
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if (fd > SHRT_MAX) {
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errno = EMFILE;
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return (NULL);
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}
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if ((flags = __sflags(mode, &oflags)) == 0)
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return (NULL);
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/* Make sure the mode the user wants is a subset of the actual mode. */
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if ((fdflags = _fcntl(fd, F_GETFL, 0)) < 0)
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return (NULL);
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tmp = fdflags & O_ACCMODE;
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if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE))) {
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errno = EINVAL;
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return (NULL);
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}
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if ((fp = __sfp()) == NULL)
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return (NULL);
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fp->_flags = flags;
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/*
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* If opened for appending, but underlying descriptor does not have
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* O_APPEND bit set, assert __SAPP so that __swrite() caller
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* will _sseek() to the end before write.
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*/
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if ((oflags & O_APPEND) && !(fdflags & O_APPEND))
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fp->_flags |= __SAPP;
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fp->_file = fd;
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fp->_cookie = fp;
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fp->_read = __sread;
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fp->_write = __swrite;
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fp->_seek = __sseek;
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fp->_close = __sclose;
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return (fp);
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}
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