freebsd-skq/lib/libnv/common_impl.h
markj 1c1781ccce Ensure that libnv can be used when kern.trap_enotcap=1.
libnv used fcntl(fd, F_GETFL) to test whether fd is a valid file
descriptor.  Aside from being racy, this check requires CAP_FCNTL
rights on fd.  Instead, use fcntl(fd, F_GETFD), which does not require
any capability rights.

Also remove some redundant fd_is_valid() checks to avoid extra system
calls; in many cases we were performing this check immediately before
dup()ing the descriptor.

Reviewed by:	cem, oshogbo (previous version)
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D17963
2018-11-13 20:07:55 +00:00

49 lines
1.7 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2013 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Pawel Jakub Dawidek under sponsorship from
* the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _COMMON_IMPL_H_
#define _COMMON_IMPL_H_
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
static inline bool
fd_is_valid(int fd)
{
return (fcntl(fd, F_GETFD) != -1 || errno != EBADF);
}
#endif /* !_COMMON_IMPL_H_ */