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/*
* Copyright (c) 2004-2005, 2007, 2010, 2012-2015, 2017-2022
* Todd C. Miller <Todd.Miller@sudo.ws>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#ifdef HAVE_LINUX_CLOSE_RANGE_H
#include <linux/close_range.h>
#endif
#include <sys/syscall.h>
#include <limits.h>
#include "unistd.h"
#ifndef OPEN_MAX
# define OPEN_MAX 256
#endif
#if defined(HAVE_CLOSE_RANGE)
void
closefrom(int lowfd)
{
close_range(lowfd, ~0U, 0);
}
#else
/*
* Close all file descriptors greater than or equal to lowfd.
* This is the expensive (fallback) method.
*/
void
closefrom(int lowfd)
{
long fd, maxfd;
/*
* Fall back on sysconf(_SC_OPEN_MAX). This is equivalent to
* checking the RLIMIT_NOFILE soft limit. It is possible for
* there to be open file descriptors past this limit but there's
* not much we can do about that since the hard limit may be
* RLIM_INFINITY (LLONG_MAX or ULLONG_MAX on modern systems).
*/
maxfd = sysconf(_SC_OPEN_MAX);
if (maxfd < OPEN_MAX)
maxfd = OPEN_MAX;
/* Make sure we didn't get RLIM_INFINITY as the upper limit. */
if (maxfd > INT_MAX)
maxfd = INT_MAX;
for (fd = lowfd; fd < maxfd; fd++) {
(void)close((int)fd);
}
}
#endif
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