mirror of
https://github.com/rsmarples/dhcpcd.git
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6a6c13f46d
We had compat support in older dhcpcd but we want it faster when linux supports faster, because, you know, fast.
78 lines
2.0 KiB
C
78 lines
2.0 KiB
C
/*
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* SPDX-License-Identifier: ISC
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*
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* Copyright (c) 2004-2005, 2007, 2010, 2012-2015, 2017-2018
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* Todd C. Miller <Todd.Miller@sudo.ws>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "config.h"
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#ifdef __linux__
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# include <sys/syscall.h>
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# if defined(__NR_close_range) && !defined(SYS_close_range)
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# define SYS_close_range __NR_close_range
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# endif
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#endif
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#include <fcntl.h>
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#include <unistd.h>
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#if defined(__linux__) && defined(SYS_close_range)
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static inline int
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sys_close_range(unsigned int fd, unsigned int max_fd, unsigned int flags)
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{
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return (int)syscall(SYS_close_range, fd, max_fd, flags);
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}
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#endif
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/*
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* Close all file descriptors greater than or equal to lowfd.
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* This is the expensive (fallback) method.
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*/
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static int
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closefrom_fallback(int lowfd)
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{
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int fd, maxfd;
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#ifdef _SC_OPEN_MAX
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maxfd = (int)sysconf(_SC_OPEN_MAX);
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#else
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maxfd = getdtablesize();
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#endif
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if (maxfd == -1)
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return -1;
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for (fd = lowfd; fd < maxfd; fd++)
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close(fd);
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return 0;
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}
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/*
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* * Close all file descriptors greater than or equal to lowfd.
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* * We try the fast way first, falling back on the slow method.
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* */
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void
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closefrom(int lowfd)
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{
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#if defined(__linux__) && defined(SYS_close_range)
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if (sys_close_range((unsigned int)lowfd, UINT_MAX, 0) == 0)
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return;
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#endif
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closefrom_fallback(lowfd);
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}
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