26d4f5e969
A more elegant way of obtaining a name of a character device by its file descriptor on FreeBSD, is to use the FIODGNAME ioctl. Because a valid file descriptor implies a file descriptor is visible in /dev, it will always resolve a valid device name. I'm adding a more friendly wrapper for this ioctl, called fdevname(). It is a lot easier to use than devname() and also has better error handling. When a device name cannot be resolved, it will just return NULL instead of a generated device name that makes no sense. Discussed with: kib
55 lines
1.8 KiB
C
55 lines
1.8 KiB
C
/*-
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* Copyright (c) 2009 Ed Schouten <ed@FreeBSD.org>
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* All rights reserved.
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "namespace.h"
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#include <sys/param.h>
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#include <sys/ioctl.h>
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#include "un-namespace.h"
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char *
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fdevname_r(int fd, char *buf, int len)
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{
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struct fiodgname_arg fgn;
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fgn.buf = buf;
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fgn.len = len;
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if (_ioctl(fd, FIODGNAME, &fgn) == -1)
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return (NULL);
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return (buf);
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}
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char *
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fdevname(int fd)
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{
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static char buf[SPECNAMELEN + 1];
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return (fdevname_r(fd, buf, sizeof(buf)));
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}
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