de78bbbfe8
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
111 lines
3.2 KiB
C
111 lines
3.2 KiB
C
/*
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* Copyright (c) 1988, 1993
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* The Regents of the University of California. 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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* 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[] = "@(#)ttyname.c 8.2 (Berkeley) 1/27/94";
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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 <sys/ioctl.h>
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#include <sys/filio.h>
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#include <fcntl.h>
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#include <dirent.h>
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#include <stdlib.h>
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#include <termios.h>
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#include <unistd.h>
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#include <string.h>
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#include <paths.h>
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#include <errno.h>
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#include "reentrant.h"
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#include "un-namespace.h"
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#include "libc_private.h"
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static char ttyname_buf[sizeof(_PATH_DEV) + MAXNAMLEN];
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static once_t ttyname_init_once = ONCE_INITIALIZER;
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static thread_key_t ttyname_key;
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static int ttyname_keycreated = 0;
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int
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ttyname_r(int fd, char *buf, size_t len)
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{
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size_t used;
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*buf = '\0';
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/* Must be a terminal. */
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if (!isatty(fd))
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return (ENOTTY);
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/* Must have enough room */
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if (len <= sizeof(_PATH_DEV))
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return (ERANGE);
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strcpy(buf, _PATH_DEV);
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used = strlen(buf);
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if (fdevname_r(fd, buf + used, len - used) == NULL)
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return (ENOTTY);
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return (0);
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}
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static void
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ttyname_keycreate(void)
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{
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ttyname_keycreated = (thr_keycreate(&ttyname_key, free) == 0);
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}
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char *
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ttyname(int fd)
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{
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char *buf;
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if (thr_main() != 0)
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buf = ttyname_buf;
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else {
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if (thr_once(&ttyname_init_once, ttyname_keycreate) != 0 ||
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!ttyname_keycreated)
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return (NULL);
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if ((buf = thr_getspecific(ttyname_key)) == NULL) {
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if ((buf = malloc(sizeof ttyname_buf)) == NULL)
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return (NULL);
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if (thr_setspecific(ttyname_key, buf) != 0) {
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free(buf);
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return (NULL);
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}
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}
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}
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if (ttyname_r(fd, buf, sizeof ttyname_buf) != 0)
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return (NULL);
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return (buf);
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}
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