freebsd-dev/lib/libc/gen/devname.c
Poul-Henning Kamp 8d25eb2c3a Add code to devname(3) so it can find the names of devices which
were not present when dev_mkdb(8) was run.

First the dev_mkdb(8) database is searched, this caters for non-DEVFS
cases where people have renamed a device.

If that fails we ask the kernel using sysctl kern.devname if the device
driver has put a name in the dev_t.  This covers DEVFS cloned devices.

If that also fails we format a string which isn't entirely useless.
2000-09-09 11:39:59 +00:00

121 lines
3.5 KiB
C

/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* $FreeBSD$
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)devname.c 8.2 (Berkeley) 4/29/95";
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
#include <sys/sysctl.h>
#include <db.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
static char *
xdevname(dev, type)
dev_t dev;
mode_t type;
{
struct {
mode_t type;
dev_t dev;
} bkey;
static DB *db;
static int failure;
DBT data, key;
if (!db && !failure &&
!(db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL))) {
warn("warning: %s", _PATH_DEVDB);
failure = 1;
}
if (failure)
return (NULL);
/*
* Keys are a mode_t followed by a dev_t. The former is the type of
* the file (mode & S_IFMT), the latter is the st_rdev field. Be
* sure to clear any padding that may be found in bkey.
*/
memset(&bkey, 0, sizeof(bkey));
bkey.dev = dev;
bkey.type = type;
key.data = &bkey;
key.size = sizeof(bkey);
return ((db->get)(db, &key, &data, 0) ? NULL : (char *)data.data);
}
char *
devname(dev, type)
dev_t dev;
mode_t type;
{
static char buf[30]; /* XXX: pick up from <sys/conf.h> */
int i, j;
char *r;
/* First check the DB file. */
r = xdevname(dev, type);
if (r != NULL)
return (r);
/* Then ask the kernel. */
if ((type & S_IFMT) == S_IFCHR) {
j = sizeof(buf);
i = sysctlbyname("kern.devname", buf, &j, &dev, sizeof (dev));
if (i == 0)
return (buf);
}
/* Finally just format it */
r = buf;
if (minor(dev) > 255) {
sprintf(buf, "#%c%d:0x%x",
(type & S_IFMT) == S_IFCHR ? 'C' : 'B',
major(dev), minor(dev));
} else {
sprintf(buf, "#%c%d:%d",
(type & S_IFMT) == S_IFCHR ? 'C' : 'B',
major(dev), minor(dev));
}
return (r);
}