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/*
* base_device.c
*
* Return the "base device" given a particular device; this is used to
* assure that we only fsck one partition on a particular drive at any
* one time. Otherwise, the disk heads will be seeking all over the
* place. If the base device can not be determined, return NULL.
*
* The base_device() function returns an allocated string which must
* be freed.
*
* Written by Theodore Ts'o, <tytso@mit.edu>
*
* Copyright (C) 2000 Theodore Ts'o.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Public
* License.
* %End-Header%
*/
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include "busybox.h"
#ifdef CONFIG_FEATURE_DEVFS
/*
* Required for the uber-silly devfs /dev/ide/host1/bus2/target3/lun3
* pathames.
*/
static const char *devfs_hier[] = {
"host", "bus", "target", "lun", 0
};
#endif
char *base_device(const char *device)
{
char *str, *cp;
#ifdef CONFIG_FEATURE_DEVFS
const char **hier, *disk;
int len;
#endif
cp = str = bb_xstrdup(device);
/* Skip over /dev/; if it's not present, give up. */
if (strncmp(cp, "/dev/", 5) != 0)
goto errout;
cp += 5;
#if 0 /* this is for old stuff no one uses anymore ? */
/* Skip over /dev/dsk/... */
if (strncmp(cp, "dsk/", 4) == 0)
cp += 4;
#endif
/*
* For md devices, we treat them all as if they were all
* on one disk, since we don't know how to parallelize them.
*/
if (cp[0] == 'm' && cp[1] == 'd') {
*(cp+2) = 0;
return str;
}
/* Handle DAC 960 devices */
if (strncmp(cp, "rd/", 3) == 0) {
cp += 3;
if (cp[0] != 'c' || cp[2] != 'd' ||
!isdigit(cp[1]) || !isdigit(cp[3]))
goto errout;
*(cp+4) = 0;
return str;
}
/* Now let's handle /dev/hd* and /dev/sd* devices.... */
if ((cp[0] == 'h' || cp[0] == 's') && (cp[1] == 'd')) {
cp += 2;
/* If there's a single number after /dev/hd, skip it */
if (isdigit(*cp))
cp++;
/* What follows must be an alpha char, or give up */
if (!isalpha(*cp))
goto errout;
*(cp + 1) = 0;
return str;
}
#ifdef CONFIG_FEATURE_DEVFS
/* Now let's handle devfs (ugh) names */
len = 0;
if (strncmp(cp, "ide/", 4) == 0)
len = 4;
if (strncmp(cp, "scsi/", 5) == 0)
len = 5;
if (len) {
cp += len;
/*
* Now we proceed down the expected devfs hierarchy.
* i.e., .../host1/bus2/target3/lun4/...
* If we don't find the expected token, followed by
* some number of digits at each level, abort.
*/
for (hier = devfs_hier; *hier; hier++) {
len = strlen(*hier);
if (strncmp(cp, *hier, len) != 0)
goto errout;
cp += len;
while (*cp != '/' && *cp != 0) {
if (!isdigit(*cp))
goto errout;
cp++;
}
cp++;
}
*(cp - 1) = 0;
return str;
}
/* Now handle devfs /dev/disc or /dev/disk names */
disk = 0;
if (strncmp(cp, "discs/", 6) == 0)
disk = "disc";
else if (strncmp(cp, "disks/", 6) == 0)
disk = "disk";
if (disk) {
cp += 6;
if (strncmp(cp, disk, 4) != 0)
goto errout;
cp += 4;
while (*cp != '/' && *cp != 0) {
if (!isdigit(*cp))
goto errout;
cp++;
}
*cp = 0;
return str;
}
#endif
errout:
free(str);
return NULL;
}
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