busybox/util-linux/volume_id/get_devname.c
Denis Vlasenko 28ea4298e3 volume_id: abort early on read failures.
should help with probing missing fdd's
2009-02-15 05:51:19 +00:00

255 lines
5.4 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Support functions for mounting devices by label/uuid
*
* Copyright (C) 2006 by Jason Schoon <floydpink@gmail.com>
* Some portions cribbed from e2fsprogs, util-linux, dosfstools
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include "volume_id_internal.h"
//#define BLKGETSIZE64 _IOR(0x12,114,size_t)
static struct uuidCache_s {
struct uuidCache_s *next;
// int major, minor;
char *device;
char *label;
char *uc_uuid; /* prefix makes it easier to grep for */
} *uuidCache;
/* Returns !0 on error.
* Otherwise, returns malloc'ed strings for label and uuid
* (and they can't be NULL, although they can be "").
* NB: closes fd. */
static int
get_label_uuid(int fd, char **label, char **uuid)
{
int rv = 1;
uint64_t size;
struct volume_id *vid;
/* fd is owned by vid now */
vid = volume_id_open_node(fd);
if (ioctl(/*vid->*/fd, BLKGETSIZE64, &size) != 0)
size = 0;
if (volume_id_probe_all(vid, /*0,*/ size) != 0)
goto ret;
if (vid->label[0] != '\0' || vid->uuid[0] != '\0') {
*label = xstrndup(vid->label, sizeof(vid->label));
*uuid = xstrndup(vid->uuid, sizeof(vid->uuid));
dbg("found label '%s', uuid '%s' on %s", *label, *uuid, device);
rv = 0;
}
ret:
free_volume_id(vid); /* also closes fd */
return rv;
}
/* NB: we take ownership of (malloc'ed) label and uuid */
static void
uuidcache_addentry(char *device, /*int major, int minor,*/ char *label, char *uuid)
{
struct uuidCache_s *last;
if (!uuidCache) {
last = uuidCache = xzalloc(sizeof(*uuidCache));
} else {
for (last = uuidCache; last->next; last = last->next)
continue;
last->next = xzalloc(sizeof(*uuidCache));
last = last->next;
}
/*last->next = NULL; - xzalloc did it*/
// last->major = major;
// last->minor = minor;
last->device = device;
last->label = label;
last->uc_uuid = uuid;
}
/* If get_label_uuid() on device_name returns success,
* add a cache entry for this device.
* If device node does not exist, it will be temporarily created. */
static int FAST_FUNC
uuidcache_check_device(const char *device,
struct stat *statbuf,
void *userData UNUSED_PARAM,
int depth UNUSED_PARAM)
{
char *uuid = uuid; /* for compiler */
char *label = label;
int fd;
if (!S_ISBLK(statbuf->st_mode))
return TRUE;
fd = open(device, O_RDONLY);
if (fd < 0)
return TRUE;
/* get_label_uuid() closes fd in all cases (success & failure) */
if (get_label_uuid(fd, &label, &uuid) == 0) {
/* uuidcache_addentry() takes ownership of all three params */
uuidcache_addentry(xstrdup(device), /*ma, mi,*/ label, uuid);
}
return TRUE;
}
static void
uuidcache_init(void)
{
if (uuidCache)
return;
/* We were scanning /proc/partitions
* and /proc/sys/dev/cdrom/info here.
* Missed volume managers. I see that "standard" blkid uses these:
* /dev/mapper/control
* /proc/devices
* /proc/evms/volumes
* /proc/lvm/VGs
* This is unacceptably complex. Let's just scan /dev.
* (Maybe add scanning of /sys/block/XXX/dev for devices
* somehow not having their /dev/XXX entries created?) */
recursive_action("/dev", ACTION_RECURSE,
uuidcache_check_device, /* file_action */
NULL, /* dir_action */
NULL, /* userData */
0 /* depth */);
}
#define UUID 1
#define VOL 2
#ifdef UNUSED
static char *
get_spec_by_x(int n, const char *t, int *majorPtr, int *minorPtr)
{
struct uuidCache_s *uc;
uuidcache_init();
uc = uuidCache;
while (uc) {
switch (n) {
case UUID:
if (strcmp(t, uc->uc_uuid) == 0) {
*majorPtr = uc->major;
*minorPtr = uc->minor;
return uc->device;
}
break;
case VOL:
if (strcmp(t, uc->label) == 0) {
*majorPtr = uc->major;
*minorPtr = uc->minor;
return uc->device;
}
break;
}
uc = uc->next;
}
return NULL;
}
static unsigned char
fromhex(char c)
{
if (isdigit(c))
return (c - '0');
return ((c|0x20) - 'a' + 10);
}
static char *
get_spec_by_uuid(const char *s, int *major, int *minor)
{
unsigned char uuid[16];
int i;
if (strlen(s) != 36 || s[8] != '-' || s[13] != '-'
|| s[18] != '-' || s[23] != '-'
) {
goto bad_uuid;
}
for (i = 0; i < 16; i++) {
if (*s == '-')
s++;
if (!isxdigit(s[0]) || !isxdigit(s[1]))
goto bad_uuid;
uuid[i] = ((fromhex(s[0]) << 4) | fromhex(s[1]));
s += 2;
}
return get_spec_by_x(UUID, (char *)uuid, major, minor);
bad_uuid:
fprintf(stderr, _("mount: bad UUID"));
return 0;
}
static char *
get_spec_by_volume_label(const char *s, int *major, int *minor)
{
return get_spec_by_x(VOL, s, major, minor);
}
#endif // UNUSED
/* Used by blkid */
void display_uuid_cache(void)
{
struct uuidCache_s *u;
uuidcache_init();
u = uuidCache;
while (u) {
printf("%s:", u->device);
if (u->label[0])
printf(" LABEL=\"%s\"", u->label);
if (u->uc_uuid[0])
printf(" UUID=\"%s\"", u->uc_uuid);
bb_putchar('\n');
u = u->next;
}
}
/* Used by mount and findfs */
char *get_devname_from_label(const char *spec)
{
struct uuidCache_s *uc;
int spec_len = strlen(spec);
uuidcache_init();
uc = uuidCache;
while (uc) {
// FIXME: empty label ("LABEL=") matches anything??!
if (uc->label[0] && strncmp(spec, uc->label, spec_len) == 0) {
return xstrdup(uc->device);
}
uc = uc->next;
}
return NULL;
}
char *get_devname_from_uuid(const char *spec)
{
struct uuidCache_s *uc;
uuidcache_init();
uc = uuidCache;
while (uc) {
/* case of hex numbers doesn't matter */
if (strcasecmp(spec, uc->uc_uuid) == 0) {
return xstrdup(uc->device);
}
uc = uc->next;
}
return NULL;
}