busybox/util-linux/volume_id/get_devname.c
Denis Vlasenko de7684a309 support for mount by label (not yet tested)
Also adds findfs applet. Closes bug 1143.
2008-02-18 21:08:49 +00:00

400 lines
8.1 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)
#define PROC_PARTITIONS "/proc/partitions"
#define PROC_CDROMS "/proc/sys/dev/cdrom/info"
#define DEVLABELDIR "/dev"
#define SYS_BLOCK "/sys/block"
static struct uuidCache_s {
struct uuidCache_s *next;
char uuid[16];
char *device;
char *label;
int major, minor;
} *uuidCache;
/* for now, only ext2, ext3 and xfs are supported */
static int
get_label_uuid(const char *device, char **label, char **uuid, int iso_only)
{
int rv = 1;
uint64_t size;
struct volume_id *vid;
vid = volume_id_open_node(device);
if (ioctl(vid->fd, BLKGETSIZE64, &size) != 0) {
size = 0;
}
#if ENABLE_FEATURE_VOLUMEID_ISO9660
if (iso_only ?
volume_id_probe_iso9660(vid, 0) != 0 :
volume_id_probe_all(vid, 0, size) != 0) {
goto ret;
}
#else
if (volume_id_probe_all(vid, 0, size) != 0) {
goto ret;
}
#endif
if (vid->label[0] != '\0') {
*label = xstrndup(vid->label, sizeof(vid->label));
*uuid = xstrndup(vid->uuid, sizeof(vid->uuid));
printf("Found label %s on %s (uuid:%s)\n", *label, device, *uuid);
rv = 0;
}
ret:
free_volume_id(vid);
return rv;
}
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->label = label;
last->device = device;
last->major = major;
last->minor = minor;
memcpy(last->uuid, uuid, sizeof(last->uuid));
}
static void
uuidcache_check_device(const char *device_name, int ma, int mi, int iso_only)
{
char device[110];
char *uuid = NULL, *label = NULL;
char *ptr;
char *deviceDir = NULL;
int mustRemove = 0;
int mustRemoveDir = 0;
int i;
sprintf(device, "%s/%s", DEVLABELDIR, device_name);
if (access(device, F_OK)) {
ptr = device;
i = 0;
while (*ptr)
if (*ptr++ == '/')
i++;
if (i > 2) {
deviceDir = alloca(strlen(device) + 1);
strcpy(deviceDir, device);
ptr = deviceDir + (strlen(device) - 1);
while (*ptr != '/')
*ptr-- = '\0';
if (mkdir(deviceDir, 0644)) {
printf("mkdir: cannot create directory %s: %d\n", deviceDir, errno);
} else {
mustRemoveDir = 1;
}
}
mknod(device, S_IFBLK | 0600, makedev(ma, mi));
mustRemove = 1;
}
if (!get_label_uuid(device, &label, &uuid, iso_only))
uuidcache_addentry(strdup(device), ma, mi,
label, uuid);
if (mustRemove) unlink(device);
if (mustRemoveDir) rmdir(deviceDir);
}
static void
uuidcache_init_partitions(void)
{
char line[100];
int ma, mi;
unsigned long long sz;
FILE *procpt;
int firstPass;
int handleOnFirst;
char *chptr;
procpt = xfopen(PROC_PARTITIONS, "r");
/*
# cat /proc/partitions
major minor #blocks name
8 0 293036184 sda
8 1 6835626 sda1
8 2 1 sda2
8 5 979933 sda5
8 6 15623181 sda6
8 7 97659103 sda7
8 8 171935631 sda8
*/
for (firstPass = 1; firstPass >= 0; firstPass--) {
fseek(procpt, 0, SEEK_SET);
while (fgets(line, sizeof(line), procpt)) {
/* The original version of this code used sscanf, but
diet's sscanf is quite limited */
chptr = line;
if (*chptr != ' ') continue;
chptr++;
ma = bb_strtou(chptr, &chptr, 0);
if (ma < 0) continue;
chptr = skip_whitespace(chptr);
mi = bb_strtou(chptr, &chptr, 0);
if (mi < 0) continue;
chptr = skip_whitespace(chptr);
sz = bb_strtoull(chptr, &chptr, 0);
if ((long long)sz == -1LL) continue;
chptr = skip_whitespace(chptr);
/* skip extended partitions (heuristic: size 1) */
if (sz == 1)
continue;
*strchrnul(chptr, '\n') = '\0';
/* now chptr => device name */
if (!chptr[0])
continue;
/* look only at md devices on first pass */
handleOnFirst = (chptr[0] == 'm' && chptr[1] == 'd');
if (firstPass != handleOnFirst)
continue;
/* heuristic: partition name ends in a digit */
if (isdigit(chptr[strlen(chptr) - 1])) {
uuidcache_check_device(chptr, ma, mi, 0);
}
}
}
fclose(procpt);
}
static int
dev_get_major_minor(char *device_name, int *major, int *minor)
{
char * dev_path;
int fd;
char dev[7];
char *major_ptr, *minor_ptr;
dev_path = alloca(strlen(SYS_BLOCK) + strlen(device_name) + 6);
sprintf(dev_path, "%s/%s/dev", SYS_BLOCK, device_name);
fd = open(dev_path, O_RDONLY);
if (fd < 0) return 1;
full_read(fd, dev, sizeof(dev));
close(fd);
major_ptr = dev;
minor_ptr = strchr(dev, ':');
if (!minor_ptr) return 1;
*minor_ptr++ = '\0';
*major = strtol(major_ptr, NULL, 10);
*minor = strtol(minor_ptr, NULL, 10);
return 0;
}
static void
uuidcache_init_cdroms(void)
{
char line[100];
int ma, mi;
FILE *proccd;
proccd = fopen(PROC_CDROMS, "r");
if (!proccd) {
static smallint warn = 0;
if (!warn) {
warn = 1;
bb_error_msg("mount: could not open %s, so UUID and LABEL "
"conversion cannot be done for CD-Roms.",
PROC_CDROMS);
}
return;
}
while (fgets(line, sizeof(line), proccd)) {
const char *drive_name_string = "drive name:\t\t";
if (!strncmp(line, drive_name_string, strlen(drive_name_string))) {
char *device_name;
device_name = strtok(line + strlen(drive_name_string), "\t\n");
while (device_name) {
dev_get_major_minor(device_name, &ma, &mi);
uuidcache_check_device(device_name, ma, mi, 1);
device_name = strtok(NULL, "\t\n");
}
break;
}
}
fclose(proccd);
}
static void
uuidcache_init(void)
{
if (uuidCache)
return;
uuidcache_init_partitions();
uuidcache_init_cdroms();
}
#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 (!memcmp(t, uc->uuid, sizeof(uc->uuid))) {
*majorPtr = uc->major;
*minorPtr = uc->minor;
return uc->device;
}
break;
case VOL:
if (!strcmp(t, uc->label)) {
*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');
if (islower(c))
return (c - 'a' + 10);
return (c - '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);
}
static int display_uuid_cache(void)
{
struct uuidCache_s *u;
size_t i;
uuidcache_init();
u = uuidCache;
while (u) {
printf("%s %s ", u->device, u->label);
for (i = 0; i < sizeof(u->uuid); i++) {
if (i == 4 || i == 6 || i == 8 || i == 10)
printf("-");
printf("%x", u->uuid[i] & 0xff);
}
printf("\n");
u = u->next;
}
return 0;
}
#endif // UNUSED
/* 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) {
if (uc->label && !strncmp(spec, uc->label, spec_len)) {
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) {
if (!memcmp(spec, uc->uuid, sizeof(uc->uuid))) {
return xstrdup(uc->device);
}
uc = uc->next;
}
return NULL;
}