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util-linux/libblkid/src/devname.c

705 lines
17 KiB

/*
* devname.c - get a dev by its device inode name
*
* Copyright (C) Andries Brouwer
* Copyright (C) 1999, 2000, 2001, 2002, 2003 Theodore Ts'o
* Copyright (C) 2001 Andreas Dilger
*
* %Begin-Header%
* This file may be redistributed under the terms of the
* GNU Lesser General Public License.
* %End-Header%
*/
#define _GNU_SOURCE 1
#include <stdio.h>
#include <string.h>
#include <limits.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <stdlib.h>
#include <ctype.h>
#include <fcntl.h>
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#include <dirent.h>
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#include <time.h>
#include "blkidP.h"
#include "canonicalize.h" /* $(top_srcdir)/include */
#include "pathnames.h"
#include "sysfs.h"
/*
* Find a dev struct in the cache by device name, if available.
*
* If there is no entry with the specified device name, and the create
* flag is set, then create an empty device entry.
*/
blkid_dev blkid_get_dev(blkid_cache cache, const char *devname, int flags)
{
blkid_dev dev = NULL, tmp;
struct list_head *p, *pnext;
char *cn = NULL;
if (!cache || !devname)
return NULL;
/* search by name */
list_for_each(p, &cache->bic_devs) {
tmp = list_entry(p, struct blkid_struct_dev, bid_devs);
if (strcmp(tmp->bid_name, devname))
continue;
dev = tmp;
break;
}
/* try canonicalize the name */
if (!dev && (cn = canonicalize_path(devname))) {
if (strcmp(cn, devname) != 0) {
DBG(DEVNAME, ul_debug("search canonical %s", cn));
list_for_each(p, &cache->bic_devs) {
tmp = list_entry(p, struct blkid_struct_dev, bid_devs);
if (strcmp(tmp->bid_name, cn))
continue;
dev = tmp;
/* update name returned by blkid_dev_devname() */
free(dev->bid_xname);
dev->bid_xname = strdup(devname);
break;
}
} else {
free(cn);
cn = NULL;
}
}
if (!dev && (flags & BLKID_DEV_CREATE)) {
if (access(devname, F_OK) < 0)
goto done;
dev = blkid_new_dev();
if (!dev)
goto done;
dev->bid_time = INT_MIN;
if (cn) {
dev->bid_name = cn;
dev->bid_xname = strdup(devname);
cn = NULL; /* see free() below */
} else
dev->bid_name = strdup(devname);
dev->bid_cache = cache;
list_add_tail(&dev->bid_devs, &cache->bic_devs);
cache->bic_flags |= BLKID_BIC_FL_CHANGED;
}
if (flags & BLKID_DEV_VERIFY) {
dev = blkid_verify(cache, dev);
if (!dev || !(dev->bid_flags & BLKID_BID_FL_VERIFIED))
goto done;
/*
* If the device is verified, then search the blkid
* cache for any entries that match on the type, uuid,
* and label, and verify them; if a cache entry can
* not be verified, then it's stale and so we remove
* it.
*/
list_for_each_safe(p, pnext, &cache->bic_devs) {
blkid_dev dev2 = list_entry(p, struct blkid_struct_dev, bid_devs);
if (dev2->bid_flags & BLKID_BID_FL_VERIFIED)
continue;
if (!dev->bid_type || !dev2->bid_type ||
strcmp(dev->bid_type, dev2->bid_type))
continue;
if (dev->bid_label && dev2->bid_label &&
strcmp(dev->bid_label, dev2->bid_label))
continue;
if (dev->bid_uuid && dev2->bid_uuid &&
strcmp(dev->bid_uuid, dev2->bid_uuid))
continue;
if ((dev->bid_label && !dev2->bid_label) ||
(!dev->bid_label && dev2->bid_label) ||
(dev->bid_uuid && !dev2->bid_uuid) ||
(!dev->bid_uuid && dev2->bid_uuid))
continue;
dev2 = blkid_verify(cache, dev2);
if (dev2 && !(dev2->bid_flags & BLKID_BID_FL_VERIFIED))
blkid_free_dev(dev2);
}
}
done:
if (dev)
DBG(DEVNAME, ul_debug("%s requested, found %s in cache", devname, dev->bid_name));
free(cn);
return dev;
}
/* Directories where we will try to search for device names */
static const char *dirlist[] = { "/dev", "/devfs", "/devices", NULL };
static int is_dm_leaf(const char *devname)
{
struct dirent *de, *d_de;
DIR *dir, *d_dir;
char path[256];
int ret = 1;
if ((dir = opendir("/sys/block")) == NULL)
return 0;
while ((de = readdir(dir)) != NULL) {
if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..") ||
!strcmp(de->d_name, devname) ||
strncmp(de->d_name, "dm-", 3) ||
strlen(de->d_name) > sizeof(path)-32)
continue;
sprintf(path, "/sys/block/%s/slaves", de->d_name);
if ((d_dir = opendir(path)) == NULL)
continue;
while ((d_de = readdir(d_dir)) != NULL) {
if (!strcmp(d_de->d_name, devname)) {
ret = 0;
break;
}
}
closedir(d_dir);
if (!ret)
break;
}
closedir(dir);
return ret;
}
/*
* Probe a single block device to add to the device cache.
*/
static void probe_one(blkid_cache cache, const char *ptname,
dev_t devno, int pri, int only_if_new, int removable)
{
blkid_dev dev = NULL;
struct list_head *p, *pnext;
const char **dir;
char *devname = NULL;
/* See if we already have this device number in the cache. */
list_for_each_safe(p, pnext, &cache->bic_devs) {
blkid_dev tmp = list_entry(p, struct blkid_struct_dev,
bid_devs);
if (tmp->bid_devno == devno) {
if (only_if_new && !access(tmp->bid_name, F_OK))
return;
dev = blkid_verify(cache, tmp);
if (dev && (dev->bid_flags & BLKID_BID_FL_VERIFIED))
break;
dev = 0;
}
}
if (dev && dev->bid_devno == devno)
goto set_pri;
/* Try to translate private device-mapper dm-<N> names
* to standard /dev/mapper/<name>.
*/
if (!strncmp(ptname, "dm-", 3) && isdigit(ptname[3])) {
devname = canonicalize_dm_name(ptname);
if (!devname)
blkid__scan_dir("/dev/mapper", devno, 0, &devname);
if (devname)
goto get_dev;
}
/*
* Take a quick look at /dev/ptname for the device number. We check
* all of the likely device directories. If we don't find it, or if
* the stat information doesn't check out, use blkid_devno_to_devname()
* to find it via an exhaustive search for the device major/minor.
*/
for (dir = dirlist; *dir; dir++) {
struct stat st;
char device[256];
snprintf(device, sizeof(device), "%s/%s", *dir, ptname);
if ((dev = blkid_get_dev(cache, device, BLKID_DEV_FIND)) &&
dev->bid_devno == devno)
goto set_pri;
if (stat(device, &st) == 0 &&
(S_ISBLK(st.st_mode) ||
(S_ISCHR(st.st_mode) && !strncmp(ptname, "ubi", 3))) &&
st.st_rdev == devno) {
devname = strdup(device);
goto get_dev;
}
}
/* Do a short-cut scan of /dev/mapper first */
if (!devname)
blkid__scan_dir("/dev/mapper", devno, 0, &devname);
if (!devname) {
devname = blkid_devno_to_devname(devno);
if (!devname)
return;
}
get_dev:
dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
free(devname);
set_pri:
if (dev) {
if (pri)
dev->bid_pri = pri;
else if (!strncmp(dev->bid_name, "/dev/mapper/", 11)) {
dev->bid_pri = BLKID_PRI_DM;
if (is_dm_leaf(ptname))
dev->bid_pri += 5;
} else if (!strncmp(ptname, "md", 2))
dev->bid_pri = BLKID_PRI_MD;
if (removable)
dev->bid_flags |= BLKID_BID_FL_REMOVABLE;
}
return;
}
#define PROC_PARTITIONS "/proc/partitions"
#define VG_DIR "/proc/lvm/VGs"
/*
* This function initializes the UUID cache with devices from the LVM
* proc hierarchy. We currently depend on the names of the LVM
* hierarchy giving us the device structure in /dev. (XXX is this a
* safe thing to do?)
*/
#ifdef VG_DIR
static dev_t lvm_get_devno(const char *lvm_device)
{
FILE *lvf;
char buf[1024];
int ma, mi;
dev_t ret = 0;
DBG(DEVNAME, ul_debug("opening %s", lvm_device));
if ((lvf = fopen(lvm_device, "r" UL_CLOEXECSTR)) == NULL) {
DBG(DEVNAME, ul_debug("%s: (%d) %m", lvm_device, errno));
return 0;
}
while (fgets(buf, sizeof(buf), lvf)) {
if (sscanf(buf, "device: %d:%d", &ma, &mi) == 2) {
ret = makedev(ma, mi);
break;
}
}
fclose(lvf);
return ret;
}
static void lvm_probe_all(blkid_cache cache, int only_if_new)
{
DIR *vg_list;
struct dirent *vg_iter;
int vg_len = strlen(VG_DIR);
dev_t dev;
if ((vg_list = opendir(VG_DIR)) == NULL)
return;
DBG(DEVNAME, ul_debug("probing LVM devices under %s", VG_DIR));
while ((vg_iter = readdir(vg_list)) != NULL) {
DIR *lv_list;
char *vdirname;
char *vg_name;
struct dirent *lv_iter;
vg_name = vg_iter->d_name;
if (!strcmp(vg_name, ".") || !strcmp(vg_name, ".."))
continue;
vdirname = malloc(vg_len + strlen(vg_name) + 8);
if (!vdirname)
goto exit;
sprintf(vdirname, "%s/%s/LVs", VG_DIR, vg_name);
lv_list = opendir(vdirname);
free(vdirname);
if (lv_list == NULL)
continue;
while ((lv_iter = readdir(lv_list)) != NULL) {
char *lv_name, *lvm_device;
lv_name = lv_iter->d_name;
if (!strcmp(lv_name, ".") || !strcmp(lv_name, ".."))
continue;
lvm_device = malloc(vg_len + strlen(vg_name) +
strlen(lv_name) + 8);
if (!lvm_device) {
closedir(lv_list);
goto exit;
}
sprintf(lvm_device, "%s/%s/LVs/%s", VG_DIR, vg_name,
lv_name);
dev = lvm_get_devno(lvm_device);
sprintf(lvm_device, "%s/%s", vg_name, lv_name);
DBG(DEVNAME, ul_debug("LVM dev %s: devno 0x%04X",
lvm_device,
(unsigned int) dev));
probe_one(cache, lvm_device, dev, BLKID_PRI_LVM,
only_if_new, 0);
free(lvm_device);
}
closedir(lv_list);
}
exit:
closedir(vg_list);
}
#endif
#define PROC_EVMS_VOLUMES "/proc/evms/volumes"
static int
evms_probe_all(blkid_cache cache, int only_if_new)
{
char line[100];
int ma, mi, sz, num = 0;
FILE *procpt;
char device[110];
procpt = fopen(PROC_EVMS_VOLUMES, "r" UL_CLOEXECSTR);
if (!procpt)
return 0;
while (fgets(line, sizeof(line), procpt)) {
if (sscanf (line, " %d %d %d %*s %*s %[^\n ]",
&ma, &mi, &sz, device) != 4)
continue;
DBG(DEVNAME, ul_debug("Checking partition %s (%d, %d)",
device, ma, mi));
probe_one(cache, device, makedev(ma, mi), BLKID_PRI_EVMS,
only_if_new, 0);
num++;
}
fclose(procpt);
return num;
}
static void
ubi_probe_all(blkid_cache cache, int only_if_new)
{
const char **dirname;
for (dirname = dirlist; *dirname; dirname++) {
DIR *dir;
struct dirent *iter;
DBG(DEVNAME, ul_debug("probing UBI volumes under %s",
*dirname));
dir = opendir(*dirname);
if (dir == NULL)
continue ;
while ((iter = readdir(dir)) != NULL) {
char *name;
struct stat st;
dev_t dev;
name = iter->d_name;
#ifdef _DIRENT_HAVE_D_TYPE
if (iter->d_type != DT_UNKNOWN &&
iter->d_type != DT_CHR && iter->d_type != DT_LNK)
continue;
#endif
if (!strcmp(name, ".") || !strcmp(name, "..") ||
!strstr(name, "ubi"))
continue;
if (!strcmp(name, "ubi_ctrl"))
continue;
if (fstatat(dirfd(dir), name, &st, 0))
continue;
dev = st.st_rdev;
if (!S_ISCHR(st.st_mode) || !minor(dev))
continue;
DBG(DEVNAME, ul_debug("UBI vol %s/%s: devno 0x%04X",
*dirname, name, (int) dev));
probe_one(cache, name, dev, BLKID_PRI_UBI, only_if_new, 0);
}
closedir(dir);
}
}
/*
* Read the device data for all available block devices in the system.
*/
static int probe_all(blkid_cache cache, int only_if_new)
{
FILE *proc;
char line[1024];
char ptname0[128 + 1], ptname1[128 + 1], *ptname = 0;
char *ptnames[2];
dev_t devs[2];
int ma, mi;
unsigned long long sz;
int lens[2] = { 0, 0 };
int which = 0, last = 0;
struct list_head *p, *pnext;
ptnames[0] = ptname0;
ptnames[1] = ptname1;
if (!cache)
return -BLKID_ERR_PARAM;
if (cache->bic_flags & BLKID_BIC_FL_PROBED &&
time(0) - cache->bic_time < BLKID_PROBE_INTERVAL)
return 0;
blkid_read_cache(cache);
evms_probe_all(cache, only_if_new);
#ifdef VG_DIR
lvm_probe_all(cache, only_if_new);
#endif
ubi_probe_all(cache, only_if_new);
proc = fopen(PROC_PARTITIONS, "r" UL_CLOEXECSTR);
if (!proc)
return -BLKID_ERR_PROC;
while (fgets(line, sizeof(line), proc)) {
last = which;
which ^= 1;
ptname = ptnames[which];
if (sscanf(line, " %d %d %llu %128[^\n ]",
&ma, &mi, &sz, ptname) != 4)
continue;
devs[which] = makedev(ma, mi);
DBG(DEVNAME, ul_debug("read partition name %s", ptname));
/* Skip whole disk devs unless they have no partitions.
* If base name of device has changed, also
* check previous dev to see if it didn't have a partn.
* heuristic: partition name ends in a digit, & partition
* names contain whole device name as substring.
*
* Skip extended partitions.
* heuristic: size is 1
*
* FIXME: skip /dev/{ida,cciss,rd} whole-disk devs
*/
lens[which] = strlen(ptname);
/* ends in a digit, clearly a partition, so check */
if (isdigit(ptname[lens[which] - 1])) {
DBG(DEVNAME, ul_debug("partition dev %s, devno 0x%04X",
ptname, (unsigned int) devs[which]));
if (sz > 1)
probe_one(cache, ptname, devs[which], 0,
only_if_new, 0);
lens[which] = 0; /* mark as checked */
}
/*
* If last was a whole disk and we just found a partition
* on it, remove the whole-disk dev from the cache if
* it exists.
*/
if (lens[last] && !strncmp(ptnames[last], ptname, lens[last])) {
list_for_each_safe(p, pnext, &cache->bic_devs) {
blkid_dev tmp;
/* find blkid dev for the whole-disk devno */
tmp = list_entry(p, struct blkid_struct_dev,
bid_devs);
if (tmp->bid_devno == devs[last]) {
DBG(DEVNAME, ul_debug("freeing %s",
tmp->bid_name));
blkid_free_dev(tmp);
cache->bic_flags |= BLKID_BIC_FL_CHANGED;
break;
}
}
lens[last] = 0;
}
/*
* If last was not checked because it looked like a whole-disk
* dev, and the device's base name has changed,
* check last as well.
*/
if (lens[last] && strncmp(ptnames[last], ptname, lens[last])) {
DBG(DEVNAME, ul_debug("whole dev %s, devno 0x%04X",
ptnames[last], (unsigned int) devs[last]));
probe_one(cache, ptnames[last], devs[last], 0,
only_if_new, 0);
lens[last] = 0;
}
}
/* Handle the last device if it wasn't partitioned */
if (lens[which])
probe_one(cache, ptname, devs[which], 0, only_if_new, 0);
fclose(proc);
blkid_flush_cache(cache);
return 0;
}
/* Don't use it by default -- it's pretty slow (because cdroms, floppy, ...)
*/
static int probe_all_removable(blkid_cache cache)
{
DIR *dir;
struct dirent *d;
if (!cache)
return -BLKID_ERR_PARAM;
dir = opendir(_PATH_SYS_BLOCK);
if (!dir)
return -BLKID_ERR_PROC;
while((d = readdir(dir))) {
struct sysfs_cxt sysfs = UL_SYSFSCXT_EMPTY;
int removable = 0;
dev_t devno;
#ifdef _DIRENT_HAVE_D_TYPE
if (d->d_type != DT_UNKNOWN && d->d_type != DT_LNK)
continue;
#endif
if (d->d_name[0] == '.' &&
((d->d_name[1] == 0) ||
((d->d_name[1] == '.') && (d->d_name[2] == 0))))
continue;
devno = sysfs_devname_to_devno(d->d_name, NULL);
if (!devno)
continue;
if (sysfs_init(&sysfs, devno, NULL) == 0) {
if (sysfs_read_int(&sysfs, "removable", &removable) != 0)
removable = 0;
sysfs_deinit(&sysfs);
}
if (removable)
probe_one(cache, d->d_name, devno, 0, 0, 1);
}
closedir(dir);
return 0;
}
/**
* blkid_probe_all:
* @cache: cache handler
*
* Probes all block devices.
*
* Returns: 0 on success, or number less than zero in case of error.
*/
int blkid_probe_all(blkid_cache cache)
{
int ret;
DBG(PROBE, ul_debug("Begin blkid_probe_all()"));
ret = probe_all(cache, 0);
if (ret == 0) {
cache->bic_time = time(0);
cache->bic_flags |= BLKID_BIC_FL_PROBED;
}
DBG(PROBE, ul_debug("End blkid_probe_all() [rc=%d]", ret));
return ret;
}
/**
* blkid_probe_all_new:
* @cache: cache handler
*
* Probes all new block devices.
*
* Returns: 0 on success, or number less than zero in case of error.
*/
int blkid_probe_all_new(blkid_cache cache)
{
int ret;
DBG(PROBE, ul_debug("Begin blkid_probe_all_new()"));
ret = probe_all(cache, 1);
DBG(PROBE, ul_debug("End blkid_probe_all_new() [rc=%d]", ret));
return ret;
}
/**
* blkid_probe_all_removable:
* @cache: cache handler
*
* The libblkid probing is based on devices from /proc/partitions by default.
* This file usually does not contain removable devices (e.g. CDROMs) and this kind
* of devices are invisible for libblkid.
*
* This function adds removable block devices to @cache (probing is based on
* information from the /sys directory). Don't forget that removable devices
* (floppies, CDROMs, ...) could be pretty slow. It's very bad idea to call
* this function by default.
*
* Note that devices which were detected by this function won't be written to
* blkid.tab cache file.
*
* Returns: 0 on success, or number less than zero in case of error.
*/
int blkid_probe_all_removable(blkid_cache cache)
{
int ret;
DBG(PROBE, ul_debug("Begin blkid_probe_all_removable()"));
ret = probe_all_removable(cache);
DBG(PROBE, ul_debug("End blkid_probe_all_removable() [rc=%d]", ret));
return ret;
}
#ifdef TEST_PROGRAM
int main(int argc, char **argv)
{
blkid_cache cache = NULL;
int ret;
blkid_init_debug(BLKID_DEBUG_ALL);
if (argc != 1) {
fprintf(stderr, "Usage: %s\n"
"Probe all devices and exit\n", argv[0]);
exit(1);
}
if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
fprintf(stderr, "%s: error creating cache (%d)\n",
argv[0], ret);
exit(1);
}
if (blkid_probe_all(cache) < 0)
printf("%s: error probing devices\n", argv[0]);
if (blkid_probe_all_removable(cache) < 0)
printf("%s: error probing removable devices\n", argv[0]);
blkid_put_cache(cache);
return (0);
}
#endif