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* devname.c - get a dev by its device inode name
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* Copyright (C) Andries Brouwer
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* Copyright (C) 1999, 2000, 2001, 2002, 2003 Theodore Ts'o
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* Copyright (C) 2001 Andreas Dilger
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* This file may be redistributed under the terms of the
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* GNU Lesser General Public License.
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#include <sys/types.h>
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#include "canonicalize.h" /* $(top_srcdir)/include */
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#include "pathnames.h"
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* Find a dev struct in the cache by device name, if available.
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* If there is no entry with the specified device name, and the create
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* flag is set, then create an empty device entry.
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blkid_dev blkid_get_dev(blkid_cache cache, const char *devname, int flags)
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blkid_dev dev = NULL, tmp;
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struct list_head *p, *pnext;
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if (!cache || !devname)
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list_for_each(p, &cache->bic_devs) {
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tmp = list_entry(p, struct blkid_struct_dev, bid_devs);
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if (strcmp(tmp->bid_name, devname))
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printf("found devname %s in cache\n", tmp->bid_name));
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if (!dev && (flags & BLKID_DEV_CREATE)) {
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if (access(devname, F_OK) < 0)
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dev = blkid_new_dev();
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dev->bid_time = INT_MIN;
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dev->bid_name = blkid_strdup(devname);
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dev->bid_cache = cache;
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list_add_tail(&dev->bid_devs, &cache->bic_devs);
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cache->bic_flags |= BLKID_BIC_FL_CHANGED;
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if (flags & BLKID_DEV_VERIFY) {
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dev = blkid_verify(cache, dev);
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if (!dev || !(dev->bid_flags & BLKID_BID_FL_VERIFIED))
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* If the device is verified, then search the blkid
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* cache for any entries that match on the type, uuid,
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* and label, and verify them; if a cache entry can
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* not be verified, then it's stale and so we remove
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list_for_each_safe(p, pnext, &cache->bic_devs) {
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dev2 = list_entry(p, struct blkid_struct_dev, bid_devs);
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if (dev2->bid_flags & BLKID_BID_FL_VERIFIED)
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if (!dev->bid_type || !dev2->bid_type ||
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strcmp(dev->bid_type, dev2->bid_type))
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if (dev->bid_label && dev2->bid_label &&
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strcmp(dev->bid_label, dev2->bid_label))
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if (dev->bid_uuid && dev2->bid_uuid &&
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strcmp(dev->bid_uuid, dev2->bid_uuid))
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if ((dev->bid_label && !dev2->bid_label) ||
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(!dev->bid_label && dev2->bid_label) ||
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(dev->bid_uuid && !dev2->bid_uuid) ||
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(!dev->bid_uuid && dev2->bid_uuid))
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dev2 = blkid_verify(cache, dev2);
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if (dev2 && !(dev2->bid_flags & BLKID_BID_FL_VERIFIED))
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blkid_free_dev(dev2);
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/* Directories where we will try to search for device names */
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static const char *dirlist[] = { "/dev", "/devfs", "/devices", NULL };
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static int is_dm_leaf(const char *devname)
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struct dirent *de, *d_de;
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if ((dir = opendir("/sys/block")) == NULL)
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while ((de = readdir(dir)) != NULL) {
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if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..") ||
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!strcmp(de->d_name, devname) ||
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strncmp(de->d_name, "dm-", 3) ||
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strlen(de->d_name) > sizeof(path)-32)
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sprintf(path, "/sys/block/%s/slaves", de->d_name);
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if ((d_dir = opendir(path)) == NULL)
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while ((d_de = readdir(d_dir)) != NULL) {
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if (!strcmp(d_de->d_name, devname)) {
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* Probe a single block device to add to the device cache.
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static void probe_one(blkid_cache cache, const char *ptname,
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dev_t devno, int pri, int only_if_new, int removable)
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blkid_dev dev = NULL;
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struct list_head *p, *pnext;
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char *devname = NULL;
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/* See if we already have this device number in the cache. */
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list_for_each_safe(p, pnext, &cache->bic_devs) {
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blkid_dev tmp = list_entry(p, struct blkid_struct_dev,
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if (tmp->bid_devno == devno) {
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if (only_if_new && !access(tmp->bid_name, F_OK))
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dev = blkid_verify(cache, tmp);
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if (dev && (dev->bid_flags & BLKID_BID_FL_VERIFIED))
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if (dev && dev->bid_devno == devno)
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/* Try to translate private device-mapper dm-<N> names
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* to standard /dev/mapper/<name>.
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if (!strncmp(ptname, "dm-", 3) && isdigit(ptname[3])) {
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devname = canonicalize_dm_name(ptname);
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blkid__scan_dir("/dev/mapper", devno, 0, &devname);
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* Take a quick look at /dev/ptname for the device number. We check
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* all of the likely device directories. If we don't find it, or if
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* the stat information doesn't check out, use blkid_devno_to_devname()
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* to find it via an exhaustive search for the device major/minor.
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for (dir = dirlist; *dir; dir++) {
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sprintf(device, "%s/%s", *dir, ptname);
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if ((dev = blkid_get_dev(cache, device, BLKID_DEV_FIND)) &&
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dev->bid_devno == devno)
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if (stat(device, &st) == 0 &&
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(S_ISBLK(st.st_mode) ||
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(S_ISCHR(st.st_mode) && !strncmp(ptname, "ubi", 3))) &&
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st.st_rdev == devno) {
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devname = blkid_strdup(device);
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/* Do a short-cut scan of /dev/mapper first */
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blkid__scan_dir("/dev/mapper", devno, 0, &devname);
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devname = blkid_devno_to_devname(devno);
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dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
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else if (!strncmp(dev->bid_name, "/dev/mapper/", 11)) {
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dev->bid_pri = BLKID_PRI_DM;
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if (is_dm_leaf(ptname))
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} else if (!strncmp(ptname, "md", 2))
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dev->bid_pri = BLKID_PRI_MD;
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dev->bid_flags |= BLKID_BID_FL_REMOVABLE;
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#define PROC_PARTITIONS "/proc/partitions"
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#define VG_DIR "/proc/lvm/VGs"
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* This function initializes the UUID cache with devices from the LVM
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* proc hierarchy. We currently depend on the names of the LVM
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* hierarchy giving us the device structure in /dev. (XXX is this a
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static dev_t lvm_get_devno(const char *lvm_device)
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DBG(DEBUG_DEVNAME, printf("opening %s\n", lvm_device));
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if ((lvf = fopen(lvm_device, "r")) == NULL) {
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DBG(DEBUG_DEVNAME, printf("%s: (%d) %s\n", lvm_device, errno,
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while (fgets(buf, sizeof(buf), lvf)) {
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if (sscanf(buf, "device: %d:%d", &ma, &mi) == 2) {
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ret = makedev(ma, mi);
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static void lvm_probe_all(blkid_cache cache, int only_if_new)
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struct dirent *vg_iter;
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int vg_len = strlen(VG_DIR);
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if ((vg_list = opendir(VG_DIR)) == NULL)
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DBG(DEBUG_DEVNAME, printf("probing LVM devices under %s\n", VG_DIR));
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while ((vg_iter = readdir(vg_list)) != NULL) {
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struct dirent *lv_iter;
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vg_name = vg_iter->d_name;
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if (!strcmp(vg_name, ".") || !strcmp(vg_name, ".."))
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vdirname = malloc(vg_len + strlen(vg_name) + 8);
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sprintf(vdirname, "%s/%s/LVs", VG_DIR, vg_name);
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lv_list = opendir(vdirname);
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while ((lv_iter = readdir(lv_list)) != NULL) {
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char *lv_name, *lvm_device;
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lv_name = lv_iter->d_name;
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if (!strcmp(lv_name, ".") || !strcmp(lv_name, ".."))
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lvm_device = malloc(vg_len + strlen(vg_name) +
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strlen(lv_name) + 8);
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sprintf(lvm_device, "%s/%s/LVs/%s", VG_DIR, vg_name,
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dev = lvm_get_devno(lvm_device);
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sprintf(lvm_device, "%s/%s", vg_name, lv_name);
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DBG(DEBUG_DEVNAME, printf("LVM dev %s: devno 0x%04X\n",
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(unsigned int) dev));
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probe_one(cache, lvm_device, dev, BLKID_PRI_LVM,
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#define PROC_EVMS_VOLUMES "/proc/evms/volumes"
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evms_probe_all(blkid_cache cache, int only_if_new)
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int ma, mi, sz, num = 0;
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procpt = fopen(PROC_EVMS_VOLUMES, "r");
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while (fgets(line, sizeof(line), procpt)) {
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if (sscanf (line, " %d %d %d %*s %*s %[^\n ]",
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&ma, &mi, &sz, device) != 4)
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DBG(DEBUG_DEVNAME, printf("Checking partition %s (%d, %d)\n",
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probe_one(cache, device, makedev(ma, mi), BLKID_PRI_EVMS,
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ubi_probe_all(blkid_cache cache, int only_if_new)
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const char **dirname;
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for (dirname = dirlist; *dirname; dirname++) {
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DBG(DEBUG_DEVNAME, printf("probing UBI volumes under %s\n",
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dir = opendir(*dirname);
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while ((iter = readdir(dir)) != NULL) {
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#ifdef _DIRENT_HAVE_D_TYPE
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if (iter->d_type != DT_UNKNOWN &&
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iter->d_type != DT_CHR && iter->d_type != DT_LNK)
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if (!strcmp(name, ".") || !strcmp(name, "..") ||
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!strstr(name, "ubi"))
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if (!strcmp(name, "ubi_ctrl"))
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if (blkid_fstatat(dir, *dirname, name, &st, 0))
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if (!S_ISCHR(st.st_mode) || !minor(dev))
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DBG(DEBUG_DEVNAME, printf("UBI vol %s/%s: devno 0x%04X\n",
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*dirname, name, (int) dev));
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probe_one(cache, name, dev, BLKID_PRI_UBI, only_if_new, 0);
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* Read the device data for all available block devices in the system.
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static int probe_all(blkid_cache cache, int only_if_new)
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char ptname0[128], ptname1[128], *ptname = 0;
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unsigned long long sz;
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int lens[2] = { 0, 0 };
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int which = 0, last = 0;
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struct list_head *p, *pnext;
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ptnames[0] = ptname0;
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ptnames[1] = ptname1;
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return -BLKID_ERR_PARAM;
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if (cache->bic_flags & BLKID_BIC_FL_PROBED &&
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time(0) - cache->bic_time < BLKID_PROBE_INTERVAL)
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blkid_read_cache(cache);
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evms_probe_all(cache, only_if_new);
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lvm_probe_all(cache, only_if_new);
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ubi_probe_all(cache, only_if_new);
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proc = fopen(PROC_PARTITIONS, "r");
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return -BLKID_ERR_PROC;
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while (fgets(line, sizeof(line), proc)) {
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ptname = ptnames[which];
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if (sscanf(line, " %d %d %llu %128[^\n ]",
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&ma, &mi, &sz, ptname) != 4)
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devs[which] = makedev(ma, mi);
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DBG(DEBUG_DEVNAME, printf("read partition name %s\n", ptname));
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/* Skip whole disk devs unless they have no partitions.
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* If base name of device has changed, also
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* check previous dev to see if it didn't have a partn.
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* heuristic: partition name ends in a digit, & partition
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* names contain whole device name as substring.
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* Skip extended partitions.
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* heuristic: size is 1
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* FIXME: skip /dev/{ida,cciss,rd} whole-disk devs
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lens[which] = strlen(ptname);
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/* ends in a digit, clearly a partition, so check */
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if (isdigit(ptname[lens[which] - 1])) {
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printf("partition dev %s, devno 0x%04X\n",
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ptname, (unsigned int) devs[which]));
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probe_one(cache, ptname, devs[which], 0,
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lens[which] = 0; /* mark as checked */
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* If last was a whole disk and we just found a partition
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* on it, remove the whole-disk dev from the cache if
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if (lens[last] && !strncmp(ptnames[last], ptname, lens[last])) {
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list_for_each_safe(p, pnext, &cache->bic_devs) {
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/* find blkid dev for the whole-disk devno */
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tmp = list_entry(p, struct blkid_struct_dev,
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if (tmp->bid_devno == devs[last]) {
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printf("freeing %s\n",
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cache->bic_flags |= BLKID_BIC_FL_CHANGED;
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* If last was not checked because it looked like a whole-disk
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* dev, and the device's base name has changed,
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* check last as well.
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if (lens[last] && strncmp(ptnames[last], ptname, lens[last])) {
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printf("whole dev %s, devno 0x%04X\n",
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ptnames[last], (unsigned int) devs[last]));
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probe_one(cache, ptnames[last], devs[last], 0,
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/* Handle the last device if it wasn't partitioned */
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probe_one(cache, ptname, devs[which], 0, only_if_new, 0);
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blkid_flush_cache(cache);
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/* Don't use it by default -- it's pretty slow (because cdroms, floppy, ...)
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static int probe_all_removable(blkid_cache cache)
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return -BLKID_ERR_PARAM;
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dir = opendir(_PATH_SYS_BLOCK);
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return -BLKID_ERR_PROC;
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while((d = readdir(dir))) {
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#ifdef _DIRENT_HAVE_D_TYPE
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if (d->d_type != DT_UNKNOWN && d->d_type != DT_LNK)
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if (d->d_name[0] == '.' &&
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((d->d_name[1] == 0) ||
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((d->d_name[1] == '.') && (d->d_name[2] == 0))))
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snprintf(buf, sizeof(buf), "%s/removable", d->d_name);
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fd = blkid_openat(dir, _PATH_SYS_BLOCK, buf, O_RDONLY);
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rc = read(fd, buf, 1);
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if (rc != 1 || *buf != '1')
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continue; /* not removable device */
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snprintf(buf, sizeof(buf), "%s/dev", d->d_name);
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fd = blkid_openat(dir, _PATH_SYS_BLOCK, buf, O_RDONLY);
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rc = read(fd, buf, sizeof(buf));
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if (sscanf(buf, "%d:%d", &ma, &mi) != 2)
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probe_one(cache, d->d_name, makedev(ma, mi), 0, 0, 1);
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* @cache: cache handler
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* Probes all block devices.
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* Returns: 0 on success, or number less than zero in case of error.
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int blkid_probe_all(blkid_cache cache)
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DBG(DEBUG_PROBE, printf("Begin blkid_probe_all()\n"));
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ret = probe_all(cache, 0);
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cache->bic_time = time(0);
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cache->bic_flags |= BLKID_BIC_FL_PROBED;
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DBG(DEBUG_PROBE, printf("End blkid_probe_all()\n"));
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* blkid_probe_all_new:
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* @cache: cache handler
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* Probes all new block devices.
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* Returns: 0 on success, or number less than zero in case of error.
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int blkid_probe_all_new(blkid_cache cache)
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DBG(DEBUG_PROBE, printf("Begin blkid_probe_all_new()\n"));
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ret = probe_all(cache, 1);
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DBG(DEBUG_PROBE, printf("End blkid_probe_all_new()\n"));
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* blkid_probe_all_removable:
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* @cache: cache handler
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* The libblkid probing is based on devices from /proc/partitions by default.
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* This file usually does not contain removable devices (e.g. CDROMs) and this kind
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* of devices are invisible for libblkid.
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* This function adds removable block devices to @cache (probing is based on
648
* information from the /sys directory). Don't forget that removable devices
649
* (floppies, CDROMs, ...) could be pretty slow. It's very bad idea to call
650
* this function by default.
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* Note that devices which were detected by this function won't be written to
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* blkid.tab cache file.
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* Returns: 0 on success, or number less than zero in case of error.
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int blkid_probe_all_removable(blkid_cache cache)
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DBG(DEBUG_PROBE, printf("Begin blkid_probe_all_removable()\n"));
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ret = probe_all_removable(cache);
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DBG(DEBUG_PROBE, printf("End blkid_probe_all_removable()\n"));
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int main(int argc, char **argv)
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blkid_cache cache = NULL;
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blkid_init_debug(DEBUG_ALL);
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fprintf(stderr, "Usage: %s\n"
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"Probe all devices and exit\n", argv[0]);
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if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
680
fprintf(stderr, "%s: error creating cache (%d)\n",
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if (blkid_probe_all(cache) < 0)
685
printf("%s: error probing devices\n", argv[0]);
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if (blkid_probe_all_removable(cache) < 0)
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printf("%s: error probing removable devices\n", argv[0]);
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blkid_put_cache(cache);
added
removed
shlibs/blkid/src/devname.c
