/* * 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 #include #include #ifdef HAVE_UNISTD_H #include #endif #include #include #include #ifdef HAVE_SYS_TYPES_H #include #endif #include #ifdef HAVE_SYS_STAT_H #include #endif #ifdef HAVE_ERRNO_H #include #endif #include #include "blkidP.h" #include "canonicalize.h" /* $(top_srcdir)/include */ #include "pathnames.h" #include "sysfs.h" #include "fileutils.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) != 0) 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) != 0) 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 = (uintmax_t)1 << (sizeof(time_t) * 8 - 1); 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) != 0) continue; if (dev->bid_label && dev2->bid_label && strcmp(dev->bid_label, dev2->bid_label) != 0) continue; if (dev->bid_uuid && dev2->bid_uuid && strcmp(dev->bid_uuid, dev2->bid_uuid) != 0) 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 }; /* * Return 1 if the device is a device-mapper 'leaf' node * not holding any other devices in its hierarchy. */ static int is_dm_leaf(const char *devname) { DIR *dir; char path[NAME_MAX + 18 + 1]; int ret; snprintf(path, sizeof(path), "/sys/block/%s/holders", devname); if ((dir = opendir(path)) == NULL) return 0; ret = xreaddir(dir) == NULL ? 1 : 0; /* 'leaf' has no entries */ 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 = NULL; } } if (dev && dev->bid_devno == devno) goto set_pri; /* Try to translate private device-mapper dm- names * to standard /dev/mapper/. */ if (!strncmp(ptname, "dm-", 3) && isdigit(ptname[3])) { devname = canonicalize_dm_name(ptname); if (!devname) blkid__scan_dir("/dev/mapper", devno, NULL, &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, NULL, &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/", 12)) { 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; } } #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; size_t len; vg_name = vg_iter->d_name; if (!strcmp(vg_name, ".") || !strcmp(vg_name, "..")) continue; len = vg_len + strlen(vg_name) + 8; vdirname = malloc(len); if (!vdirname) goto exit; snprintf(vdirname, len, "%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; len = vg_len + strlen(vg_name) + strlen(lv_name) + 8; lvm_device = malloc(len); if (!lvm_device) { closedir(lv_list); goto exit; } snprintf(lvm_device, len, "%s/%s/LVs/%s", VG_DIR, vg_name, lv_name); dev = lvm_get_devno(lvm_device); snprintf(lvm_device, len, "%s/%s", vg_name, lv_name); DBG(DEVNAME, ul_debug("Probe 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 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("Probe 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); } } /* * This function uses /sys to read all block devices in way compatible with * /proc/partitions (like the original libblkid implementation) */ static int sysfs_probe_all(blkid_cache cache, int only_if_new, int only_removable) { DIR *sysfs; struct dirent *dev; sysfs = opendir(_PATH_SYS_BLOCK); if (!sysfs) return -BLKID_ERR_SYSFS; DBG(DEVNAME, ul_debug(" probe /sys/block")); /* scan /sys/block */ while ((dev = xreaddir(sysfs))) { DIR *dir = NULL; dev_t devno; size_t nparts = 0; unsigned int maxparts = 0, removable = 0; struct dirent *part; struct path_cxt *pc = NULL; uint64_t size = 0; DBG(DEVNAME, ul_debug("checking %s", dev->d_name)); devno = sysfs_devname_to_devno(dev->d_name); if (!devno) goto next; pc = ul_new_sysfs_path(devno, NULL, NULL); if (!pc) goto next; if (ul_path_read_u64(pc, &size, "size") != 0) size = 0; if (ul_path_read_u32(pc, &removable, "removable") != 0) removable = 0; /* ignore empty devices */ if (!size) goto next; /* accept removable if only removable requested */ if (only_removable) { if (!removable) goto next; /* emulate /proc/partitions * -- ignore empty devices and non-partitionable removable devices */ } else { if (ul_path_read_u32(pc, &maxparts, "ext_range") != 0) maxparts = 0; if (!maxparts && removable) goto next; } DBG(DEVNAME, ul_debug("read device name %s", dev->d_name)); dir = ul_path_opendir(pc, NULL); if (!dir) goto next; /* read /sys/block// do get partitions */ while ((part = xreaddir(dir))) { dev_t partno; if (!sysfs_blkdev_is_partition_dirent(dir, part, dev->d_name)) continue; /* ignore extended partitions * -- recount size to blocks like /proc/partitions */ if (ul_path_readf_u64(pc, &size, "%s/size", part->d_name) == 0 && (size >> 1) == 1) continue; partno = __sysfs_devname_to_devno(NULL, part->d_name, dev->d_name); if (!partno) continue; DBG(DEVNAME, ul_debug(" Probe partition dev %s, devno 0x%04X", part->d_name, (unsigned int) partno)); nparts++; probe_one(cache, part->d_name, partno, 0, only_if_new, 0); } if (!nparts) { /* add non-partitioned whole disk to cache */ DBG(DEVNAME, ul_debug(" Probe whole dev %s, devno 0x%04X", dev->d_name, (unsigned int) devno)); probe_one(cache, dev->d_name, devno, 0, only_if_new, 0); } else { /* remove partitioned whole-disk from cache */ struct list_head *p, *pnext; 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) { DBG(DEVNAME, ul_debug(" freeing %s", tmp->bid_name)); blkid_free_dev(tmp); cache->bic_flags |= BLKID_BIC_FL_CHANGED; break; } } } next: if (dir) closedir(dir); if (pc) ul_unref_path(pc); } closedir(sysfs); return 0; } /* * Read the device data for all available block devices in the system. */ static int probe_all(blkid_cache cache, int only_if_new, int update_interval) { int rc; if (!cache) return -BLKID_ERR_PARAM; if (cache->bic_flags & BLKID_BIC_FL_PROBED && time(NULL) - cache->bic_time < BLKID_PROBE_INTERVAL) { DBG(PROBE, ul_debug("don't re-probe [delay < %d]", BLKID_PROBE_INTERVAL)); return 0; } blkid_read_cache(cache); #ifdef VG_DIR lvm_probe_all(cache, only_if_new); #endif ubi_probe_all(cache, only_if_new); rc = sysfs_probe_all(cache, only_if_new, 0); /* Don't mark the change as "probed" if /sys not avalable */ if (update_interval && rc == 0) { cache->bic_time = time(NULL); cache->bic_flags |= BLKID_BIC_FL_PROBED; } blkid_flush_cache(cache); 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, 1); 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, 0); 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 = sysfs_probe_all(cache, 0, 1); 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