/* * devno.c - find a particular device by its device number (major/minor) * * Copyright (C) 2000, 2001, 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% */ #include #include #ifdef HAVE_UNISTD_H #include #endif #include #ifdef HAVE_SYS_TYPES_H #include #endif #ifdef HAVE_SYS_STAT_H #include #endif #include #ifdef HAVE_ERRNO_H #include #endif #ifdef HAVE_SYS_MKDEV_H #include #endif #include #include #include "blkidP.h" #include "pathnames.h" #include "sysfs.h" static char *blkid_strconcat(const char *a, const char *b, const char *c) { char *res, *p; size_t len, al, bl, cl; al = a ? strlen(a) : 0; bl = b ? strlen(b) : 0; cl = c ? strlen(c) : 0; len = al + bl + cl; if (!len) return NULL; p = res = malloc(len + 1); if (!res) return NULL; if (al) { memcpy(p, a, al); p += al; } if (bl) { memcpy(p, b, bl); p += bl; } if (cl) { memcpy(p, c, cl); p += cl; } *p = '\0'; return res; } /* * This function adds an entry to the directory list */ static void add_to_dirlist(const char *dir, const char *subdir, struct dir_list **list) { struct dir_list *dp; dp = malloc(sizeof(struct dir_list)); if (!dp) return; dp->name = subdir ? blkid_strconcat(dir, "/", subdir) : dir ? strdup(dir) : NULL; if (!dp->name) { free(dp); return; } dp->next = *list; *list = dp; } /* * This function frees a directory list */ static void free_dirlist(struct dir_list **list) { struct dir_list *dp, *next; for (dp = *list; dp; dp = next) { next = dp->next; free(dp->name); free(dp); } *list = NULL; } void blkid__scan_dir(char *dirname, dev_t devno, struct dir_list **list, char **devname) { DIR *dir; struct dirent *dp; struct stat st; if ((dir = opendir(dirname)) == NULL) return; while ((dp = readdir(dir)) != NULL) { #ifdef _DIRENT_HAVE_D_TYPE if (dp->d_type != DT_UNKNOWN && dp->d_type != DT_BLK && dp->d_type != DT_LNK && dp->d_type != DT_DIR) continue; #endif if (dp->d_name[0] == '.' && ((dp->d_name[1] == 0) || ((dp->d_name[1] == '.') && (dp->d_name[2] == 0)))) continue; if (fstatat(dirfd(dir), dp->d_name, &st, 0)) continue; if (S_ISBLK(st.st_mode) && st.st_rdev == devno) { *devname = blkid_strconcat(dirname, "/", dp->d_name); DBG(DEVNO, ul_debug("found 0x%llx at %s", (long long)devno, *devname)); break; } if (!list || !S_ISDIR(st.st_mode)) continue; /* add subdirectory (but not symlink) to the list */ #ifdef _DIRENT_HAVE_D_TYPE if (dp->d_type == DT_LNK) continue; if (dp->d_type == DT_UNKNOWN) #endif { if (fstatat(dirfd(dir), dp->d_name, &st, 1) || !S_ISDIR(st.st_mode)) continue; /* symlink or lstat() failed */ } if (*dp->d_name == '.' || ( #ifdef _DIRENT_HAVE_D_TYPE dp->d_type == DT_DIR && #endif strcmp(dp->d_name, "shm") == 0)) /* ignore /dev/.{udev,mount,mdadm} and /dev/shm */ continue; add_to_dirlist(dirname, dp->d_name, list); } closedir(dir); return; } /* Directories where we will try to search for device numbers */ static const char *devdirs[] = { "/devices", "/devfs", "/dev", NULL }; /** * SECTION: misc * @title: Miscellaneous utils * @short_description: mix of various utils for low-level and high-level API */ static char *scandev_devno_to_devpath(dev_t devno) { struct dir_list *list = NULL, *new_list = NULL; char *devname = NULL; const char **dir; /* * Add the starting directories to search in reverse order of * importance, since we are using a stack... */ for (dir = devdirs; *dir; dir++) add_to_dirlist(*dir, NULL, &list); while (list) { struct dir_list *current = list; list = list->next; DBG(DEVNO, ul_debug("directory %s", current->name)); blkid__scan_dir(current->name, devno, &new_list, &devname); free(current->name); free(current); if (devname) break; /* * If we're done checking at this level, descend to * the next level of subdirectories. (breadth-first) */ if (list == NULL) { list = new_list; new_list = NULL; } } free_dirlist(&list); free_dirlist(&new_list); return devname; } /** * blkid_devno_to_devname: * @devno: device number * * This function finds the pathname to a block device with a given * device number. * * Returns: a pointer to allocated memory to the pathname on success, * and NULL on failure. */ char *blkid_devno_to_devname(dev_t devno) { char *path = NULL; char buf[PATH_MAX]; path = sysfs_devno_to_devpath(devno, buf, sizeof(buf)); if (path) path = strdup(path); if (!path) path = scandev_devno_to_devpath(devno); if (!path) { DBG(DEVNO, ul_debug("blkid: couldn't find devno 0x%04lx", (unsigned long) devno)); } else { DBG(DEVNO, ul_debug("found devno 0x%04llx as %s", (long long)devno, path)); } return path; } /** * blkid_devno_to_wholedisk: * @dev: device number * @diskname: buffer to return diskname (or NULL) * @len: diskname buffer size (or 0) * @diskdevno: pointer to returns devno of entire disk (or NULL) * * This function uses sysfs to convert the @devno device number to the *name* * of the whole disk. The function DOES NOT return full device name. The @dev * argument could be partition or whole disk -- both is converted. * * For example: sda1, 0x0801 --> sda, 0x0800 * * For conversion to the full disk *path* use blkid_devno_to_devname(), for * example: * * * * * dev_t dev = 0x0801, disk; // sda1 = 8:1 * char *diskpath, diskname[32]; * * blkid_devno_to_wholedisk(dev, diskname, sizeof(diskname), &disk); * diskpath = blkid_devno_to_devname(disk); * * // print "0x0801: sda, /dev/sda, 8:0 * printf("0x%x: %s, %s, %d:%d\n", * dev, diskname, diskpath, major(disk), minor(disk)); * * free(diskpath); * * * * * Returns: 0 on success or -1 in case of error. */ int blkid_devno_to_wholedisk(dev_t dev, char *diskname, size_t len, dev_t *diskdevno) { return sysfs_devno_to_wholedisk( dev, diskname, len, diskdevno); } /* * Returns 1 if the @major number is associated with @drvname. */ int blkid_driver_has_major(const char *drvname, int drvmaj) { FILE *f; char buf[128]; int match = 0; f = fopen(_PATH_PROC_DEVICES, "r" UL_CLOEXECSTR); if (!f) return 0; while (fgets(buf, sizeof(buf), f)) { /* skip to block dev section */ if (strncmp("Block devices:\n", buf, sizeof(buf)) == 0) break; } while (fgets(buf, sizeof(buf), f)) { int maj; char name[64 + 1]; if (sscanf(buf, "%d %64[^\n ]", &maj, name) != 2) continue; if (maj == drvmaj && strcmp(name, drvname) == 0) { match = 1; break; } } fclose(f); DBG(DEVNO, ul_debug("major %d %s associated with '%s' driver", drvmaj, match ? "is" : "is NOT", drvname)); return match; } #ifdef TEST_PROGRAM int main(int argc, char** argv) { char *devname, *tmp; char diskname[PATH_MAX]; int devmaj, devmin; dev_t devno, disk_devno; const char *errmsg = "Couldn't parse %s: %s\n"; blkid_init_debug(BLKID_DEBUG_ALL); if ((argc != 2) && (argc != 3)) { fprintf(stderr, "Usage:\t%s device_number\n\t%s major minor\n" "Resolve a device number to a device name\n", argv[0], argv[0]); exit(1); } if (argc == 2) { devno = strtoul(argv[1], &tmp, 0); if (*tmp) { fprintf(stderr, errmsg, "device number", argv[1]); exit(1); } } else { devmaj = strtoul(argv[1], &tmp, 0); if (*tmp) { fprintf(stderr, errmsg, "major number", argv[1]); exit(1); } devmin = strtoul(argv[2], &tmp, 0); if (*tmp) { fprintf(stderr, errmsg, "minor number", argv[2]); exit(1); } devno = makedev(devmaj, devmin); } printf("Looking for device 0x%04llx\n", (long long)devno); devname = blkid_devno_to_devname(devno); free(devname); printf("Looking for whole-device for 0x%04llx\n", (long long)devno); if (blkid_devno_to_wholedisk(devno, diskname, sizeof(diskname), &disk_devno) == 0) printf("found devno 0x%04llx as /dev/%s\n", (long long) disk_devno, diskname); return 0; } #endif