/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include #include #include "alloc-util.h" #include "blockdev-util.h" #include "btrfs-util.h" #include "dirent-util.h" #include "fd-util.h" #include "fileio.h" #include "missing_magic.h" #include "parse-util.h" #include "stat-util.h" int block_get_whole_disk(dev_t d, dev_t *ret) { char p[SYS_BLOCK_PATH_MAX("/partition")]; _cleanup_free_ char *s = NULL; dev_t devt; int r; assert(ret); if (major(d) == 0) return -ENODEV; /* If it has a queue this is good enough for us */ xsprintf_sys_block_path(p, "/queue", d); if (access(p, F_OK) >= 0) { *ret = d; return 0; } if (errno != ENOENT) return -errno; /* If it is a partition find the originating device */ xsprintf_sys_block_path(p, "/partition", d); if (access(p, F_OK) < 0) return -errno; /* Get parent dev_t */ xsprintf_sys_block_path(p, "/../dev", d); r = read_one_line_file(p, &s); if (r < 0) return r; r = parse_dev(s, &devt); if (r < 0) return r; /* Only return this if it is really good enough for us. */ xsprintf_sys_block_path(p, "/queue", devt); if (access(p, F_OK) < 0) return -errno; *ret = devt; return 1; } int get_block_device(const char *path, dev_t *ret) { _cleanup_close_ int fd = -1; struct stat st; int r; assert(path); assert(ret); /* Gets the block device directly backing a file system. If the block device is encrypted, returns * the device mapper block device. */ fd = open(path, O_NOFOLLOW|O_CLOEXEC); if (fd < 0) return -errno; if (fstat(fd, &st)) return -errno; if (major(st.st_dev) != 0) { *ret = st.st_dev; return 1; } r = btrfs_get_block_device_fd(fd, ret); if (r > 0) return 1; if (r != -ENOTTY) /* not btrfs */ return r; *ret = 0; return 0; } int block_get_originating(dev_t dt, dev_t *ret) { _cleanup_closedir_ DIR *d = NULL; _cleanup_free_ char *t = NULL; char p[SYS_BLOCK_PATH_MAX("/slaves")]; struct dirent *de, *found = NULL; const char *q; dev_t devt; int r; /* For the specified block device tries to chase it through the layers, in case LUKS-style DM stacking is used, * trying to find the next underlying layer. */ xsprintf_sys_block_path(p, "/slaves", dt); d = opendir(p); if (!d) return -errno; FOREACH_DIRENT_ALL(de, d, return -errno) { if (dot_or_dot_dot(de->d_name)) continue; if (!IN_SET(de->d_type, DT_LNK, DT_UNKNOWN)) continue; if (found) { _cleanup_free_ char *u = NULL, *v = NULL, *a = NULL, *b = NULL; /* We found a device backed by multiple other devices. We don't really support automatic * discovery on such setups, with the exception of dm-verity partitions. In this case there are * two backing devices: the data partition and the hash partition. We are fine with such * setups, however, only if both partitions are on the same physical device. Hence, let's * verify this. */ u = path_join(p, de->d_name, "../dev"); if (!u) return -ENOMEM; v = path_join(p, found->d_name, "../dev"); if (!v) return -ENOMEM; r = read_one_line_file(u, &a); if (r < 0) return log_debug_errno(r, "Failed to read %s: %m", u); r = read_one_line_file(v, &b); if (r < 0) return log_debug_errno(r, "Failed to read %s: %m", v); /* Check if the parent device is the same. If not, then the two backing devices are on * different physical devices, and we don't support that. */ if (!streq(a, b)) return -ENOTUNIQ; } found = de; } if (!found) return -ENOENT; q = strjoina(p, "/", found->d_name, "/dev"); r = read_one_line_file(q, &t); if (r < 0) return r; r = parse_dev(t, &devt); if (r < 0) return -EINVAL; if (major(devt) == 0) return -ENOENT; *ret = devt; return 1; } int get_block_device_harder(const char *path, dev_t *ret) { int r; assert(path); assert(ret); /* Gets the backing block device for a file system, and handles LUKS encrypted file systems, looking for its * immediate parent, if there is one. */ r = get_block_device(path, ret); if (r <= 0) return r; r = block_get_originating(*ret, ret); if (r < 0) log_debug_errno(r, "Failed to chase block device '%s', ignoring: %m", path); return 1; } int lock_whole_block_device(dev_t devt, int operation) { _cleanup_free_ char *whole_node = NULL; _cleanup_close_ int lock_fd = -1; dev_t whole_devt; int r; /* Let's get a BSD file lock on the whole block device, as per: https://systemd.io/BLOCK_DEVICE_LOCKING */ r = block_get_whole_disk(devt, &whole_devt); if (r < 0) return r; r = device_path_make_major_minor(S_IFBLK, whole_devt, &whole_node); if (r < 0) return r; lock_fd = open(whole_node, O_RDONLY|O_CLOEXEC|O_NONBLOCK); if (lock_fd < 0) return -errno; if (flock(lock_fd, operation) < 0) return -errno; return TAKE_FD(lock_fd); } int blockdev_partscan_enabled(int fd) { _cleanup_free_ char *p = NULL, *buf = NULL; unsigned long long ull; struct stat st; int r; /* Checks if partition scanning is correctly enabled on the block device */ if (fstat(fd, &st) < 0) return -errno; if (!S_ISBLK(st.st_mode)) return -ENOTBLK; if (asprintf(&p, "/sys/dev/block/%u:%u/capability", major(st.st_rdev), minor(st.st_rdev)) < 0) return -ENOMEM; r = read_one_line_file(p, &buf); if (r == -ENOENT) /* If the capability file doesn't exist then we are most likely looking at a * partition block device, not the whole block device. And that means we have no * partition scanning on for it (we do for its parent, but not for the partition * itself). */ return false; if (r < 0) return r; r = safe_atollu_full(buf, 16, &ull); if (r < 0) return r; #ifndef GENHD_FL_NO_PART_SCAN #define GENHD_FL_NO_PART_SCAN (0x0200) #endif return !FLAGS_SET(ull, GENHD_FL_NO_PART_SCAN); }