summaryrefslogtreecommitdiffstats
path: root/src/shared/blockdev-util.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/shared/blockdev-util.c')
-rw-r--r--src/shared/blockdev-util.c790
1 files changed, 790 insertions, 0 deletions
diff --git a/src/shared/blockdev-util.c b/src/shared/blockdev-util.c
new file mode 100644
index 0000000..72fad16
--- /dev/null
+++ b/src/shared/blockdev-util.c
@@ -0,0 +1,790 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <linux/blkpg.h>
+#include <sys/file.h>
+#include <sys/ioctl.h>
+#include <sys/mount.h>
+#include <unistd.h>
+
+#include "sd-device.h"
+
+#include "alloc-util.h"
+#include "blockdev-util.h"
+#include "btrfs-util.h"
+#include "device-util.h"
+#include "devnum-util.h"
+#include "dirent-util.h"
+#include "errno-util.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "missing_magic.h"
+#include "parse-util.h"
+
+static int fd_get_devnum(int fd, BlockDeviceLookupFlag flags, dev_t *ret) {
+ struct stat st;
+ dev_t devnum;
+ int r;
+
+ assert(fd >= 0);
+ assert(ret);
+
+ if (fstat(fd, &st) < 0)
+ return -errno;
+
+ if (S_ISBLK(st.st_mode))
+ devnum = st.st_rdev;
+ else if (!FLAGS_SET(flags, BLOCK_DEVICE_LOOKUP_BACKING))
+ return -ENOTBLK;
+ else if (!S_ISREG(st.st_mode) && !S_ISDIR(st.st_mode))
+ return -ENOTBLK;
+ else if (major(st.st_dev) != 0)
+ devnum = st.st_dev;
+ else {
+ /* If major(st.st_dev) is zero, this might mean we are backed by btrfs, which needs special
+ * handing, to get the backing device node. */
+
+ r = fcntl(fd, F_GETFL);
+ if (r < 0)
+ return -errno;
+
+ if (FLAGS_SET(r, O_PATH)) {
+ _cleanup_close_ int regfd = -1;
+
+ /* The fstat() above we can execute on an O_PATH fd. But the btrfs ioctl we cannot.
+ * Hence acquire a "real" fd first, without the O_PATH flag. */
+
+ regfd = fd_reopen(fd, O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
+ if (regfd < 0)
+ return regfd;
+
+ r = btrfs_get_block_device_fd(regfd, &devnum);
+ } else
+ r = btrfs_get_block_device_fd(fd, &devnum);
+ if (r == -ENOTTY) /* not btrfs */
+ return -ENOTBLK;
+ if (r < 0)
+ return r;
+ }
+
+ *ret = devnum;
+ return 0;
+}
+
+int block_device_is_whole_disk(sd_device *dev) {
+ const char *s;
+ int r;
+
+ assert(dev);
+
+ r = sd_device_get_subsystem(dev, &s);
+ if (r < 0)
+ return r;
+
+ if (!streq(s, "block"))
+ return -ENOTBLK;
+
+ r = sd_device_get_devtype(dev, &s);
+ if (r < 0)
+ return r;
+
+ return streq(s, "disk");
+}
+
+int block_device_get_whole_disk(sd_device *dev, sd_device **ret) {
+ int r;
+
+ assert(dev);
+ assert(ret);
+
+ /* Do not unref returned sd_device object. */
+
+ r = block_device_is_whole_disk(dev);
+ if (r < 0)
+ return r;
+ if (r == 0) {
+ r = sd_device_get_parent(dev, &dev);
+ if (r == -ENOENT) /* Already removed? Let's return a recognizable error. */
+ return -ENODEV;
+ if (r < 0)
+ return r;
+
+ r = block_device_is_whole_disk(dev);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ return -ENXIO;
+ }
+
+ *ret = dev;
+ return 0;
+}
+
+static int block_device_get_originating(sd_device *dev, sd_device **ret) {
+ _cleanup_(sd_device_unrefp) sd_device *first_found = NULL;
+ const char *suffix;
+ sd_device *child;
+ dev_t devnum = 0; /* avoid false maybe-uninitialized warning */
+
+ /* 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. */
+
+ assert(dev);
+ assert(ret);
+
+ FOREACH_DEVICE_CHILD_WITH_SUFFIX(dev, child, suffix) {
+ sd_device *child_whole_disk;
+ dev_t n;
+
+ if (!path_startswith(suffix, "slaves"))
+ continue;
+
+ if (block_device_get_whole_disk(child, &child_whole_disk) < 0)
+ continue;
+
+ if (sd_device_get_devnum(child_whole_disk, &n) < 0)
+ continue;
+
+ if (!first_found) {
+ first_found = sd_device_ref(child);
+ devnum = n;
+ continue;
+ }
+
+ /* 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 by iterating over every node in the 'slaves/' directory and comparing them with
+ * the first that gets returned by readdir(), to ensure they all point to the same device. */
+ if (n != devnum)
+ return -ENOTUNIQ;
+ }
+
+ if (!first_found)
+ return -ENOENT;
+
+ *ret = TAKE_PTR(first_found);
+ return 1; /* found */
+}
+
+int block_device_new_from_fd(int fd, BlockDeviceLookupFlag flags, sd_device **ret) {
+ _cleanup_(sd_device_unrefp) sd_device *dev = NULL;
+ dev_t devnum;
+ int r;
+
+ assert(fd >= 0);
+ assert(ret);
+
+ r = fd_get_devnum(fd, flags, &devnum);
+ if (r < 0)
+ return r;
+
+ r = sd_device_new_from_devnum(&dev, 'b', devnum);
+ if (r < 0)
+ return r;
+
+ if (FLAGS_SET(flags, BLOCK_DEVICE_LOOKUP_ORIGINATING)) {
+ _cleanup_(sd_device_unrefp) sd_device *dev_origin = NULL;
+ sd_device *dev_whole_disk;
+
+ r = block_device_get_whole_disk(dev, &dev_whole_disk);
+ if (r < 0)
+ return r;
+
+ r = block_device_get_originating(dev_whole_disk, &dev_origin);
+ if (r < 0 && r != -ENOENT)
+ return r;
+ if (r > 0)
+ device_unref_and_replace(dev, dev_origin);
+ }
+
+ if (FLAGS_SET(flags, BLOCK_DEVICE_LOOKUP_WHOLE_DISK)) {
+ sd_device *dev_whole_disk;
+
+ r = block_device_get_whole_disk(dev, &dev_whole_disk);
+ if (r < 0)
+ return r;
+
+ *ret = sd_device_ref(dev_whole_disk);
+ return 0;
+ }
+
+ *ret = sd_device_ref(dev);
+ return 0;
+}
+
+int block_device_new_from_path(const char *path, BlockDeviceLookupFlag flags, sd_device **ret) {
+ _cleanup_close_ int fd = -1;
+
+ assert(path);
+ assert(ret);
+
+ fd = open(path, O_CLOEXEC|O_PATH);
+ if (fd < 0)
+ return -errno;
+
+ return block_device_new_from_fd(fd, flags, ret);
+}
+
+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_devnum(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_fd(int fd, dev_t *ret) {
+ struct stat st;
+ int r;
+
+ assert(fd >= 0);
+ assert(ret);
+
+ /* Gets the block device directly backing a file system. If the block device is encrypted, returns
+ * the device mapper block device. */
+
+ if (fstat(fd, &st))
+ return -errno;
+
+ if (major(st.st_dev) != 0) {
+ *ret = st.st_dev;
+ return 1;
+ }
+
+ r = fcntl(fd, F_GETFL);
+ if (r < 0)
+ return -errno;
+ if (FLAGS_SET(r, O_PATH) && (S_ISREG(st.st_mode) || S_ISDIR(st.st_mode))) {
+ _cleanup_close_ int real_fd = -1;
+
+ /* The fstat() above we can execute on an O_PATH fd. But the btrfs ioctl we cannot. Hence
+ * acquire a "real" fd first, without the O_PATH flag. */
+
+ real_fd = fd_reopen(fd, O_RDONLY|O_CLOEXEC);
+ if (real_fd < 0)
+ return real_fd;
+ r = btrfs_get_block_device_fd(real_fd, ret);
+ } else
+ 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 get_block_device(const char *path, dev_t *ret) {
+ _cleanup_close_ int fd = -1;
+
+ assert(path);
+ assert(ret);
+
+ fd = open(path, O_RDONLY|O_NOFOLLOW|O_CLOEXEC);
+ if (fd < 0)
+ return -errno;
+
+ return get_block_device_fd(fd, ret);
+}
+
+int block_get_originating(dev_t dt, dev_t *ret) {
+ _cleanup_(sd_device_unrefp) sd_device *dev = NULL, *origin = NULL;
+ int r;
+
+ assert(ret);
+
+ r = sd_device_new_from_devnum(&dev, 'b', dt);
+ if (r < 0)
+ return r;
+
+ r = block_device_get_originating(dev, &origin);
+ if (r < 0)
+ return r;
+
+ return sd_device_get_devnum(origin, ret);
+}
+
+int get_block_device_harder_fd(int fd, dev_t *ret) {
+ int r;
+
+ assert(fd >= 0);
+ 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_fd(fd, ret);
+ if (r <= 0)
+ return r;
+
+ r = block_get_originating(*ret, ret);
+ if (r < 0)
+ log_debug_errno(r, "Failed to chase block device, ignoring: %m");
+
+ return 1;
+}
+
+int get_block_device_harder(const char *path, dev_t *ret) {
+ _cleanup_close_ int fd = -1;
+
+ assert(path);
+ assert(ret);
+
+ fd = open(path, O_RDONLY|O_NOFOLLOW|O_CLOEXEC);
+ if (fd < 0)
+ return -errno;
+
+ return get_block_device_harder_fd(fd, ret);
+}
+
+int lock_whole_block_device(dev_t devt, int operation) {
+ _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;
+
+ lock_fd = r = device_open_from_devnum(S_IFBLK, whole_devt, O_RDONLY|O_CLOEXEC|O_NONBLOCK, NULL);
+ if (r < 0)
+ return r;
+
+ 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);
+}
+
+static int blockdev_is_encrypted(const char *sysfs_path, unsigned depth_left) {
+ _cleanup_free_ char *p = NULL, *uuids = NULL;
+ _cleanup_closedir_ DIR *d = NULL;
+ int r, found_encrypted = false;
+
+ assert(sysfs_path);
+
+ if (depth_left == 0)
+ return -EINVAL;
+
+ p = path_join(sysfs_path, "dm/uuid");
+ if (!p)
+ return -ENOMEM;
+
+ r = read_one_line_file(p, &uuids);
+ if (r != -ENOENT) {
+ if (r < 0)
+ return r;
+
+ /* The DM device's uuid attribute is prefixed with "CRYPT-" if this is a dm-crypt device. */
+ if (startswith(uuids, "CRYPT-"))
+ return true;
+ }
+
+ /* Not a dm-crypt device itself. But maybe it is on top of one? Follow the links in the "slaves/"
+ * subdir. */
+
+ p = mfree(p);
+ p = path_join(sysfs_path, "slaves");
+ if (!p)
+ return -ENOMEM;
+
+ d = opendir(p);
+ if (!d) {
+ if (errno == ENOENT) /* Doesn't have underlying devices */
+ return false;
+
+ return -errno;
+ }
+
+ for (;;) {
+ _cleanup_free_ char *q = NULL;
+ struct dirent *de;
+
+ errno = 0;
+ de = readdir_no_dot(d);
+ if (!de) {
+ if (errno != 0)
+ return -errno;
+
+ break; /* No more underlying devices */
+ }
+
+ q = path_join(p, de->d_name);
+ if (!q)
+ return -ENOMEM;
+
+ r = blockdev_is_encrypted(q, depth_left - 1);
+ if (r < 0)
+ return r;
+ if (r == 0) /* we found one that is not encrypted? then propagate that immediately */
+ return false;
+
+ found_encrypted = true;
+ }
+
+ return found_encrypted;
+}
+
+int fd_is_encrypted(int fd) {
+ char p[SYS_BLOCK_PATH_MAX(NULL)];
+ dev_t devt;
+ int r;
+
+ r = get_block_device_fd(fd, &devt);
+ if (r < 0)
+ return r;
+ if (r == 0) /* doesn't have a block device */
+ return false;
+
+ xsprintf_sys_block_path(p, NULL, devt);
+
+ return blockdev_is_encrypted(p, 10 /* safety net: maximum recursion depth */);
+}
+
+int path_is_encrypted(const char *path) {
+ char p[SYS_BLOCK_PATH_MAX(NULL)];
+ dev_t devt;
+ int r;
+
+ r = get_block_device(path, &devt);
+ if (r < 0)
+ return r;
+ if (r == 0) /* doesn't have a block device */
+ return false;
+
+ xsprintf_sys_block_path(p, NULL, devt);
+
+ return blockdev_is_encrypted(p, 10 /* safety net: maximum recursion depth */);
+}
+
+int fd_get_whole_disk(int fd, bool backing, dev_t *ret) {
+ dev_t devt;
+ int r;
+
+ assert(fd >= 0);
+ assert(ret);
+
+ r = fd_get_devnum(fd, backing ? BLOCK_DEVICE_LOOKUP_BACKING : 0, &devt);
+ if (r < 0)
+ return r;
+
+ return block_get_whole_disk(devt, ret);
+}
+
+int path_get_whole_disk(const char *path, bool backing, dev_t *ret) {
+ _cleanup_close_ int fd = -1;
+
+ fd = open(path, O_CLOEXEC|O_PATH);
+ if (fd < 0)
+ return -errno;
+
+ return fd_get_whole_disk(fd, backing, ret);
+}
+
+int block_device_add_partition(
+ int fd,
+ const char *name,
+ int nr,
+ uint64_t start,
+ uint64_t size) {
+
+ assert(fd >= 0);
+ assert(name);
+ assert(nr > 0);
+
+ struct blkpg_partition bp = {
+ .pno = nr,
+ .start = start,
+ .length = size,
+ };
+
+ struct blkpg_ioctl_arg ba = {
+ .op = BLKPG_ADD_PARTITION,
+ .data = &bp,
+ .datalen = sizeof(bp),
+ };
+
+ if (strlen(name) >= sizeof(bp.devname))
+ return -EINVAL;
+
+ strcpy(bp.devname, name);
+
+ return RET_NERRNO(ioctl(fd, BLKPG, &ba));
+}
+
+int block_device_remove_partition(
+ int fd,
+ const char *name,
+ int nr) {
+
+ assert(fd >= 0);
+ assert(name);
+ assert(nr > 0);
+
+ struct blkpg_partition bp = {
+ .pno = nr,
+ };
+
+ struct blkpg_ioctl_arg ba = {
+ .op = BLKPG_DEL_PARTITION,
+ .data = &bp,
+ .datalen = sizeof(bp),
+ };
+
+ if (strlen(name) >= sizeof(bp.devname))
+ return -EINVAL;
+
+ strcpy(bp.devname, name);
+
+ return RET_NERRNO(ioctl(fd, BLKPG, &ba));
+}
+
+int block_device_resize_partition(
+ int fd,
+ int nr,
+ uint64_t start,
+ uint64_t size) {
+
+ assert(fd >= 0);
+ assert(nr > 0);
+
+ struct blkpg_partition bp = {
+ .pno = nr,
+ .start = start,
+ .length = size,
+ };
+
+ struct blkpg_ioctl_arg ba = {
+ .op = BLKPG_RESIZE_PARTITION,
+ .data = &bp,
+ .datalen = sizeof(bp),
+ };
+
+ return RET_NERRNO(ioctl(fd, BLKPG, &ba));
+}
+
+int partition_enumerator_new(sd_device *dev, sd_device_enumerator **ret) {
+ _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+ const char *s;
+ int r;
+
+ assert(dev);
+ assert(ret);
+
+ /* Refuse invocation on partition block device, insist on "whole" device */
+ r = block_device_is_whole_disk(dev);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ return -ENXIO; /* return a recognizable error */
+
+ r = sd_device_enumerator_new(&e);
+ if (r < 0)
+ return r;
+
+ r = sd_device_enumerator_allow_uninitialized(e);
+ if (r < 0)
+ return r;
+
+ r = sd_device_enumerator_add_match_parent(e, dev);
+ if (r < 0)
+ return r;
+
+ r = sd_device_get_sysname(dev, &s);
+ if (r < 0)
+ return r;
+
+ /* Also add sysname check for safety. Hopefully, this also improves performance. */
+ s = strjoina(s, "*");
+ r = sd_device_enumerator_add_match_sysname(e, s);
+ if (r < 0)
+ return r;
+
+ r = sd_device_enumerator_add_match_subsystem(e, "block", /* match = */ true);
+ if (r < 0)
+ return r;
+
+ r = sd_device_enumerator_add_match_property(e, "DEVTYPE", "partition");
+ if (r < 0)
+ return r;
+
+ *ret = TAKE_PTR(e);
+ return 0;
+}
+
+int block_device_remove_all_partitions(sd_device *dev, int fd) {
+ _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+ _cleanup_(sd_device_unrefp) sd_device *dev_unref = NULL;
+ _cleanup_close_ int fd_close = -1;
+ bool has_partitions = false;
+ sd_device *part;
+ int r, k = 0;
+
+ assert(dev || fd >= 0);
+
+ if (!dev) {
+ r = block_device_new_from_fd(fd, 0, &dev_unref);
+ if (r < 0)
+ return r;
+
+ dev = dev_unref;
+ }
+
+ r = partition_enumerator_new(dev, &e);
+ if (r < 0)
+ return r;
+
+ if (fd < 0) {
+ fd_close = sd_device_open(dev, O_CLOEXEC|O_NONBLOCK|O_NOCTTY|O_RDONLY);
+ if (fd_close < 0)
+ return fd_close;
+
+ fd = fd_close;
+ }
+
+ FOREACH_DEVICE(e, part) {
+ const char *v, *devname;
+ int nr;
+
+ has_partitions = true;
+
+ r = sd_device_get_devname(part, &devname);
+ if (r < 0)
+ return r;
+
+ r = sd_device_get_property_value(part, "PARTN", &v);
+ if (r < 0)
+ return r;
+
+ r = safe_atoi(v, &nr);
+ if (r < 0)
+ return r;
+
+ r = block_device_remove_partition(fd, devname, nr);
+ if (r == -ENODEV) {
+ log_debug("Kernel removed partition %s before us, ignoring", devname);
+ continue;
+ }
+ if (r < 0) {
+ log_debug_errno(r, "Failed to remove partition %s: %m", devname);
+ k = k < 0 ? k : r;
+ continue;
+ }
+
+ log_debug("Removed partition %s", devname);
+ }
+
+ return k < 0 ? k : has_partitions;
+}
+
+int block_device_has_partitions(sd_device *dev) {
+ _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+ int r;
+
+ assert(dev);
+
+ /* Checks if the specified device currently has partitions. */
+
+ r = partition_enumerator_new(dev, &e);
+ if (r < 0)
+ return r;
+
+ return !!sd_device_enumerator_get_device_first(e);
+}
+
+int blockdev_reread_partition_table(sd_device *dev) {
+ _cleanup_close_ int fd = -1;
+
+ assert(dev);
+
+ /* Try to re-read the partition table. This only succeeds if none of the devices is busy. */
+
+ fd = sd_device_open(dev, O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
+ if (fd < 0)
+ return fd;
+
+ if (flock(fd, LOCK_EX|LOCK_NB) < 0)
+ return -errno;
+
+ if (ioctl(fd, BLKRRPART, 0) < 0)
+ return -errno;
+
+ return 0;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-05 20:42:32 +0000