summaryrefslogtreecommitdiffstats
path: root/lib/utils_devpath.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--lib/utils_devpath.c459
1 files changed, 459 insertions, 0 deletions
diff --git a/lib/utils_devpath.c b/lib/utils_devpath.c
new file mode 100644
index 0000000..dc5a5bb
--- /dev/null
+++ b/lib/utils_devpath.c
@@ -0,0 +1,459 @@
+/*
+ * devname - search for device name
+ *
+ * Copyright (C) 2004 Jana Saout <jana@saout.de>
+ * Copyright (C) 2004-2007 Clemens Fruhwirth <clemens@endorphin.org>
+ * Copyright (C) 2009-2023 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2009-2023 Milan Broz
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <errno.h>
+#include <limits.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#ifdef HAVE_SYS_SYSMACROS_H
+# include <sys/sysmacros.h> /* for major, minor */
+#endif
+#include "internal.h"
+
+static char *__lookup_dev(char *path, dev_t dev, int dir_level, const int max_level)
+{
+ struct dirent *entry;
+ struct stat st;
+ char *ptr;
+ char *result = NULL;
+ DIR *dir;
+ int space;
+
+ /* Ignore strange nested directories */
+ if (dir_level > max_level)
+ return NULL;
+
+ path[PATH_MAX - 1] = '\0';
+ ptr = path + strlen(path);
+ *ptr++ = '/';
+ *ptr = '\0';
+ space = PATH_MAX - (ptr - path);
+
+ dir = opendir(path);
+ if (!dir)
+ return NULL;
+
+ while((entry = readdir(dir))) {
+ if (entry->d_name[0] == '.' ||
+ !strncmp(entry->d_name, "..", 2))
+ continue;
+
+ if (dir_level == 0 &&
+ (!strcmp(entry->d_name, "shm") ||
+ !strcmp(entry->d_name, "fd") ||
+ !strcmp(entry->d_name, "char") ||
+ !strcmp(entry->d_name, "pts")))
+ continue;
+
+ strncpy(ptr, entry->d_name, space);
+ if (stat(path, &st) < 0)
+ continue;
+
+ if (S_ISDIR(st.st_mode)) {
+ result = __lookup_dev(path, dev, dir_level + 1, max_level);
+ if (result)
+ break;
+ } else if (S_ISBLK(st.st_mode)) {
+ /* workaround: ignore dm-X devices, these are internal kernel names */
+ if (dir_level == 0 && dm_is_dm_kernel_name(entry->d_name))
+ continue;
+ if (st.st_rdev == dev) {
+ result = strdup(path);
+ break;
+ }
+ }
+ }
+
+ closedir(dir);
+ return result;
+}
+
+/*
+ * Non-udev systemd need to scan for device here.
+ */
+static char *lookup_dev_old(int major, int minor)
+{
+ dev_t dev;
+ char *result = NULL, buf[PATH_MAX + 1];
+
+ dev = makedev(major, minor);
+ strncpy(buf, "/dev", PATH_MAX);
+ buf[PATH_MAX] = '\0';
+
+ /* First try low level device */
+ if ((result = __lookup_dev(buf, dev, 0, 0)))
+ return result;
+
+ /* If it is dm, try DM dir */
+ if (dm_is_dm_device(major)) {
+ strncpy(buf, dm_get_dir(), PATH_MAX);
+ if ((result = __lookup_dev(buf, dev, 0, 0)))
+ return result;
+ }
+
+ strncpy(buf, "/dev", PATH_MAX);
+ return __lookup_dev(buf, dev, 0, 4);
+}
+
+/*
+ * Returns string pointing to device in /dev according to "major:minor" dev_id
+ */
+char *crypt_lookup_dev(const char *dev_id)
+{
+ int major, minor;
+ char link[PATH_MAX], path[PATH_MAX], *devname, *devpath = NULL;
+ struct stat st;
+ ssize_t len;
+
+ if (sscanf(dev_id, "%d:%d", &major, &minor) != 2)
+ return NULL;
+
+ if (snprintf(path, sizeof(path), "/sys/dev/block/%s", dev_id) < 0)
+ return NULL;
+
+ len = readlink(path, link, sizeof(link) - 1);
+ if (len < 0) {
+ /* Without /sys use old scan */
+ if (stat("/sys/dev/block", &st) < 0)
+ return lookup_dev_old(major, minor);
+ return NULL;
+ }
+
+ link[len] = '\0';
+ devname = strrchr(link, '/');
+ if (!devname)
+ return NULL;
+ devname++;
+
+ if (dm_is_dm_kernel_name(devname))
+ devpath = dm_device_path("/dev/mapper/", major, minor);
+ else if (snprintf(path, sizeof(path), "/dev/%s", devname) > 0)
+ devpath = strdup(path);
+
+ /*
+ * Check that path is correct.
+ */
+ if (devpath && ((stat(devpath, &st) < 0) ||
+ !S_ISBLK(st.st_mode) ||
+ (st.st_rdev != makedev(major, minor)))) {
+ free(devpath);
+ /* Should never happen unless user mangles with dev nodes. */
+ return lookup_dev_old(major, minor);
+ }
+
+ return devpath;
+}
+
+static int _read_uint64(const char *sysfs_path, uint64_t *value)
+{
+ char tmp[64] = {0};
+ int fd, r;
+
+ if ((fd = open(sysfs_path, O_RDONLY)) < 0)
+ return 0;
+ r = read(fd, tmp, sizeof(tmp));
+ close(fd);
+
+ if (r <= 0)
+ return 0;
+
+ if (sscanf(tmp, "%" PRIu64, value) != 1)
+ return 0;
+
+ return 1;
+}
+
+static int _sysfs_get_uint64(int major, int minor, uint64_t *value, const char *attr)
+{
+ char path[PATH_MAX];
+
+ if (snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/%s",
+ major, minor, attr) < 0)
+ return 0;
+
+ return _read_uint64(path, value);
+}
+
+static int _path_get_uint64(const char *sysfs_path, uint64_t *value, const char *attr)
+{
+ char path[PATH_MAX];
+
+ if (snprintf(path, sizeof(path), "%s/%s",
+ sysfs_path, attr) < 0)
+ return 0;
+
+ return _read_uint64(path, value);
+}
+
+int crypt_dev_is_rotational(int major, int minor)
+{
+ uint64_t val;
+
+ if (!_sysfs_get_uint64(major, minor, &val, "queue/rotational"))
+ return 1; /* if failed, expect rotational disk */
+
+ return val ? 1 : 0;
+}
+
+int crypt_dev_is_partition(const char *dev_path)
+{
+ uint64_t val;
+ struct stat st;
+
+ if (stat(dev_path, &st) < 0)
+ return 0;
+
+ if (!S_ISBLK(st.st_mode))
+ return 0;
+
+ if (!_sysfs_get_uint64(major(st.st_rdev), minor(st.st_rdev),
+ &val, "partition"))
+ return 0;
+
+ return val ? 1 : 0;
+}
+
+uint64_t crypt_dev_partition_offset(const char *dev_path)
+{
+ uint64_t val;
+ struct stat st;
+
+ if (!crypt_dev_is_partition(dev_path))
+ return 0;
+
+ if (stat(dev_path, &st) < 0)
+ return 0;
+
+ if (!_sysfs_get_uint64(major(st.st_rdev), minor(st.st_rdev),
+ &val, "start"))
+ return 0;
+
+ return val;
+}
+
+/* Try to find partition which match offset and size on top level device */
+char *crypt_get_partition_device(const char *dev_path, uint64_t offset, uint64_t size)
+{
+ char link[PATH_MAX], path[PATH_MAX], part_path[PATH_MAX], *devname;
+ char *result = NULL;
+ struct stat st;
+ size_t devname_len;
+ ssize_t len;
+ struct dirent *entry;
+ DIR *dir;
+ uint64_t part_offset, part_size;
+
+ if (stat(dev_path, &st) < 0)
+ return NULL;
+
+ if (!S_ISBLK(st.st_mode))
+ return NULL;
+
+ if (snprintf(path, sizeof(path), "/sys/dev/block/%d:%d",
+ major(st.st_rdev), minor(st.st_rdev)) < 0)
+ return NULL;
+
+ dir = opendir(path);
+ if (!dir)
+ return NULL;
+
+ len = readlink(path, link, sizeof(link) - 1);
+ if (len < 0) {
+ closedir(dir);
+ return NULL;
+ }
+
+ /* Get top level disk name for sysfs search */
+ link[len] = '\0';
+ devname = strrchr(link, '/');
+ if (!devname) {
+ closedir(dir);
+ return NULL;
+ }
+ devname++;
+
+ /* DM devices do not use kernel partitions. */
+ if (dm_is_dm_kernel_name(devname)) {
+ closedir(dir);
+ return NULL;
+ }
+
+ devname_len = strlen(devname);
+ while((entry = readdir(dir))) {
+ if (strncmp(entry->d_name, devname, devname_len))
+ continue;
+
+ if (snprintf(part_path, sizeof(part_path), "%s/%s",
+ path, entry->d_name) < 0)
+ continue;
+
+ if (stat(part_path, &st) < 0)
+ continue;
+
+ if (S_ISDIR(st.st_mode)) {
+ if (!_path_get_uint64(part_path, &part_offset, "start") ||
+ !_path_get_uint64(part_path, &part_size, "size"))
+ continue;
+ if (part_offset == offset && part_size == size &&
+ snprintf(part_path, sizeof(part_path), "/dev/%s",
+ entry->d_name) > 0) {
+ result = strdup(part_path);
+ break;
+ }
+ }
+ }
+ closedir(dir);
+
+ return result;
+}
+
+/* Try to find base device from partition */
+char *crypt_get_base_device(const char *dev_path)
+{
+ char link[PATH_MAX], path[PATH_MAX], part_path[PATH_MAX], *devname;
+ struct stat st;
+ ssize_t len;
+
+ if (!crypt_dev_is_partition(dev_path))
+ return NULL;
+
+ if (stat(dev_path, &st) < 0)
+ return NULL;
+
+ if (snprintf(path, sizeof(path), "/sys/dev/block/%d:%d",
+ major(st.st_rdev), minor(st.st_rdev)) < 0)
+ return NULL;
+
+ len = readlink(path, link, sizeof(link) - 1);
+ if (len < 0)
+ return NULL;
+
+ /* Get top level disk name for sysfs search */
+ link[len] = '\0';
+ devname = strrchr(link, '/');
+ if (!devname)
+ return NULL;
+ *devname = '\0';
+ devname = strrchr(link, '/');
+ if (!devname)
+ return NULL;
+ devname++;
+
+ if (dm_is_dm_kernel_name(devname))
+ return NULL;
+
+ if (snprintf(part_path, sizeof(part_path), "/dev/%s", devname) < 0)
+ return NULL;
+
+ return strdup(part_path);
+}
+
+int lookup_by_disk_id(const char *dm_uuid)
+{
+ struct dirent *entry;
+ struct stat st;
+ int r = 0; /* not found */
+ DIR *dir = opendir("/dev/disk/by-id");
+
+ if (!dir)
+ /* map ENOTDIR to ENOENT we'll handle both errors same */
+ return errno == ENOTDIR ? -ENOENT : -errno;
+
+ while ((entry = readdir(dir))) {
+ if (entry->d_name[0] == '.' ||
+ !strncmp(entry->d_name, "..", 2))
+ continue;
+
+ if (fstatat(dirfd(dir), entry->d_name, &st, AT_SYMLINK_NOFOLLOW)) {
+ r = -EINVAL;
+ break;
+ }
+
+ if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode))
+ continue;
+
+ if (!strncmp(entry->d_name, dm_uuid, strlen(dm_uuid))) {
+ r = 1;
+ break;
+ }
+ }
+
+ closedir(dir);
+
+ return r;
+}
+
+int lookup_by_sysfs_uuid_field(const char *dm_uuid)
+{
+ struct dirent *entry;
+ char subpath[PATH_MAX], uuid[DM_UUID_LEN];
+ ssize_t s;
+ struct stat st;
+ int fd, len, r = 0; /* not found */
+ DIR *dir = opendir("/sys/block/");
+
+ if (!dir)
+ /* map ENOTDIR to ENOENT we'll handle both errors same */
+ return errno == ENOTDIR ? -ENOENT : -errno;
+
+ while (r != 1 && (entry = readdir(dir))) {
+ if (entry->d_name[0] == '.' ||
+ !strncmp(entry->d_name, "..", 2))
+ continue;
+
+ len = snprintf(subpath, PATH_MAX, "%s/%s", entry->d_name, "dm/uuid");
+ if (len < 0 || len >= PATH_MAX) {
+ r = -EINVAL;
+ break;
+ }
+
+ /* looking for dm-X/dm/uuid file, symlinks are fine */
+ fd = openat(dirfd(dir), subpath, O_RDONLY | O_CLOEXEC);
+ if (fd < 0)
+ continue;
+
+ if (fstat(fd, &st) || !S_ISREG(st.st_mode)) {
+ close(fd);
+ continue;
+ }
+
+ /* reads binary data */
+ s = read_buffer(fd, uuid, sizeof(uuid) - 1);
+ if (s > 0) {
+ uuid[s] = '\0';
+ if (!strncmp(uuid, dm_uuid, strlen(dm_uuid)))
+ r = 1;
+ }
+
+ close(fd);
+ }
+
+ closedir(dir);
+
+ return r;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-08 20:46:10 +0000