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Diffstat (limited to '')
| -rw-r--r-- | lib/utils_devpath.c | 458 |
1 files changed, 458 insertions, 0 deletions
diff --git a/lib/utils_devpath.c b/lib/utils_devpath.c new file mode 100644 index 0000000..0e92252 --- /dev/null +++ b/lib/utils_devpath.c @@ -0,0 +1,458 @@ +/* + * devname - search for device name + * + * Copyright (C) 2004 Jana Saout <jana@saout.de> + * Copyright (C) 2004-2007 Clemens Fruhwirth <clemens@endorphin.org> + * Copyright (C) 2009-2019 Red Hat, Inc. All rights reserved. + * Copyright (C) 2009-2019 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 <fcntl.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, minor)) { + 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; + + snprintf(part_path, sizeof(part_path), "/dev/%s", devname); + 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, size_t max_len) +{ + struct dirent *entry; + char subpath[PATH_MAX], uuid[max_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, max_len - 1); + if (s > 0) { + uuid[s] = '\0'; + if (!strncmp(uuid, dm_uuid, strlen(dm_uuid))) + r = 1; + } + + close(fd); + } + + closedir(dir); + + return r; +} |