diff options
Diffstat (limited to 'src/shared/mount-util.h')
| -rw-r--r-- | src/shared/mount-util.h | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/src/shared/mount-util.h b/src/shared/mount-util.h new file mode 100644 index 0000000..ef31104 --- /dev/null +++ b/src/shared/mount-util.h @@ -0,0 +1,143 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +#pragma once + +#include <mntent.h> +#include <stdio.h> +#include <sys/stat.h> +#include <unistd.h> + +#include "alloc-util.h" +#include "dissect-image.h" +#include "errno-util.h" +#include "macro.h" +#include "pidref.h" + +int repeat_unmount(const char *path, int flags); + +int umount_recursive_full(const char *target, int flags, char **keep); + +static inline int umount_recursive(const char *target, int flags) { + return umount_recursive_full(target, flags, NULL); +} + +int bind_remount_recursive_with_mountinfo(const char *prefix, unsigned long new_flags, unsigned long flags_mask, char **deny_list, FILE *proc_self_mountinfo); +static inline int bind_remount_recursive(const char *prefix, unsigned long new_flags, unsigned long flags_mask, char **deny_list) { + return bind_remount_recursive_with_mountinfo(prefix, new_flags, flags_mask, deny_list, NULL); +} + +int bind_remount_one_with_mountinfo(const char *path, unsigned long new_flags, unsigned long flags_mask, FILE *proc_self_mountinfo); + +int mount_switch_root_full(const char *path, unsigned long mount_propagation_flag, bool force_ms_move); +static inline int mount_switch_root(const char *path, unsigned long mount_propagation_flag) { + return mount_switch_root_full(path, mount_propagation_flag, false); +} + +DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(FILE*, endmntent, NULL); +#define _cleanup_endmntent_ _cleanup_(endmntentp) + +int mount_verbose_full( + int error_log_level, + const char *what, + const char *where, + const char *type, + unsigned long flags, + const char *options, + bool follow_symlink); + +static inline int mount_follow_verbose( + int error_log_level, + const char *what, + const char *where, + const char *type, + unsigned long flags, + const char *options) { + return mount_verbose_full(error_log_level, what, where, type, flags, options, true); +} + +static inline int mount_nofollow_verbose( + int error_log_level, + const char *what, + const char *where, + const char *type, + unsigned long flags, + const char *options) { + return mount_verbose_full(error_log_level, what, where, type, flags, options, false); +} + +int umount_verbose( + int error_log_level, + const char *where, + int flags); + +int mount_exchange_graceful(int fsmount_fd, const char *dest, bool mount_beneath); + +int mount_option_mangle( + const char *options, + unsigned long mount_flags, + unsigned long *ret_mount_flags, + char **ret_remaining_options); + +int mode_to_inaccessible_node(const char *runtime_dir, mode_t mode, char **dest); +int mount_flags_to_string(unsigned long flags, char **ret); + +/* Useful for usage with _cleanup_(), unmounts, removes a directory and frees the pointer */ +static inline char* umount_and_rmdir_and_free(char *p) { + PROTECT_ERRNO; + if (p) { + (void) umount_recursive(p, 0); + (void) rmdir(p); + } + return mfree(p); +} +DEFINE_TRIVIAL_CLEANUP_FUNC(char*, umount_and_rmdir_and_free); + +static inline char *umount_and_free(char *p) { + PROTECT_ERRNO; + if (p) + (void) umount_recursive(p, 0); + return mfree(p); +} +DEFINE_TRIVIAL_CLEANUP_FUNC(char*, umount_and_free); + +int bind_mount_in_namespace(PidRef *target, const char *propagate_path, const char *incoming_path, const char *src, const char *dest, bool read_only, bool make_file_or_directory); +int mount_image_in_namespace(PidRef *target, const char *propagate_path, const char *incoming_path, const char *src, const char *dest, bool read_only, bool make_file_or_directory, const MountOptions *options, const ImagePolicy *image_policy); + +int make_mount_point(const char *path); +int fd_make_mount_point(int fd); + +typedef enum RemountIdmapping { + REMOUNT_IDMAPPING_NONE, + /* Include a mapping from UID_MAPPED_ROOT (i.e. UID 2^31-2) on the backing fs to UID 0 on the + * uidmapped fs. This is useful to ensure that the host root user can safely add inodes to the + * uidmapped fs (which otherwise wouldn't work as the host root user is not defined on the uidmapped + * mount and any attempts to create inodes will then be refused with EOVERFLOW). The idea is that + * these inodes are quickly re-chown()ed to more suitable UIDs/GIDs. Any code that intends to be able + * to add inodes to file systems mapped this way should set this flag, but given it comes with + * certain security implications defaults to off, and requires explicit opt-in. */ + REMOUNT_IDMAPPING_HOST_ROOT, + /* Define a mapping from root user within the container to the owner of the bind mounted directory. + * This ensure no root-owned files will be written in a bind-mounted directory owned by a different + * user. No other users are mapped. */ + REMOUNT_IDMAPPING_HOST_OWNER, + _REMOUNT_IDMAPPING_MAX, + _REMOUNT_IDMAPPING_INVALID = -EINVAL, +} RemountIdmapping; + +int make_userns(uid_t uid_shift, uid_t uid_range, uid_t owner, RemountIdmapping idmapping); +int remount_idmap_fd(char **p, int userns_fd); +int remount_idmap(char **p, uid_t uid_shift, uid_t uid_range, uid_t owner, RemountIdmapping idmapping); + +int bind_mount_submounts( + const char *source, + const char *target); + +/* Creates a mount point (not parents) based on the source path or stat - ie, a file or a directory */ +int make_mount_point_inode_from_stat(const struct stat *st, const char *dest, mode_t mode); +int make_mount_point_inode_from_path(const char *source, const char *dest, mode_t mode); + +int trigger_automount_at(int dir_fd, const char *path); + +unsigned long credentials_fs_mount_flags(bool ro); +int mount_credentials_fs(const char *path, size_t size, bool ro); + +int make_fsmount(int error_log_level, const char *what, const char *type, unsigned long flags, const char *options, int userns_fd); |