src/shared/mount-util.h

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2 #pragma once
   3
   4 #include <mntent.h>
   5 #include <stdio.h>
   6 #include <sys/stat.h>
   7 #include <unistd.h>
   8
   9 #include "alloc-util.h"
  10 #include "dissect-image.h"
  11 #include "errno-util.h"
  12 #include "macro.h"
  13
  14 int repeat_unmount(const char *path, int flags);
  15 int umount_recursive(const char *target, int flags);
  16
  17 int bind_remount_recursive_with_mountinfo(const char *prefix, unsigned long new_flags, unsigned long flags_mask, char **deny_list, FILE *proc_self_mountinfo);
  18 static inline int bind_remount_recursive(const char *prefix, unsigned long new_flags, unsigned long flags_mask, char **deny_list) {
  19         return bind_remount_recursive_with_mountinfo(prefix, new_flags, flags_mask, deny_list, NULL);
  20 }
  21
  22 int bind_remount_one_with_mountinfo(const char *path, unsigned long new_flags, unsigned long flags_mask, FILE *proc_self_mountinfo);
  23
  24 int mount_switch_root(const char *path, unsigned long mount_propagation_flag);
  25
  26 DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(FILE*, endmntent, NULL);
  27 #define _cleanup_endmntent_ _cleanup_(endmntentp)
  28
  29 int mount_verbose_full(
  30                 int error_log_level,
  31                 const char *what,
  32                 const char *where,
  33                 const char *type,
  34                 unsigned long flags,
  35                 const char *options,
  36                 bool follow_symlink);
  37
  38 static inline int mount_follow_verbose(
  39                 int error_log_level,
  40                 const char *what,
  41                 const char *where,
  42                 const char *type,
  43                 unsigned long flags,
  44                 const char *options) {
  45         return mount_verbose_full(error_log_level, what, where, type, flags, options, true);
  46 }
  47
  48 static inline int mount_nofollow_verbose(
  49                 int error_log_level,
  50                 const char *what,
  51                 const char *where,
  52                 const char *type,
  53                 unsigned long flags,
  54                 const char *options) {
  55         return mount_verbose_full(error_log_level, what, where, type, flags, options, false);
  56 }
  57
  58 int umount_verbose(
  59                 int error_log_level,
  60                 const char *where,
  61                 int flags);
  62
  63 int mount_option_mangle(
  64                 const char *options,
  65                 unsigned long mount_flags,
  66                 unsigned long *ret_mount_flags,
  67                 char **ret_remaining_options);
  68
  69 int mode_to_inaccessible_node(const char *runtime_dir, mode_t mode, char **dest);
  70 int mount_flags_to_string(unsigned long flags, char **ret);
  71
  72 /* Useful for usage with _cleanup_(), unmounts, removes a directory and frees the pointer */
  73 static inline char* umount_and_rmdir_and_free(char *p) {
  74         PROTECT_ERRNO;
  75         if (p) {
  76                 (void) umount_recursive(p, 0);
  77                 (void) rmdir(p);
  78         }
  79         return mfree(p);
  80 }
  81 DEFINE_TRIVIAL_CLEANUP_FUNC(char*, umount_and_rmdir_and_free);
  82
  83 int bind_mount_in_namespace(pid_t target, const char *propagate_path, const char *incoming_path, const char *src, const char *dest, bool read_only, bool make_file_or_directory);
  84 int mount_image_in_namespace(pid_t 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);
  85
  86 int make_mount_point(const char *path);
  87
  88 typedef enum RemountIdmapping {
  89         REMOUNT_IDMAPPING_NONE,
  90         /* Include a mapping from UID_MAPPED_ROOT (i.e. UID 2^31-2) on the backing fs to UID 0 on the
  91          * uidmapped fs. This is useful to ensure that the host root user can safely add inodes to the
  92          * uidmapped fs (which otherwise wouldn't work as the host root user is not defined on the uidmapped
  93          * mount and any attempts to create inodes will then be refused with EOVERFLOW). The idea is that
  94          * these inodes are quickly re-chown()ed to more suitable UIDs/GIDs. Any code that intends to be able
  95          * to add inodes to file systems mapped this way should set this flag, but given it comes with
  96          * certain security implications defaults to off, and requires explicit opt-in. */
  97         REMOUNT_IDMAPPING_HOST_ROOT,
  98         /* Define a mapping from root user within the container to the owner of the bind mounted directory.
  99          * This ensure no root-owned files will be written in a bind-mounted directory owned by a different
 100          * user. No other users are mapped. */
 101         REMOUNT_IDMAPPING_HOST_OWNER,
 102         _REMOUNT_IDMAPPING_MAX,
 103         _REMOUNT_IDMAPPING_INVALID = -EINVAL,
 104 } RemountIdmapping;
 105
 106 int make_userns(uid_t uid_shift, uid_t uid_range, uid_t owner, RemountIdmapping idmapping);
 107 int remount_idmap_fd(const char *p, int userns_fd);
 108 int remount_idmap(const char *p, uid_t uid_shift, uid_t uid_range, uid_t owner, RemountIdmapping idmapping);
 109
 110 int remount_and_move_sub_mounts(
 111                 const char *what,
 112                 const char *where,
 113                 const char *type,
 114                 unsigned long flags,
 115                 const char *options);
 116 int remount_sysfs(const char *where);
 117
 118 /* Creates a mount point (not parents) based on the source path or stat - ie, a file or a directory */
 119 int make_mount_point_inode_from_stat(const struct stat *st, const char *dest, mode_t mode);
 120 int make_mount_point_inode_from_path(const char *source, const char *dest, mode_t mode);