diff options
Diffstat (limited to 'src/shared/mount-util.c')
| -rw-r--r-- | src/shared/mount-util.c | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/src/shared/mount-util.c b/src/shared/mount-util.c index a7217adfa1..25dde7b0e2 100644 --- a/src/shared/mount-util.c +++ b/src/shared/mount-util.c @@ -134,6 +134,31 @@ int umount_recursive(const char *prefix, int flags) { return n; } +#define MS_CONVERTIBLE_FLAGS (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_NOSYMFOLLOW) + +static uint64_t ms_flags_to_mount_attr(unsigned long a) { + uint64_t f = 0; + + if (FLAGS_SET(a, MS_RDONLY)) + f |= MOUNT_ATTR_RDONLY; + + if (FLAGS_SET(a, MS_NOSUID)) + f |= MOUNT_ATTR_NOSUID; + + if (FLAGS_SET(a, MS_NODEV)) + f |= MOUNT_ATTR_NODEV; + + if (FLAGS_SET(a, MS_NOEXEC)) + f |= MOUNT_ATTR_NOEXEC; + + if (FLAGS_SET(a, MS_NOSYMFOLLOW)) + f |= MOUNT_ATTR_NOSYMFOLLOW; + + return f; +} + +static bool skip_mount_set_attr = false; + /* Use this function only if you do not have direct access to /proc/self/mountinfo but the caller can open it * for you. This is the case when /proc is masked or not mounted. Otherwise, use bind_remount_recursive. */ int bind_remount_recursive_with_mountinfo( @@ -374,6 +399,23 @@ int bind_remount_one_with_mountinfo( assert(path); assert(proc_self_mountinfo); + if ((flags_mask & ~MS_CONVERTIBLE_FLAGS) == 0 && !skip_mount_set_attr) { + /* Let's take a shortcut for all the flags we know how to convert into mount_setattr() flags */ + + if (mount_setattr(AT_FDCWD, path, AT_SYMLINK_NOFOLLOW, + &(struct mount_attr) { + .attr_set = ms_flags_to_mount_attr(new_flags & flags_mask), + .attr_clr = ms_flags_to_mount_attr(~new_flags & flags_mask), + }, MOUNT_ATTR_SIZE_VER0) < 0) { + + log_debug_errno(errno, "mount_setattr() didn't work, falling back to classic remounting: %m"); + + if (ERRNO_IS_NOT_SUPPORTED(errno)) /* if not supported, then don't bother at all anymore */ + skip_mount_set_attr = true; + } else + return 0; /* Nice, this worked! */ + } + rewind(proc_self_mountinfo); table = mnt_new_table(); |