mirror of
https://github.com/flatpak/flatpak.git
synced 2026-03-20 16:04:29 -04:00
97dabb10a8
When we start a sandbox and one of the directories we bind-mount into the sandbox, for example one of the top dirs like /boot, is an autofs, then the bind mount will trigger an automount. Often this is not really a problem, but in some cases (such as a missing device or a network mount that is not available) this can block for potentially a very long time. Ideally we would like to avoid this by not triggering the automount when bind-mounting, but that doesn't seem possible with the current kernel APIs. So, instead we try to detect any autofs paths and try to do a blocking operation on them, if this takes more than 200 milliseconds we assume the mountpoint is broken and ignore it. There are various technical details here: We can check for autofs using open(O_PATH) + fstatfs() and looking for f_type == AUTOFS_SUPER_MAGIC (as described in the open manpage). The blocking operation we do is open(O_DIRECTORY), but to allow this to timeout we need to fork() and do this in the child, which we can kill after timing out, whick we detect via select() using a self-pipe. This fixes https://github.com/flatpak/flatpak/issues/1633 Closes: #1648 Approved by: alexlarsson