Hi Rumen,

'Patching' Genode to make it support hardlinks, even limiting said support to local

file systems (no <fs/> connection to a vfs server), would probably be involved :

There a stack of different layers involved, you'd probably need to patch each one of them

to 'propagate' the call from top to bottom layer.

The example below does not use LibC but directly calls the Genode API, that's one

less thing to worry about, but there still remains a few layers:

* an FS plug-in is a subclass of Vfs::File_system ; in the below example, you've added a hardlink() method to the subclass, but (like other methods) it should probably be an "override" of a base-class 'abstract' method/hook

* once the Vfs::File_system base class does have the abstract hook, that hook must be called from other layers above it.

If it was me, I might start my deep dive by doing a "grep -r openlink" or "opendir". (openlink() and opendir() are some of the hooks provided by File_system I think, there are others of course but grepping for it should yield a better digest of results than grepping for more generic terms like open/close/directory etc).

Is there no way for you to use sym-links instead ?

Cédric

De : Rumen Mitov Rumen.Mitov@constructor.tech À : users@lists.genode.org users@lists.genode.org Sujet : Extending the VFS with hard-links Date : 02/04/2025 08:00:28 Europe/Paris

Hello,

I need some help with extending the VFS for my project. I need hardlink support, so I added the following to repos/os/include/vfs/directory_service.h's Directory_service struct:

virtual int hardlink(char const *path, char const *hardlink_path)

{

(void) path;

(void)hardlink_path;

Genode::error("not implemented!");

return 0;

}

I have the Lwext4 plugin (https://codeberg.org/jws/genode-wundertuete/src/branch/import-lwext4_from_wo... for my project so I then extended repos/wundertuete/src/lib/vfs/lwext4/vfs.cc's Lwext4_vfs_file_system struct:

int hardlink(char const *path, char const *hardlink_path) override

{

return ext4_flink(path, hardlink_path);

}

The problem is that hardlink uses the default implementation in my main code: squidutils->_vfs_env.root_dir().hardlink(p2.string(), p1.string());  // Prints 'not implemented'

From what I have read online the issue is that squidutils->_vfs_env.root_dir() is of type Directory_service, whereas I need it to be Lwext4_vfs_file_system. However, Lwext4_vfs_file_system is declared in the vfs.cc file above as opposed to being declared in a header.

Is there a way to use Lwext4_vfs_file_system without copying the entire source of Lwext4 into my project's source code? Or am I perhaps going in the wrong direction with all of this?

Best, Rumen _______________________________________________ users mailing list -- users@lists.genode.org To unsubscribe send an email to users-leave@lists.genode.org Archived at https://lists.genode.org/mailman3/hyperkitty/list/users@lists.genode.org/mes...