Hello,

I am writing a custom VFS module for Samba. As you know I need to compile my modules from sources. So I cloned the samba from main (Version 4.23.0) and my Samba server is 4.21.4 (Ubuntu). When I connect to my samba server with smbcli, I get error:

[2025/07/04 17:07:09.048960,  0] lib/util/modules.c:49(load_module)
  Error loading module '/usr/lib/x86_64-linux-gnu/samba/vfs/tracim.so': /home/xxx...xxx/samba/bin/shared/private/libsamba-hostconfig-private-samba.so: undefined symbol: get_dyn_HIMMELBLAUD_HSM_PIN_PATH, version SAMBA_UTIL_0.0.1
[2025/07/04 17:07:09.049002,  0, pid=294191, effective(0, 0), real(0, 0), class=vfs] source3/smbd/vfs.c:185(vfs_init_custom)
  error probing vfs module 'tracim': NT_STATUS_UNSUCCESSFUL
[2025/07/04 17:07:09.049015,  0, pid=294191, effective(0, 0), real(0, 0), class=vfs] source3/smbd/vfs.c:399(smbd_vfs_init)
  smbd_vfs_init: vfs_init_custom failed for tracim
This error seam because of the difference of samba versions because in lib/param/loadparm.c in loadparm_init() we call get_dyn_HIMMELBLAUD_HSM_PIN_PATH() and too in source3/param/loadparm.c in loadparm_s3_init_globals(). get_dyn_HIMMELBLAUD_HSM_PIN_PATH() implementation don't exist in Version 4.21.4 unlike in 4.23.0. HIMMELBLAUD is a new testing feature on Samba. It shouldn't be a problem because in vfs_mymodule.so, there isn't that call. But for an reason I don't know, know my smbd call libsamba-hostconfig-private-samba.so (due to rust/param/build.rs ?). This is the same major version, and closed minor versions.

For me, a possible solution is to adjust the samba source with the version. It's more complicate but if I want to deploy it on many server it could become really complex and risky.

I could suggest to make a change to use HIMMELBLAUD code only if get_dyn_HIMMELBLAUD_HSM_PIN_PATH() is implementated. But is it the best option?

Thank-you for any help/suggestions.