Linux-to-Linux permissions, group ownership and ACL's

[JS761 (JS)]

I read calmh’s reply which mentioned ACL’s

it sets the owner and group of a thing to the same as the parent dir. I don’t know why that results in a different set of permissions. My suspicion is that the system actually uses ACLs or something under the hood.

That makes it sound like Syncthing will honor ACL’s and group sticky bits under Linux. Correct?

If we are exclusively syncing files between Linux machines, and we have default ACL’s and group sticky bits set, will those things continue to determine the file permissions without interference from Syncthing?

The group sticky bit is particularly important.

Do we have to configure Syncthing in a particular way to achieve this goal?

I read about the ignorePerms option in the docs:

ignorePerms: True if the folder should ignore permissions.

However, that doesn’t make it clear what it does. Does that option leave permissions up to the file system (and default ACL’s) or does it attempt to set permissions to some vanilla value? What about the owner or group?

(Also, if the above will work Linux-to-Linux, will it also work if a Mac is in the mix?) Thank you.

[JS761 (JS)]

In regard to the ignorePerms option, I found an answer here:

[v0.8.10] Ignore Permissions

Version 0.8.10 includes a new “Ignore Permissions” flag per repository. The primary use case is for filesystems that do not support permissions, such as FAT, or environments where changing permissions is impossible. When the checkbox is checked for a given repo files originating from this node will be announced with the “no permission bits” flag. Other nodes will use whatever their default permission setting is when creating the file. Nodes running older versions than 0.8.10 will use the permis…

I’m still not 100% sure what Syncthing does in Linux-to-Linux sync with ACL’s and group sticky bits.

My guess is that when ACL’s and group sticky bits are set on all devices, we can use the ignorePerms option to make those things entirely control the file permissions and group ownership.

However, I have read a number of statements like this one: Sync file ownership, and permissions

Permissions are synchronized. Owner and group would require running as root; this is neither recommended nor supported right now. There would be a bunch of corner cases to solve in that case as well…

That makes it sound like Syncthing cannot do what I am asking. Hence confusion.

[calmh (Jakob Borg)]

“Ignore permissions” on the receiving side basically means Syncthing doesn’t chmod and just lets the file get whatever permissions happen to be default. This might be what you want.

[JS761 (JS)]

Thank you for continuing to use your time to respond to so many questions here, as well as for your efforts maintaining Syncthing!

[JS761 (JS)]

@calmh

“Ignore permissions” on the receiving side basically means Syncthing doesn’t chmod and just lets the file get whatever permissions happen to be default. This might be what you want.

It does seem to work. I’m just testing so far, but it has worked as expected.