[parted-devel] [PATCH] arch: allow to open devices in read-only mode

[Brian C. Lane]

On Fri, Jan 13, 2023 at 11:51:45AM +0300, Konstantin Kharlamov wrote:
> Before this patch API like `ped_disk_new()` were unconditionally opening
> the disk in O_RDWR mode. Now it may be opened in readonly mode by
> setting `read_only = 1` field of `PedDevice` before calling the
> function.
> 
> This allows to avoid kernel/udev events like "remove/add" and "change"
> in cases, where users are only interested in read-only functional, like
> reading a partitions list.

I like this. Nice and simple, and minimal chance of breaking the parted
command :) I've got a test written for this that I'll post in a sec...

To answer your question in the other email -- no there is no way to open
it read only. We changed the initial probe to be read only, but normal
operation is still R/W because of how it parses the commands, it doesn't
know ahead of time if it will need it to be writable.

I looked at the lazy patch from Arvin, but I'm not too excited about
re-opening things in the middle of it being used. Just seems dangerous,
but I'll think about it some more.

This patch is a good intermediate step though, thanks!

Brian

-- 
Brian C. Lane (PST8PDT) - weldr.io - lorax - parted - pykickstart