Devicetree firmware contains an "aliases" node, containing various
aliases for devices described by the firmware. For ethernet devices,
these are named "ethernet0", "ethernet1", etc. They provide a convenient
means of numbering ethernet devices, especially on systems with no other
stable number other than the address. In particular, U-Boot already uses
these aliases to name its ethernet devices.
Previously, there have been attempts (such as [1]) to add support for
these aliases to Linux. However, these patches have been rejected
because it is the maintainers' view that naming policy be left to
userspace. Well, systemd is userspace, so here we are.
In terms of implementation, apparently there can be multiple device
trees at once. I have decided to dodge this problem for now, and just
use /proc/device-tree. If it is desired to support multiple device trees
later, then the scheme can be modified to include the device tree's
index. For example, /sys/firmware/devicetree/base2/aliases/ethernet3
might be named enb2d3.
For the moment we only support "ethernetX" aliases. Future patches might
want to also handle "canX" and "wifiX".
It is common on boards with only one ethernet device to use an alias of
just "ethernet". In this case, the index is an implicit 0. In case the
author of the firmware made a mistake, we check to ensure that aliases
of "ethernet" and "ethernet0" do not both exist.
[1] https://patchwork.kernel.org/project/linux-arm-kernel/patch/1399390594-1409-1-git-send-email-boris.brezillon@free-electrons.com/Closes: #17625
ifname_resolvconf_mangle is supposed to remove protocol suffixes like .dhcp
from interface names. But this removed also valid parts of the ifname like
VLAN IDs, e.g. enp2s0u4.72.dhcp -> enp2s0u4 instead of enp2s0u4.72
After this change, everything behind the last dot is removed instead of the first.
While this provides some marginal speedup, the disadvantage is
that files are never removed when doing cached builds, which can
sometimes lead to hard to debug issues. So let's not do this by
default.
They're floppy disk flux readers and writers used in digital
preservation and can be broadly considered to be "analyzers" of magnetic
fluxes.
This will have the intended side-effect of giving access to the device
to users at the console, obsoleting:
https://github.com/keirf/greaseweazle/blob/master/scripts/49-greaseweazle.rules
This tweaks user creation logic to properly take into consideration
an explicitly requested GID.
It fixes a bug where the creation flow would mistakenly fall back
to use the username instead, resulting in wrong lookups in case of
users and groups using the same name.
This relaxes the availability check when creating a group, if an
explicit GID has been requested.
It avoids mixing up users and groups entries with valid and unique
UIDs/GIDs, but each having the same ID number.
Previously, if sd_device_enumerator_add_match_sysattr() is called for
the same sysattr with different values, then no device passed the filter.
Now, the accepted values (or patterns) are stored in strv, and if the
sysattr value of a device matches with the strv, then the device passes
the filter.