A section can be marked as preseved by setting the gluon_preserve option
to 1. In addition the following conditions must hold:

- The preserved section must not already exist after OpenWrt's and
  Gluons setup scripts run. Modifying existing sections is currently
  unsupported.
- Preserved sections must be named, so it can be detected whether a
  section conflicts with a preexisting one.

Allow interface names to change on updates to handle hwconfig -> DSA and
similar migrations.

On devices with only a single interface, a sysconfig single_ifname is
created instead of wan_ifname or lan_ifname to allow separate
configuration in site.conf.

With the new role-based interface configuration, it would be better to
rename the wan/wan6 interfaces to uplink/uplink6, but that would cause
unnecessary churn for the firewall configuration, so it is left for a
later update.

As all interfaces with the 'uplink' role are in the br-wan bridge, it is
not possible to assign these to the 'mesh' role independently - instead,
br-wan is added as a mesh interface as soon as a single interface has
both the 'uplink' and 'mesh' roles. The UCI section for this
configuration is now called 'mesh_uplink' instead of 'mesh_wan'.

For all interfaces that have the 'mesh', but not the 'uplink' role a
second configuration 'mesh_other' is created. If there is more than one
such interface, all these interfaces are bridged as well (creating a
bridge 'br-mesh_other'). This replaces the 'mesh_lan' section with its
optional 'br-mesh_lan' bridge, but can also include interfaces that were
not considered "LAN" when interfaces roles are modified (via site.conf
or manually).

The new configuration generates sections iface_single/lan/wan in
/etc/config/gluon. These sections usually refer to a sysconfig-controlled
interface list, but adding custom sections with verbatim interfaces names
is also possible.

Each interface section contains a list of roles. The supported roles are
'client', 'uplink' and 'mesh'. Multiple roles can be configured on the
same interface (for example the old 'mesh_on_wan' setting would become
'uplink'+'mesh').

'client' is subsumed by any other role configured on the same interface
('client'+'mesh' is equivalent to 'mesh'). This property is important, as
it allows the Wired Mesh settings in gluon-web-network to simply add and
remove the mesh role without having to care what other roles are set -
so in the default setup, this would switch between 'client' and
'client'+'mesh' for the LAN interface.

By default, the WAN interface has role 'uplink' and the LAN interface
'client'; if only a single interface exists, the roles from the WAN
interface are used by default. The default for each of the three
interfaces (WAN/LAN/single) can be changed separated in site.conf,
superseding the old mesh_on_wan, mesh_on_lan and single_as_lan settings.

Do not write files when the content is unchanged.

Avoids a few unnecessary filesystem writes when resetting ifname
sysconfigs on each upgrade.

The stdout output of gluon-web scripts is directly sent to uhttpd,
becoming a part of the HTML output or even replacing HTTP status or
headers. The output of gluon-reconfigure is not supposed to end up
there.

While we're at it, also add an exec to avoid an unnecessary shell
process.

The OpenLayers JS/CSS download URL is dead. Update it to make the map
work again:

- Update from OpenLayers 5.2.0 to 5.3.0
- Switch from the obsolete rawgit.com URL to jsdelivr.net (rawgit.com
  was only redirecting to jsdelivr.net for the last few years anyways)
- Set a fixed commit in the URL, so the URL doesn't become outdated again

Prevents spurious build failures.

x86: copy separate kernel and rootfs images to "other" directory

gluon-web: prohibit cross-origin POST requests

Update OpenWrt base, clean up patches

lint-sh fixes

Removal of more obsolete migrations, minor cleanup and improvements to lsupgrade.sh

As gluon-web uses standard multipart/form-data requests, browsers don't
enforce any cross-origin restrictions. To prevent malicious injection of
POST requests into the config mode, match the Origin header against the
Host header of the request.

Actually raise an error and turn it into an HTTP 400 return code when
something goes wrong, rather than ignoring the error.

We also improve the conditions under which errors are thrown before
pump() is called: We don't need to check for the multipart/form-data
content-type twice, and a POST without this content-type is now always
an error.

Having a trailing newline is nice when viewing the returned data in a
terminal.

This was a remnant of LuCI that was never used in gluon-web.

Using apt in scripts is discouraged. Also add an update to hopefully fix
the lua-check installation failure in CI.

By applying a label `backport <branch>` the action will automatically
try to cherry-pick the change to the target branch after the pull
request was successfully merged.

Swap the interfaces so than the PoE input port LAN0 is used for WAN and
config mode, and LAN1 becomes LAN.

To this end, the code previously used for ar71xx and removed in
commit 9fdc57c1 ("treewide: drop ar71xx platform specific code") is
reintroduced.

Fixes #2384

/etc/config/gluon-core is used for nothing else.

As /etc/config/gluon uses a named wireless section, also change the
get_first() to get().

There wasn't really a reason to have a separate script to set a single
value.

In addition, the old script was using the identifier 'c' instead of
'uci' for the UCI cursor. Following the convention of the other scripts
is helpful so it is easy to grep for all uses of a certain config file/
option.

- Use printf instead of echo for better portability
- Print whole path without reordering components
- Deduplicate code

Iterating over all the package directories in the OpenWrt feed takes a
while, even though it doesn't contain any upgrade scripts. Skip the
whole directory.

We are on Linux 5.4, so these patches for Linux 4.14 don't do anything.

97b95ef8b918 uci: update to the latest master

Replace the downstream UCI patch with a proper OpenWrt 21.02 backport.

modules: updates

5bca036 pretty-hostname: instantly apply hostname
a85fa33 treewide: change Github URLs from git:// to https:// (#252)

c2e138d olsrd: add ubus ipc integration to olsrd
7d07ef9 CI: fix runtime testing for non master branch
61cd00c naywatch: introduce kick-count
440e7af naywatch: fix mode without watchdog
c8b613e olsrd: fix meshing via wireguard tunnels