Phosh image: GDM's login-screen schema, so Settings can enrol a finger

GNOME Settings 51 shows the Users page's "Fingerprint Login" row only when
GDM's org.gnome.login-screen schema exists and its
enable-fingerprint-authentication key is true. The Phosh image logs in
through greetd/phrog, so without GDM the row never appeared and no finger
could be enrolled from the GUI; Settings never asked fingerprintd.

fp6-login-screen-schema installs GDM's schema file, unchanged, from
Alpine's gdm-48.0-r8, and nothing else of GDM. It is the only key Settings
reads, and nothing else on the image looks the schema up. replaces="gdm"
keeps a single copy if GDM is ever installed as well (tested in alpine:edge
in both orders; glib-compile-schemas stays clean). Added to the Phosh
image's packages.

Tested on the dev phone: the row appears, a thumb enrolled through
Settings' dialog, and it unlocks the lock screen.

aports/device/fp6-login-screen-schema/APKBUILD

@@ -0,0 +1,31 @@
+# GNOME Settings shows the Users page's "Fingerprint Login" row only when
+# GDM's org.gnome.login-screen schema exists and its
+# enable-fingerprint-authentication key is true (51.0,
+# panels/system/users/cc-user-page.c). The Phosh image logs in through
+# greetd/phrog, so without GDM the row never appears and no finger can be
+# enrolled from the GUI. This installs GDM's schema file unchanged, taken
+# from Alpine's gdm-48.0-r8, and nothing else of GDM. It is the only key
+# Settings reads from it, and nothing else on the image looks the schema up.
+# replaces="gdm" keeps one copy if GDM is ever installed as well: two
+# definitions of one schema make glib-compile-schemas fail for every schema.
+# glib's trigger on /usr/share/glib-2.0/schemas compiles it on install.
+maintainer="Jorijn van der Graaf <jorijnvdgraaf@catcrafts.net>"
+pkgname=fp6-login-screen-schema
+pkgver=48.0
+pkgrel=0
+pkgdesc="GDM's org.gnome.login-screen schema without GDM, for GNOME Settings' fingerprint row"
+url="https://forgejo.catcrafts.net/Catcrafts/fp6-img"
+arch="noarch"
+license="GPL-2.0-or-later"
+replaces="gdm"
+options="!check"
+source="org.gnome.login-screen.gschema.xml"
+
+package() {
+	install -Dm644 "$srcdir"/org.gnome.login-screen.gschema.xml \
+		"$pkgdir"/usr/share/glib-2.0/schemas/org.gnome.login-screen.gschema.xml
+}
+
+sha512sums="
+7ff27457fb409cf7f235c2e075455aa62045d801c592dcd43ca786478d59ba7205d5a69ea84e4fc88ce2e43607d75d8587cec96df0513435ddd114258c331694  org.gnome.login-screen.gschema.xml
+"

aports/device/fp6-login-screen-schema/org.gnome.login-screen.gschema.xml

@@ -0,0 +1,135 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<schemalist gettext-domain="gdm">
+  <enum id="org.gnome.login-screen.BannerSource">
+    <value value="1" nick="settings"/>
+    <value value="2" nick="file"/>
+  </enum>
+
+  <schema id="org.gnome.login-screen" path="/org/gnome/login-screen/">
+    <key name="enable-fingerprint-authentication" type="b">
+      <default>true</default>
+      <summary>
+        Whether or not to allow fingerprint readers for login
+      </summary>
+      <description>
+        The login screen can optionally allow users who have enrolled
+        their fingerprints to log in using those prints.
+      </description>
+    </key>
+    <key name="enable-smartcard-authentication" type="b">
+      <default>true</default>
+      <summary>
+        Whether or not to allow smartcard readers for login
+      </summary>
+      <description>
+        The login screen can optionally allow users who have smartcards
+        to log in using those smartcards.
+      </description>
+    </key>
+    <key name="enable-switchable-authentication" type="b">
+      <default>false</default>
+      <summary>
+        Whether or not to allow switchable authentication for login
+      </summary>
+      <description>
+        The login screen can optionally allow a single PAM service to provide
+        multiple authentication mechanisms via a GDM PAM.
+      </description>
+    </key>
+    <key name="enable-password-authentication" type="b">
+      <default>true</default>
+      <summary>
+        Whether or not to allow passwords for login
+      </summary>
+      <description>
+        The login screen can be configured to disallow password authentication,
+        forcing the user to use smartcard or fingerprint authentication.
+      </description>
+    </key>
+    <key name="logo" type="s">
+      <default>''</default>
+      <summary>
+        Path to small image at top of user list
+      </summary>
+      <description>
+        The login screen can optionally show a small image to provide site
+        administrators and distributions a way to display branding.
+      </description>
+    </key>
+    <key name="fallback-logo" type="s">
+      <default>''</default>
+      <summary>
+        Path to small image at top of user list
+      </summary>
+      <description>
+        The fallback login screen can optionally show a small image to provide
+        site administrators and distributions a way to display branding.
+      </description>
+    </key>
+    <key name="disable-user-list" type="b">
+      <default>false</default>
+      <summary>
+        Avoid showing user list
+      </summary>
+      <description>
+        The login screen normally shows a list of available users to log in
+        as. This setting can be toggled to disable showing the user list.
+      </description>
+    </key>
+    <key name="banner-message-enable" type="b">
+      <default>false</default>
+      <summary>
+        Enable showing the banner message
+      </summary>
+      <description>
+        Set to true to show the banner message text.
+      </description>
+    </key>
+    <key name="banner-message-source" enum="org.gnome.login-screen.BannerSource">
+      <default>"settings"</default>
+      <summary>
+        Banner message source
+      </summary>
+      <description>
+        The source of the text banner message on the login screen.
+      </description>
+    </key>
+    <key name="banner-message-text" type="s">
+      <default>''</default>
+      <summary>
+        Banner message text
+      </summary>
+      <description>
+        Text banner message to show in the login window.
+      </description>
+    </key>
+    <key name="banner-message-path" type="s">
+      <default>''</default>
+      <summary>
+        Banner message path
+      </summary>
+      <description>
+        Path to text file with banner message to show in the login window.
+      </description>
+    </key>
+    <key name="disable-restart-buttons" type="b">
+      <default>false</default>
+      <summary>
+        Disable showing the restart buttons
+      </summary>
+      <description>
+        Set to true to disable showing the restart buttons in the login window.
+      </description>
+    </key>
+    <key name="allowed-failures" type="i">
+      <default>3</default>
+      <summary>
+        Number of allowed authentication failures
+      </summary>
+      <description>
+        The number of times a user is allowed to attempt authentication, before
+        giving up and going back to user selection.
+      </description>
+    </key>
+  </schema>
+</schemalist>

build.sh

@@ -33,13 +33,14 @@ REGISTRY=https://forgejo.catcrafts.net/api/packages/Catcrafts/alpine/edge/fp6
 # FP6IMG_UI: which postmarketOS UI the image boots into. plasma-mobile (the
 # default) gets imsd-dialerd from the imsd package itself; phosh gets the
 # opt-in imsd-ofono subpackage (imsd-ofonod + the GNOME Calls plugin
-# override) on top. Everything else in the package set is UI-agnostic. The
+# override) and fp6-login-screen-schema (GNOME Settings' fingerprint row) on
+# top. Everything else in the package set is UI-agnostic. The
 # archive is named after it: fp6-img.tar.xz for plasma-mobile,
 # fp6-img-<ui>.tar.xz otherwise, so one release can carry both.
 FP6IMG_UI=${FP6IMG_UI:-plasma-mobile}
 case "$FP6IMG_UI" in
 plasma-mobile) UI_PACKAGES=; IMG_NAME=fp6-img ;;
-phosh)         UI_PACKAGES=,imsd-ofono; IMG_NAME=fp6-img-phosh ;;
+phosh)         UI_PACKAGES=,imsd-ofono,fp6-login-screen-schema; IMG_NAME=fp6-img-phosh ;;
 *) echo "FP6IMG_UI=$FP6IMG_UI: expected plasma-mobile or phosh" >&2; exit 1 ;;
 esac
 PMAPORTS_REPO=https://gitlab.postmarketos.org/postmarketOS/pmaports.git
@@ -159,6 +160,7 @@ cp -r aports/device/linux-postmarketos-qcom-milos "$WORK/pmaports/device/testing
 cp -r aports/device/soc-fairphone-fp6-audio "$WORK/pmaports/device/"
 cp -r aports/device/fp6-vendor-blobs "$WORK/pmaports/device/"
 cp -r aports/device/callaudioshim "$WORK/pmaports/device/"
+cp -r aports/device/fp6-login-screen-schema "$WORK/pmaports/device/"
 cp -r aports/device/fp6-device-tweaks "$WORK/pmaports/device/"
 cp -r aports/device/fp6-charging-mode "$WORK/pmaports/device/"
 cp -r aports/device/catcrafts-fp6-repo "$WORK/pmaports/device/"