add buffyboard systemd service

this is an optional feature. systemd distributions wishing to deploy
buffyboard may add `WantedBy=default.target` to the Install section.

CHANGELOG.md

@@ -15,6 +15,8 @@ If a change only affects particular applications, they are listed in parentheses
 - misc: Unify build system (!23 & !29, thanks @Jarrah & @vladimir.stoyakin)
 - misc: Ensure stable file order during builds (!24, thanks @devrtz)
 - fix: Prevent logging internal LVGL errors to stdout
+- misc: Make scdoc a native dependency to enable cross-compilation (!30, thanks @uninsane)
+- fix: Use usleep to release CPU when possible (!31, thanks @uninsane)
 
 ## 3.2.0 (2024-06-03)
 

buffyboard/buffyboard.service.in

@@ -0,0 +1,38 @@
+[Unit]
+Documentation=https://gitlab.postmarketos.org/postmarketOS/buffybox
+
+[Service]
+ExecStart=@bindir@/buffyboard
+Restart=on-failure
+
+# Allow access to input devices, framebuffer, tty
+DevicePolicy=closed
+DeviceAllow=/dev/uinput rw
+DeviceAllow=char-fb rw
+DeviceAllow=char-input rw
+DeviceAllow=char-tty rw
+# udev requires some limited networking
+RestrictAddressFamilies=AF_NETLINK
+
+# Hardening
+CapabilityBoundingSet=
+NoNewPrivileges=true
+RestrictSUIDSGID=true
+PrivateMounts=true
+PrivateTmp=true
+PrivateUsers=true
+ProtectClock=true
+ProtectControlGroups=true
+ProtectHome=true
+ProtectHostname=true
+ProtectKernelLogs=true
+ProtectKernelModules=true
+ProtectKernelTunables=true
+ProtectSystem=strict
+RemoveIPC=true
+LockPersonality=true
+MemoryDenyWriteExecute=true
+SystemCallArchitectures=native
+SystemCallFilter=@system-service
+SystemCallFilter=~@privileged
+SystemCallFilter=~@resources

buffyboard/main.c

@@ -284,7 +284,8 @@ int main(int argc, char *argv[]) {
 
     /* Periodically run timer / task handler */
     while(1) {
-        lv_timer_periodic_handler();
+        uint32_t time_till_next = lv_timer_handler();
+        usleep(time_till_next * 1000);
     }
 
     return 0;

buffyboard/meson.build

@@ -24,3 +24,13 @@ executable('buffyboard',
 
 install_data('buffyboard.conf', install_dir: get_option('sysconfdir'))
 
+
+configure_file(
+  input : 'buffyboard.service.in',
+  output : 'buffyboard.service',
+  install : true,
+  install_dir : get_option('libdir') / 'systemd/system',
+  configuration : {
+    'bindir' : get_option('prefix') / get_option('bindir'),
+  },
+)

meson.build

@@ -11,7 +11,7 @@ deplibinput  = dependency('libinput')
 deplibudev   = dependency('libudev')
 
 if get_option('man')
-    depscdoc = dependency('scdoc')
+    depscdoc = dependency('scdoc', native: true)
 endif
 
 common_include_dirs = include_directories('.')

unl0kr/main.c

@@ -591,7 +591,8 @@ int main(int argc, char *argv[]) {
     uint32_t timeout = conf_opts.general.timeout * 1000; /* ms */
     while(1) {
         if (!timeout || lv_disp_get_inactive_time(NULL) < timeout) {
-            lv_timer_periodic_handler();
+            uint32_t time_till_next = lv_timer_handler();
+            usleep(time_till_next * 1000);
         } else if (timeout) {
             shutdown();
         }