Bug 1515451 Part 3 - Install, uninstall update agent r=mhowell

This was originally planned in bugs 1458282 and 1458283, but it
fits naturally in this patch series.

Differential Revision: https://phabricator.services.mozilla.com/D37141

--HG--
extra : moz-landing-system : lando

browser/installer/package-manifest.in

@@ -403,6 +403,11 @@ bin/libfreebl_64int_3.so
 @BINPATH@/maintenanceservice_installer.exe
 #endif
 
+; [Background Update Agent]
+#ifdef MOZ_UPDATE_AGENT
+@BINPATH@/updateagent@BIN_SUFFIX@
+#endif
+
 ; [Crash Reporter]
 ;
 #ifdef MOZ_CRASHREPORTER

browser/installer/windows/nsis/defines.nsi.in

@@ -118,6 +118,11 @@
 !define MOZ_MAINTENANCE_SERVICE
 #endif
 
+#ifdef MOZ_UPDATE_AGENT
+!define MOZ_UPDATE_AGENT
+!define UpdateAgentFullName "Mozilla Update Agent"
+#endif
+
 #ifdef MOZ_BITS_DOWNLOAD
 !define MOZ_BITS_DOWNLOAD
 #endif

browser/installer/windows/nsis/installer.nsi

@@ -487,6 +487,17 @@ Section "-Application" APP_IDX
   ${EndIf}
 !endif
 
+!ifdef MOZ_UPDATE_AGENT
+  ${PushRegisterUpdateAgentTaskCommand} "register"
+  Pop $0
+  ${If} "$0" != ""
+    ${LogMsg} "Registering update agent task: $0"
+    nsExec::Exec $0
+    Pop $0
+    ${LogMsg} "nsExec::Exec returned $0"
+  ${EndIf}
+!endif
+
   ; These need special handling on uninstall since they may be overwritten by
   ; an install into a different location.
   StrCpy $0 "Software\Microsoft\Windows\CurrentVersion\App Paths\${FileMainEXE}"

browser/installer/windows/nsis/shared.nsh

@@ -159,6 +159,25 @@
   ${EndIf}
 !endif
 
+!ifdef MOZ_UPDATE_AGENT
+  ; This macro runs the update agent with the update-task-local-service
+  ; command, if it detects the needed admin privileges. Otherwise it
+  ; runs with update-task.
+  ; Both commands attempt to remove the scheduled task, then register
+  ; a new one. If the task was registered by an elevated user, it won't
+  ; be removable when not elevated, so the unelevated attempt will fail
+  ; harmlessly.
+  ; Therefore it is safe to run this in both elevated and nonelevated
+  ; PostUpdate: The highest privileged run will win out, so the task can
+  ; run as Local Service if it was ever possible to register it that way.
+  ${PushRegisterUpdateAgentTaskCommand} "update"
+  Pop $0
+  ${If} "$0" != ""
+    nsExec::Exec $0
+    Pop $0
+  ${EndIf}
+!endif
+
 !ifdef MOZ_LAUNCHER_PROCESS
   ${ResetLauncherProcessDefaults}
 !endif
@@ -1384,6 +1403,7 @@
   Push "minidump-analyzer.exe"
   Push "pingsender.exe"
   Push "updater.exe"
+  Push "updateagent.exe"
   Push "${FileMainEXE}"
 !macroend
 !define PushFilesToCheck "!insertmacro PushFilesToCheck"
@@ -1648,3 +1668,44 @@ FunctionEnd
 !macroend
 !define ResetLauncherProcessDefaults "!insertmacro ResetLauncherProcessDefaults"
 !endif
+
+!ifdef MOZ_UPDATE_AGENT
+; Push, onto the stack, the command line used to register (or update) the
+; update agent scheduled task.
+;
+; InitHashAppModelId must have already been called to set $AppUserModelID,
+; if that is empty then an empty string will be pushed instead.
+;
+; COMMAND_BASE must be "register" or "update". Both will remove any
+; pre-existing task and register a new one, but "update" will first attempt
+; to copy some settings.
+!macro PushRegisterUpdateAgentTaskCommand COMMAND_BASE
+  Push $0
+  Push $1
+
+  Call IsUserAdmin
+  Pop $0
+  ; Register the update agent to run as Local Service if the user is an admin...
+  ${If} $0 == "true"
+  ; ...and if we have HKLM write access
+  ${AndIf} $TmpVal == "HKLM"
+    StrCpy $1 "${COMMAND_BASE}-task-local-service"
+  ${Else}
+    ; Otherwise attempt to register the task for the current user.
+    ; If we had previously registered the task while elevated, then we shouldn't
+    ; be able to replace it now with another task of the same name, so this
+    ; will fail harmlessly.
+    StrCpy $1 "${COMMAND_BASE}-task"
+  ${EndIf}
+
+  ${If} "$AppUserModelID" != ""
+    StrCpy $0 '"$INSTDIR\updateagent.exe" $1 "${UpdateAgentFullName} $AppUserModelID" "$AppUserModelID" "$INSTDIR"'
+  ${Else}
+    StrCpy $0 ''
+  ${EndIf}
+
+  Pop $1
+  Exch $0
+!macroend
+!define PushRegisterUpdateAgentTaskCommand "!insertmacro PushRegisterUpdateAgentTaskCommand"
+!endif

browser/installer/windows/nsis/uninstaller.nsi

@@ -453,6 +453,11 @@ Section "Uninstall"
   DeleteRegValue HKCU ${MOZ_LAUNCHER_SUBKEY} "$INSTDIR\${FileMainEXE}|Telemetry"
 !endif
 
+!ifdef MOZ_UPDATE_AGENT
+  ; Unregister the update agent
+  nsExec::Exec '"$INSTDIR\updateagent.exe" unregister-task "${UpdateAgentFullName} $AppUserModelID"'
+!endif
+
   ${un.RemovePrecompleteEntries} "false"
 
   ${If} ${FileExists} "$INSTDIR\defaults\pref\channel-prefs.js"