SymbolServer: Add symbolication service for out-of-process ELF parsing

This patch adds SymbolServer, a service daemon that provides
symbolication of ELF binaries. It has a very simple IPC API at the
moment that only turns addresses into symbol names.

This can be used to implement symbolication without having to do
in-process ELF parsing yourself. :^)

Base/etc/SystemServer.ini

@@ -26,6 +26,12 @@ BootModes=graphical
 MultiInstance=1
 AcceptSocketConnections=1
 
+[SymbolServer]
+Socket=/tmp/portal/symbol
+SocketPermissions=660
+User=symbol
+Lazy=1
+
 [LookupServer]
 Socket=/tmp/portal/lookup
 SocketPermissions=660

Base/etc/group

@@ -11,4 +11,5 @@ window:x:13:anon,notify
 clipboard:x:14:anon,notify
 webcontent:x:15:anon
 image:x:16:anon,webcontent
+symbol:x:17:anon
 users:x:100:anon

Base/etc/passwd

@@ -6,5 +6,6 @@ window:!:13:13:WindowServer,,,:/:/bin/false
 clipboard:!:14:14:Clipboard,,,:/:/bin/false
 webcontent:!:15:15:WebContent,,,:/:/bin/false
 image:!:16:16:ImageDecoder,,,:/:/bin/false
+symbol:!:17:17:SymbolServer,,,:/:/bin/false
 anon:!:100:100:Anonymous,,,:/home/anon:/bin/sh
 nona:!:200:200:Nona,,,:/home/nona:/bin/sh