libs/ipkg: add overlay_root(), determines the overlay used by opkg

diff --git a/libs/ipkg/luasrc/model/ipkg.lua b/libs/ipkg/luasrc/model/ipkg.lua
index 12e5a94..cda23af 100644 (file)
--- a/libs/ipkg/luasrc/model/ipkg.lua
+++ b/libs/ipkg/luasrc/model/ipkg.lua
@@ -15,6 +15,7 @@ $Id$
 
 local os   = require "os"
 local io   = require "io"
+local fs   = require "nixio.fs"
 local util = require "luci.util"
 
 local type  = type
@@ -23,6 +24,7 @@ local error = error
 local table = table
 
 local ipkg = "opkg --force-removal-of-dependent-packages --force-overwrite"
+local icfg = "/etc/opkg.conf"
 
 --- LuCI IPKG/OPKG call abstraction library
 module "luci.model.ipkg"
@@ -192,3 +194,33 @@ end
 function list_installed(pat, cb)
        _list("list_installed", pat, cb)
 end
+
+--- Determines the overlay root used by opkg.
+-- @return             String containing the directory path of the overlay root.
+function overlay_root()
+       local od = "/"
+       local fd = io.open(icfg, "r")
+
+       if fd then
+               local ln
+
+               repeat
+                       ln = fd:read("*l")
+                       if ln and ln:match("^%s*option%s+overlay_root%s+") then
+                               od = ln:match("^%s*option%s+overlay_root%s+(%S+)")
+
+                               local s = fs.stat(od)
+                               if not s or s.type ~= "dir" then
+                                       od = "/"
+                               end
+
+                               break
+                       end
+               until not ln
+
+               fd:close()
+       end
+
+       return od
+end
+