relocatable.bbclass: Improve logic and style

The initial pass at this class was pretty lame and broke on a lot of native
packages. This rewrite makes the code a lot more dynamic, removing use of hard
coded paths and improving the logic.

The class now runs a chrpath -l over the binary to determine what rpaths are
currently set. It then munges the output and determines relative versions of
each component of the rpath and uses chrpath -r to set them.

Signed-off-by: Joshua Lock <josh@linux.intel.com>

meta/classes/relocatable.bbclass

@@ -2,23 +2,39 @@ SYSROOT_PREPROCESS_FUNCS += "relocatable_binaries_preprocess"
 
 CHRPATH_BIN ?= "chrpath"
 
-def rpath_replace (paths, d):
-    chrpath = bb.data.expand('${CHRPATH_BIN}', d)
+def rpath_replace (path, d):
+    import subprocess as sub
 
-    for path in paths:
-        for root, dirs, files in os.walk(path):
-            for f in files:
-                if 'usr' in path:
-                    os.system("%s -r $ORIGIN/../lib:$ORIGIN/../../lib %s/%s" % (chrpath, path,f))
-                else:
-                    os.system("%s -r $ORIGIN/../lib %s/%s" % (chrpath, path, f))
+    cmd = bb.data.expand('${CHRPATH_BIN}', d)
+    tmpdir = bb.data.expand('${base_prefix}', d)
+
+    for root, dirs, files in os.walk(path):
+        for file in files:
+            fpath = root + '/' + file
+            if '/bin/' in fpath:
+                p = sub.Popen([cmd, '-l', fpath],stdout=sub.PIPE,stderr=sub.PIPE)
+                err, out = p.communicate()
+                # If returned succesfully, process stderr for results
+                if p.returncode == 0:
+                    # Throw away everything other than the rpath list
+                    curr_rpath = err.partition("RPATH=")[2]
+                    #bb.note("Current rpath for %s is %s" % (fpath, curr_rpath.strip()))
+                    rpaths = curr_rpath.split(":")
+                    new_rpaths = []
+                    for rpath in rpaths:
+                        depth = fpath.partition(tmpdir)[2].strip().count('/')
+                        if depth == 3:
+                            # / is two levels up
+                            root = "$ORIGIN/../.."
+                        else:
+                            root = "$ORIGIN/.."
+
+                        # kill everything up to "/"
+                        new_rpaths.append("%s%s" % (root, rpath.partition(tmpdir)[2].strip()))
+                    args = ":".join(new_rpaths)
+                    #bb.note("Setting rpath to " + args)
+                    sub.call([cmd, '-r', args, fpath])
 
 python relocatable_binaries_preprocess() {
-    paths = []
-    target = bb.data.expand("${SYSROOT_DESTDIR}${TMPDIR}/sysroots/${TARGET_ARCH}-${TARGET_OS}", d)
-
-    paths.append(target + "/bin")
-    paths.append(target + "/usr/bin")
-
-    rpath_replace(paths, d)
+    rpath_replace(bb.data.expand("${SYSROOT_DESTDIR}${TMPDIR}/sysroots/${TARGET_ARCH}-${TARGET_OS}", d), d)
 }