libcdb.unstrip_libc: debug symbols are fetched only if not present

* Usage of `ELF.debuginfo` to check if debug symbols exist

closes #2324

---------

Signed-off-by: sswastik02 <[email protected]>

Author: sswastik02

pwnlib/libcdb.py

@@ -291,6 +291,10 @@ def unstrip_libc(filename):
         log.warn_once('Given libc does not have a buildid. Cannot look for debuginfo to unstrip.')
         return False
 
+    if libc.debuginfo:
+        log.debug('Given libc already contains debug information. Skipping unstrip.')
+        return True
+
     log.debug('Trying debuginfod servers: %r', DEBUGINFOD_SERVERS)
 
     for server_url in DEBUGINFOD_SERVERS: