From 9fdf787d2e57f77cfc4df0af8dfdadb8a5582847 Mon Sep 17 00:00:00 2001
From: David Smith <dsmith@redhat.com>
Date: Wed, 18 Jul 2012 13:30:59 -0500
Subject: [PATCH] Fixed PR11424 by using System.map data to validate dwarfless
 kprobe probes.

* tapsets.cxx (kprobe_builder::load_function_name_cache): New function.
  (kprobe_builder::build): Use parsed System.map data to validate
  kprobe.function probe names.
---
 tapsets.cxx | 115 ++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 102 insertions(+), 13 deletions(-)

diff --git a/tapsets.cxx b/tapsets.cxx
index 354b40d1d..9280032cf 100644
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -8119,7 +8119,25 @@ kprobe_derived_probe_group::emit_module_exit (systemtap_session& s)
 
 struct kprobe_builder: public derived_probe_builder
 {
-  kprobe_builder() {}
+private:
+  bool cache_initialized;
+  vector<string> function_name_cache;
+
+  void load_function_name_cache(systemtap_session & sess);
+
+public:
+  kprobe_builder(): cache_initialized(false) {}
+
+  void build_no_more (systemtap_session &s)
+  {
+    if (! function_name_cache.empty())
+      {
+	if (s.verbose > 3)
+          clog << _("kprobe_builder releasing cache") << endl;
+	function_name_cache.clear();
+      }
+  }
+
   virtual void build(systemtap_session & sess,
 		     probe * base,
 		     probe_point * location,
@@ -8128,6 +8146,57 @@ struct kprobe_builder: public derived_probe_builder
 };
 
 
+void
+kprobe_builder::load_function_name_cache(systemtap_session &sess)
+{
+  if (! cache_initialized)
+    {
+      cache_initialized = true;
+      string system_map_path = sess.kernel_build_tree + "/System.map";
+      ifstream system_map;
+
+      system_map.open(system_map_path.c_str(), ifstream::in);
+      if (! system_map.is_open())
+        {
+	  string system_map_path2 = "/boot/System.map-" + sess.kernel_release;
+
+	  system_map.clear();
+	  system_map.open(system_map_path2.c_str(), ifstream::in);
+	  if (! system_map.is_open())
+	    {
+	      if (sess.verbose > 3)
+		//TRANSLATORS: specific path cannot be opened
+		clog << system_map_path << _(" and ")
+		     << system_map_path2 << _(" cannot be opened: ")
+		     << strerror(errno) << endl;
+	      return;
+	    }
+        }
+
+      string address, type, name;
+      do
+        {
+	  system_map >> address >> type >> name;
+
+	  if (sess.verbose > 3)
+	    clog << "'" << address << "' '" << type << "' '" << name
+		 << "'" << endl;
+
+	  // 'T'/'t' are text code symbols
+	  if (type != "t" && type != "T")
+	      continue;
+
+	  // FIXME: better things to do here - look for _stext before
+	  // remembering symbols. Also:
+	  // - stop remembering names at ???
+	  // - what about __kprobes_text_start/__kprobes_text_end?
+	  function_name_cache.push_back(name);
+	}
+      while (! system_map.eof());
+      system_map.close();
+    }
+}
+
 void
 kprobe_builder::build(systemtap_session & sess,
 		      probe * base,
@@ -8165,19 +8234,39 @@ kprobe_builder::build(systemtap_session & sess,
 
   if (has_function_str)
     {
-      if (has_module_str)
-	function_string_val = module_string_val + ":" + function_string_val;
+      if (has_module_str) 
+        {
+	  function_string_val = module_string_val + ":" + function_string_val;
+	  derived_probe *dp
+	    = new kprobe_derived_probe (base, location, function_string_val,
+					0, has_return, has_statement_num,
+					has_maxactive, has_path, has_library,
+					maxactive_val, path_tgt, library_tgt);
+	  finished_results.push_back (dp);
+	}
+      else
+        {
+	  load_function_name_cache(sess);
 
-      finished_results.push_back (new kprobe_derived_probe (base,
-							    location, function_string_val,
-							    0, has_return,
-							    has_statement_num,
-							    has_maxactive,
-							    has_path,
-							    has_library,
-							    maxactive_val,
-							    path_tgt,
-							    library_tgt));
+	  // Search function name list for matching names
+	  for (vector<string>::const_iterator it = function_name_cache.begin();
+	       it != function_name_cache.end(); it++)
+	    {
+	      // Below, "rc" has negative polarity: zero iff matching.
+	      int rc = fnmatch(function_string_val.c_str(), (*it).c_str(), 0);
+	      if (! rc)
+	        {
+		  derived_probe *dp
+		    = new kprobe_derived_probe (base, location, *it,
+						0, has_return,
+						has_statement_num,
+						has_maxactive, has_path,
+						has_library, maxactive_val,
+						path_tgt, library_tgt);
+		  finished_results.push_back (dp);
+		}
+	    }
+	}
     }
   else
     {
-- 
2.43.5