[Lldb-commits] [PATCH] D92264: [lldb] [POSIX-DYLD] Update the cached exe path after attach

[Michał Górny via Phabricator via lldb-commits]

mgorny updated this revision to Diff 309684.
mgorny added a comment.

With D92667 <https://reviews.llvm.org/D92667>, I've finally found a way to reproduce this without running lldb-server explicitly — we need to spawn the program via relative path though. I've added a test that does that, and compares the address from `image list` with the one gotten after explicitly creating target via file path. This clearly reproduces the problem if you don't modify the sources (i.e. mismatch between `0x400000` and `0x200000`).


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D92264/new/

https://reviews.llvm.org/D92264

Files:
  lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.cpp
  lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.h
  lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
  lldb/test/API/commands/process/attach/TestProcessAttach.py


Index: lldb/test/API/commands/process/attach/TestProcessAttach.py
===================================================================
--- lldb/test/API/commands/process/attach/TestProcessAttach.py
+++ lldb/test/API/commands/process/attach/TestProcessAttach.py
@@ -77,6 +77,41 @@
         process = target.GetProcess()
         self.assertTrue(process, PROCESS_IS_VALID)
 
+    def test_attach_to_process_by_id_correct_executable_offset(self):
+        """
+        Test that after attaching to a process the executable offset
+        is determined correctly on FreeBSD.  This is a regression test
+        for dyld plugin getting the correct executable path,
+        and therefore being able to identify it in the module list.
+        """
+
+        self.build()
+        exe = self.getBuildArtifact(exe_name)
+
+        # In order to reproduce, we must spawn using a relative path
+        popen = self.spawnSubprocess(os.path.relpath(exe))
+
+        self.runCmd("process attach -p " + str(popen.pid))
+
+        # Grab the offset and filename from the image list
+        m = self.match("image list -h -f",
+                       [r"^\[\s*0\]\s*(0x[0-9a-fA-F]+)\s*([^\n]*)"])
+        self.assertTrue(os.path.samefile(m.group(2), exe))
+        offset_attach = m.group(1)
+
+        target = self.dbg.GetSelectedTarget()
+        process = target.GetProcess()
+        self.assertTrue(process, PROCESS_IS_VALID)
+
+        # Now grab the file itself and compare the offset
+        self.runCmd("target create " + exe)
+        m = self.match("image list -h -f",
+                       [r"^\[\s*0\]\s*(0x[0-9a-fA-F]+)\s*([^\n]*)"])
+        self.assertTrue(os.path.samefile(m.group(2), exe))
+        offset_target = m.group(1)
+
+        self.assertEqual(offset_attach, offset_target)
+
     def tearDown(self):
         # Destroy process before TestBase.tearDown()
         self.dbg.GetSelectedTarget().GetProcess().Destroy()
Index: lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
===================================================================
--- lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
+++ lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
@@ -101,6 +101,7 @@
 
   ModuleSP executable_sp = GetTargetExecutable();
   ResolveExecutableModule(executable_sp);
+  m_rendezvous.UpdateExecutablePath();
 
   // find the main process load offset
   addr_t load_offset = ComputeLoadOffset();
Index: lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.h
===================================================================
--- lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.h
+++ lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.h
@@ -60,6 +60,9 @@
 
   DYLDRendezvous(lldb_private::Process *process);
 
+  /// Update the cached executable path.
+  void UpdateExecutablePath();
+
   /// Update the internal snapshot of runtime linker rendezvous and recompute
   /// the currently loaded modules.
   ///
Index: lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.cpp
===================================================================
--- lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.cpp
+++ lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.cpp
@@ -94,12 +94,13 @@
     : m_process(process), m_rendezvous_addr(LLDB_INVALID_ADDRESS), m_current(),
       m_previous(), m_loaded_modules(), m_soentries(), m_added_soentries(),
       m_removed_soentries() {
-  Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
-
   m_thread_info.valid = false;
+  UpdateExecutablePath();
+}
 
-  // Cache a copy of the executable path
+void DYLDRendezvous::UpdateExecutablePath() {
   if (m_process) {
+    Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
     Module *exe_mod = m_process->GetTarget().GetExecutableModulePointer();
     if (exe_mod) {
       m_exe_file_spec = exe_mod->GetPlatformFileSpec();


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