[Lldb-commits] [lldb] r179152 - When ObjectFileMachO::ParseSections() notices that it has a truncated file, zero out the

[Jason Molenda]

Author: jmolenda
Date: Wed Apr 10 00:58:57 2013
New Revision: 179152

URL: http://llvm.org/viewvc/llvm-project?rev=179152&view=rev
Log:
When ObjectFileMachO::ParseSections() notices that it has a truncated file, zero out the
SectionList so we don't try to do anything with this file.  Currently we end up crashing
later in the debug session when we read past the end of the file -- this at least gets us
closer with something like ProcessMachCore printing "error: core file has no sections".
<rdar://problem/13468295>

Modified:
    lldb/trunk/include/lldb/Core/Section.h
    lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp

Modified: lldb/trunk/include/lldb/Core/Section.h
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/include/lldb/Core/Section.h?rev=179152&r1=179151&r2=179152&view=diff
==============================================================================
--- lldb/trunk/include/lldb/Core/Section.h (original)
+++ lldb/trunk/include/lldb/Core/Section.h Wed Apr 10 00:58:57 2013
@@ -88,6 +88,12 @@ public:
     void
     Finalize ();
 
+    void
+    Clear ()
+    {
+        m_sections.clear();
+    }
+
 protected:
     collection  m_sections;
 };

Modified: lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp?rev=179152&r1=179151&r2=179152&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp (original)
+++ lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp Wed Apr 10 00:58:57 2013
@@ -15,6 +15,7 @@
 #include "lldb/lldb-private-log.h"
 #include "lldb/Core/ArchSpec.h"
 #include "lldb/Core/DataBuffer.h"
+#include "lldb/Core/Debugger.h"
 #include "lldb/Core/FileSpecList.h"
 #include "lldb/Core/Log.h"
 #include "lldb/Core/Module.h"
@@ -836,6 +837,31 @@ ObjectFileMachO::ParseSections ()
                 load_cmd.vmsize = m_data.GetAddress(&offset);
                 load_cmd.fileoff = m_data.GetAddress(&offset);
                 load_cmd.filesize = m_data.GetAddress(&offset);
+                if (m_length != 0 && load_cmd.filesize != 0)
+                {
+                    if (load_cmd.fileoff + load_cmd.filesize > m_length)
+                    {
+                        // We have a load command that says it extends past the end of hte file.  This is likely
+                        // a corrupt file.  We don't have any way to return an error condition here (this method
+                        // was likely invokved from something like ObjectFile::GetSectionList()) -- all we can do
+                        // is null out the SectionList vector and if a process has been set up, dump a message
+                        // to stdout.  The most common case here is core file debugging with a truncated file - and
+                        // in that case we don't have a Process yet so nothing will be printed.  Not really ideal;
+                        // the ObjectFile needs some way of reporting an error message for methods like GetSectionList
+                        // which fail.
+                        ProcessSP process_sp (m_process_wp.lock());
+                        if (process_sp)
+                        {
+                            Stream *s = &process_sp->GetTarget().GetDebugger().GetOutputStream();
+                            if (s)
+                            {
+                                s->Printf ("Corrupt/invalid Mach-O object file -- a load command extends past the end of the file.\n");
+                            }
+                        }
+                        m_sections_ap->Clear();
+                        return 0;
+                    }
+                }
                 if (m_data.GetU32(&offset, &load_cmd.maxprot, 4))
                 {