[Lldb-commits] [PATCH] Add process launch --enable-aslr option, tweak handling of flag

[Todd Fiala]

This change modifies the logic used to set the
eLaunchFlagDisableASLR ProcessLaunchInfo setting for inferior process
launching.  Now, if 'process launch' is provided with either --disable-aslr
or --enable-aslr, then the launch flag is set accordingly.  If niether
--disable-aslr or --enable-aslr are specified, then the setting for
target.disable-aslr is used to determine the setting or clearing of the
eLaunchFlagDisableASLR setting.  The target.disable-aslr setting currently
defaults to true, so the default behavior when nothing is specified on the
'process launch' (i.e. 'run' command) is to disable ASLR.

-- 
-Todd
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Index: include/lldb/Target/Process.h
===================================================================
--- include/lldb/Target/Process.h	(revision 215871)
+++ include/lldb/Target/Process.h	(working copy)
@@ -392,6 +392,7 @@
     OptionParsingStarting ()
     {
         launch_info.Clear();
+        disable_aslr = eLazyBoolCalculate;
     }
     
     const OptionDefinition*
@@ -407,6 +408,7 @@
     // Instance variables to hold the values for command options.
     
     ProcessLaunchInfo launch_info;
+    lldb_private::LazyBool disable_aslr;
 };
 
 //----------------------------------------------------------------------
Index: source/Commands/CommandObjectProcess.cpp
===================================================================
--- source/Commands/CommandObjectProcess.cpp	(revision 215871)
+++ source/Commands/CommandObjectProcess.cpp	(working copy)
@@ -205,8 +205,19 @@
         
         const char *target_settings_argv0 = target->GetArg0();
         
-        if (target->GetDisableASLR())
+        // Determine whether we will disable ASLR or leave it in the default state (i.e. enabled if the platform supports it).
+        // First check if the process launch options explicitly set it to enabled or disabled.  If so, use that setting;
+        // otherwise, use the 'settings target.disable-aslr' setting.
+        bool disable_aslr = false;
+        if (m_options.disable_aslr != eLazyBoolCalculate)
+            disable_aslr = (m_options.disable_aslr == eLazyBoolYes);
+        else
+            disable_aslr = target->GetDisableASLR ();
+        
+        if (disable_aslr)
             m_options.launch_info.GetFlags().Set (eLaunchFlagDisableASLR);
+        else
+            m_options.launch_info.GetFlags().Clear (eLaunchFlagDisableASLR);
         
         if (target->GetDetachOnError())
             m_options.launch_info.GetFlags().Set (eLaunchFlagDetachOnError);
Index: source/Target/Process.cpp
===================================================================
--- source/Target/Process.cpp	(revision 215871)
+++ source/Target/Process.cpp	(working copy)
@@ -454,11 +454,15 @@
                 launch_info.GetArchitecture().SetTriple (option_arg);
             break;
             
-        case 'A':   
-            launch_info.GetFlags().Set (eLaunchFlagDisableASLR); 
+        case 'A':   // Disable ASLR.
+            disable_aslr = eLazyBoolYes;
             break;
-            
-        case 'c':   
+
+        case 'r':   // Enable ASLR (i.e. 'r'andomize).
+            disable_aslr = eLazyBoolNo;
+            break;
+
+        case 'c':
             if (option_arg && option_arg[0])
                 launch_info.SetShell (option_arg);
             else
@@ -481,6 +485,7 @@
 {
 { LLDB_OPT_SET_ALL, false, "stop-at-entry", 's', OptionParser::eNoArgument,       NULL, NULL, 0, eArgTypeNone,          "Stop at the entry point of the program when launching a process."},
 { LLDB_OPT_SET_ALL, false, "disable-aslr",  'A', OptionParser::eNoArgument,       NULL, NULL, 0, eArgTypeNone,          "Disable address space layout randomization when launching a process."},
+{ LLDB_OPT_SET_ALL, false, "enable-aslr",   'r', OptionParser::eNoArgument,       NULL, NULL, 0, eArgTypeNone,          "Enable address space layout randomization when launching a process."},
 { LLDB_OPT_SET_ALL, false, "plugin",        'p', OptionParser::eRequiredArgument, NULL, NULL, 0, eArgTypePlugin,        "Name of the process plugin you want to use."},
 { LLDB_OPT_SET_ALL, false, "working-dir",   'w', OptionParser::eRequiredArgument, NULL, NULL, 0, eArgTypeDirectoryName,          "Set the current working directory to <path> when running the inferior."},
 { LLDB_OPT_SET_ALL, false, "arch",          'a', OptionParser::eRequiredArgument, NULL, NULL, 0, eArgTypeArchitecture,  "Set the architecture for the process to launch when ambiguous."},