[Lldb-commits] [lldb] r242729 - Correctly get the arguments and environment, even for processes that have a large amount or arguments and/or environment variables.

[Greg Clayton]

Author: gclayton
Date: Mon Jul 20 17:52:13 2015
New Revision: 242729

URL: http://llvm.org/viewvc/llvm-project?rev=242729&view=rev
Log:
Correctly get the arguments and environment, even for processes that have a large amount or arguments and/or environment variables.

We previously passed in a 8192 byte buffer but this wasn't large enough. We now calculate the size we need and then add 128 to it and get the environment. If we pass exactly the number of bytes it says is needs, the sysctl() returns junk. Adding 1 seemed to do the trick, but to err on the side of caution, I added a few bytes more.

<rdar://problem/21883842>


Modified:
    lldb/trunk/source/Host/macosx/Host.mm

Modified: lldb/trunk/source/Host/macosx/Host.mm
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Host/macosx/Host.mm?rev=242729&r1=242728&r2=242729&view=diff
==============================================================================
--- lldb/trunk/source/Host/macosx/Host.mm (original)
+++ lldb/trunk/source/Host/macosx/Host.mm Mon Jul 20 17:52:13 2015
@@ -39,6 +39,7 @@
 
 #include "lldb/Core/ArchSpec.h"
 #include "lldb/Core/Communication.h"
+#include "lldb/Core/DataBufferHeap.h"
 #include "lldb/Core/DataExtractor.h"
 #include "lldb/Core/Log.h"
 #include "lldb/Core/Module.h"
@@ -790,21 +791,23 @@ GetMacOSXProcessArgs (const ProcessInsta
     {
         int proc_args_mib[3] = { CTL_KERN, KERN_PROCARGS2, (int)process_info.GetProcessID() };
 
-        char arg_data[8192];
-        size_t arg_data_size = sizeof(arg_data);
-        if (::sysctl (proc_args_mib, 3, arg_data, &arg_data_size , NULL, 0) == 0)
+        size_t arg_data_size = 0;
+        if (::sysctl (proc_args_mib, 3, nullptr, &arg_data_size, NULL, 0) || arg_data_size == 0)
+            arg_data_size = 8192;
+
+        // Add a few bytes to the calculated length, I know we need to add at least one byte
+        // to this number otherwise we get junk back, so add 128 just in case...
+        DataBufferHeap arg_data(arg_data_size+128, 0);
+        arg_data_size = arg_data.GetByteSize();
+        if (::sysctl (proc_args_mib, 3, arg_data.GetBytes(), &arg_data_size , NULL, 0) == 0)
         {
-            DataExtractor data (arg_data, arg_data_size, lldb::endian::InlHostByteOrder(), sizeof(void *));
+            DataExtractor data (arg_data.GetBytes(), arg_data_size, lldb::endian::InlHostByteOrder(), sizeof(void *));
             lldb::offset_t offset = 0;
             uint32_t argc = data.GetU32 (&offset);
-            const char *cstr;
-            
-            
             llvm::Triple &triple = process_info.GetArchitecture().GetTriple();
             const llvm::Triple::ArchType triple_arch = triple.getArch();
             const bool check_for_ios_simulator = (triple_arch == llvm::Triple::x86 || triple_arch == llvm::Triple::x86_64);
-            
-            cstr = data.GetCStr (&offset);
+            const char *cstr = data.GetCStr (&offset);
             if (cstr)
             {
                 process_info.GetExecutableFile().SetFile(cstr, false);