[lldb] Extend SWIG SBProcess interface with WriteMemoryAsCString method

This patch tries to address an interoperability issue when writing
python string into the process memory.

Since the python string is not null-terminated, it would still be
written to memory however, when trying to read it again with
`SBProcess::ReadCStringFromMemory`, the memory read would fail, since
the read string doens't contain a null-terminator, and therefore is not
a valid C string.

To address that, this patch extends the `SBProcess` SWIG interface to
expose a new `WriteMemoryAsCString` method that is only exposed to the
SWIG target language. That method checks that the buffer to write is
null-terminated and otherwise, it appends a null byte at the end of it.

Signed-off-by: Med Ismail Bennani <[email protected]>
(cherry picked from commit e6cac17)

Author: medismailben

lldb/bindings/interface/SBProcessExtensions.i

@@ -2,6 +2,18 @@ STRING_EXTENSION_OUTSIDE(SBProcess)
 %extend lldb::SBProcess {
 #ifdef SWIGPYTHON
     %pythoncode %{
+        def WriteMemoryAsCString(self, addr, str, error):
+            '''
+              WriteMemoryAsCString(self, addr, str, error):
+                This functions the same as `WriteMemory` except a null-terminator is appended
+                to the end of the buffer if it is not there already.
+            '''
+            if not str or len(str) == 0:
+                return 0
+            if not str[-1] == '\0':
+                str += '\0'
+            return self.WriteMemory(addr, str, error)
+
         def __get_is_alive__(self):
             '''Returns "True" if the process is currently alive, "False" otherwise'''
             s = self.GetState()