Add ProcessGDBRemote::GetAuxvData() and fix multiple-packet concatenation for binary data.

ProcessGDBRemote::GetAuxvData obtains the auxv from a remote gdbserver (via a binary-data packet), and returns the data as a DataBufferSP.

The patch includes a small fix to GDBRemoteCommunicationClient::SendPacketsAndConcatenateResponses() to support binary file format packet returns (by not assuming each binary packet is a null-terminated string when concatenating them).

llvm-svn: 202907

lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp

@@ -66,6 +66,7 @@ GDBRemoteCommunicationClient::GDBRemoteCommunicationClient(bool is_platform) :
     m_prepare_for_reg_writing_reply (eLazyBoolCalculate),
     m_supports_p (eLazyBoolCalculate),
     m_supports_QSaveRegisterState (eLazyBoolCalculate),
+    m_supports_qXfer_auxv_read (eLazyBoolCalculate),
     m_supports_qXfer_libraries_read (eLazyBoolCalculate),
     m_supports_qXfer_libraries_svr4_read (eLazyBoolCalculate),
     m_supports_augmented_libraries_svr4_read (eLazyBoolCalculate),
@@ -187,6 +188,16 @@ GDBRemoteCommunicationClient::GetQXferLibrariesReadSupported ()
     return (m_supports_qXfer_libraries_read == eLazyBoolYes);
 }
 
+bool
+GDBRemoteCommunicationClient::GetQXferAuxvReadSupported ()
+{
+    if (m_supports_qXfer_auxv_read == eLazyBoolCalculate)
+    {
+        GetRemoteQSupported();
+    }
+    return (m_supports_qXfer_auxv_read == eLazyBoolYes);
+}
+
 uint64_t
 GDBRemoteCommunicationClient::GetRemoteMaxPacketSize()
 {
@@ -294,6 +305,7 @@ GDBRemoteCommunicationClient::ResetDiscoverableSettings()
     m_supports_memory_region_info = eLazyBoolCalculate;
     m_prepare_for_reg_writing_reply = eLazyBoolCalculate;
     m_attach_or_wait_reply = eLazyBoolCalculate;
+    m_supports_qXfer_auxv_read = eLazyBoolCalculate;
     m_supports_qXfer_libraries_read = eLazyBoolCalculate;
     m_supports_qXfer_libraries_svr4_read = eLazyBoolCalculate;
     m_supports_augmented_libraries_svr4_read = eLazyBoolCalculate;
@@ -320,8 +332,9 @@ void
 GDBRemoteCommunicationClient::GetRemoteQSupported ()
 {
     // Clear out any capabilities we expect to see in the qSupported response
-    m_supports_qXfer_libraries_svr4_read = eLazyBoolNo;
+    m_supports_qXfer_auxv_read = eLazyBoolNo;
     m_supports_qXfer_libraries_read = eLazyBoolNo;
+    m_supports_qXfer_libraries_svr4_read = eLazyBoolNo;
     m_supports_augmented_libraries_svr4_read = eLazyBoolNo;
     m_max_packet_size = UINT64_MAX;  // It's supposed to always be there, but if not, we assume no limit
 
@@ -331,6 +344,8 @@ GDBRemoteCommunicationClient::GetRemoteQSupported ()
                                      /*send_async=*/false) == PacketResult::Success)
     {
         const char *response_cstr = response.GetStringRef().c_str();
+        if (::strstr (response_cstr, "qXfer:auxv:read+"))
+            m_supports_qXfer_auxv_read = eLazyBoolYes;
         if (::strstr (response_cstr, "qXfer:libraries-svr4:read+"))
             m_supports_qXfer_libraries_svr4_read = eLazyBoolYes;
         if (::strstr (response_cstr, "augmented-libraries-svr4-read"))
@@ -502,11 +517,8 @@ GDBRemoteCommunicationClient::SendPacketsAndConcatenateResponses
         {
             return PacketResult::ErrorReplyInvalid;
         }
-        // Skip past m or l
+        // Concatenate the result so far (skipping 'm' or 'l')
-        const char *s = this_string.c_str() + 1;
+        response_string.append(this_string, 1, std::string::npos);
-
-        // Concatenate the result so far
-        response_string += s;
         if (first_char == 'l')
             // We're done
             return PacketResult::Success;

lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h

@@ -383,6 +383,9 @@ public:
     bool
     SetCurrentThreadForRun (uint64_t tid);
 
+    bool
+    GetQXferAuxvReadSupported ();
+
     bool
     GetQXferLibrariesReadSupported ();
 
@@ -525,6 +528,7 @@ protected:
     lldb_private::LazyBool m_prepare_for_reg_writing_reply;
     lldb_private::LazyBool m_supports_p;
     lldb_private::LazyBool m_supports_QSaveRegisterState;
+    lldb_private::LazyBool m_supports_qXfer_auxv_read;
     lldb_private::LazyBool m_supports_qXfer_libraries_read;
     lldb_private::LazyBool m_supports_qXfer_libraries_svr4_read;
     lldb_private::LazyBool m_supports_augmented_libraries_svr4_read;

lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp

@@ -3060,6 +3060,19 @@ ProcessGDBRemote::GetDynamicLoader ()
     return m_dyld_ap.get();
 }
 
+const DataBufferSP
+ProcessGDBRemote::GetAuxvData()
+{
+    DataBufferSP buf;
+    if (m_gdb_comm.GetQXferAuxvReadSupported())
+    {
+        std::string response_string;
+        if (m_gdb_comm.SendPacketsAndConcatenateResponses("qXfer:auxv:read::", response_string) == GDBRemoteCommunication::PacketResult::Success)
+            buf.reset(new DataBufferHeap(response_string.c_str(), response_string.length()));
+    }
+    return buf;
+}
+
 
 class CommandObjectProcessGDBRemotePacketHistory : public CommandObjectParsed
 {

lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h

@@ -299,6 +299,9 @@ protected:
     bool
     ParseRegisters(lldb_private::ScriptInterpreterObject *registers_array);
 
+    virtual const lldb::DataBufferSP
+    GetAuxvData();
+
     //------------------------------------------------------------------
     /// Broadcaster event bits definitions.
     //------------------------------------------------------------------