[lldb-dev] [PATCH] new utility methods in GDBRemoteCommunicationClient
Steve Pucci
spucci at google.com
Thu Jan 23 13:03:49 PST 2014
I'm working on better support for debugging against a remote stock
gdbserver, and these are some new support methods I'm using. I'm sending
this separately for easier digestion.
There are a couple of pieces:
* some lazy-evaluation members that store info listed in a qSupported
response
* new method SendPacketsAndConcatenateResponses which is used for fetching
fixed-size objects from the remote gdbserver by using multiple packets if
necessary (first use will be to fetch shared-library XML files).
Thanks,
Steve
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diff --git a/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h b/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
index dcf638b..2026e50 100644
--- a/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
+++ b/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
@@ -58,6 +58,21 @@ public:
StringExtractorGDBRemote &response,
bool send_async);
+ // For packets which specify a range of output to be returned,
+ // return all of the output via a series of packets of the form
+ // <prefix>:000,<size>
+ // <prefix>:<size>,<size>
+ // <prefix>:<size>*2,<size>
+ // <prefix>:<size>*3,<size>
+ // ...
+ // until a "$l..." packet is received, indicating the end.
+ // Concatenate the results together and return in response.
+ // If any packet fails, the response indicates that failure
+ // and the returned string value is undefined.
+ PacketResult
+ SendPacketsAndConcatenateResponses (const char *send_payload_prefix,
+ std::string &response_string);
+
lldb::StateType
SendContinuePacketAndWaitForResponse (ProcessGDBRemote *process,
const char *packet_payload,
@@ -248,6 +263,9 @@ public:
const lldb_private::ArchSpec &
GetProcessArchitecture ();
+ void
+ GetRemoteQSupported();
+
bool
GetVContSupported (char flavor);
@@ -359,6 +377,18 @@ public:
bool
SetCurrentThreadForRun (uint64_t tid);
+ bool
+ GetQXferLibrariesReadSupported ();
+
+ bool
+ GetQXferLibrariesSVR4ReadSupported ();
+
+ uint64_t
+ GetRemoteMaxPacketSize();
+
+ bool
+ GetAugmentedLibrariesSVR4ReadSupported ();
+
lldb_private::LazyBool
SupportsAllocDeallocMemory () // const
{
@@ -489,7 +519,10 @@ 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_libraries_read;
+ lldb_private::LazyBool m_supports_qXfer_libraries_svr4_read;
+ lldb_private::LazyBool m_supports_augmented_libraries_svr4_read;
+
bool
m_supports_qProcessInfoPID:1,
m_supports_qfProcessInfo:1,
@@ -532,6 +565,7 @@ protected:
std::string m_os_kernel;
std::string m_hostname;
uint32_t m_default_packet_timeout;
+ uint64_t m_max_packet_size; // as returned by qSupported
bool
DecodeProcessInfoResponse (StringExtractorGDBRemote &response,
diff --git a/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp b/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
index aae3aaa..9f591c8 100644
--- a/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ b/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
@@ -66,6 +66,9 @@ GDBRemoteCommunicationClient::GDBRemoteCommunicationClient(bool is_platform) :
m_prepare_for_reg_writing_reply (eLazyBoolCalculate),
m_supports_p (eLazyBoolCalculate),
m_supports_QSaveRegisterState (eLazyBoolCalculate),
+ m_supports_qXfer_libraries_read (eLazyBoolCalculate),
+ m_supports_qXfer_libraries_svr4_read (eLazyBoolCalculate),
+ m_supports_augmented_libraries_svr4_read (eLazyBoolCalculate),
m_supports_qProcessInfoPID (true),
m_supports_qfProcessInfo (true),
m_supports_qUserName (true),
@@ -96,7 +99,8 @@ GDBRemoteCommunicationClient::GDBRemoteCommunicationClient(bool is_platform) :
m_os_build (),
m_os_kernel (),
m_hostname (),
- m_default_packet_timeout (0)
+ m_default_packet_timeout (0),
+ m_max_packet_size (0)
{
}
@@ -149,6 +153,46 @@ GDBRemoteCommunicationClient::HandshakeWithServer (Error *error_ptr)
}
bool
+GDBRemoteCommunicationClient::GetAugmentedLibrariesSVR4ReadSupported ()
+{
+ if (m_supports_augmented_libraries_svr4_read == eLazyBoolCalculate)
+ {
+ GetRemoteQSupported();
+ }
+ return (m_supports_augmented_libraries_svr4_read == eLazyBoolYes);
+}
+
+bool
+GDBRemoteCommunicationClient::GetQXferLibrariesSVR4ReadSupported ()
+{
+ if (m_supports_qXfer_libraries_svr4_read == eLazyBoolCalculate)
+ {
+ GetRemoteQSupported();
+ }
+ return (m_supports_qXfer_libraries_svr4_read == eLazyBoolYes);
+}
+
+bool
+GDBRemoteCommunicationClient::GetQXferLibrariesReadSupported ()
+{
+ if (m_supports_qXfer_libraries_read == eLazyBoolCalculate)
+ {
+ GetRemoteQSupported();
+ }
+ return (m_supports_qXfer_libraries_read == eLazyBoolYes);
+}
+
+uint64_t
+GDBRemoteCommunicationClient::GetRemoteMaxPacketSize()
+{
+ if (m_max_packet_size == 0)
+ {
+ GetRemoteQSupported();
+ }
+ return m_max_packet_size;
+}
+
+bool
GDBRemoteCommunicationClient::QueryNoAckModeSupported ()
{
if (m_supports_not_sending_acks == eLazyBoolCalculate)
@@ -245,6 +289,9 @@ GDBRemoteCommunicationClient::ResetDiscoverableSettings()
m_supports_memory_region_info = eLazyBoolCalculate;
m_prepare_for_reg_writing_reply = eLazyBoolCalculate;
m_attach_or_wait_reply = eLazyBoolCalculate;
+ m_supports_qXfer_libraries_read = eLazyBoolCalculate;
+ m_supports_qXfer_libraries_svr4_read = eLazyBoolCalculate;
+ m_supports_augmented_libraries_svr4_read = eLazyBoolCalculate;
m_supports_qProcessInfoPID = true;
m_supports_qfProcessInfo = true;
@@ -260,8 +307,51 @@ GDBRemoteCommunicationClient::ResetDiscoverableSettings()
m_supports_QEnvironmentHexEncoded = true;
m_host_arch.Clear();
m_process_arch.Clear();
+
+ m_max_packet_size = 0;
}
+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_libraries_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
+
+ StringExtractorGDBRemote response;
+ if (SendPacketAndWaitForResponse("qSupported",
+ response,
+ /*send_async=*/false) == PacketResult::Success)
+ {
+ const char *response_cstr = response.GetStringRef().c_str();
+ if (::strstr (response_cstr, "qXfer:libraries-svr4:read+"))
+ m_supports_qXfer_libraries_svr4_read = eLazyBoolYes;
+ if (::strstr (response_cstr, "augmented-libraries-svr4-read"))
+ {
+ m_supports_qXfer_libraries_svr4_read = eLazyBoolYes; // implied
+ m_supports_augmented_libraries_svr4_read = eLazyBoolYes;
+ }
+ if (::strstr (response_cstr, "qXfer:libraries:read+"))
+ m_supports_qXfer_libraries_read = eLazyBoolYes;
+
+ const char *packet_size_str = ::strstr (response_cstr, "PacketSize=");
+ if (packet_size_str)
+ {
+ StringExtractorGDBRemote packet_response(packet_size_str + strlen("PacketSize="));
+ m_max_packet_size = packet_response.GetHexMaxU64(/*little_endian=*/false, UINT64_MAX);
+ printf("max packet size %lu\n", (unsigned long)m_max_packet_size);
+ if (m_max_packet_size == 0)
+ {
+ m_max_packet_size = UINT64_MAX; // Must have been a garbled response
+ Log *log (ProcessGDBRemoteLog::GetLogIfAllCategoriesSet (GDBR_LOG_PROCESS));
+ if (log)
+ log->Printf ("Garbled PacketSize spec in qSupported response");
+ }
+ }
+ }
+}
bool
GDBRemoteCommunicationClient::GetThreadSuffixSupported ()
@@ -364,6 +454,51 @@ GDBRemoteCommunicationClient::GetpPacketSupported (lldb::tid_t tid)
}
GDBRemoteCommunicationClient::PacketResult
+GDBRemoteCommunicationClient::SendPacketsAndConcatenateResponses
+(
+ const char *payload_prefix,
+ std::string &response_string
+)
+{
+ response_string = "";
+ std::string payload_prefix_str(payload_prefix);
+ unsigned int response_size = 0x1000;
+ if (response_size > GetRemoteMaxPacketSize()) { // May send qSupported packet
+ response_size = GetRemoteMaxPacketSize();
+ }
+
+ for (unsigned int offset = 0; true; offset += response_size)
+ {
+ StringExtractorGDBRemote this_response;
+ // Construct payload
+ char sizeDescriptor[128];
+ snprintf(sizeDescriptor, sizeof(sizeDescriptor), "%x,%x", offset, response_size);
+ PacketResult result = SendPacketAndWaitForResponse((payload_prefix_str + sizeDescriptor).c_str(),
+ this_response,
+ /*send_async=*/false);
+ if (result != PacketResult::Success)
+ return result;
+
+ const std::string &this_string = this_response.GetStringRef();
+
+ // Check for m or l as first character; l seems to mean this is the last chunk
+ char first_char = *this_string.c_str();
+ if (first_char != 'm' && first_char != 'l')
+ {
+ return PacketResult::ErrorReplyInvalid;
+ }
+ // Skip past m or l
+ const char *s = this_string.c_str() + 1;
+
+ // Concatenate the result so far
+ response_string += s;
+ if (first_char == 'l')
+ // We're done
+ return PacketResult::Success;
+ }
+}
+
+GDBRemoteCommunicationClient::PacketResult
GDBRemoteCommunicationClient::SendPacketAndWaitForResponse
(
const char *payload,
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