Add GoOffsetLocator that fulfills DwarfReader API. Use as shim for Go Uprobes (#2207)

Summary: Add `GoOffsetLocator` that fulfills DwarfReader APIs. Use as
shim for Go Uprobes

Our current Go uprobe implementation relies on parsing DWARF
information. This is memory intensive and is not ideal if end users want
to keep the PEM's memory usage low (results in 100-150MB memory spikes).

In order to support lower memory uprobes and to support Go binaries
without DWARF, we can introduce a shim for the existing DwarfReader API
that can read the offsets from a file (via
openteletrmy-go-instrumentation generated offsets) or from the existing
DWARF information.

This PR introduces the `GoOffsetLocator` and tests that it functions
properly while leaving the DWARF based tracing in place. The next set of
changes will populate the offsets from
pixie-io/opentelemetry-go-instrumentation#1 and
provide configuration to choose the desired implementation: solely
DWARF, solely static offsets or to use them in tandem.

Relevant Issues: N/A

Type of change: /kind feature

Test Plan: Existing Go bpf trace tests should pass

---------

Signed-off-by: Dom Del Nano <[email protected]>

Author: ddelnano

src/stirling/binaries/go_binary_parse_profiling.cc

@@ -21,9 +21,11 @@
 #include "src/stirling/source_connectors/socket_tracer/uprobe_symaddrs.h"
 
 using px::StatusOr;
+using px::stirling::GoOffsetLocator;
 using px::stirling::PopulateGoTLSDebugSymbols;
 using px::stirling::obj_tools::DwarfReader;
 using px::stirling::obj_tools::ElfReader;
+using px::stirling::obj_tools::ReadGoBuildInfo;
 
 //-----------------------------------------------------------------------------
 // This utility is designed to isolate parsing the debug symbols of a Go binary. This
@@ -62,8 +64,15 @@ int main(int argc, char** argv) {
   }
   std::unique_ptr<DwarfReader> dwarf_reader = dwarf_reader_status.ConsumeValueOrDie();
 
+  auto build_info_s = ReadGoBuildInfo(elf_reader.get());
+  const auto& [go_version, build_info] = build_info_s.ConsumeValueOrDie();
+  px::stirling::StructOffsetMap struct_offsets;
+  px::stirling::FunctionArgMap function_args;
+  std::unique_ptr<GoOffsetLocator> go_offset_locator = std::make_unique<GoOffsetLocator>(
+      dwarf_reader.get(), struct_offsets, function_args, build_info, go_version);
+
   struct go_tls_symaddrs_t symaddrs;
-  auto status = PopulateGoTLSDebugSymbols(elf_reader.get(), dwarf_reader.get(), &symaddrs);
+  auto status = PopulateGoTLSDebugSymbols(go_offset_locator.get(), &symaddrs);
 
   if (!status.ok()) {
     LOG(ERROR) << absl::Substitute("debug symbol parsing failed with: $0", status.msg());

src/stirling/source_connectors/socket_tracer/uprobe_manager.cc

@@ -174,10 +174,10 @@ Status UProbeManager::UpdateOpenSSLSymAddrs(obj_tools::RawFptrManager* fptr_mana
   return Status::OK();
 }
 
-Status UProbeManager::UpdateGoCommonSymAddrs(ElfReader* elf_reader, DwarfReader* dwarf_reader,
+Status UProbeManager::UpdateGoCommonSymAddrs(ElfReader* elf_reader, GoOffsetLocator* offset_locator,
                                              const std::vector<int32_t>& pids) {
   PX_ASSIGN_OR_RETURN(struct go_common_symaddrs_t symaddrs,
-                      GoCommonSymAddrs(elf_reader, dwarf_reader));
+                      GoCommonSymAddrs(elf_reader, offset_locator));
 
   for (auto& pid : pids) {
     PX_RETURN_IF_ERROR(go_common_symaddrs_map_->SetValue(pid, symaddrs));
@@ -186,10 +186,10 @@ Status UProbeManager::UpdateGoCommonSymAddrs(ElfReader* elf_reader, DwarfReader*
   return Status::OK();
 }
 
-Status UProbeManager::UpdateGoHTTP2SymAddrs(ElfReader* elf_reader, DwarfReader* dwarf_reader,
+Status UProbeManager::UpdateGoHTTP2SymAddrs(ElfReader* elf_reader, GoOffsetLocator* offset_locator,
                                             const std::vector<int32_t>& pids) {
   PX_ASSIGN_OR_RETURN(struct go_http2_symaddrs_t symaddrs,
-                      GoHTTP2SymAddrs(elf_reader, dwarf_reader));
+                      GoHTTP2SymAddrs(elf_reader, offset_locator));
 
   for (auto& pid : pids) {
     PX_RETURN_IF_ERROR(go_http2_symaddrs_map_->SetValue(pid, symaddrs));
@@ -198,9 +198,9 @@ Status UProbeManager::UpdateGoHTTP2SymAddrs(ElfReader* elf_reader, DwarfReader*
   return Status::OK();
 }
 
-Status UProbeManager::UpdateGoTLSSymAddrs(ElfReader* elf_reader, DwarfReader* dwarf_reader,
+Status UProbeManager::UpdateGoTLSSymAddrs(GoOffsetLocator* offset_locator,
                                           const std::vector<int32_t>& pids) {
-  PX_ASSIGN_OR_RETURN(struct go_tls_symaddrs_t symaddrs, GoTLSSymAddrs(elf_reader, dwarf_reader));
+  PX_ASSIGN_OR_RETURN(struct go_tls_symaddrs_t symaddrs, GoTLSSymAddrs(offset_locator));
 
   for (auto& pid : pids) {
     PX_RETURN_IF_ERROR(go_tls_symaddrs_map_->SetValue(pid, symaddrs));
@@ -524,10 +524,10 @@ StatusOr<int> UProbeManager::AttachNodeJsOpenSSLUprobes(const uint32_t pid,
 
 StatusOr<int> UProbeManager::AttachGoTLSUProbes(const std::string& binary,
                                                 obj_tools::ElfReader* elf_reader,
-                                                obj_tools::DwarfReader* dwarf_reader,
+                                                GoOffsetLocator* offset_locator,
                                                 const std::vector<int32_t>& pids) {
   // Step 1: Update BPF symbols_map on all new PIDs.
-  Status s = UpdateGoTLSSymAddrs(elf_reader, dwarf_reader, pids);
+  Status s = UpdateGoTLSSymAddrs(offset_locator, pids);
   if (!s.ok()) {
     // Doesn't appear to be a binary with the mandatory symbols.
     // Might not even be a golang binary.
@@ -546,10 +546,10 @@ StatusOr<int> UProbeManager::AttachGoTLSUProbes(const std::string& binary,
 
 StatusOr<int> UProbeManager::AttachGoHTTP2UProbes(const std::string& binary,
                                                   obj_tools::ElfReader* elf_reader,
-                                                  obj_tools::DwarfReader* dwarf_reader,
+                                                  GoOffsetLocator* offset_locator,
                                                   const std::vector<int32_t>& pids) {
   // Step 1: Update BPF symaddrs for this binary.
-  Status s = UpdateGoHTTP2SymAddrs(elf_reader, dwarf_reader, pids);
+  Status s = UpdateGoHTTP2SymAddrs(elf_reader, offset_locator, pids);
   if (!s.ok()) {
     return 0;
   }
@@ -886,8 +886,30 @@ int UProbeManager::DeployGoUProbes(const absl::flat_hash_set<md::UPID>& pids) {
           binary, dwarf_reader_status.msg());
       continue;
     }
+
+    auto build_info_s = ReadGoBuildInfo(elf_reader.get());
+    obj_tools::BuildInfo build_info;
+    std::string go_version;
+    if (build_info_s.ok()) {
+      auto& build_info_pair = build_info_s.ValueOrDie();
+      go_version = build_info_pair.first;
+      build_info = std::move(build_info_pair.second);
+    } else {
+      VLOG(1) << absl::Substitute("Failed to read build info from binary $0. Message = $1", binary,
+                                  build_info_s.status().msg());
+
+      continue;
+    }
+
     std::unique_ptr<DwarfReader> dwarf_reader = dwarf_reader_status.ConsumeValueOrDie();
-    Status s = UpdateGoCommonSymAddrs(elf_reader.get(), dwarf_reader.get(), pid_vec);
+
+    // TODO(ddelnano): The struct and function offsets will be populated by the
+    // next set of changes.
+    StructOffsetMap struct_offsets;
+    FunctionArgMap function_offsets;
+    std::unique_ptr<GoOffsetLocator> offset_locator = std::make_unique<GoOffsetLocator>(
+        dwarf_reader.get(), struct_offsets, function_offsets, build_info, go_version);
+    Status s = UpdateGoCommonSymAddrs(elf_reader.get(), offset_locator.get(), pid_vec);
     if (!s.ok()) {
       VLOG(1) << absl::Substitute(
           "Golang binary $0 does not have the mandatory symbols (e.g. TCPConn).", binary);
@@ -898,7 +920,7 @@ int UProbeManager::DeployGoUProbes(const absl::flat_hash_set<md::UPID>& pids) {
     if (!cfg_disable_go_tls_tracing_) {
       VLOG(1) << absl::Substitute("Attempting to attach Go TLS uprobes to binary $0", binary);
       StatusOr<int> attach_status =
-          AttachGoTLSUProbes(binary, elf_reader.get(), dwarf_reader.get(), pid_vec);
+          AttachGoTLSUProbes(binary, elf_reader.get(), offset_locator.get(), pid_vec);
       if (!attach_status.ok()) {
         monitor_.AppendSourceStatusRecord("socket_tracer", attach_status.status(),
                                           "AttachGoTLSUProbes");
@@ -912,7 +934,7 @@ int UProbeManager::DeployGoUProbes(const absl::flat_hash_set<md::UPID>& pids) {
     // Go HTTP2 Probes.
     if (!cfg_disable_go_tls_tracing_ && cfg_enable_http2_tracing_) {
       StatusOr<int> attach_status =
-          AttachGoHTTP2UProbes(binary, elf_reader.get(), dwarf_reader.get(), pid_vec);
+          AttachGoHTTP2UProbes(binary, elf_reader.get(), offset_locator.get(), pid_vec);
       if (!attach_status.ok()) {
         monitor_.AppendSourceStatusRecord("socket_tracer", attach_status.status(),
                                           "AttachGoHTTP2UProbes");

src/stirling/source_connectors/socket_tracer/uprobe_manager.h

@@ -493,15 +493,15 @@ class UProbeManager {
    *
    * @param binary The path to the binary on which to deploy Go HTTP2 probes.
    * @param elf_reader ELF reader for the binary.
-   * @param dwarf_reader DWARF reader for the binary.
+   * @param offset_locator DWARF reader for the binary.
    * @param pids The list of PIDs that are new instances of the binary. Used to populate symbol
    *             addresses.
    * @return The number of uprobes deployed, or error. It is not considered an error if the binary
    *         is not a Go binary or doesn't use a Go HTTP2 library; instead the return value will be
    *         zero.
    */
   StatusOr<int> AttachGoHTTP2UProbes(const std::string& binary, obj_tools::ElfReader* elf_reader,
-                                     obj_tools::DwarfReader* dwarf_reader,
+                                     GoOffsetLocator* offset_locator,
                                      const std::vector<int32_t>& pids);
 
   /**
@@ -510,14 +510,14 @@ class UProbeManager {
    *
    * @param binary The path to the binary on which to deploy Go HTTP2 probes.
    * @param elf_reader ELF reader for the binary.
-   * @param dwarf_reader DWARF reader for the binary.
+   * @param offset_locator DWARF reader for the binary.
    * @param pids The list of PIDs that are new instances of the binary. Used to populate symbol
    *             addresses.
    * @return The number of uprobes deployed, or error. It is not an error if the binary
    *         is not a Go binary or doesn't use Go TLS; instead the return value will be zero.
    */
   StatusOr<int> AttachGoTLSUProbes(const std::string& binary, obj_tools::ElfReader* elf_reader,
-                                   obj_tools::DwarfReader* dwarf_reader,
+                                   GoOffsetLocator* offset_locator,
                                    const std::vector<int32_t>& new_pids);
 
   /**
@@ -579,14 +579,11 @@ class UProbeManager {
 
   Status UpdateOpenSSLSymAddrs(px::stirling::obj_tools::RawFptrManager* fptrManager,
                                std::filesystem::path container_lib, uint32_t pid);
-  Status UpdateGoCommonSymAddrs(obj_tools::ElfReader* elf_reader,
-                                obj_tools::DwarfReader* dwarf_reader,
+  Status UpdateGoCommonSymAddrs(obj_tools::ElfReader* elf_reader, GoOffsetLocator* offset_locator,
                                 const std::vector<int32_t>& pids);
-  Status UpdateGoHTTP2SymAddrs(obj_tools::ElfReader* elf_reader,
-                               obj_tools::DwarfReader* dwarf_reader,
+  Status UpdateGoHTTP2SymAddrs(obj_tools::ElfReader* elf_reader, GoOffsetLocator* offset_locator,
                                const std::vector<int32_t>& pids);
-  Status UpdateGoTLSSymAddrs(obj_tools::ElfReader* elf_reader, obj_tools::DwarfReader* dwarf_reader,
-                             const std::vector<int32_t>& pids);
+  Status UpdateGoTLSSymAddrs(GoOffsetLocator* offset_locator, const std::vector<int32_t>& pids);
   Status UpdateNodeTLSWrapSymAddrs(int32_t pid, const std::filesystem::path& node_exe,
                                    const SemVer& ver);