allow passing info about known memory mappings to MinidumpWriter and ExceptionHandler

r=thestig at http://breakpad.appspot.com/242001/show

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@741 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/client/linux/handler/exception_handler.cc

@@ -88,10 +88,12 @@
 #include <unistd.h>
 
 #include <algorithm>
+#include <utility>
 #include <vector>
 
 #include "common/linux/linux_libc_support.h"
 #include "common/memory.h"
+#include "client/linux/minidump_writer/linux_dumper.h"
 #include "client/linux/minidump_writer/minidump_writer.h"
 #include "common/linux/guid_creator.h"
 #include "common/linux/eintr_wrapper.h"
@@ -449,8 +451,11 @@ void ExceptionHandler::WaitForContinueSignal() {
 // Runs on the cloned process.
 bool ExceptionHandler::DoDump(pid_t crashing_process, const void* context,
                               size_t context_size) {
-  return google_breakpad::WriteMinidump(
-      next_minidump_path_c_, crashing_process, context, context_size);
+  return google_breakpad::WriteMinidump(next_minidump_path_c_,
+                                        crashing_process,
+                                        context,
+                                        context_size,
+                                        mapping_list_);
 }
 
 // static
@@ -482,4 +487,21 @@ bool ExceptionHandler::WriteMinidump() {
 #endif  // !defined(__ARM_EABI__)
 }
 
+void ExceptionHandler::AddMappingInfo(const std::string& name,
+                                      const u_int8_t identifier[sizeof(MDGUID)],
+                                      uintptr_t start_address,
+                                      size_t mapping_size,
+                                      size_t file_offset) {
+  MappingInfo info;
+  info.start_addr = start_address;
+  info.size = mapping_size;
+  info.offset = file_offset;
+  strncpy(info.name, name.c_str(), std::min(name.size(), sizeof(info)));
+
+  MappingEntry mapping;
+  mapping.first = info;
+  memcpy(mapping.second, identifier, sizeof(MDGUID));
+  mapping_list_.push_back(mapping);
+}
+
 }  // namespace google_breakpad

src/client/linux/handler/exception_handler.h

@@ -30,17 +30,20 @@
 #ifndef CLIENT_LINUX_HANDLER_EXCEPTION_HANDLER_H_
 #define CLIENT_LINUX_HANDLER_EXCEPTION_HANDLER_H_
 
-#include <vector>
 #include <string>
+#include <vector>
 
 #include <pthread.h>
 #include <signal.h>
+#include <stdint.h>
 #include <stdio.h>
 
 #if defined(__ANDROID__)
 #include "client/linux/android_ucontext.h"
 #endif
 #include "client/linux/crash_generation/crash_generation_client.h"
+#include "client/linux/minidump_writer/minidump_writer.h"
+#include "google_breakpad/common/minidump_format.h"
 #include "processor/scoped_ptr.h"
 
 struct sigaction;
@@ -181,6 +184,15 @@ class ExceptionHandler {
       return crash_generation_client_.get() != NULL;
   }
 
+  // Add information about a memory mapping. This can be used if
+  // a custom library loader is used that maps things in a way
+  // that the linux dumper can't handle by reading the maps file.
+  void AddMappingInfo(const std::string& name,
+                      const u_int8_t identifier[sizeof(MDGUID)],
+                      uintptr_t start_address,
+                      size_t mapping_size,
+                      size_t file_offset);
+
  private:
   void Init(const std::string &dump_path,
             const int server_fd);
@@ -236,6 +248,10 @@ class ExceptionHandler {
   // cloned process after creating it, until we have explicitly enabled 
   // ptrace. This is used to store the file descriptors for the pipe
   int fdes[2];
+
+  // Callers can add extra info about mappings for cases where the
+  // dumper code cannot extract enough information from /proc/<pid>/maps.
+  MappingList mapping_list_;
 };
 
 }  // namespace google_breakpad

src/client/linux/handler/exception_handler_unittest.cc

@@ -42,6 +42,7 @@
 #include "client/linux/handler/exception_handler.h"
 #include "client/linux/minidump_writer/minidump_writer.h"
 #include "common/linux/eintr_wrapper.h"
+#include "common/linux/file_id.h"
 #include "common/linux/linux_libc_support.h"
 #include "third_party/lss/linux_syscall_support.h"
 #include "google_breakpad/processor/minidump.h"
@@ -54,6 +55,10 @@ using namespace google_breakpad;
 #define TEMPDIR "/data/local/tmp"
 #endif
 
+// Length of a formatted GUID string =
+// sizeof(MDGUID) * 2 + 4 (for dashes) + 1 (null terminator)
+const int kGUIDStringSize = 37;
+
 static void sigchld_handler(int signo) { }
 
 class ExceptionHandlerTest : public ::testing::Test {
@@ -573,6 +578,87 @@ TEST(ExceptionHandlerTest, InstructionPointerMemoryNullPointer) {
   free(filename);
 }
 
+static bool SimpleCallback(const char* dump_path,
+                           const char* minidump_id,
+                           void* context,
+                           bool succeeded) {
+  if (!succeeded)
+    return succeeded;
+
+  string* minidump_file = reinterpret_cast<string*>(context);
+  minidump_file->append(dump_path);
+  minidump_file->append("/");
+  minidump_file->append(minidump_id);
+  minidump_file->append(".dmp");
+  return true;
+}
+
+// Test that anonymous memory maps can be annotated with names and IDs.
+TEST(ExceptionHandlerTest, ModuleInfo) {
+  // These are defined here so the parent can use them to check the
+  // data from the minidump afterwards.
+  const u_int32_t kMemorySize = sysconf(_SC_PAGESIZE);
+  const char* kMemoryName = "a fake module";
+  const u_int8_t kModuleGUID[sizeof(MDGUID)] = {
+    0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
+    0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF
+  };
+  char module_identifier_buffer[kGUIDStringSize];
+  FileID::ConvertIdentifierToString(kModuleGUID,
+                                    module_identifier_buffer,
+                                    sizeof(module_identifier_buffer));
+  string module_identifier(module_identifier_buffer);
+  // Strip out dashes
+  size_t pos;
+  while ((pos = module_identifier.find('-')) != string::npos) {
+    module_identifier.erase(pos, 1);
+  }
+  // And append a zero, because module IDs include an "age" field
+  // which is always zero on Linux.
+  module_identifier += "0";
+
+  // Get some memory.
+  char* memory =
+    reinterpret_cast<char*>(mmap(NULL,
+                                 kMemorySize,
+                                 PROT_READ | PROT_WRITE,
+                                 MAP_PRIVATE | MAP_ANON,
+                                 -1,
+                                 0));
+  const u_int64_t kMemoryAddress = reinterpret_cast<u_int64_t>(memory);
+  ASSERT_TRUE(memory);
+
+  string minidump_filename;
+  ExceptionHandler handler(TEMPDIR, NULL, SimpleCallback,
+                           (void*)&minidump_filename, true);
+  // Add info about the anonymous memory mapping.
+  handler.AddMappingInfo(kMemoryName,
+                         kModuleGUID,
+                         kMemoryAddress,
+                         kMemorySize,
+                         0);
+  handler.WriteMinidump();
+
+  // Read the minidump. Load the module list, and ensure that
+  // the mmap'ed |memory| is listed with the given module name
+  // and debug ID.
+  Minidump minidump(minidump_filename);
+  ASSERT_TRUE(minidump.Read());
+
+  MinidumpModuleList* module_list = minidump.GetModuleList();
+  ASSERT_TRUE(module_list);
+  const MinidumpModule* module =
+    module_list->GetModuleForAddress(kMemoryAddress);
+  ASSERT_TRUE(module);
+
+  EXPECT_EQ(kMemoryAddress, module->base_address());
+  EXPECT_EQ(kMemorySize, module->size());
+  EXPECT_EQ(kMemoryName, module->code_file());
+  EXPECT_EQ(module_identifier, module->debug_identifier());
+
+  unlink(minidump_filename.c_str());
+}
+
 static const unsigned kControlMsgSize =
     CMSG_SPACE(sizeof(int)) + CMSG_SPACE(sizeof(struct ucred));