Allow adding extra memory regions to minidump on linux/windows

A=Bill McCloskey <wmccloskey@mozilla.com> R=ted at https://bugzilla.mozilla.org/show_bug.cgi?id=662646

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@989 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/client/linux/handler/exception_handler.cc

@@ -465,7 +465,8 @@ bool ExceptionHandler::DoDump(pid_t crashing_process, const void* context,
                                         crashing_process,
                                         context,
                                         context_size,
-                                        mapping_list_);
+                                        mapping_list_,
+                                        app_memory_list_);
 }
 
 // static
@@ -515,4 +516,19 @@ void ExceptionHandler::AddMappingInfo(const string& name,
   mapping_list_.push_back(mapping);
 }
 
+void ExceptionHandler::RegisterAppMemory(void *ptr, size_t length) {
+  app_memory_list_.push_back(AppMemory(ptr, length));
+}
+
+void ExceptionHandler::UnregisterAppMemory(void *ptr) {
+  for (AppMemoryList::iterator iter = app_memory_list_.begin();
+       iter != app_memory_list_.end();
+       ++iter) {
+    if (iter->ptr == ptr) {
+      app_memory_list_.erase(iter);
+      return;
+    }
+  }
+}
+
 }  // namespace google_breakpad

src/client/linux/handler/exception_handler.h

@@ -194,6 +194,13 @@ class ExceptionHandler {
                       size_t mapping_size,
                       size_t file_offset);
 
+  // Register a block of memory of len bytes starting at address p
+  // to be copied to the minidump when a crash happens.
+  void RegisterAppMemory(void *ptr, size_t length);
+
+  // Unregister a block of memory that was registered with RegisterAppMemory.
+  void UnregisterAppMemory(void *ptr);
+
  private:
   void Init(const string &dump_path,
             const int server_fd);
@@ -252,6 +259,10 @@ class ExceptionHandler {
   // Callers can add extra info about mappings for cases where the
   // dumper code cannot extract enough information from /proc/<pid>/maps.
   MappingList mapping_list_;
+
+  // Callers can request additional memory regions to be included in
+  // the dump.
+  AppMemoryList app_memory_list_;
 };
 
 }  // namespace google_breakpad

src/client/linux/handler/exception_handler_unittest.cc

@@ -785,3 +785,42 @@ TEST(ExceptionHandlerTest, ExternalDumper) {
   ASSERT_GT(st.st_size, 0u);
   unlink(templ.c_str());
 }
+
+// Test that an additional memory region can be added to the minidump.
+TEST(ExceptionHandlerTest, AdditionalMemory) {
+  const u_int32_t kMemorySize = sysconf(_SC_PAGESIZE);
+  // Get some heap memory.
+  u_int8_t* memory = new u_int8_t[kMemorySize];
+  const uintptr_t kMemoryAddress = reinterpret_cast<uintptr_t>(memory);
+  ASSERT_TRUE(memory);
+  // Stick some data into the memory so the contents can be verified.
+  for (unsigned int i = 0; i < kMemorySize; ++i) {
+    memory[i] = i % 255;
+  }
+
+  string minidump_filename;
+  AutoTempDir temp_dir;
+  ExceptionHandler handler(temp_dir.path(), NULL, SimpleCallback,
+                           (void*)&minidump_filename, true);
+  // Add the memory region to the list of memory to be included.
+  handler.RegisterAppMemory(memory, kMemorySize);
+  handler.WriteMinidump();
+
+  // Read the minidump. Ensure that the memory region is present
+  Minidump minidump(minidump_filename);
+  ASSERT_TRUE(minidump.Read());
+
+  MinidumpMemoryList* dump_memory_list = minidump.GetMemoryList();
+  ASSERT_TRUE(dump_memory_list);
+  const MinidumpMemoryRegion* region =
+    dump_memory_list->GetMemoryRegionForAddress(kMemoryAddress);
+  ASSERT_TRUE(region);
+
+  EXPECT_EQ(kMemoryAddress, region->GetBase());
+  EXPECT_EQ(kMemorySize, region->GetSize());
+
+  // Verify memory contents.
+  EXPECT_EQ(0, memcmp(region->GetMemory(), memory, kMemorySize));
+
+  delete[] memory;
+}

src/client/linux/minidump_writer/minidump_writer.cc

@@ -374,6 +374,7 @@ class MinidumpWriter {
   MinidumpWriter(const char* filename,
                  const ExceptionHandler::CrashContext* context,
                  const MappingList& mappings,
+                 const AppMemoryList& appmem,
                  LinuxDumper* dumper)
       : filename_(filename),
         ucontext_(context ? &context->context : NULL),
@@ -385,7 +386,8 @@ class MinidumpWriter {
 #endif
         dumper_(dumper),
         memory_blocks_(dumper_->allocator()),
-        mapping_list_(mappings) {
+        mapping_list_(mappings),
+        app_memory_list_(appmem) {
   }
 
   bool Init() {
@@ -459,6 +461,9 @@ class MinidumpWriter {
       return false;
     dir.CopyIndex(dir_index++, &dirent);
 
+    if (!WriteAppMemory())
+      return false;
+
     if (!WriteMemoryListStream(&dirent))
       return false;
     dir.CopyIndex(dir_index++, &dirent);
@@ -760,6 +765,30 @@ class MinidumpWriter {
     return true;
   }
 
+  // Write application-provided memory regions.
+  bool WriteAppMemory() {
+    for (AppMemoryList::const_iterator iter = app_memory_list_.begin();
+         iter != app_memory_list_.end();
+         ++iter) {
+      uint8_t* data_copy =
+	(uint8_t*) dumper_->allocator()->Alloc(iter->length);
+      dumper_->CopyFromProcess(data_copy, GetCrashThread(), iter->ptr,
+                               iter->length);
+
+      UntypedMDRVA memory(&minidump_writer_);
+      if (!memory.Allocate(iter->length)) {
+        return false;
+      }
+      memory.Copy(data_copy, iter->length);
+      MDMemoryDescriptor desc;
+      desc.start_of_memory_range = (uintptr_t)iter->ptr;
+      desc.memory = memory.location();
+      memory_blocks_.push_back(desc);
+    }
+
+    return true;
+  }
+
   static bool ShouldIncludeMapping(const MappingInfo& mapping) {
     if (mapping.name[0] == 0 ||  // only want modules with filenames.
         mapping.offset ||  // only want to include one mapping per shared lib.
@@ -1335,17 +1364,22 @@ class MinidumpWriter {
   wasteful_vector<MDMemoryDescriptor> memory_blocks_;
   // Additional information about some mappings provided by the caller.
   const MappingList& mapping_list_;
+  // Additional memory regions to be included in the dump,
+  // provided by the caller.
+  const AppMemoryList& app_memory_list_;
 };
 
 bool WriteMinidump(const char* filename, pid_t crashing_process,
                    const void* blob, size_t blob_size) {
   MappingList m;
-  return WriteMinidump(filename, crashing_process, blob, blob_size, m);
+  AppMemoryList a;
+  return WriteMinidump(filename, crashing_process, blob, blob_size, m, a);
 }
 
 bool WriteMinidump(const char* filename, pid_t crashing_process,
                    const void* blob, size_t blob_size,
-                   const MappingList& mappings) {
+                   const MappingList& mappings,
+                   const AppMemoryList& appmem) {
   if (blob_size != sizeof(ExceptionHandler::CrashContext))
     return false;
   const ExceptionHandler::CrashContext* context =
@@ -1355,7 +1389,7 @@ bool WriteMinidump(const char* filename, pid_t crashing_process,
       reinterpret_cast<uintptr_t>(context->siginfo.si_addr));
   dumper.set_crash_signal(context->siginfo.si_signo);
   dumper.set_crash_thread(context->tid);
-  MinidumpWriter writer(filename, context, mappings, &dumper);
+  MinidumpWriter writer(filename, context, mappings, appmem, &dumper);
   if (!writer.Init())
     return false;
   return writer.Dump();
@@ -1363,8 +1397,9 @@ bool WriteMinidump(const char* filename, pid_t crashing_process,
 
 bool WriteMinidump(const char* filename,
                    const MappingList& mappings,
+                   const AppMemoryList& appmem,
                    LinuxDumper* dumper) {
-  MinidumpWriter writer(filename, NULL, mappings, dumper);
+  MinidumpWriter writer(filename, NULL, mappings, appmem, dumper);
   if (!writer.Init())
     return false;
   return writer.Dump();

src/client/linux/minidump_writer/minidump_writer.h

@@ -51,6 +51,16 @@ struct MappingEntry {
 // A list of <MappingInfo, GUID>
 typedef std::list<MappingEntry> MappingList;
 
+// These entries store a list of memory regions that the client wants included
+// in the minidump.
+struct AppMemory {
+  AppMemory(void *ptr, size_t length) : ptr(ptr), length(length) {}
+
+  void *ptr;
+  size_t length;
+};
+typedef std::list<AppMemory> AppMemoryList;
+
 // Write a minidump to the filesystem. This function does not malloc nor use
 // libc functions which may. Thus, it can be used in contexts where the state
 // of the heap may be corrupt.
@@ -64,13 +74,16 @@ typedef std::list<MappingEntry> MappingList;
 bool WriteMinidump(const char* filename, pid_t crashing_process,
                    const void* blob, size_t blob_size);
 
-// This overload also allows passing a list of known mappings.
+// This overload also allows passing a list of known mappings and
+// a list of additional memory regions to be included in the minidump.
 bool WriteMinidump(const char* filename, pid_t crashing_process,
                    const void* blob, size_t blob_size,
-                   const MappingList& mappings);
+                   const MappingList& mappings,
+                   const AppMemoryList& appdata);
 
 bool WriteMinidump(const char* filename,
                    const MappingList& mappings,
+                   const AppMemoryList& appdata,
                    LinuxDumper* dumper);
 
 }  // namespace google_breakpad

src/client/linux/minidump_writer/minidump_writer_unittest.cc

@@ -32,6 +32,7 @@
 #include <sys/stat.h>
 #include <sys/syscall.h>
 #include <sys/types.h>
+#include <ucontext.h>
 #include <unistd.h>
 
 #include <string>
@@ -152,12 +153,13 @@ TEST(MinidumpWriterTest, MappingInfo) {
   strcpy(info.name, kMemoryName);
 
   MappingList mappings;
+  AppMemoryList memory_list;
   MappingEntry mapping;
   mapping.first = info;
   memcpy(mapping.second, kModuleGUID, sizeof(MDGUID));
   mappings.push_back(mapping);
   ASSERT_TRUE(WriteMinidump(templ.c_str(), child, &context, sizeof(context),
-                            mappings));
+                            mappings, memory_list));
 
   // Read the minidump. Load the module list, and ensure that
   // the mmap'ed |memory| is listed with the given module name
@@ -256,13 +258,14 @@ TEST(MinidumpWriterTest, MappingInfoContained) {
   strcpy(info.name, kMemoryName);
 
   MappingList mappings;
+  AppMemoryList memory_list;
   MappingEntry mapping;
   mapping.first = info;
   memcpy(mapping.second, kModuleGUID, sizeof(MDGUID));
   mappings.push_back(mapping);
   ASSERT_TRUE(
       WriteMinidump(dumpfile.c_str(), child, &context, sizeof(context),
-                    mappings));
+                    mappings, memory_list));
 
   // Read the minidump. Load the module list, and ensure that
   // the mmap'ed |memory| is listed with the given module name
@@ -383,3 +386,69 @@ TEST(MinidumpWriterTest, DeletedBinary) {
   module_identifier += "0";
   EXPECT_EQ(module_identifier, module->debug_identifier());
 }
+
+// Test that an additional memory region can be added to the minidump.
+TEST(MinidumpWriterTest, AdditionalMemory) {
+  int fds[2];
+  ASSERT_NE(-1, pipe(fds));
+
+  // 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);
+  // Get some heap memory.
+  u_int8_t* memory = new u_int8_t[kMemorySize];
+  const uintptr_t kMemoryAddress = reinterpret_cast<uintptr_t>(memory);
+  ASSERT_TRUE(memory);
+  // Stick some data into the memory so the contents can be verified.
+  for (int i = 0; i < kMemorySize; ++i) {
+    memory[i] = i % 255;
+  }
+
+  const pid_t child = fork();
+  if (child == 0) {
+    close(fds[1]);
+    char b;
+    HANDLE_EINTR(read(fds[0], &b, sizeof(b)));
+    close(fds[0]);
+    syscall(__NR_exit);
+  }
+  close(fds[0]);
+
+  ExceptionHandler::CrashContext context;
+  // This needs a valid context for minidump writing to work, but getting
+  // a useful one from the child is too much work, so just use one from
+  // the parent since the child is just a forked copy anyway.
+  //TODO(ted): this won't work for Android if unit tests ever get run there.
+  ASSERT_EQ(0, getcontext(&context.context));
+  context.tid = child;
+
+  AutoTempDir temp_dir;
+  string templ = "/tmp/minidump-memory.dmp"; //temp_dir.path() + "/minidump-writer-unittest";
+  unlink(templ.c_str());
+
+  MappingList mappings;
+  AppMemoryList memory_list;
+  // Add the memory region to the list of memory to be included.
+  memory_list.push_back(AppMemory(memory, kMemorySize));
+  ASSERT_TRUE(WriteMinidump(templ.c_str(), child, &context, sizeof(context),
+                            mappings, memory_list));
+
+  // Read the minidump. Ensure that the memory region is present
+  Minidump minidump(templ.c_str());
+  ASSERT_TRUE(minidump.Read());
+
+  MinidumpMemoryList* dump_memory_list = minidump.GetMemoryList();
+  ASSERT_TRUE(dump_memory_list);
+  const MinidumpMemoryRegion* region =
+    dump_memory_list->GetMemoryRegionForAddress(kMemoryAddress);
+  ASSERT_TRUE(region);
+
+  EXPECT_EQ(kMemoryAddress, region->GetBase());
+  EXPECT_EQ(kMemorySize, region->GetSize());
+
+  // Verify memory contents.
+  EXPECT_EQ(0, memcmp(region->GetMemory(), memory, kMemorySize));
+
+  delete[] memory;
+  close(fds[1]);
+}