Don't bail if a thread's stack pointer is invalid

Currently, if a thread's stack pointer is not within a valid memory page,
the minidump writing will fail with an error.  This change allows an invalid
stack pointer by simply setting the memory size to zero in the minidump.
The processing code already checks for the size being zero, although it
currently just gives an error (see https://breakpad.appspot.com/413002/).

BUG=google-breakpad:499, chromium-os:34880
TEST=make check, manually ran minidump-2-core and core2md
Review URL: https://breakpad.appspot.com/478002

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1065 4c0a9323-5329-0410-9bdc-e9ce6186880e

1 files changed, 45 insertions, 27 deletions

diff --git a/src/client/linux/minidump_writer/minidump_writer.cc b/src/client/linux/minidump_writer/minidump_writer.cc
index 02f6c3e2..43ad05b6 100644
--- a/src/client/linux/minidump_writer/minidump_writer.cc
+++ b/src/client/linux/minidump_writer/minidump_writer.cc
@@ -628,6 +628,31 @@ class MinidumpWriter {
 #endif
   }
 
+  bool FillThreadStack(MDRawThread* thread, uintptr_t stack_pointer,
+                       uint8_t** stack_copy) {
+    *stack_copy = NULL;
+    const void* stack;
+    size_t stack_len;
+    if (dumper_->GetStackInfo(&stack, &stack_len, stack_pointer)) {
+      UntypedMDRVA memory(&minidump_writer_);
+      if (!memory.Allocate(stack_len))
+        return false;
+      *stack_copy = reinterpret_cast<uint8_t*>(Alloc(stack_len));
+      dumper_->CopyFromProcess(*stack_copy, thread->thread_id, stack,
+                               stack_len);
+      memory.Copy(*stack_copy, stack_len);
+      thread->stack.start_of_memory_range =
+          reinterpret_cast<uintptr_t>(stack);
+      thread->stack.memory = memory.location();
+      memory_blocks_.push_back(thread->stack);
+    } else {
+      thread->stack.start_of_memory_range = stack_pointer;
+      thread->stack.memory.data_size = 0;
+      thread->stack.memory.rva = minidump_writer_.position();
+    }
+    return true;
+  }
+
   // Write information about the threads.
   bool WriteThreadListStream(MDRawDirectory* dirent) {
     const unsigned num_threads = dumper_->threads().size();
@@ -645,6 +670,7 @@ class MinidumpWriter {
       MDRawThread thread;
       my_memset(&thread, 0, sizeof(thread));
       thread.thread_id = dumper_->threads()[i];
+
       // We have a different source of information for the crashing thread. If
       // we used the actual state of the thread we would find it running in the
       // signal handler with the alternative stack, which would be deeply
@@ -652,20 +678,9 @@ class MinidumpWriter {
       if (static_cast<pid_t>(thread.thread_id) == GetCrashThread() &&
           ucontext_ &&
           !dumper_->IsPostMortem()) {
-        const void* stack;
-        size_t stack_len;
-        if (!dumper_->GetStackInfo(&stack, &stack_len, GetStackPointer()))
+        uint8_t* stack_copy;
+        if (!FillThreadStack(&thread, GetStackPointer(), &stack_copy))
           return false;
-        UntypedMDRVA memory(&minidump_writer_);
-        if (!memory.Allocate(stack_len))
-          return false;
-        uint8_t* stack_copy = reinterpret_cast<uint8_t*>(Alloc(stack_len));
-        dumper_->CopyFromProcess(stack_copy, thread.thread_id, stack,
-                                 stack_len);
-        memory.Copy(stack_copy, stack_len);
-        thread.stack.start_of_memory_range = (uintptr_t) (stack);
-        thread.stack.memory = memory.location();
-        memory_blocks_.push_back(thread.stack);
 
         // Copy 256 bytes around crashing instruction pointer to minidump.
         const size_t kIPMemorySize = 256;
@@ -715,30 +730,26 @@ class MinidumpWriter {
           return false;
         my_memset(cpu.get(), 0, sizeof(RawContextCPU));
         CPUFillFromUContext(cpu.get(), ucontext_, float_state_);
-        PopSeccompStackFrame(cpu.get(), thread, stack_copy);
+        if (stack_copy)
+          PopSeccompStackFrame(cpu.get(), thread, stack_copy);
         thread.thread_context = cpu.location();
         crashing_thread_context_ = cpu.location();
       } else {
         ThreadInfo info;
         if (!dumper_->GetThreadInfoByIndex(i, &info))
           return false;
-        UntypedMDRVA memory(&minidump_writer_);
-        if (!memory.Allocate(info.stack_len))
+
+        uint8_t* stack_copy;
+        if (!FillThreadStack(&thread, info.stack_pointer, &stack_copy))
           return false;
-        uint8_t* stack_copy = reinterpret_cast<uint8_t*>(Alloc(info.stack_len));
-        dumper_->CopyFromProcess(stack_copy, thread.thread_id, info.stack,
-                                 info.stack_len);
-        memory.Copy(stack_copy, info.stack_len);
-        thread.stack.start_of_memory_range = (uintptr_t)(info.stack);
-        thread.stack.memory = memory.location();
-        memory_blocks_.push_back(thread.stack);
 
         TypedMDRVA<RawContextCPU> cpu(&minidump_writer_);
         if (!cpu.Allocate())
           return false;
         my_memset(cpu.get(), 0, sizeof(RawContextCPU));
         CPUFillFromThreadInfo(cpu.get(), info);
-        PopSeccompStackFrame(cpu.get(), thread, stack_copy);
+        if (stack_copy)
+          PopSeccompStackFrame(cpu.get(), thread, stack_copy);
         thread.thread_context = cpu.location();
         if (dumper_->threads()[i] == GetCrashThread()) {
           crashing_thread_context_ = cpu.location();
@@ -916,9 +927,16 @@ class MinidumpWriter {
 
   bool WriteMemoryListStream(MDRawDirectory* dirent) {
     TypedMDRVA<uint32_t> list(&minidump_writer_);
-    if (!list.AllocateObjectAndArray(memory_blocks_.size(),
-                                     sizeof(MDMemoryDescriptor)))
-      return false;
+    if (memory_blocks_.size()) {
+      if (!list.AllocateObjectAndArray(memory_blocks_.size(),
+                                       sizeof(MDMemoryDescriptor)))
+        return false;
+    } else {
+      // Still create the memory list stream, although it will have zero
+      // memory blocks.
+      if (!list.Allocate())
+        return false;
+    }
 
     dirent->stream_type = MD_MEMORY_LIST_STREAM;
     dirent->location = list.location();