commit 52c4f25d6e584e5a61e887cd652d1d9c460310d3
author Vishnu Nair <vishnun@google.com> Wed Jun 14 15:25:12 2023 -0700
committer Vishnu Nair <vishnun@google.com> Wed Jun 14 20:28:39 2023 -0700
tree 4be6f162cbd264d87038d7415b72a52fe972fbc0
parent 580fb3af1743d2a6e12bd8c3f933641644e5eb4a

[sf] fix overflow in snapshot generator

Fixes a couple of issues that caused the snapshot
builder to crash from a stack overflow:
- mirror layers were temporarily rooted to the display
with the default layer stack
- there was no check to prevent a layer from mirroring
itself (causing a cycle in the hierarchy)

Also modifies the layer trace generator to easily generate
test data for the transaction trace test suite.

Test: atest transactiontrace_testsuite
Fixes: 282110579
Change-Id: I2954f838e333b857b4b755e11666c2580d97c2b6

services/surfaceflinger/Tracing/tools/LayerTraceGenerator.cpp

diff --git a/services/surfaceflinger/Tracing/tools/LayerTraceGenerator.cpp b/services/surfaceflinger/Tracing/tools/LayerTraceGenerator.cpp
index 72a11c6..519ef44 100644
--- a/services/surfaceflinger/Tracing/tools/LayerTraceGenerator.cpp
+++ b/services/surfaceflinger/Tracing/tools/LayerTraceGenerator.cpp
@@ -41,7 +41,7 @@
 using namespace ftl::flag_operators;
 
 bool LayerTraceGenerator::generate(const proto::TransactionTraceFile& traceFile,
-                                   const char* outputLayersTracePath) {
+                                   const char* outputLayersTracePath, bool onlyLastEntry) {
     if (traceFile.entry_size() == 0) {
         ALOGD("Trace file is empty");
         return false;
@@ -158,9 +158,11 @@
                                                                   layerTracing.getFlags())
                                           .generate(hierarchyBuilder.getHierarchy());
         auto displayProtos = LayerProtoHelper::writeDisplayInfoToProto(displayInfos);
-        layerTracing.notify(visibleRegionsDirty, entry.elapsed_realtime_nanos(), entry.vsync_id(),
-                            &layersProto, {}, &displayProtos);
-        layerTracing.appendToStream(out);
+        if (!onlyLastEntry || (i == traceFile.entry_size() - 1)) {
+            layerTracing.notify(visibleRegionsDirty, entry.elapsed_realtime_nanos(),
+                                entry.vsync_id(), &layersProto, {}, &displayProtos);
+            layerTracing.appendToStream(out);
+        }
     }
     layerTracing.disable("", /*writeToFile=*/false);
     out.close();

services/surfaceflinger/Tracing/tools/LayerTraceGenerator.h

diff --git a/services/surfaceflinger/Tracing/tools/LayerTraceGenerator.h b/services/surfaceflinger/Tracing/tools/LayerTraceGenerator.h
index ee1ea6c..e41d1e6 100644
--- a/services/surfaceflinger/Tracing/tools/LayerTraceGenerator.h
+++ b/services/surfaceflinger/Tracing/tools/LayerTraceGenerator.h
@@ -21,6 +21,7 @@
 namespace android {
 class LayerTraceGenerator {
 public:
-    bool generate(const proto::TransactionTraceFile&, const char* outputLayersTracePath);
+    bool generate(const proto::TransactionTraceFile&, const char* outputLayersTracePath,
+                  bool onlyLastEntry);
 };
 } // namespace android
\ No newline at end of file

services/surfaceflinger/Tracing/tools/main.cpp

diff --git a/services/surfaceflinger/Tracing/tools/main.cpp b/services/surfaceflinger/Tracing/tools/main.cpp
index c440c19..5ca87e4 100644
--- a/services/surfaceflinger/Tracing/tools/main.cpp
+++ b/services/surfaceflinger/Tracing/tools/main.cpp
@@ -26,9 +26,9 @@
 using namespace android;
 
 int main(int argc, char** argv) {
-    if (argc > 3) {
+    if (argc > 4) {
         std::cout << "Usage: " << argv[0]
-                  << " [transaction-trace-path] [output-layers-trace-path]\n";
+                  << " [transaction-trace-path] [output-layers-trace-path] [--last-entry-only]\n";
         return -1;
     }
 
@@ -48,12 +48,16 @@
     }
 
     const char* outputLayersTracePath =
-            (argc == 3) ? argv[2] : "/data/misc/wmtrace/layers_trace.winscope";
-    ;
+            (argc >= 3) ? argv[2] : "/data/misc/wmtrace/layers_trace.winscope";
+
+    const bool generateLastEntryOnly =
+            argc >= 4 && std::string_view(argv[3]) == "--last-entry-only";
+
     ALOGD("Generating %s...", outputLayersTracePath);
     std::cout << "Generating " << outputLayersTracePath << "\n";
 
-    if (!LayerTraceGenerator().generate(transactionTraceFile, outputLayersTracePath)) {
+    if (!LayerTraceGenerator().generate(transactionTraceFile, outputLayersTracePath,
+                                        generateLastEntryOnly)) {
         std::cout << "Error: Failed to generate layers trace " << outputLayersTracePath;
         return -1;
     }