1 files changed, 28 insertions, 0 deletions
diff --git a/simpleperf/environment.cpp b/simpleperf/environment.cpp
index ed161c23..0ad2d6bd 100644
--- a/simpleperf/environment.cpp
+++ b/simpleperf/environment.cpp
@@ -475,3 +475,31 @@ ArchType GetMachineArch() {
   }
   return GetBuildArch();
 }
+
+void PrepareVdsoFile() {
+  // vdso is an elf file in memory loaded in each process's user space by the kernel. To read
+  // symbols from it and unwind through it, we need to dump it into a file in storage.
+  // It doesn't affect much when failed to prepare vdso file, so there is no need to return values.
+  std::vector<ThreadMmap> thread_mmaps;
+  if (!GetThreadMmapsInProcess(getpid(), &thread_mmaps)) {
+    return;
+  }
+  const ThreadMmap* vdso_map = nullptr;
+  for (const auto& map : thread_mmaps) {
+    if (map.name == "[vdso]") {
+      vdso_map = &map;
+      break;
+    }
+  }
+  if (vdso_map == nullptr) {
+    return;
+  }
+  std::string s(vdso_map->len, '\0');
+  memcpy(&s[0], reinterpret_cast<void*>(static_cast<uintptr_t>(vdso_map->start_addr)),
+         vdso_map->len);
+  std::unique_ptr<TemporaryFile> tmpfile(new TemporaryFile);
+  if (!android::base::WriteStringToFile(s, tmpfile->path)) {
+    return;
+  }
+  Dso::SetVdsoFile(std::move(tmpfile), sizeof(size_t) == sizeof(uint64_t));
+}