1 files changed, 144 insertions, 0 deletions
diff --git a/lib/lsan/lsan_common_linux.cpp b/lib/lsan/lsan_common_linux.cpp
new file mode 100644
index 000000000000..ea1a4a2f569d
--- /dev/null
+++ b/lib/lsan/lsan_common_linux.cpp
@@ -0,0 +1,144 @@
+//=-- lsan_common_linux.cpp -----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of LeakSanitizer.
+// Implementation of common leak checking functionality. Linux/NetBSD-specific
+// code.
+//
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_platform.h"
+#include "lsan_common.h"
+
+#if CAN_SANITIZE_LEAKS && (SANITIZER_LINUX || SANITIZER_NETBSD)
+#include <link.h>
+
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_flags.h"
+#include "sanitizer_common/sanitizer_getauxval.h"
+#include "sanitizer_common/sanitizer_linux.h"
+#include "sanitizer_common/sanitizer_stackdepot.h"
+
+namespace __lsan {
+
+static const char kLinkerName[] = "ld";
+
+static char linker_placeholder[sizeof(LoadedModule)] ALIGNED(64);
+static LoadedModule *linker = nullptr;
+
+static bool IsLinker(const LoadedModule& module) {
+#if SANITIZER_USE_GETAUXVAL
+  return module.base_address() == getauxval(AT_BASE);
+#else
+  return LibraryNameIs(module.full_name(), kLinkerName);
+#endif  // SANITIZER_USE_GETAUXVAL
+}
+
+__attribute__((tls_model("initial-exec")))
+THREADLOCAL int disable_counter;
+bool DisabledInThisThread() { return disable_counter > 0; }
+void DisableInThisThread() { disable_counter++; }
+void EnableInThisThread() {
+  if (disable_counter == 0) {
+    DisableCounterUnderflow();
+  }
+  disable_counter--;
+}
+
+void InitializePlatformSpecificModules() {
+  ListOfModules modules;
+  modules.init();
+  for (LoadedModule &module : modules) {
+    if (!IsLinker(module))
+      continue;
+    if (linker == nullptr) {
+      linker = reinterpret_cast<LoadedModule *>(linker_placeholder);
+      *linker = module;
+      module = LoadedModule();
+    } else {
+      VReport(1, "LeakSanitizer: Multiple modules match \"%s\". "
+              "TLS and other allocations originating from linker might be "
+              "falsely reported as leaks.\n", kLinkerName);
+      linker->clear();
+      linker = nullptr;
+      return;
+    }
+  }
+  if (linker == nullptr) {
+    VReport(1, "LeakSanitizer: Dynamic linker not found. TLS and other "
+               "allocations originating from linker might be falsely reported "
+                "as leaks.\n");
+  }
+}
+
+static int ProcessGlobalRegionsCallback(struct dl_phdr_info *info, size_t size,
+                                        void *data) {
+  Frontier *frontier = reinterpret_cast<Frontier *>(data);
+  for (uptr j = 0; j < info->dlpi_phnum; j++) {
+    const ElfW(Phdr) *phdr = &(info->dlpi_phdr[j]);
+    // We're looking for .data and .bss sections, which reside in writeable,
+    // loadable segments.
+    if (!(phdr->p_flags & PF_W) || (phdr->p_type != PT_LOAD) ||
+        (phdr->p_memsz == 0))
+      continue;
+    uptr begin = info->dlpi_addr + phdr->p_vaddr;
+    uptr end = begin + phdr->p_memsz;
+    ScanGlobalRange(begin, end, frontier);
+  }
+  return 0;
+}
+
+// Scans global variables for heap pointers.
+void ProcessGlobalRegions(Frontier *frontier) {
+  if (!flags()->use_globals) return;
+  dl_iterate_phdr(ProcessGlobalRegionsCallback, frontier);
+}
+
+LoadedModule *GetLinker() { return linker; }
+
+void ProcessPlatformSpecificAllocations(Frontier *frontier) {}
+
+struct DoStopTheWorldParam {
+  StopTheWorldCallback callback;
+  void *argument;
+};
+
+// While calling Die() here is undefined behavior and can potentially
+// cause race conditions, it isn't possible to intercept exit on linux,
+// so we have no choice but to call Die() from the atexit handler.
+void HandleLeaks() {
+  if (common_flags()->exitcode) Die();
+}
+
+static int LockStuffAndStopTheWorldCallback(struct dl_phdr_info *info,
+                                            size_t size, void *data) {
+  LockThreadRegistry();
+  LockAllocator();
+  DoStopTheWorldParam *param = reinterpret_cast<DoStopTheWorldParam *>(data);
+  StopTheWorld(param->callback, param->argument);
+  UnlockAllocator();
+  UnlockThreadRegistry();
+  return 1;
+}
+
+// LSan calls dl_iterate_phdr() from the tracer task. This may deadlock: if one
+// of the threads is frozen while holding the libdl lock, the tracer will hang
+// in dl_iterate_phdr() forever.
+// Luckily, (a) the lock is reentrant and (b) libc can't distinguish between the
+// tracer task and the thread that spawned it. Thus, if we run the tracer task
+// while holding the libdl lock in the parent thread, we can safely reenter it
+// in the tracer. The solution is to run stoptheworld from a dl_iterate_phdr()
+// callback in the parent thread.
+void LockStuffAndStopTheWorld(StopTheWorldCallback callback, void *argument) {
+  DoStopTheWorldParam param = {callback, argument};
+  dl_iterate_phdr(LockStuffAndStopTheWorldCallback, &param);
+}
+
+} // namespace __lsan
+
+#endif