vendor/compiler-rt/compiler-rt-trunk-r375505vendor/compiler-rt

1 files changed, 262 insertions, 0 deletions

diff --git a/lib/msan/msan_linux.cpp b/lib/msan/msan_linux.cpp
new file mode 100644
index 000000000000..d61e9dee3065
--- /dev/null
+++ b/lib/msan/msan_linux.cpp
@@ -0,0 +1,262 @@
+//===-- msan_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 MemorySanitizer.
+//
+// Linux-, NetBSD- and FreeBSD-specific code.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_platform.h"
+#if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD
+
+#include "msan.h"
+#include "msan_report.h"
+#include "msan_thread.h"
+
+#include <elf.h>
+#include <link.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <unistd.h>
+#include <unwind.h>
+#include <execinfo.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_procmaps.h"
+
+namespace __msan {
+
+void ReportMapRange(const char *descr, uptr beg, uptr size) {
+  if (size > 0) {
+    uptr end = beg + size - 1;
+    VPrintf(1, "%s : %p - %p\n", descr, beg, end);
+  }
+}
+
+static bool CheckMemoryRangeAvailability(uptr beg, uptr size) {
+  if (size > 0) {
+    uptr end = beg + size - 1;
+    if (!MemoryRangeIsAvailable(beg, end)) {
+      Printf("FATAL: Memory range %p - %p is not available.\n", beg, end);
+      return false;
+    }
+  }
+  return true;
+}
+
+static bool ProtectMemoryRange(uptr beg, uptr size, const char *name) {
+  if (size > 0) {
+    void *addr = MmapFixedNoAccess(beg, size, name);
+    if (beg == 0 && addr) {
+      // Depending on the kernel configuration, we may not be able to protect
+      // the page at address zero.
+      uptr gap = 16 * GetPageSizeCached();
+      beg += gap;
+      size -= gap;
+      addr = MmapFixedNoAccess(beg, size, name);
+    }
+    if ((uptr)addr != beg) {
+      uptr end = beg + size - 1;
+      Printf("FATAL: Cannot protect memory range %p - %p (%s).\n", beg, end,
+             name);
+      return false;
+    }
+  }
+  return true;
+}
+
+static void CheckMemoryLayoutSanity() {
+  uptr prev_end = 0;
+  for (unsigned i = 0; i < kMemoryLayoutSize; ++i) {
+    uptr start = kMemoryLayout[i].start;
+    uptr end = kMemoryLayout[i].end;
+    MappingDesc::Type type = kMemoryLayout[i].type;
+    CHECK_LT(start, end);
+    CHECK_EQ(prev_end, start);
+    CHECK(addr_is_type(start, type));
+    CHECK(addr_is_type((start + end) / 2, type));
+    CHECK(addr_is_type(end - 1, type));
+    if (type == MappingDesc::APP) {
+      uptr addr = start;
+      CHECK(MEM_IS_SHADOW(MEM_TO_SHADOW(addr)));
+      CHECK(MEM_IS_ORIGIN(MEM_TO_ORIGIN(addr)));
+      CHECK_EQ(MEM_TO_ORIGIN(addr), SHADOW_TO_ORIGIN(MEM_TO_SHADOW(addr)));
+
+      addr = (start + end) / 2;
+      CHECK(MEM_IS_SHADOW(MEM_TO_SHADOW(addr)));
+      CHECK(MEM_IS_ORIGIN(MEM_TO_ORIGIN(addr)));
+      CHECK_EQ(MEM_TO_ORIGIN(addr), SHADOW_TO_ORIGIN(MEM_TO_SHADOW(addr)));
+
+      addr = end - 1;
+      CHECK(MEM_IS_SHADOW(MEM_TO_SHADOW(addr)));
+      CHECK(MEM_IS_ORIGIN(MEM_TO_ORIGIN(addr)));
+      CHECK_EQ(MEM_TO_ORIGIN(addr), SHADOW_TO_ORIGIN(MEM_TO_SHADOW(addr)));
+    }
+    prev_end = end;
+  }
+}
+
+bool InitShadow(bool init_origins) {
+  // Let user know mapping parameters first.
+  VPrintf(1, "__msan_init %p\n", &__msan_init);
+  for (unsigned i = 0; i < kMemoryLayoutSize; ++i)
+    VPrintf(1, "%s: %zx - %zx\n", kMemoryLayout[i].name, kMemoryLayout[i].start,
+            kMemoryLayout[i].end - 1);
+
+  CheckMemoryLayoutSanity();
+
+  if (!MEM_IS_APP(&__msan_init)) {
+    Printf("FATAL: Code %p is out of application range. Non-PIE build?\n",
+           (uptr)&__msan_init);
+    return false;
+  }
+
+  const uptr maxVirtualAddress = GetMaxUserVirtualAddress();
+
+  for (unsigned i = 0; i < kMemoryLayoutSize; ++i) {
+    uptr start = kMemoryLayout[i].start;
+    uptr end = kMemoryLayout[i].end;
+    uptr size = end - start;
+    MappingDesc::Type type = kMemoryLayout[i].type;
+
+    // Check if the segment should be mapped based on platform constraints.
+    if (start >= maxVirtualAddress)
+      continue;
+
+    bool map = type == MappingDesc::SHADOW ||
+               (init_origins && type == MappingDesc::ORIGIN);
+    bool protect = type == MappingDesc::INVALID ||
+                   (!init_origins && type == MappingDesc::ORIGIN);
+    CHECK(!(map && protect));
+    if (!map && !protect)
+      CHECK(type == MappingDesc::APP);
+    if (map) {
+      if (!CheckMemoryRangeAvailability(start, size))
+        return false;
+      if (!MmapFixedNoReserve(start, size, kMemoryLayout[i].name))
+        return false;
+      if (common_flags()->use_madv_dontdump)
+        DontDumpShadowMemory(start, size);
+    }
+    if (protect) {
+      if (!CheckMemoryRangeAvailability(start, size))
+        return false;
+      if (!ProtectMemoryRange(start, size, kMemoryLayout[i].name))
+        return false;
+    }
+  }
+
+  return true;
+}
+
+static void MsanAtExit(void) {
+  if (flags()->print_stats && (flags()->atexit || msan_report_count > 0))
+    ReportStats();
+  if (msan_report_count > 0) {
+    ReportAtExitStatistics();
+    if (common_flags()->exitcode)
+      internal__exit(common_flags()->exitcode);
+  }
+}
+
+void InstallAtExitHandler() {
+  atexit(MsanAtExit);
+}
+
+// ---------------------- TSD ---------------- {{{1
+
+#if SANITIZER_NETBSD
+// Thread Static Data cannot be used in early init on NetBSD.
+// Reuse the MSan TSD API for compatibility with existing code
+// with an alternative implementation.
+
+static void (*tsd_destructor)(void *tsd) = nullptr;
+
+struct tsd_key {
+  tsd_key() : key(nullptr) {}
+  ~tsd_key() {
+    CHECK(tsd_destructor);
+    if (key)
+      (*tsd_destructor)(key);
+  }
+  MsanThread *key;
+};
+
+static thread_local struct tsd_key key;
+
+void MsanTSDInit(void (*destructor)(void *tsd)) {
+  CHECK(!tsd_destructor);
+  tsd_destructor = destructor;
+}
+
+MsanThread *GetCurrentThread() {
+  CHECK(tsd_destructor);
+  return key.key;
+}
+
+void SetCurrentThread(MsanThread *tsd) {
+  CHECK(tsd_destructor);
+  CHECK(tsd);
+  CHECK(!key.key);
+  key.key = tsd;
+}
+
+void MsanTSDDtor(void *tsd) {
+  CHECK(tsd_destructor);
+  CHECK_EQ(key.key, tsd);
+  key.key = nullptr;
+  // Make sure that signal handler can not see a stale current thread pointer.
+  atomic_signal_fence(memory_order_seq_cst);
+  MsanThread::TSDDtor(tsd);
+}
+#else
+static pthread_key_t tsd_key;
+static bool tsd_key_inited = false;
+
+void MsanTSDInit(void (*destructor)(void *tsd)) {
+  CHECK(!tsd_key_inited);
+  tsd_key_inited = true;
+  CHECK_EQ(0, pthread_key_create(&tsd_key, destructor));
+}
+
+static THREADLOCAL MsanThread* msan_current_thread;
+
+MsanThread *GetCurrentThread() {
+  return msan_current_thread;
+}
+
+void SetCurrentThread(MsanThread *t) {
+  // Make sure we do not reset the current MsanThread.
+  CHECK_EQ(0, msan_current_thread);
+  msan_current_thread = t;
+  // Make sure that MsanTSDDtor gets called at the end.
+  CHECK(tsd_key_inited);
+  pthread_setspecific(tsd_key, (void *)t);
+}
+
+void MsanTSDDtor(void *tsd) {
+  MsanThread *t = (MsanThread*)tsd;
+  if (t->destructor_iterations_ > 1) {
+    t->destructor_iterations_--;
+    CHECK_EQ(0, pthread_setspecific(tsd_key, tsd));
+    return;
+  }
+  msan_current_thread = nullptr;
+  // Make sure that signal handler can not see a stale current thread pointer.
+  atomic_signal_fence(memory_order_seq_cst);
+  MsanThread::TSDDtor(tsd);
+}
+#endif
+
+} // namespace __msan
+
+#endif // SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD