[sanitizer_common] Implement MemoryMappingLayout for Fuchsia

This is needed to port lsan to Fuchsia.

Patch By: mcgrathr

Differential Revision: https://reviews.llvm.org/D72886

Author: frobtech

compiler-rt/lib/sanitizer_common/CMakeLists.txt

@@ -29,6 +29,7 @@ set(SANITIZER_SOURCES_NOTERMINATION
   sanitizer_printf.cpp
   sanitizer_procmaps_common.cpp
   sanitizer_procmaps_bsd.cpp
+  sanitizer_procmaps_fuchsia.cpp
   sanitizer_procmaps_linux.cpp
   sanitizer_procmaps_mac.cpp
   sanitizer_procmaps_solaris.cpp

compiler-rt/lib/sanitizer_common/sanitizer_fuchsia.h

@@ -18,12 +18,18 @@
 #include "sanitizer_common.h"
 
 #include <zircon/sanitizer.h>
+#include <zircon/syscalls/object.h>
 
 namespace __sanitizer {
 
 extern uptr MainThreadStackBase, MainThreadStackSize;
 extern sanitizer_shadow_bounds_t ShadowBounds;
 
+struct MemoryMappingLayoutData {
+  InternalMmapVector<zx_info_maps_t> data;
+  size_t current;  // Current index into the vector.
+};
+
 }  // namespace __sanitizer
 
 #endif  // SANITIZER_FUCHSIA

compiler-rt/lib/sanitizer_common/sanitizer_procmaps.h

@@ -15,18 +15,19 @@
 
 #include "sanitizer_platform.h"
 
-#if SANITIZER_LINUX || SANITIZER_FREEBSD || SANITIZER_NETBSD ||                \
-    SANITIZER_OPENBSD || SANITIZER_MAC || SANITIZER_SOLARIS
+#if SANITIZER_LINUX || SANITIZER_FREEBSD || SANITIZER_NETBSD || \
+    SANITIZER_OPENBSD || SANITIZER_MAC || SANITIZER_SOLARIS ||  \
+    SANITIZER_FUCHSIA
 
 #include "sanitizer_common.h"
 #include "sanitizer_internal_defs.h"
+#include "sanitizer_fuchsia.h"
 #include "sanitizer_linux.h"
 #include "sanitizer_mac.h"
 #include "sanitizer_mutex.h"
 
 namespace __sanitizer {
 
-
 // Memory protection masks.
 static const uptr kProtectionRead = 1;
 static const uptr kProtectionWrite = 2;

compiler-rt/lib/sanitizer_common/sanitizer_procmaps_fuchsia.cpp

@@ -0,0 +1,80 @@
+//===-- sanitizer_procmaps_fuchsia.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
+//
+//===----------------------------------------------------------------------===//
+//
+// Information about the process mappings (Fuchsia-specific parts).
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_platform.h"
+#if SANITIZER_FUCHSIA
+#include <zircon/process.h>
+#include <zircon/syscalls.h>
+
+#include "sanitizer_common.h"
+#include "sanitizer_procmaps.h"
+
+namespace __sanitizer {
+
+// The cache flag is ignored on Fuchsia because a process can always get this
+// information via its process-self handle.
+MemoryMappingLayout::MemoryMappingLayout(bool) { Reset(); }
+
+void MemoryMappingLayout::Reset() {
+  data_.data.clear();
+  data_.current = 0;
+
+  size_t count;
+  zx_status_t status = _zx_object_get_info(
+      _zx_process_self(), ZX_INFO_PROCESS_MAPS, nullptr, 0, nullptr, &count);
+  if (status != ZX_OK) {
+    return;
+  }
+
+  size_t filled;
+  do {
+    data_.data.resize(count);
+    status = _zx_object_get_info(
+        _zx_process_self(), ZX_INFO_PROCESS_MAPS, data_.data.data(),
+        count * sizeof(zx_info_maps_t), &filled, &count);
+    if (status != ZX_OK) {
+      data_.data.clear();
+      return;
+    }
+  } while (filled < count);
+}
+
+MemoryMappingLayout::~MemoryMappingLayout() {}
+
+bool MemoryMappingLayout::Error() const { return data_.data.empty(); }
+
+bool MemoryMappingLayout::Next(MemoryMappedSegment *segment) {
+  while (data_.current < data_.data.size()) {
+    const auto &entry = data_.data[data_.current++];
+    if (entry.type == ZX_INFO_MAPS_TYPE_MAPPING) {
+      segment->start = entry.base;
+      segment->end = entry.base + entry.size;
+      segment->offset = entry.u.mapping.vmo_offset;
+      const auto flags = entry.u.mapping.mmu_flags;
+      segment->protection =
+          ((flags & ZX_VM_PERM_READ) ? kProtectionRead : 0) |
+          ((flags & ZX_VM_PERM_WRITE) ? kProtectionWrite : 0) |
+          ((flags & ZX_VM_PERM_EXECUTE) ? kProtectionExecute : 0);
+      if (segment->filename && segment->filename_size > 0) {
+        uptr len = Min(sizeof(entry.name), segment->filename_size) - 1;
+        internal_strncpy(segment->filename, entry.name, len);
+        segment->filename[len] = 0;
+      }
+      return true;
+    }
+  }
+  return false;
+}
+
+}  // namespace __sanitizer
+
+#endif  // SANITIZER_FUCHSIA