text: //===-- fuchsia.cpp ---------------------------------------------*- C++ -*-===//
  //
  // 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
  //
  //===----------------------------------------------------------------------===//
  
  #include "platform.h"
  
  #if SCUDO_FUCHSIA
  
  #include "common.h"
  #include "mutex.h"
  #include "string_utils.h"
  
  #include <lib/sync/mutex.h> // for sync_mutex_t
  #include <limits.h>         // for PAGE_SIZE
  #include <stdlib.h>         // for getenv()
  #include <zircon/compiler.h>
  #include <zircon/sanitizer.h>
  #include <zircon/syscalls.h>
  
  namespace scudo {
  
  uptr getPageSize() { return PAGE_SIZE; }
  
  void NORETURN die() { __builtin_trap(); }
  
  // We zero-initialize the Extra parameter of map(), make sure this is consistent
  // with ZX_HANDLE_INVALID.
  static_assert(ZX_HANDLE_INVALID == 0, "");
  
  static void *allocateVmar(uptr Size, MapPlatformData *Data, bool AllowNoMem) {
    // Only scenario so far.
    DCHECK(Data);
    DCHECK_EQ(Data->Vmar, ZX_HANDLE_INVALID);
  
    const zx_status_t Status = _zx_vmar_allocate(
        _zx_vmar_root_self(),
        ZX_VM_CAN_MAP_READ | ZX_VM_CAN_MAP_WRITE | ZX_VM_CAN_MAP_SPECIFIC, 0,
        Size, &Data->Vmar, &Data->VmarBase);
    if (UNLIKELY(Status != ZX_OK)) {
      if (Status != ZX_ERR_NO_MEMORY || !AllowNoMem)
        dieOnMapUnmapError(Status == ZX_ERR_NO_MEMORY);
      return nullptr;
    }
    return reinterpret_cast<void *>(Data->VmarBase);
  }
  
  void *map(void *Addr, uptr Size, const char *Name, uptr Flags,
            MapPlatformData *Data) {
    DCHECK_EQ(Size % PAGE_SIZE, 0);
    const bool AllowNoMem = !!(Flags & MAP_ALLOWNOMEM);
  
    // For MAP_NOACCESS, just allocate a Vmar and return.
    if (Flags & MAP_NOACCESS)
      return allocateVmar(Size, Data, AllowNoMem);
  
    const zx_handle_t Vmar = Data ? Data->Vmar : _zx_vmar_root_self();
    CHECK_NE(Vmar, ZX_HANDLE_INVALID);
  
    zx_status_t Status;
    zx_handle_t Vmo;
    uint64_t VmoSize = 0;
    if (Data && Data->Vmo != ZX_HANDLE_INVALID) {
      // If a Vmo was specified, it's a resize operation.
      CHECK(Addr);
      DCHECK(Flags & MAP_RESIZABLE);
      Vmo = Data->Vmo;
      VmoSize = Data->VmoSize;
      Status = _zx_vmo_set_size(Vmo, VmoSize + Size);
      if (Status != ZX_OK) {
        if (Status != ZX_ERR_NO_MEMORY || !AllowNoMem)
          dieOnMapUnmapError(Status == ZX_ERR_NO_MEMORY);
        return nullptr;
      }
    } else {
      // Otherwise, create a Vmo and set its name.
      Status = _zx_vmo_create(Size, ZX_VMO_RESIZABLE, &Vmo);
      if (UNLIKELY(Status != ZX_OK)) {
        if (Status != ZX_ERR_NO_MEMORY || !AllowNoMem)
          dieOnMapUnmapError(Status == ZX_ERR_NO_MEMORY);
        return nullptr;
      }
      _zx_object_set_property(Vmo, ZX_PROP_NAME, Name, strlen(Name));
    }
  
    uintptr_t P;
    zx_vm_option_t MapFlags =
        ZX_VM_PERM_READ | ZX_VM_PERM_WRITE | ZX_VM_ALLOW_FAULTS;
    const uint64_t Offset =
        Addr ? reinterpret_cast<uintptr_t>(Addr) - Data->VmarBase : 0;
    if (Offset)
      MapFlags |= ZX_VM_SPECIFIC;
    Status = _zx_vmar_map(Vmar, MapFlags, Offset, Vmo, VmoSize, Size, &P);
    // No need to track the Vmo if we don't intend on resizing it. Close it.
    if (Flags & MAP_RESIZABLE) {
      DCHECK(Data);
      DCHECK_EQ(Data->Vmo, ZX_HANDLE_INVALID);
      Data->Vmo = Vmo;
    } else {
      CHECK_EQ(_zx_handle_close(Vmo), ZX_OK);
    }
    if (UNLIKELY(Status != ZX_OK)) {
      if (Status != ZX_ERR_NO_MEMORY || !AllowNoMem)
        dieOnMapUnmapError(Status == ZX_ERR_NO_MEMORY);
      return nullptr;
    }
    if (Data)
      Data->VmoSize += Size;
  
    return reinterpret_cast<void *>(P);
  }
  
  void unmap(void *Addr, uptr Size, uptr Flags, MapPlatformData *Data) {
    if (Flags & UNMAP_ALL) {
      DCHECK_NE(Data, nullptr);
      const zx_handle_t Vmar = Data->Vmar;
      DCHECK_NE(Vmar, _zx_vmar_root_self());
      // Destroying the vmar effectively unmaps the whole mapping.
      CHECK_EQ(_zx_vmar_destroy(Vmar), ZX_OK);
      CHECK_EQ(_zx_handle_close(Vmar), ZX_OK);
    } else {
      const zx_handle_t Vmar = Data ? Data->Vmar : _zx_vmar_root_self();
      const zx_status_t Status =
          _zx_vmar_unmap(Vmar, reinterpret_cast<uintptr_t>(Addr), Size);
      if (UNLIKELY(Status != ZX_OK))
        dieOnMapUnmapError();
    }
    if (Data) {
      if (Data->Vmo != ZX_HANDLE_INVALID)
        CHECK_EQ(_zx_handle_close(Data->Vmo), ZX_OK);
      memset(Data, 0, sizeof(*Data));
    }
  }
  
  void releasePagesToOS(UNUSED uptr BaseAddress, uptr Offset, uptr Size,
                        MapPlatformData *Data) {
    DCHECK(Data);
    DCHECK_NE(Data->Vmar, ZX_HANDLE_INVALID);
    DCHECK_NE(Data->Vmo, ZX_HANDLE_INVALID);
    const zx_status_t Status =
        _zx_vmo_op_range(Data->Vmo, ZX_VMO_OP_DECOMMIT, Offset, Size, NULL, 0);
    CHECK_EQ(Status, ZX_OK);
  }
  
  const char *getEnv(const char *Name) { return getenv(Name); }
  
  // Note: we need to flag these methods with __TA_NO_THREAD_SAFETY_ANALYSIS
  // because the Fuchsia implementation of sync_mutex_t has clang thread safety
  // annotations. Were we to apply proper capability annotations to the top level
  // HybridMutex class itself, they would not be needed. As it stands, the
  // thread analysis thinks that we are locking the mutex and accidentally leaving
  // it locked on the way out.
  bool HybridMutex::tryLock() __TA_NO_THREAD_SAFETY_ANALYSIS {
    // Size and alignment must be compatible between both types.
    return sync_mutex_trylock(&M) == ZX_OK;
  }
  
  void HybridMutex::lockSlow() __TA_NO_THREAD_SAFETY_ANALYSIS {
    sync_mutex_lock(&M);
  }
  
  void HybridMutex::unlock() __TA_NO_THREAD_SAFETY_ANALYSIS {
    sync_mutex_unlock(&M);
  }
  
  u64 getMonotonicTime() { return _zx_clock_get_monotonic(); }
  
  u32 getNumberOfCPUs() { return _zx_system_get_num_cpus(); }
  
  u32 getThreadID() { return 0; }
  
  bool getRandom(void *Buffer, uptr Length, UNUSED bool Blocking) {
    static_assert(MaxRandomLength <= ZX_CPRNG_DRAW_MAX_LEN, "");
    if (UNLIKELY(!Buffer || !Length || Length > MaxRandomLength))
      return false;
    _zx_cprng_draw(Buffer, Length);
    return true;
  }
  
  void outputRaw(const char *Buffer) {
    __sanitizer_log_write(Buffer, strlen(Buffer));
  }
  
  void setAbortMessage(const char *Message) {}
  
  } // namespace scudo
  
  #endif // SCUDO_FUCHSIA
  