PPAPI: Implement PPB_FileMapping on POSIX

ppapi/proxy/file_mapping_resource_posix.cc

+// Copyright (c) 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ppapi/proxy/file_mapping_resource.h"
+
+#include <stdio.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include "ppapi/c/pp_errors.h"
+
+namespace ppapi {
+namespace proxy {
+
+namespace {
+
+int32_t ErrnoToPPError(int error_code) {
+  switch (error_code) {
+    case EACCES:
+      return PP_ERROR_NOACCESS;
+    case EAGAIN:
+      return PP_ERROR_NOMEMORY;
+    case EINVAL:
+      return PP_ERROR_BADARGUMENT;
+    case ENFILE:
+    case ENOMEM:
+      return PP_ERROR_NOMEMORY;
+    default:
+      return PP_ERROR_FAILED;
+  }
+}
+
+}  // namespace
+
+// static
+FileMappingResource::MapResult FileMappingResource::DoMap(
+    scoped_refptr<FileIOResource::FileHandleHolder> handle,
+    void* address_hint,
+    int64_t length,
+    uint32_t map_protection,
+    uint32_t map_flags,
+    int64_t offset) {
+  int prot_for_mmap = 0;
+  if (map_protection & PP_FILEMAPPROTECTION_READ)
+    prot_for_mmap |= PROT_READ;
+  if (map_protection & PP_FILEMAPPROTECTION_WRITE)
+    prot_for_mmap |= PROT_WRITE;
+  if (prot_for_mmap == 0)
+    prot_for_mmap = PROT_NONE;
+
+  int flags_for_mmap = 0;
+  if (map_flags & PP_FILEMAPFLAG_SHARED)
+    flags_for_mmap |= MAP_SHARED;
+  if (map_flags & PP_FILEMAPFLAG_PRIVATE)
+    flags_for_mmap |= MAP_PRIVATE;
+  if (map_flags & PP_FILEMAPFLAG_FIXED)
+    flags_for_mmap |= MAP_FIXED;
+
+  MapResult map_result;
+  map_result.address =
+      mmap(address_hint,
+           static_cast<size_t>(length),
+           prot_for_mmap,
+           flags_for_mmap,
+           handle->raw_handle(),
+           static_cast<off_t>(offset));
+  if (map_result.address != MAP_FAILED)
+    map_result.result = PP_OK;
+  else
+    map_result.result = ErrnoToPPError(errno);
+  return map_result;
+}
+
+// static
+int32_t FileMappingResource::DoUnmap(const void* address, int64_t length) {
+  int result = munmap(const_cast<void*>(address), static_cast<size_t>(length));

[bbudge, 2014/01/25 01:04:55]

Since we don't otherwise use result could it just be if (munmap... ?

[dmichael (off chromium), 2014/01/27 18:29:53]

Done.

+  if (result)
+    return ErrnoToPPError(errno);
+  return PP_OK;
+}
+
+// static
+int64_t FileMappingResource::DoGetMapPageSize() {
+  // TODO(dmichael): It might be better to port sys_info_posix.cc to NaCl and

[bbudge, 2014/01/25 01:04:55]

That file just calls getpagesize() and the rest is really non-portable to NaCl.
So I would remove the TODO.

[dmichael (off chromium), 2014/01/27 18:29:53]

Done.

+  // call Sysinfo::VMAllocationGranularity.
+  return getpagesize();
+}
+
+}  // namespace proxy
+}  // namespace ppapi