platform_bionic/libc/bionic/sys_statfs.cpp

/*
 * Copyright (C) 2013 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <sys/statfs.h>

// Paper over the fact that 32-bit kernels use fstatfs64/statfs64 with
// an extra argument, but 64-bit kernels don't have the "64" bit suffix or
// the extra size_t argument.
#if defined(__LP64__)
extern "C" int __fstatfs(int, struct statfs*);
extern "C" int __statfs(const char*, struct statfs*);
#  define __fstatfs64(fd,size,buf) __fstatfs(fd,buf)
#  define __statfs64(path,size,buf) __statfs(path,buf)
#else
extern "C" int __fstatfs64(int, size_t, struct statfs*);
extern "C" int __statfs64(const char*, size_t, struct statfs*);
#endif

// The kernel sets a private ST_VALID flag to signal to the C library
// whether the f_flags field is valid. This flag should not be exposed to
// users of the C library.
#define ST_VALID 0x0020

int fstatfs(int fd, struct statfs* result) {
  int rc = __fstatfs64(fd, sizeof(*result), result);
  if (rc != 0) {
    return rc;
  }
  result->f_flags &= ~ST_VALID;
  return 0;
}
__strong_alias(fstatfs64, fstatfs);

int statfs(const char* path, struct statfs* result) {
  int rc = __statfs64(path, sizeof(*result), result);
  if (rc != 0) {
    return rc;
  }
  result->f_flags &= ~ST_VALID;
  return 0;
}
__strong_alias(statfs64, statfs);