platform.cc

Go to the documentation of this file.

#if defined(__linux__) || defined(__FreeBSD__) || defined(__OpenBSD__) || \
    defined(__DragonFly__)
 
#include <errno.h>
#include <pthread.h>
#include <string.h>
#include <sys/mman.h>
 
#include "src/globals.h"
#include "src/macros.h"
#include "src/platform/platform-base.h"
 
namespace broom {
namespace platform {
// Some platforms require the file descriptor to be -1, even when
// MAP_ANONYMOUS/MAP_ANON is specified.
constexpr const int kInvalidFd = -1;
 
void UnmapMemorySpace(const MemorySpace& space) {
  BENSURE_EQ(munmap(space.StartPtr(), space.Size()), 0,
             "Failed to unmap memory: {}", strerror(errno));
}
 
int GetProtectionFromMemoryPermissions(MemoryPermissions permissions) {
  switch (permissions) {
    case MemoryPermissions::kReadOnly:
      return PROT_READ;
    case MemoryPermissions::kWriteOnly:
      return PROT_WRITE;
    case MemoryPermissions::kReadWrite:
      return PROT_READ | PROT_WRITE;
    case MemoryPermissions::kNone:
      return 0;
  }
  ABORT("Unexpected permissions");
}
 
int GetFlagsFromMemoryPermissions(BROOM_UNUSED MemoryPermissions permissions) {
  return 0;
}
 
MemorySpace MapMemorySpace(size_t space_size, MemoryPermissions permissions) {
  int prot = GetProtectionFromMemoryPermissions(permissions);
  int flags = GetFlagsFromMemoryPermissions(permissions);
  flags |= MAP_ANON;
  flags |= MAP_PRIVATE;
  void* maybe_pointer = mmap(nullptr, space_size, prot, flags, kInvalidFd, 0);
  return MemorySpace{maybe_pointer, space_size};
}
}  // namespace platform
}  // namespace broom
#endif