smalloc.h

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#ifndef CVMFS_SMALLOC_H_
#define CVMFS_SMALLOC_H_

#include <stdint.h>
#include <stdlib.h>
#include <sys/mman.h>

#include <cassert>
// #include <cstdio>

#include <limits>

#ifdef __APPLE__
#define PLATFORM_MAP_ANONYMOUS MAP_ANON
#else
#define PLATFORM_MAP_ANONYMOUS MAP_ANONYMOUS
#endif


#ifdef CVMFS_NAMESPACE_GUARD
namespace CVMFS_NAMESPACE_GUARD {
#endif

// Checkerboard marker (binary 101010...)
const uint32_t kMemMarker = 0xAAAAAAAA;

static inline uint64_t RoundUp8(const uint64_t size) {
  return (size + 7) & ~static_cast<uint64_t>(7);
}

static inline void * __attribute__((used)) smalloc(size_t size) {
  void *mem = malloc(size);
  assert((mem || (size == 0)) && "Out Of Memory");
  return mem;
}

static inline void * __attribute__((used)) srealloc(void *ptr, size_t size) {
  void *mem = realloc(ptr, size);
  assert((mem || (size == 0)) && "Out Of Memory");
  return mem;
}

static inline void * __attribute__((used)) scalloc(size_t count, size_t size) {
  void *mem = calloc(count, size);
  assert((mem || ((count * size) == 0)) && "Out Of Memory");
  return mem;
}

static inline void * __attribute__((used)) smmap(size_t size) {
  // TODO(reneme): make page size platform independent
  assert(size > 0);
  assert(size < std::numeric_limits<size_t>::max() - 4096);

  const int anonymous_fd = -1;
  const off_t offset = 0;
  size_t pages = ((size + 2*sizeof(size_t))+4095)/4096;  // round to full page
  unsigned char *mem = static_cast<unsigned char *>(
    mmap(NULL,
         pages*4096,
         PROT_READ | PROT_WRITE,
         MAP_PRIVATE | PLATFORM_MAP_ANONYMOUS,
         anonymous_fd,
         offset));
  // printf("SMMAP %d bytes at %p\n", pages*4096, mem);
  // NOLINTNEXTLINE(performance-no-int-to-ptr)
  assert((mem != MAP_FAILED) && "Out Of Memory");
  *(reinterpret_cast<size_t *>(mem)) = kMemMarker;
  *(reinterpret_cast<size_t *>(mem) + 1) = pages;
  return mem + 2*sizeof(size_t);
}

static inline void __attribute__((used)) smunmap(void *mem) {
  unsigned char *area = static_cast<unsigned char *>(mem);
  area = area - sizeof(size_t);
  size_t pages = *(reinterpret_cast<size_t *>(area));
  int retval = munmap(area-sizeof(size_t), pages*4096);
  // printf("SUNMMAP %d bytes at %p\n", pages*4096, area);
  assert((retval == 0) && "Invalid umnmap");
}


static inline void * __attribute__((used)) sxmmap(size_t size) {
  const int anonymous_fd = -1;
  const off_t offset = 0;
  void *mem = mmap(NULL,
                   size,
                   PROT_READ | PROT_WRITE,
                   MAP_PRIVATE | PLATFORM_MAP_ANONYMOUS,
                   anonymous_fd,
                   offset);
  // NOLINTNEXTLINE(performance-no-int-to-ptr)
  assert((mem != MAP_FAILED) && "Out Of Memory");
  return mem;
}


static inline void __attribute__((used)) sxunmap(void *mem, size_t size) {
  int retval = munmap(mem, size);
  assert((retval == 0) && "Invalid umnmap");
}


static inline void * __attribute__((used)) sxmmap_align(size_t size) {
  assert((size % (2 * 1024 * 1024)) == 0);
  char *mem = reinterpret_cast<char *>(sxmmap(2 * size));
  uintptr_t head = size - (uintptr_t(mem) % size);
  sxunmap(mem, head);
  mem += head;
  uintptr_t tail = size - head;
  if (tail > 0)
    sxunmap(mem + size, tail);
  return mem;
}


#ifdef CVMFS_NAMESPACE_GUARD
}  // namespace CVMFS_NAMESPACE_GUARD
#endif

#endif  // CVMFS_SMALLOC_H_