src/test/mmap_shared_subpage.c

/* -*- Mode: C; tab-width: 8; c-basic-offset: 2; indent-tabs-mode: nil; -*- */

#include "util.h"

static int create_segment(size_t num_bytes) {
  char filename[] = "/dev/shm/rr-test-XXXXXX";
  int fd = mkstemp(filename);
  unlink(filename);
  test_assert(fd >= 0);
  ftruncate(fd, num_bytes);
  return fd;
}

int main(void) {
  size_t num_bytes = 120; /* Not a multiple of the page size */
  int fd = create_segment(num_bytes);
  int* wpage = mmap(NULL, num_bytes, PROT_WRITE, MAP_SHARED, fd, 0);
  int* rpage = mmap(NULL, num_bytes, PROT_READ, MAP_SHARED, fd, 0);
  size_t i;

  test_assert(wpage != (void*)-1 && rpage != (void*)-1 && rpage != wpage);

  close(128);

  for (i = 0; i < num_bytes / sizeof(int); ++i) {
    wpage[i] = i;
    test_assert(rpage[i] == (ssize_t)i);
    atomic_printf("%d,", rpage[i]);
  }

  atomic_puts("EXIT-SUCCESS");

  return 0;
}