tests/tcg/multiarch/linux/linux-madvise.c

   1 #include <assert.h>
   2 #include <stdlib.h>
   3 #include <sys/mman.h>
   4 #include <unistd.h>
   5
   6 static void test_anonymous(void)
   7 {
   8     int pagesize = getpagesize();
   9     char *page;
  10     int ret;
  11
  12     page = mmap(NULL, pagesize, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
  13     assert(page != MAP_FAILED);
  14
  15     /* Check that mprotect() does not interfere with MADV_DONTNEED. */
  16     ret = mprotect(page, pagesize, PROT_READ | PROT_WRITE);
  17     assert(ret == 0);
  18
  19     /* Check that MADV_DONTNEED clears the page. */
  20     *page = 42;
  21     ret = madvise(page, pagesize, MADV_DONTNEED);
  22     assert(ret == 0);
  23     assert(*page == 0);
  24
  25     ret = munmap(page, pagesize);
  26     assert(ret == 0);
  27 }
  28
  29 static void test_file(void)
  30 {
  31     char tempname[] = "/tmp/.cmadviseXXXXXX";
  32     int pagesize = getpagesize();
  33     ssize_t written;
  34     char c = 42;
  35     char *page;
  36     int ret;
  37     int fd;
  38
  39     fd = mkstemp(tempname);
  40     assert(fd != -1);
  41     ret = unlink(tempname);
  42     assert(ret == 0);
  43     written = write(fd, &c, sizeof(c));
  44     assert(written == sizeof(c));
  45     page = mmap(NULL, pagesize, PROT_READ, MAP_PRIVATE, fd, 0);
  46     assert(page != MAP_FAILED);
  47
  48     /* Check that mprotect() does not interfere with MADV_DONTNEED. */
  49     ret = mprotect(page, pagesize, PROT_READ | PROT_WRITE);
  50     assert(ret == 0);
  51
  52     /* Check that MADV_DONTNEED resets the page. */
  53     *page = 0;
  54     ret = madvise(page, pagesize, MADV_DONTNEED);
  55     assert(ret == 0);
  56     assert(*page == c);
  57
  58     ret = munmap(page, pagesize);
  59     assert(ret == 0);
  60     ret = close(fd);
  61     assert(ret == 0);
  62 }
  63
  64 int main(void)
  65 {
  66     test_anonymous();
  67     test_file();
  68
  69     return EXIT_SUCCESS;
  70 }