none/tests/linux/mremap.c

   1 #define _GNU_SOURCE
   2 #include "tests/sys_mman.h"
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5
   6 static char *mkmap(unsigned sz)
   7 {
   8         static char *map;
   9         static unsigned mapsz;
  10         char *p;
  11
  12         if (map != NULL)
  13                 munmap(map, mapsz);
  14
  15         p = (char *)mmap(0, sz, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
  16
  17         if (p == (char *)-1) {
  18                 perror("mmap");
  19                 exit(1);
  20         }
  21
  22         map = p;
  23         mapsz = sz;
  24
  25         return p;
  26 }
  27
  28
  29 int main()
  30 {
  31         char *np;
  32         char *p;
  33
  34         p = mkmap(1024*1024);
  35         np = mremap(p, 1024*1024, 256*1024, 0); /* shrink, fixed */
  36         if (np == (char *)-1)
  37                 perror("mremap(shrink, fixed)");
  38         if (np != p)
  39                 fprintf(stderr, "shrink, nomove: p=%p np=%p: shrink moved?!\n",
  40                         p, np);
  41         if (np != (char *)-1)
  42                 munmap(np, 256*1024);
  43
  44         p = mkmap(1024*1024);
  45         np = mremap(p, 1024*1024, 256*1024, MREMAP_MAYMOVE);    /* shrink, maymove */
  46         if (np == (char *)-1)
  47                 perror("mremap(shrink, maymove)");
  48         if (np != p)
  49                 fprintf(stderr, "shrink, maymove: p=%p np=%p: shrink moved?!\n",
  50                         p, np);
  51         if (np != (char *)-1)
  52                 munmap(np, 256*1024);
  53
  54         p = mkmap(1024*1024);
  55         np = mremap(p, 1024*1024, 2048*1024, 0); /* grow, fixed */
  56         if (np == (char *)-1)
  57                 perror("mremap(grow, fixed)");
  58         if (np != p)
  59                 fprintf(stderr, "grow, nomove: p=%p np=%p: shrink moved?!\n",
  60                         p, np);
  61         if (np != (char *)-1)
  62                 munmap(np, 2048*1024);
  63
  64         p = mkmap(1024*1024);
  65         np = mremap(p, 1024*1024, 2048*1024, MREMAP_MAYMOVE); /* grow, maymove */
  66         if (np == (char *)-1)
  67                 perror("mremap(grow, maymove)");
  68         if (np != p)
  69                 fprintf(stderr, "grow, maymove: p=%p np=%p: shrink moved?!\n",
  70                         p, np);
  71         if (np != (char *)-1)
  72                 munmap(np, 2048*1024);
  73
  74         p = mkmap(1024*1024);
  75         munmap(p+512*1024, 4096);
  76         np = mremap(p, 512*1024, 1024*1024, 0); /* grow, nomove, constrained */
  77         if (np == (char *)-1)
  78                 perror("mremap(grow, nomove, constrained)");
  79         else if (np == p)
  80                 fprintf(stderr, "grow, maymove, constrained: p=%p np=%p (managed to grow without moving?!)\n",
  81                         p, np);
  82         if (np != (char *)-1)
  83                 munmap(np, 1024*1024);
  84
  85         p = mkmap(1024*1024);
  86         munmap(p+512*1024, 4096);
  87
  88         np = mremap(p, 512*1024, 1024*1024, MREMAP_MAYMOVE); /* grow, maymove, constrained */
  89         if (np == (char *)-1)
  90                 perror("mremap(grow, maymove, constrained)");
  91         if (np == p)
  92                 fprintf(stderr, "grow, maymove, constrained: p=%p np=%p (managed to grow without moving?!)\n",
  93                         p, np);
  94         if (np != (char *)-1)
  95                 munmap(np, 1024*1024);
  96
  97         return 0;
  98 }