root/tools/testing/selftests/vm/on-fault-limit.c

DEFINITIONS

1. test_limit
2. main

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <sys/mman.h>
   3 #include <stdio.h>
   4 #include <unistd.h>
   5 #include <string.h>
   6 #include <sys/time.h>
   7 #include <sys/resource.h>
   8 
   9 #ifndef MCL_ONFAULT
  10 #define MCL_ONFAULT (MCL_FUTURE << 1)
  11 #endif
  12 
  13 static int test_limit(void)
  14 {
  15         int ret = 1;
  16         struct rlimit lims;
  17         void *map;
  18 
  19         if (getrlimit(RLIMIT_MEMLOCK, &lims)) {
  20                 perror("getrlimit");
  21                 return ret;
  22         }
  23 
  24         if (mlockall(MCL_ONFAULT | MCL_FUTURE)) {
  25                 perror("mlockall");
  26                 return ret;
  27         }
  28 
  29         map = mmap(NULL, 2 * lims.rlim_max, PROT_READ | PROT_WRITE,
  30                    MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE, -1, 0);
  31         if (map != MAP_FAILED)
  32                 printf("mmap should have failed, but didn't\n");
  33         else {
  34                 ret = 0;
  35                 munmap(map, 2 * lims.rlim_max);
  36         }
  37 
  38         munlockall();
  39         return ret;
  40 }
  41 
  42 int main(int argc, char **argv)
  43 {
  44         int ret = 0;
  45 
  46         ret += test_limit();
  47         return ret;
  48 }