tools/testing/selftests/damon/debugfs_target_ids_pid_leak.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Author: SeongJae Park <sj@kernel.org>
   4  */
   5
   6 #define _GNU_SOURCE
   7
   8 #include <fcntl.h>
   9 #include <stdbool.h>
  10 #include <stdint.h>
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <sys/types.h>
  14 #include <sys/wait.h>
  15 #include <sys/time.h>
  16 #include <unistd.h>
  17
  18 #define DBGFS_TARGET_IDS "/sys/kernel/debug/damon/target_ids"
  19
  20 static void write_targetid_exit(void)
  21 {
  22         int target_ids_fd = open(DBGFS_TARGET_IDS, O_RDWR);
  23         char pid_str[128];
  24
  25         snprintf(pid_str, sizeof(pid_str), "%d", getpid());
  26         write(target_ids_fd, pid_str, sizeof(pid_str));
  27         close(target_ids_fd);
  28         exit(0);
  29 }
  30
  31 unsigned long msec_timestamp(void)
  32 {
  33         struct timeval tv;
  34
  35         gettimeofday(&tv, NULL);
  36         return tv.tv_sec * 1000UL + tv.tv_usec / 1000;
  37 }
  38
  39 int main(int argc, char *argv[])
  40 {
  41         unsigned long start_ms;
  42         int time_to_run, nr_forks = 0;
  43
  44         if (argc != 2) {
  45                 fprintf(stderr, "Usage: %s <msecs to run>\n", argv[0]);
  46                 exit(1);
  47         }
  48         time_to_run = atoi(argv[1]);
  49
  50         start_ms = msec_timestamp();
  51         while (true) {
  52                 int pid = fork();
  53
  54                 if (pid < 0) {
  55                         fprintf(stderr, "fork() failed\n");
  56                         exit(1);
  57                 }
  58                 if (pid == 0)
  59                         write_targetid_exit();
  60                 wait(NULL);
  61                 nr_forks++;
  62
  63                 if (msec_timestamp() - start_ms > time_to_run)
  64                         break;
  65         }
  66         printf("%d\n", nr_forks);
  67         return 0;
  68 }