tools/testing/selftests/cgroup/test_pids.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #define _GNU_SOURCE
   3
   4 #include <errno.h>
   5 #include <linux/limits.h>
   6 #include <signal.h>
   7 #include <string.h>
   8 #include <sys/stat.h>
   9 #include <sys/types.h>
  10 #include <unistd.h>
  11
  12 #include "../kselftest.h"
  13 #include "cgroup_util.h"
  14
  15 static int run_success(const char *cgroup, void *arg)
  16 {
  17         return 0;
  18 }
  19
  20 static int run_pause(const char *cgroup, void *arg)
  21 {
  22         return pause();
  23 }
  24
  25 /*
  26  * This test checks that pids.max prevents forking new children above the
  27  * specified limit in the cgroup.
  28  */
  29 static int test_pids_max(const char *root)
  30 {
  31         int ret = KSFT_FAIL;
  32         char *cg_pids;
  33         int pid;
  34
  35         cg_pids = cg_name(root, "pids_test");
  36         if (!cg_pids)
  37                 goto cleanup;
  38
  39         if (cg_create(cg_pids))
  40                 goto cleanup;
  41
  42         if (cg_read_strcmp(cg_pids, "pids.max", "max\n"))
  43                 goto cleanup;
  44
  45         if (cg_write(cg_pids, "pids.max", "2"))
  46                 goto cleanup;
  47
  48         if (cg_enter_current(cg_pids))
  49                 goto cleanup;
  50
  51         pid = cg_run_nowait(cg_pids, run_pause, NULL);
  52         if (pid < 0)
  53                 goto cleanup;
  54
  55         if (cg_run_nowait(cg_pids, run_success, NULL) != -1 || errno != EAGAIN)
  56                 goto cleanup;
  57
  58         if (kill(pid, SIGINT))
  59                 goto cleanup;
  60
  61         ret = KSFT_PASS;
  62
  63 cleanup:
  64         cg_enter_current(root);
  65         cg_destroy(cg_pids);
  66         free(cg_pids);
  67
  68         return ret;
  69 }
  70
  71 /*
  72  * This test checks that pids.events are counted in cgroup associated with pids.max
  73  */
  74 static int test_pids_events(const char *root)
  75 {
  76         int ret = KSFT_FAIL;
  77         char *cg_parent = NULL, *cg_child = NULL;
  78         int pid;
  79
  80         cg_parent = cg_name(root, "pids_parent");
  81         cg_child = cg_name(cg_parent, "pids_child");
  82         if (!cg_parent || !cg_child)
  83                 goto cleanup;
  84
  85         if (cg_create(cg_parent))
  86                 goto cleanup;
  87         if (cg_write(cg_parent, "cgroup.subtree_control", "+pids"))
  88                 goto cleanup;
  89         if (cg_create(cg_child))
  90                 goto cleanup;
  91
  92         if (cg_write(cg_parent, "pids.max", "2"))
  93                 goto cleanup;
  94
  95         if (cg_read_strcmp(cg_child, "pids.max", "max\n"))
  96                 goto cleanup;
  97
  98         if (cg_enter_current(cg_child))
  99                 goto cleanup;
 100
 101         pid = cg_run_nowait(cg_child, run_pause, NULL);
 102         if (pid < 0)
 103                 goto cleanup;
 104
 105         if (cg_run_nowait(cg_child, run_success, NULL) != -1 || errno != EAGAIN)
 106                 goto cleanup;
 107
 108         if (kill(pid, SIGINT))
 109                 goto cleanup;
 110
 111         if (cg_read_key_long(cg_child, "pids.events", "max ") != 0)
 112                 goto cleanup;
 113         if (cg_read_key_long(cg_parent, "pids.events", "max ") != 1)
 114                 goto cleanup;
 115
 116
 117         ret = KSFT_PASS;
 118
 119 cleanup:
 120         cg_enter_current(root);
 121         if (cg_child)
 122                 cg_destroy(cg_child);
 123         if (cg_parent)
 124                 cg_destroy(cg_parent);
 125         free(cg_child);
 126         free(cg_parent);
 127
 128         return ret;
 129 }
 130
 131
 132
 133 #define T(x) { x, #x }
 134 struct pids_test {
 135         int (*fn)(const char *root);
 136         const char *name;
 137 } tests[] = {
 138         T(test_pids_max),
 139         T(test_pids_events),
 140 };
 141 #undef T
 142
 143 int main(int argc, char **argv)
 144 {
 145         char root[PATH_MAX];
 146
 147         ksft_print_header();
 148         ksft_set_plan(ARRAY_SIZE(tests));
 149         if (cg_find_unified_root(root, sizeof(root), NULL))
 150                 ksft_exit_skip("cgroup v2 isn't mounted\n");
 151
 152         /*
 153          * Check that pids controller is available:
 154          * pids is listed in cgroup.controllers
 155          */
 156         if (cg_read_strstr(root, "cgroup.controllers", "pids"))
 157                 ksft_exit_skip("pids controller isn't available\n");
 158
 159         if (cg_read_strstr(root, "cgroup.subtree_control", "pids"))
 160                 if (cg_write(root, "cgroup.subtree_control", "+pids"))
 161                         ksft_exit_skip("Failed to set pids controller\n");
 162
 163         for (int i = 0; i < ARRAY_SIZE(tests); i++) {
 164                 switch (tests[i].fn(root)) {
 165                 case KSFT_PASS:
 166                         ksft_test_result_pass("%s\n", tests[i].name);
 167                         break;
 168                 case KSFT_SKIP:
 169                         ksft_test_result_skip("%s\n", tests[i].name);
 170                         break;
 171                 default:
 172                         ksft_test_result_fail("%s\n", tests[i].name);
 173                         break;
 174                 }
 175         }
 176
 177         ksft_finished();
 178 }