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
run_success(const char * cgroup,void * arg)15 static int run_success(const char *cgroup, void *arg)
16 {
17 return 0;
18 }
19
run_pause(const char * cgroup,void * arg)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 */
test_pids_max(const char * root)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 */
test_pids_events(const char * root)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 if (cgroup_feature("pids_localevents") <= 0)
81 return KSFT_SKIP;
82
83 cg_parent = cg_name(root, "pids_parent");
84 cg_child = cg_name(cg_parent, "pids_child");
85 if (!cg_parent || !cg_child)
86 goto cleanup;
87
88 if (cg_create(cg_parent))
89 goto cleanup;
90 if (cg_write(cg_parent, "cgroup.subtree_control", "+pids"))
91 goto cleanup;
92 if (cg_create(cg_child))
93 goto cleanup;
94
95 if (cg_write(cg_parent, "pids.max", "2"))
96 goto cleanup;
97
98 if (cg_read_strcmp(cg_child, "pids.max", "max\n"))
99 goto cleanup;
100
101 if (cg_enter_current(cg_child))
102 goto cleanup;
103
104 pid = cg_run_nowait(cg_child, run_pause, NULL);
105 if (pid < 0)
106 goto cleanup;
107
108 if (cg_run_nowait(cg_child, run_success, NULL) != -1 || errno != EAGAIN)
109 goto cleanup;
110
111 if (kill(pid, SIGINT))
112 goto cleanup;
113
114 if (cg_read_key_long(cg_child, "pids.events", "max ") != 0)
115 goto cleanup;
116 if (cg_read_key_long(cg_parent, "pids.events", "max ") != 1)
117 goto cleanup;
118
119
120 ret = KSFT_PASS;
121
122 cleanup:
123 cg_enter_current(root);
124 if (cg_child)
125 cg_destroy(cg_child);
126 if (cg_parent)
127 cg_destroy(cg_parent);
128 free(cg_child);
129 free(cg_parent);
130
131 return ret;
132 }
133
134
135
136 #define T(x) { x, #x }
137 struct pids_test {
138 int (*fn)(const char *root);
139 const char *name;
140 } tests[] = {
141 T(test_pids_max),
142 T(test_pids_events),
143 };
144 #undef T
145
main(int argc,char ** argv)146 int main(int argc, char **argv)
147 {
148 char root[PATH_MAX];
149
150 ksft_print_header();
151 ksft_set_plan(ARRAY_SIZE(tests));
152 if (cg_find_unified_root(root, sizeof(root), NULL))
153 ksft_exit_skip("cgroup v2 isn't mounted\n");
154
155 /*
156 * Check that pids controller is available:
157 * pids is listed in cgroup.controllers
158 */
159 if (cg_read_strstr(root, "cgroup.controllers", "pids"))
160 ksft_exit_skip("pids controller isn't available\n");
161
162 if (cg_read_strstr(root, "cgroup.subtree_control", "pids"))
163 if (cg_write(root, "cgroup.subtree_control", "+pids"))
164 ksft_exit_skip("Failed to set pids controller\n");
165
166 for (int i = 0; i < ARRAY_SIZE(tests); i++) {
167 switch (tests[i].fn(root)) {
168 case KSFT_PASS:
169 ksft_test_result_pass("%s\n", tests[i].name);
170 break;
171 case KSFT_SKIP:
172 ksft_test_result_skip("%s\n", tests[i].name);
173 break;
174 default:
175 ksft_test_result_fail("%s\n", tests[i].name);
176 break;
177 }
178 }
179
180 ksft_finished();
181 }
182