// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2022 Google */
#include <test_progs.h>
#include <bpf/libbpf.h>
#include <bpf/btf.h>
#include "iters_css_task.skel.h"
#include "cgroup_iter.skel.h"
#include "cgroup_helpers.h"
#define ROOT 0
#define PARENT 1
#define CHILD1 2
#define CHILD2 3
#define NUM_CGROUPS 4
#define PROLOGUE "prologue\n"
#define EPILOGUE "epilogue\n"
static const char *cg_path[] = {
"/", "/parent", "/parent/child1", "/parent/child2"
};
static int cg_fd[] = {-1, -1, -1, -1};
static unsigned long long cg_id[] = {0, 0, 0, 0};
static char expected_output[64];
static int setup_cgroups(void)
{
int fd, i = 0;
for (i = 0; i < NUM_CGROUPS; i++) {
fd = create_and_get_cgroup(cg_path[i]);
if (fd < 0)
return fd;
cg_fd[i] = fd;
cg_id[i] = get_cgroup_id(cg_path[i]);
}
return 0;
}
static void cleanup_cgroups(void)
{
int i;
for (i = 0; i < NUM_CGROUPS; i++)
close(cg_fd[i]);
}
static void read_from_cgroup_iter(struct bpf_program *prog, int cgroup_fd,
int order, const char *testname)
{
DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts);
union bpf_iter_link_info linfo;
struct bpf_link *link;
int len, iter_fd;
static char buf[128];
size_t left;
char *p;
memset(&linfo, 0, sizeof(linfo));
linfo.cgroup.cgroup_fd = cgroup_fd;
linfo.cgroup.order = order;
opts.link_info = &linfo;
opts.link_info_len = sizeof(linfo);
link = bpf_program__attach_iter(prog, &opts);
if (!ASSERT_OK_PTR(link, "attach_iter"))
return;
iter_fd = bpf_iter_create(bpf_link__fd(link));
if (iter_fd < 0)
goto free_link;
memset(buf, 0, sizeof(buf));
left = ARRAY_SIZE(buf);
p = buf;
while ((len = read(iter_fd, p, left)) > 0) {
p += len;
left -= len;
}
ASSERT_STREQ(buf, expected_output, testname);
/* read() after iter finishes should be ok. */
if (len == 0)
ASSERT_OK(read(iter_fd, buf, sizeof(buf)), "second_read");
close(iter_fd);
free_link:
bpf_link__destroy(link);
}
/* Invalid cgroup. */
static void test_invalid_cgroup(struct cgroup_iter *skel)
{
DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts);
union bpf_iter_link_info linfo;
struct bpf_link *link;
memset(&linfo, 0, sizeof(linfo));
linfo.cgroup.cgroup_fd = (__u32)-1;
opts.link_info = &linfo;
opts.link_info_len = sizeof(linfo);
link = bpf_program__attach_iter(skel->progs.cgroup_id_printer, &opts);
ASSERT_ERR_PTR(link, "attach_iter");
bpf_link__destroy(link);
}
/* Specifying both cgroup_fd and cgroup_id is invalid. */
static void test_invalid_cgroup_spec(struct cgroup_iter *skel)
{
DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts);
union bpf_iter_link_info linfo;
struct bpf_link *link;
memset(&linfo, 0, sizeof(linfo));
linfo.cgroup.cgroup_fd = (__u32)cg_fd[PARENT];
linfo.cgroup.cgroup_id = (__u64)cg_id[PARENT];
opts.link_info = &linfo;
opts.link_info_len = sizeof(linfo);
link = bpf_program__attach_iter(skel->progs.cgroup_id_printer, &opts);
ASSERT_ERR_PTR(link, "attach_iter");
bpf_link__destroy(link);
}
/* Preorder walk prints parent and child in order. */
static void test_walk_preorder(struct cgroup_iter *skel)
{
snprintf(expected_output, sizeof(expected_output),
PROLOGUE "%8llu\n%8llu\n%8llu\n" EPILOGUE,
cg_id[PARENT], cg_id[CHILD1], cg_id[CHILD2]);
read_from_cgroup_iter(skel->progs.cgroup_id_printer, cg_fd[PARENT],
BPF_CGROUP_ITER_DESCENDANTS_PRE, "preorder");
}
/* Postorder walk prints child and parent in order. */
static void test_walk_postorder(struct cgroup_iter *skel)
{
snprintf(expected_output, sizeof(expected_output),
PROLOGUE "%8llu\n%8llu\n%8llu\n" EPILOGUE,
cg_id[CHILD1], cg_id[CHILD2], cg_id[PARENT]);
read_from_cgroup_iter(skel->progs.cgroup_id_printer, cg_fd[PARENT],
BPF_CGROUP_ITER_DESCENDANTS_POST, "postorder");
}
/* Walking parents prints parent and then root. */
static void test_walk_ancestors_up(struct cgroup_iter *skel)
{
/* terminate the walk when ROOT is met. */
skel->bss->terminal_cgroup = cg_id[ROOT];
snprintf(expected_output, sizeof(expected_output),
PROLOGUE "%8llu\n%8llu\n" EPILOGUE,
cg_id[PARENT], cg_id[ROOT]);
read_from_cgroup_iter(skel->progs.cgroup_id_printer, cg_fd[PARENT],
BPF_CGROUP_ITER_ANCESTORS_UP, "ancestors_up");
skel->bss->terminal_cgroup = 0;
}
/* Early termination prints parent only. */
static void test_early_termination(struct cgroup_iter *skel)
{
/* terminate the walk after the first element is processed. */
skel->bss->terminate_early = 1;
snprintf(expected_output, sizeof(expected_output),
PROLOGUE "%8llu\n" EPILOGUE, cg_id[PARENT]);
read_from_cgroup_iter(skel->progs.cgroup_id_printer, cg_fd[PARENT],
BPF_CGROUP_ITER_DESCENDANTS_PRE, "early_termination");
skel->bss->terminate_early = 0;
}
/* Waling self prints self only. */
static void test_walk_self_only(struct cgroup_iter *skel)
{
snprintf(expected_output, sizeof(expected_output),
PROLOGUE "%8llu\n" EPILOGUE, cg_id[PARENT]);
read_from_cgroup_iter(skel->progs.cgroup_id_printer, cg_fd[PARENT],
BPF_CGROUP_ITER_SELF_ONLY, "self_only");
}
static void test_walk_dead_self_only(struct cgroup_iter *skel)
{
DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts);
char expected_output[128], buf[128];
const char *cgrp_name = "/dead";
union bpf_iter_link_info linfo;
int len, cgrp_fd, iter_fd;
struct bpf_link *link;
size_t left;
char *p;
cgrp_fd = create_and_get_cgroup(cgrp_name);
if (!ASSERT_GE(cgrp_fd, 0, "create cgrp"))
return;
/* The cgroup will be dead during read() iteration, so it only has
* epilogue in the output
*/
snprintf(expected_output, sizeof(expected_output), EPILOGUE);
memset(&linfo, 0, sizeof(linfo));
linfo.cgroup.cgroup_fd = cgrp_fd;
linfo.cgroup.order = BPF_CGROUP_ITER_SELF_ONLY;
opts.link_info = &linfo;
opts.link_info_len = sizeof(linfo);
link = bpf_program__attach_iter(skel->progs.cgroup_id_printer, &opts);
if (!ASSERT_OK_PTR(link, "attach_iter"))
goto close_cgrp;
iter_fd = bpf_iter_create(bpf_link__fd(link));
if (!ASSERT_GE(iter_fd, 0, "iter_create"))
goto free_link;
/* Close link fd and cgroup fd */
bpf_link__destroy(link);
close(cgrp_fd);
/* Remove cgroup to mark it as dead */
remove_cgroup(cgrp_name);
/* Two kern_sync_rcu() and usleep() pairs are used to wait for the
* releases of cgroup css, and the last kern_sync_rcu() and usleep()
* pair is used to wait for the free of cgroup itself.
*/
kern_sync_rcu();
usleep(8000);
kern_sync_rcu();
usleep(8000);
kern_sync_rcu();
usleep(1000);
memset(buf, 0, sizeof(buf));
left = ARRAY_SIZE(buf);
p = buf;
while ((len = read(iter_fd, p, left)) > 0) {
p += len;
left -= len;
}
ASSERT_STREQ(buf, expected_output, "dead cgroup output");
/* read() after iter finishes should be ok. */
if (len == 0)
ASSERT_OK(read(iter_fd, buf, sizeof(buf)), "second_read");
close(iter_fd);
return;
free_link:
bpf_link__destroy(link);
close_cgrp:
close(cgrp_fd);
}
static void test_walk_self_only_css_task(void)
{
struct iters_css_task *skel;
int err;
skel = iters_css_task__open();
if (!ASSERT_OK_PTR(skel, "skel_open"))
return;
bpf_program__set_autoload(skel->progs.cgroup_id_printer, true);
err = iters_css_task__load(skel);
if (!ASSERT_OK(err, "skel_load"))
goto cleanup;
err = join_cgroup(cg_path[CHILD2]);
if (!ASSERT_OK(err, "join_cgroup"))
goto cleanup;
skel->bss->target_pid = getpid();
snprintf(expected_output, sizeof(expected_output),
PROLOGUE "%8llu\n" EPILOGUE, cg_id[CHILD2]);
read_from_cgroup_iter(skel->progs.cgroup_id_printer, cg_fd[CHILD2],
BPF_CGROUP_ITER_SELF_ONLY, "test_walk_self_only_css_task");
ASSERT_EQ(skel->bss->css_task_cnt, 1, "css_task_cnt");
cleanup:
iters_css_task__destroy(skel);
}
void test_cgroup_iter(void)
{
struct cgroup_iter *skel = NULL;
if (setup_cgroup_environment())
return;
if (setup_cgroups())
goto out;
skel = cgroup_iter__open_and_load();
if (!ASSERT_OK_PTR(skel, "cgroup_iter__open_and_load"))
goto out;
if (test__start_subtest("cgroup_iter__invalid_cgroup"))
test_invalid_cgroup(skel);
if (test__start_subtest("cgroup_iter__invalid_cgroup_spec"))
test_invalid_cgroup_spec(skel);
if (test__start_subtest("cgroup_iter__preorder"))
test_walk_preorder(skel);
if (test__start_subtest("cgroup_iter__postorder"))
test_walk_postorder(skel);
if (test__start_subtest("cgroup_iter__ancestors_up_walk"))
test_walk_ancestors_up(skel);
if (test__start_subtest("cgroup_iter__early_termination"))
test_early_termination(skel);
if (test__start_subtest("cgroup_iter__self_only"))
test_walk_self_only(skel);
if (test__start_subtest("cgroup_iter__dead_self_only"))
test_walk_dead_self_only(skel);
if (test__start_subtest("cgroup_iter__self_only_css_task"))
test_walk_self_only_css_task();
out:
cgroup_iter__destroy(skel);
cleanup_cgroups();
cleanup_cgroup_environment();
}
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