/* SPDX-License-Identifier: GPL-2.0 */
#include <stdbool.h>
#include <linux/limits.h>
#include <sys/ptrace.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <poll.h>
#include <stdlib.h>
#include <sys/inotify.h>
#include <string.h>
#include <sys/wait.h>
#include "../kselftest.h"
#include "cgroup_util.h"
#define DEBUG
#ifdef DEBUG
#define debug(args...) fprintf(stderr, args)
#else
#define debug(args...)
#endif
/*
* Check if the cgroup is frozen by looking at the cgroup.events::frozen value.
*/
static int cg_check_frozen(const char *cgroup, bool frozen)
{
if (frozen) {
if (cg_read_strstr(cgroup, "cgroup.events", "frozen 1") != 0) {
debug("Cgroup %s isn't frozen\n", cgroup);
return -1;
}
} else {
/*
* Check the cgroup.events::frozen value.
*/
if (cg_read_strstr(cgroup, "cgroup.events", "frozen 0") != 0) {
debug("Cgroup %s is frozen\n", cgroup);
return -1;
}
}
return 0;
}
/*
* Freeze the given cgroup.
*/
static int cg_freeze_nowait(const char *cgroup, bool freeze)
{
return cg_write(cgroup, "cgroup.freeze", freeze ? "1" : "0");
}
/*
* Prepare for waiting on cgroup.events file.
*/
static int cg_prepare_for_wait(const char *cgroup)
{
int fd, ret = -1;
fd = inotify_init1(0);
if (fd == -1) {
debug("Error: inotify_init1() failed\n");
return fd;
}
ret = inotify_add_watch(fd, cg_control(cgroup, "cgroup.events"),
IN_MODIFY);
if (ret == -1) {
debug("Error: inotify_add_watch() failed\n");
close(fd);
}
return fd;
}
/*
* Wait for an event. If there are no events for 10 seconds,
* treat this an error.
*/
static int cg_wait_for(int fd)
{
int ret = -1;
struct pollfd fds = {
.fd = fd,
.events = POLLIN,
};
while (true) {
ret = poll(&fds, 1, 10000);
if (ret == -1) {
if (errno == EINTR)
continue;
debug("Error: poll() failed\n");
break;
}
if (ret > 0 && fds.revents & POLLIN) {
ret = 0;
break;
}
}
return ret;
}
/*
* Attach a task to the given cgroup and wait for a cgroup frozen event.
* All transient events (e.g. populated) are ignored.
*/
static int cg_enter_and_wait_for_frozen(const char *cgroup, int pid,
bool frozen)
{
int fd, ret = -1;
int attempts;
fd = cg_prepare_for_wait(cgroup);
if (fd < 0)
return fd;
ret = cg_enter(cgroup, pid);
if (ret)
goto out;
for (attempts = 0; attempts < 10; attempts++) {
ret = cg_wait_for(fd);
if (ret)
break;
ret = cg_check_frozen(cgroup, frozen);
if (ret)
continue;
}
out:
close(fd);
return ret;
}
/*
* Freeze the given cgroup and wait for the inotify signal.
* If there are no events in 10 seconds, treat this as an error.
* Then check that the cgroup is in the desired state.
*/
static int cg_freeze_wait(const char *cgroup, bool freeze)
{
int fd, ret = -1;
fd = cg_prepare_for_wait(cgroup);
if (fd < 0)
return fd;
ret = cg_freeze_nowait(cgroup, freeze);
if (ret) {
debug("Error: cg_freeze_nowait() failed\n");
goto out;
}
ret = cg_wait_for(fd);
if (ret)
goto out;
ret = cg_check_frozen(cgroup, freeze);
out:
close(fd);
return ret;
}
/*
* A simple process running in a sleep loop until being
* re-parented.
*/
static int child_fn(const char *cgroup, void *arg)
{
int ppid = getppid();
while (getppid() == ppid)
usleep(1000);
return getppid() == ppid;
}
/*
* A simple test for the cgroup freezer: populated the cgroup with 100
* running processes and freeze it. Then unfreeze it. Then it kills all
* processes and destroys the cgroup.
*/
static int test_cgfreezer_simple(const char *root)
{
int ret = KSFT_FAIL;
char *cgroup = NULL;
int i;
cgroup = cg_name(root, "cg_test_simple");
if (!cgroup)
goto cleanup;
if (cg_create(cgroup))
goto cleanup;
for (i = 0; i < 100; i++)
cg_run_nowait(cgroup, child_fn, NULL);
if (cg_wait_for_proc_count(cgroup, 100))
goto cleanup;
if (cg_check_frozen(cgroup, false))
goto cleanup;
if (cg_freeze_wait(cgroup, true))
goto cleanup;
if (cg_freeze_wait(cgroup, false))
goto cleanup;
ret = KSFT_PASS;
cleanup:
if (cgroup)
cg_destroy(cgroup);
free(cgroup);
return ret;
}
/*
* The test creates the following hierarchy:
* A
* / / \ \
* B E I K
* /\ |
* C D F
* |
* G
* |
* H
*
* with a process in C, H and 3 processes in K.
* Then it tries to freeze and unfreeze the whole tree.
*/
static int test_cgfreezer_tree(const char *root)
{
char *cgroup[10] = {0};
int ret = KSFT_FAIL;
int i;
cgroup[0] = cg_name(root, "cg_test_tree_A");
if (!cgroup[0])
goto cleanup;
cgroup[1] = cg_name(cgroup[0], "B");
if (!cgroup[1])
goto cleanup;
cgroup[2] = cg_name(cgroup[1], "C");
if (!cgroup[2])
goto cleanup;
cgroup[3] = cg_name(cgroup[1], "D");
if (!cgroup[3])
goto cleanup;
cgroup[4] = cg_name(cgroup[0], "E");
if (!cgroup[4])
goto cleanup;
cgroup[5] = cg_name(cgroup[4], "F");
if (!cgroup[5])
goto cleanup;
cgroup[6] = cg_name(cgroup[5], "G");
if (!cgroup[6])
goto cleanup;
cgroup[7] = cg_name(cgroup[6], "H");
if (!cgroup[7])
goto cleanup;
cgroup[8] = cg_name(cgroup[0], "I");
if (!cgroup[8])
goto cleanup;
cgroup[9] = cg_name(cgroup[0], "K");
if (!cgroup[9])
goto cleanup;
for (i = 0; i < 10; i++)
if (cg_create(cgroup[i]))
goto cleanup;
cg_run_nowait(cgroup[2], child_fn, NULL);
cg_run_nowait(cgroup[7], child_fn, NULL);
cg_run_nowait(cgroup[9], child_fn, NULL);
cg_run_nowait(cgroup[9], child_fn, NULL);
cg_run_nowait(cgroup[9], child_fn, NULL);
/*
* Wait until all child processes will enter
* corresponding cgroups.
*/
if (cg_wait_for_proc_count(cgroup[2], 1) ||
cg_wait_for_proc_count(cgroup[7], 1) ||
cg_wait_for_proc_count(cgroup[9], 3))
goto cleanup;
/*
* Freeze B.
*/
if (cg_freeze_wait(cgroup[1], true))
goto cleanup;
/*
* Freeze F.
*/
if (cg_freeze_wait(cgroup[5], true))
goto cleanup;
/*
* Freeze G.
*/
if (cg_freeze_wait(cgroup[6], true))
goto cleanup;
/*
* Check that A and E are not frozen.
*/
if (cg_check_frozen(cgroup[0], false))
goto cleanup;
if (cg_check_frozen(cgroup[4], false))
goto cleanup;
/*
* Freeze A. Check that A, B and E are frozen.
*/
if (cg_freeze_wait(cgroup[0], true))
goto cleanup;
if (cg_check_frozen(cgroup[1], true))
goto cleanup;
if (cg_check_frozen(cgroup[4], true))
goto cleanup;
/*
* Unfreeze B, F and G
*/
if (cg_freeze_nowait(cgroup[1], false))
goto cleanup;
if (cg_freeze_nowait(cgroup[5], false))
goto cleanup;
if (cg_freeze_nowait(cgroup[6], false))
goto cleanup;
/*
* Check that C and H are still frozen.
*/
if (cg_check_frozen(cgroup[2], true))
goto cleanup;
if (cg_check_frozen(cgroup[7], true))
goto cleanup;
/*
* Unfreeze A. Check that A, C and K are not frozen.
*/
if (cg_freeze_wait(cgroup[0], false))
goto cleanup;
if (cg_check_frozen(cgroup[2], false))
goto cleanup;
if (cg_check_frozen(cgroup[9], false))
goto cleanup;
ret = KSFT_PASS;
cleanup:
for (i = 9; i >= 0 && cgroup[i]; i--) {
cg_destroy(cgroup[i]);
free(cgroup[i]);
}
return ret;
}
/*
* A fork bomb emulator.
*/
static int forkbomb_fn(const char *cgroup, void *arg)
{
int ppid;
fork();
fork();
ppid = getppid();
while (getppid() == ppid)
usleep(1000);
return getppid() == ppid;
}
/*
* The test runs a fork bomb in a cgroup and tries to freeze it.
* Then it kills all processes and checks that cgroup isn't populated
* anymore.
*/
static int test_cgfreezer_forkbomb(const char *root)
{
int ret = KSFT_FAIL;
char *cgroup = NULL;
cgroup = cg_name(root, "cg_forkbomb_test");
if (!cgroup)
goto cleanup;
if (cg_create(cgroup))
goto cleanup;
cg_run_nowait(cgroup, forkbomb_fn, NULL);
usleep(100000);
if (cg_freeze_wait(cgroup, true))
goto cleanup;
if (cg_killall(cgroup))
goto cleanup;
if (cg_wait_for_proc_count(cgroup, 0))
goto cleanup;
ret = KSFT_PASS;
cleanup:
if (cgroup)
cg_destroy(cgroup);
free(cgroup);
return ret;
}
/*
* The test creates a cgroups and freezes it. Then it creates a child cgroup
* and populates it with a task. After that it checks that the child cgroup
* is frozen and the parent cgroup remains frozen too.
*/
static int test_cgfreezer_mkdir(const char *root)
{
int ret = KSFT_FAIL;
char *parent, *child = NULL;
int pid;
parent = cg_name(root, "cg_test_mkdir_A");
if (!parent)
goto cleanup;
child = cg_name(parent, "cg_test_mkdir_B");
if (!child)
goto cleanup;
if (cg_create(parent))
goto cleanup;
if (cg_freeze_wait(parent, true))
goto cleanup;
if (cg_create(child))
goto cleanup;
pid = cg_run_nowait(child, child_fn, NULL);
if (pid < 0)
goto cleanup;
if (cg_wait_for_proc_count(child, 1))
goto cleanup;
if (cg_check_frozen(child, true))
goto cleanup;
if (cg_check_frozen(parent, true))
goto cleanup;
ret = KSFT_PASS;
cleanup:
if (child)
cg_destroy(child);
free(child);
if (parent)
cg_destroy(parent);
free(parent);
return ret;
}
/*
* The test creates two nested cgroups, freezes the parent
* and removes the child. Then it checks that the parent cgroup
* remains frozen and it's possible to create a new child
* without unfreezing. The new child is frozen too.
*/
static int test_cgfreezer_rmdir(const char *root)
{
int ret = KSFT_FAIL;
char *parent, *child = NULL;
parent = cg_name(root, "cg_test_rmdir_A");
if (!parent)
goto cleanup;
child = cg_name(parent, "cg_test_rmdir_B");
if (!child)
goto cleanup;
if (cg_create(parent))
goto cleanup;
if (cg_create(child))
goto cleanup;
if (cg_freeze_wait(parent, true))
goto cleanup;
if (cg_destroy(child))
goto cleanup;
if (cg_check_frozen(parent, true))
goto cleanup;
if (cg_create(child))
goto cleanup;
if (cg_check_frozen(child, true))
goto cleanup;
ret = KSFT_PASS;
cleanup:
if (child)
cg_destroy(child);
free(child);
if (parent)
cg_destroy(parent);
free(parent);
return ret;
}
/*
* The test creates two cgroups: A and B, runs a process in A
* and performs several migrations:
* 1) A (running) -> B (frozen)
* 2) B (frozen) -> A (running)
* 3) A (frozen) -> B (frozen)
*
* On each step it checks the actual state of both cgroups.
*/
static int test_cgfreezer_migrate(const char *root)
{
int ret = KSFT_FAIL;
char *cgroup[2] = {0};
int pid;
cgroup[0] = cg_name(root, "cg_test_migrate_A");
if (!cgroup[0])
goto cleanup;
cgroup[1] = cg_name(root, "cg_test_migrate_B");
if (!cgroup[1])
goto cleanup;
if (cg_create(cgroup[0]))
goto cleanup;
if (cg_create(cgroup[1]))
goto cleanup;
pid = cg_run_nowait(cgroup[0], child_fn, NULL);
if (pid < 0)
goto cleanup;
if (cg_wait_for_proc_count(cgroup[0], 1))
goto cleanup;
/*
* Migrate from A (running) to B (frozen)
*/
if (cg_freeze_wait(cgroup[1], true))
goto cleanup;
if (cg_enter_and_wait_for_frozen(cgroup[1], pid, true))
goto cleanup;
if (cg_check_frozen(cgroup[0], false))
goto cleanup;
/*
* Migrate from B (frozen) to A (running)
*/
if (cg_enter_and_wait_for_frozen(cgroup[0], pid, false))
goto cleanup;
if (cg_check_frozen(cgroup[1], true))
goto cleanup;
/*
* Migrate from A (frozen) to B (frozen)
*/
if (cg_freeze_wait(cgroup[0], true))
goto cleanup;
if (cg_enter_and_wait_for_frozen(cgroup[1], pid, true))
goto cleanup;
if (cg_check_frozen(cgroup[0], true))
goto cleanup;
ret = KSFT_PASS;
cleanup:
if (cgroup[0])
cg_destroy(cgroup[0]);
free(cgroup[0]);
if (cgroup[1])
cg_destroy(cgroup[1]);
free(cgroup[1]);
return ret;
}
/*
* The test checks that ptrace works with a tracing process in a frozen cgroup.
*/
static int test_cgfreezer_ptrace(const char *root)
{
int ret = KSFT_FAIL;
char *cgroup = NULL;
siginfo_t siginfo;
int pid;
cgroup = cg_name(root, "cg_test_ptrace");
if (!cgroup)
goto cleanup;
if (cg_create(cgroup))
goto cleanup;
pid = cg_run_nowait(cgroup, child_fn, NULL);
if (pid < 0)
goto cleanup;
if (cg_wait_for_proc_count(cgroup, 1))
goto cleanup;
if (cg_freeze_wait(cgroup, true))
goto cleanup;
if (ptrace(PTRACE_SEIZE, pid, NULL, NULL))
goto cleanup;
if (ptrace(PTRACE_INTERRUPT, pid, NULL, NULL))
goto cleanup;
waitpid(pid, NULL, 0);
/*
* Cgroup has to remain frozen, however the test task
* is in traced state.
*/
if (cg_check_frozen(cgroup, true))
goto cleanup;
if (ptrace(PTRACE_GETSIGINFO, pid, NULL, &siginfo))
goto cleanup;
if (ptrace(PTRACE_DETACH, pid, NULL, NULL))
goto cleanup;
if (cg_check_frozen(cgroup, true))
goto cleanup;
ret = KSFT_PASS;
cleanup:
if (cgroup)
cg_destroy(cgroup);
free(cgroup);
return ret;
}
/*
* Check if the process is stopped.
*/
static int proc_check_stopped(int pid)
{
char buf[PAGE_SIZE];
int len;
len = proc_read_text(pid, "stat", buf, sizeof(buf));
if (len == -1) {
debug("Can't get %d stat\n", pid);
return -1;
}
if (strstr(buf, "(test_freezer) T ") == NULL) {
debug("Process %d in the unexpected state: %s\n", pid, buf);
return -1;
}
return 0;
}
/*
* Test that it's possible to freeze a cgroup with a stopped process.
*/
static int test_cgfreezer_stopped(const char *root)
{
int pid, ret = KSFT_FAIL;
char *cgroup = NULL;
cgroup = cg_name(root, "cg_test_stopped");
if (!cgroup)
goto cleanup;
if (cg_create(cgroup))
goto cleanup;
pid = cg_run_nowait(cgroup, child_fn, NULL);
if (cg_wait_for_proc_count(cgroup, 1))
goto cleanup;
if (kill(pid, SIGSTOP))
goto cleanup;
if (cg_check_frozen(cgroup, false))
goto cleanup;
if (cg_freeze_wait(cgroup, true))
goto cleanup;
if (cg_freeze_wait(cgroup, false))
goto cleanup;
if (proc_check_stopped(pid))
goto cleanup;
ret = KSFT_PASS;
cleanup:
if (cgroup)
cg_destroy(cgroup);
free(cgroup);
return ret;
}
/*
* Test that it's possible to freeze a cgroup with a ptraced process.
*/
static int test_cgfreezer_ptraced(const char *root)
{
int pid, ret = KSFT_FAIL;
char *cgroup = NULL;
siginfo_t siginfo;
cgroup = cg_name(root, "cg_test_ptraced");
if (!cgroup)
goto cleanup;
if (cg_create(cgroup))
goto cleanup;
pid = cg_run_nowait(cgroup, child_fn, NULL);
if (cg_wait_for_proc_count(cgroup, 1))
goto cleanup;
if (ptrace(PTRACE_SEIZE, pid, NULL, NULL))
goto cleanup;
if (ptrace(PTRACE_INTERRUPT, pid, NULL, NULL))
goto cleanup;
waitpid(pid, NULL, 0);
if (cg_check_frozen(cgroup, false))
goto cleanup;
if (cg_freeze_wait(cgroup, true))
goto cleanup;
/*
* cg_check_frozen(cgroup, true) will fail here,
* because the task in in the TRACEd state.
*/
if (cg_freeze_wait(cgroup, false))
goto cleanup;
if (ptrace(PTRACE_GETSIGINFO, pid, NULL, &siginfo))
goto cleanup;
if (ptrace(PTRACE_DETACH, pid, NULL, NULL))
goto cleanup;
ret = KSFT_PASS;
cleanup:
if (cgroup)
cg_destroy(cgroup);
free(cgroup);
return ret;
}
static int vfork_fn(const char *cgroup, void *arg)
{
int pid = vfork();
if (pid == 0)
while (true)
sleep(1);
return pid;
}
/*
* Test that it's possible to freeze a cgroup with a process,
* which called vfork() and is waiting for a child.
*/
static int test_cgfreezer_vfork(const char *root)
{
int ret = KSFT_FAIL;
char *cgroup = NULL;
cgroup = cg_name(root, "cg_test_vfork");
if (!cgroup)
goto cleanup;
if (cg_create(cgroup))
goto cleanup;
cg_run_nowait(cgroup, vfork_fn, NULL);
if (cg_wait_for_proc_count(cgroup, 2))
goto cleanup;
if (cg_freeze_wait(cgroup, true))
goto cleanup;
ret = KSFT_PASS;
cleanup:
if (cgroup)
cg_destroy(cgroup);
free(cgroup);
return ret;
}
#define T(x) { x, #x }
struct cgfreezer_test {
int (*fn)(const char *root);
const char *name;
} tests[] = {
T(test_cgfreezer_simple),
T(test_cgfreezer_tree),
T(test_cgfreezer_forkbomb),
T(test_cgfreezer_mkdir),
T(test_cgfreezer_rmdir),
T(test_cgfreezer_migrate),
T(test_cgfreezer_ptrace),
T(test_cgfreezer_stopped),
T(test_cgfreezer_ptraced),
T(test_cgfreezer_vfork),
};
#undef T
int main(int argc, char *argv[])
{
char root[PATH_MAX];
int i, ret = EXIT_SUCCESS;
if (cg_find_unified_root(root, sizeof(root)))
ksft_exit_skip("cgroup v2 isn't mounted\n");
for (i = 0; i < ARRAY_SIZE(tests); i++) {
switch (tests[i].fn(root)) {
case KSFT_PASS:
ksft_test_result_pass("%s\n", tests[i].name);
break;
case KSFT_SKIP:
ksft_test_result_skip("%s\n", tests[i].name);
break;
default:
ret = EXIT_FAILURE;
ksft_test_result_fail("%s\n", tests[i].name);
break;
}
}
return ret;
}
