zdtm: add a new test case, which generate a random process tree

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

test/zdtm/live/static/Makefile

@@ -85,6 +85,7 @@ TST_NOFILE	=				\
 		netns				\
 		session01			\
 		session02			\
+		session03			\
 		socket-ext			\
 		unhashed_proc			\
 		cow00				\

test/zdtm/live/static/session03.c

+#define _GNU_SOURCE
+#include <sys/mman.h>
+#include <sched.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <sys/prctl.h>
+#include <sys/user.h>
+
+#include "zdtmtst.h"
+
+const char *test_doc	= "Create a crazy process tree";
+const char *test_author	= "Andrew Vagin <avagin@parallels.com>";
+
+struct process
+{
+	pid_t pid;
+	pid_t sid;
+	int sks[2];
+	int dead;
+	int wait;
+};
+
+#define MEM_SIZE (2 * PAGE_SIZE)
+#define PR_MAX (MEM_SIZE / sizeof(struct process))
+
+struct process *processes;
+int nr_processes = 0;
+int current = 0;
+
+static void sigchld_handler(int signal, siginfo_t *siginfo, void *data)
+{
+	pid_t pid = siginfo->si_pid;
+	if (siginfo->si_status == 2)
+		waitpid(pid, NULL, WNOHANG);
+}
+
+static void cleanup()
+{
+	int i, ret;
+
+	for (i = 0; i < nr_processes; i++) {
+		if (processes[i].dead)
+			continue;
+		if (processes[i].pid <= 0)
+			continue;
+
+		kill(processes[i].pid, SIGKILL);
+	}
+
+	while (1) {
+		ret = wait(NULL);
+		if (ret == -1) {
+			if (errno == ECHILD)
+				break;
+			err("wait");
+			exit(1);
+		}
+	}
+}
+
+enum commands
+{
+	TEST_FORK,
+	TEST_DIE_WAIT,
+	TEST_DIE,
+	TEST_SUBREAPER,
+	TEST_SETSID,
+	TEST_MAX
+};
+
+int cmd_weght[TEST_MAX] = {10, 3, 1, 10, 7};
+int sum_weight = 0;
+static int get_rnd_op()
+{
+	int i, m;
+	if (sum_weight == 0) {
+		for (i = 0; i < TEST_MAX; i++)
+			sum_weight += cmd_weght[i];
+	}
+	m = lrand48() % sum_weight;
+	for (i = 0; i < TEST_MAX; i++) {
+		if (m > cmd_weght[i]) {
+			m -= cmd_weght[i];
+			continue;
+		}
+		return i;
+	}
+	return -1;
+}
+
+struct command
+{
+	enum commands	cmd;
+	int		arg1;
+	int		arg2;
+};
+
+static void handle_command();
+
+static void mainloop()
+{
+	while (1)
+		handle_command();
+}
+
+#define CLONE_STACK_SIZE	PAGE_SIZE
+/* All arguments should be above stack, because it grows down */
+struct clone_args {
+	char stack[CLONE_STACK_SIZE];
+	char stack_ptr[0];
+	int id;
+};
+
+static int clone_func(void *_arg)
+{
+	struct clone_args *args = (struct clone_args *) _arg;
+
+	current = args->id;
+
+	test_msg("%3d: Hello. My pid is %d\n", args->id, getpid());
+	mainloop();
+	exit(0);
+}
+
+static int make_child(int id, int flags)
+{
+	struct clone_args args;
+	pid_t cid;
+
+	args.id = id;
+
+	cid = clone(clone_func, args.stack_ptr,
+			flags | SIGCHLD, &args);
+
+	if (cid < 0)
+		err("clone(%d, %d)", id, flags);
+
+	processes[id].pid = cid;
+
+	return cid;
+}
+
+static void handle_command()
+{
+	int sk = processes[current].sks[0], ret, status = 0;
+	struct command cmd;
+
+	ret = read(sk, &cmd, sizeof(cmd));
+	if (ret != sizeof(cmd)) {
+		err("Unable to get command");
+		goto err;
+	}
+
+	switch (cmd.cmd) {
+	case TEST_FORK:
+		{
+			pid_t pid;
+
+			pid = make_child(cmd.arg1, cmd.arg2 ? CLONE_PARENT : 0);
+			if (pid < 0) {
+				status = -1;
+				goto err;
+			}
+
+			test_msg("%3d: fork(%d, %x) = %d\n",
+					current, cmd.arg1, cmd.arg2, pid);
+			processes[cmd.arg1].pid = pid;
+		}
+		break;
+	case TEST_SUBREAPER:
+		test_msg("%3d: subreaper(%d)\n", current, cmd.arg1);
+		if (prctl(PR_SET_CHILD_SUBREAPER, cmd.arg1, 0, 0, 0) == -1) {
+			err("PR_SET_CHILD_SUBREAPER");
+			status = -1;
+		}
+		break;
+	case TEST_SETSID:
+		if (getsid(getpid()) == getpid())
+			break;
+		test_msg("%3d: setsid()\n", current);
+		if(setsid() == -1) {
+			err("setsid");
+			status = -1;
+		}
+		break;
+	case TEST_DIE_WAIT:
+		test_msg("%3d: wait()\n", current);
+	case TEST_DIE:
+		test_msg("%3d: die()\n", current);
+		processes[current].dead = 1;
+		shutdown(sk, SHUT_RDWR);
+		if (cmd.cmd == TEST_DIE_WAIT)
+			exit(2);
+		exit(0);
+	default:
+		err("Unknown operation %d", cmd.cmd);
+		status = -1;
+		break;
+	}
+
+	ret = write(sk, &status, sizeof(status));
+	if (ret != sizeof(status)) {
+		err("Unable to answer");
+		goto err;
+	}
+
+	if (status < 0)
+		goto err;
+
+	return;
+err:
+	shutdown(sk, SHUT_RDWR);
+	exit(1);
+}
+
+static int send_command(int id, enum commands op, int arg)
+{
+	int sk = processes[id].sks[1], ret, status;
+	struct command cmd = {op, arg};
+
+	if (op == TEST_FORK) {
+		cmd.arg1 = nr_processes;
+		nr_processes++;
+		if (nr_processes > PR_MAX)
+			return -1;
+		cmd.arg2 = arg;
+	}
+
+	ret = write(sk, &cmd, sizeof(cmd));
+	if (ret != sizeof(cmd)) {
+		err("Unable to send command");
+		goto err;
+	}
+
+	status = 0;
+	ret = read(sk, &status, sizeof(status));
+	if (ret != sizeof(status) &&
+	    !(status == 0 && (op == TEST_DIE || op == TEST_DIE_WAIT))) {
+		err("Unable to get answer");
+		goto err;
+	}
+
+	if (status) {
+		err("The command(%d, %d, %d) failed");
+		goto err;
+	}
+
+	return 0;
+err:
+	cleanup();
+	exit(1);
+}
+
+int main(int argc, char ** argv)
+{
+	struct sigaction act;
+	int pid, i, ret;
+	int fail_cnt = 0;
+
+	test_init(argc, argv);
+
+	if (prctl(PR_SET_CHILD_SUBREAPER, 1, 0, 0, 0) == -1) {
+		err("PR_SET_CHILD_SUBREAPER");
+		return -1;
+	}
+
+	ret = sigaction(SIGCHLD, NULL, &act);
+	if (ret < 0) {
+		err("sigaction() failed\n");
+		return -1;
+	}
+
+	act.sa_flags |= SA_NOCLDSTOP | SA_SIGINFO | SA_RESTART;
+	act.sa_sigaction = sigchld_handler;
+	sigemptyset(&act.sa_mask);
+	sigaddset(&act.sa_mask, SIGCHLD);
+
+	ret = sigaction(SIGCHLD, &act, NULL);
+	if (ret < 0) {
+		err("sigaction() failed\n");
+		return -1;
+	}
+
+	processes = mmap(NULL, MEM_SIZE, PROT_WRITE | PROT_READ,
+				MAP_SHARED | MAP_ANONYMOUS, 0, 0);
+	if (processes == NULL) {
+		err("Unable to map share memory");
+		return 1;
+	}
+
+	for (i = 0; i < PR_MAX; i++) {
+		if (socketpair(PF_UNIX, SOCK_STREAM, 0, processes[i].sks) == -1) {
+			err("socketpair");
+			return 1;
+		}
+	}
+
+	nr_processes++;
+	pid = make_child(0, 0);
+	if (pid < 0)
+		return -1;
+
+	while(nr_processes < PR_MAX) {
+		int op, id;
+		int flags = lrand48() % 2;
+
+		op = get_rnd_op();
+		if (op == TEST_DIE || op == TEST_DIE_WAIT || op == TEST_SUBREAPER) {
+			if (nr_processes == 1)
+				continue;
+			else
+				id = lrand48() % (nr_processes - 1) + 1;
+		} else if (op == TEST_FORK) {
+			id = nr_processes * 9 / 10 + lrand48() % nr_processes / 10;
+			while (processes[id].dead != 0)
+				id--;
+		} else
+			id = lrand48() % nr_processes;
+
+		if (processes[id].dead)
+			continue;
+
+		send_command(id, op, flags);
+	}
+
+	for (i = 0; i < nr_processes; i++) {
+		if (processes[i].dead)
+			continue;
+		if (processes[i].pid == 0)
+			continue;
+
+		processes[i].sid = getsid(processes[i].pid);
+		if (processes[i].sid == -1) {
+			err("getsid(%d)", i);
+			goto err;
+		}
+	}
+
+	test_daemon();
+
+	test_waitsig();
+
+	for (i = 0; i < nr_processes; i++) {
+		pid_t sid;
+
+		if (processes[i].dead)
+			continue;
+		if (processes[i].pid == 0)
+			continue;
+
+		sid = getsid(processes[i].pid);
+		if (sid == -1) {
+			err("getsid(%d)", i);
+			goto err;
+		}
+
+		if (sid != processes[i].sid) {
+			fail("%d, %d: wrong sid %d (expected %d)",
+				i, processes[i].pid, sid, processes[i].sid);
+			fail_cnt++;
+		}
+	}
+
+	if (fail_cnt)
+		goto err;
+
+	pass();
+
+	cleanup();
+	return 0;
+err:
+	cleanup();
+	return 1;
+}