[CRIU] [PATCH] zdtm: Add pidns02 test

[Kirill Tkhai]

1)Create a pid namespace and child reaper in it;
2)Set a specific next pid for future created process;
3)Create one more process in the namespace and kill it;
4)Wait for signal
5)Check, that NSpids of dead task remains the same.

(Note, that currently we do not sort children to have
a specific order of their creation, and child reaper
is the second in the children list, so the test fails.
If you want to try it, replace restore_before_setsid()
in create_children_and_session() on
last_level_pid(child->pid) == 1 to have a order).

Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
---
 test/zdtm/static/Makefile     |    1 
 test/zdtm/static/pidns02.c    |  179 +++++++++++++++++++++++++++++++++++++++++
 test/zdtm/static/pidns02.desc |    1 
 3 files changed, 181 insertions(+)
 create mode 100644 test/zdtm/static/pidns02.c
 create mode 100644 test/zdtm/static/pidns02.desc

diff --git a/test/zdtm/static/Makefile b/test/zdtm/static/Makefile
index 1ea9393ce..178e564d7 100644
--- a/test/zdtm/static/Makefile
+++ b/test/zdtm/static/Makefile
@@ -178,6 +178,7 @@ TST_NOFILE	:=				\
 		netns_sub_veth			\
 		pidns00				\
 		pidns01				\
+		pidns02				\
 #		jobctl00			\
 
 ifneq ($(SRCARCH),arm)
diff --git a/test/zdtm/static/pidns02.c b/test/zdtm/static/pidns02.c
new file mode 100644
index 000000000..50277122d
--- /dev/null
+++ b/test/zdtm/static/pidns02.c
@@ -0,0 +1,179 @@
+#include <stdbool.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <signal.h>
+#include <stdio.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sched.h>
+#include <sys/wait.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <dirent.h>
+
+#include "zdtmtst.h"
+#include "lock.h"
+
+const char *test_doc	= "Check NSpids of dead tasks restore right";
+const char *test_author	= "Kirill Tkhai <ktkhai at virtuozzo.com>";
+
+enum {
+	FUTEX_INITIALIZED = 0,
+	CHILD_PREPARED,
+	EMERGENCY_ABORT,
+};
+
+futex_t *futex;
+
+#define CHILD_NS_PID 11235
+#define PARENT_NS_PID 31415
+
+static int set_ns_next_pid(pid_t pid)
+{
+	char buf[32];
+	int len, fd;
+
+	fd = open("/proc/sys/kernel/ns_last_pid", O_WRONLY);
+	if (fd < 0)
+		return -1;
+
+	len = snprintf(buf, sizeof(buf), "%d", pid - 1);
+	len -= write(fd, buf, len);
+	if (len)
+		pr_perror("Can't set ns_last_pid");
+	close(fd);
+
+	return len ? -1 : 0;
+}
+
+static int sleep_loop(void)
+{
+	while (1)
+		sleep(60);
+	return 0;
+}
+
+static int child(void)
+{
+	if (set_ns_next_pid(CHILD_NS_PID)) {
+		futex_set_and_wake(futex, EMERGENCY_ABORT);
+		exit(1);
+	}
+
+	futex_set_and_wake(futex, CHILD_PREPARED);
+	return sleep_loop();
+}
+
+static int get_ns_pid(pid_t pid, char **str)
+{
+	char buf[64];
+	FILE *fp;
+	size_t n;
+
+	snprintf(buf, sizeof(buf), "/proc/%d/status", pid);
+	fp = fopen(buf, "r");
+	if (!fp) {
+		pr_perror("Can't open %s", buf);
+		return -1;
+	}
+
+	*str = NULL;
+	while (getline(str, &n, fp) != -1) {
+		if (strncmp(*str, "NSpid:", 6) == 0) {
+			fclose(fp);
+			return 0;
+		}
+	}
+
+	pr_err("NSpid has not found\n");
+	fclose(fp);
+	return -1;
+}
+/*
+ * 1)Create a pid namespace and child reaper in it;
+ * 2)Set a specific next pid for future created process;
+ * 3)Create one more process in the namespace and kill it;
+ * 4)Wait for signal
+ * 5)Check, that NSpids of dead task remains the same.
+ */
+int main(int argc, char **argv)
+{
+	int i, status, ret = -1;
+	pid_t pid[] = {-1, -1};
+	char *ns_pid, *tmp;
+
+	test_init(argc, argv);
+	futex = mmap(NULL, sizeof(*futex), PROT_WRITE | PROT_READ, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+	if (futex == MAP_FAILED) {
+		fail("mmap futex\n");
+		return 1;
+	}
+	futex_init(futex);
+
+	if (unshare(CLONE_NEWPID) < 0) {
+		fail("Can't unshare");
+		return 1;
+	}
+
+	/* Create child 1, child reaper of the new namespace */
+	pid[0] = fork();
+	if (pid[0] < 0) {
+		fail("Can't fork");
+		return 1;
+	} else if (pid[0] == 0)
+		exit(child());
+
+	futex_wait_while_lt(futex, CHILD_PREPARED);
+	if (futex_get(futex) == EMERGENCY_ABORT) {
+		pr_err("Fail during prepare of child 1\n");
+		goto out;
+	}
+
+	if (set_ns_next_pid(PARENT_NS_PID)) {
+		pr_err("Fail during next pid write\n");
+		goto out;
+	}
+
+	/* Child 2 is in the same namespace as child 1 */
+	pid[1] = fork();
+	if (pid[1] < 0) {
+		pr_perror("Can't fork");
+		goto out;
+	} else if (pid[1] == 0)
+		exit(sleep_loop());
+
+	if (get_ns_pid(pid[1], &ns_pid) < 0) {
+		pr_perror("Can't get ns_pid");
+		goto out;
+	}
+
+	if (kill(pid[1], SIGKILL))
+		pr_perror("Can't kill");
+
+	test_daemon();
+	test_waitsig();
+
+	if (get_ns_pid(pid[1], &tmp) < 0) {
+		pr_perror("Can't fork");
+		goto out;
+	}
+
+	if (strcmp(ns_pid, tmp)) {
+		pr_err("NSpid mismatch: %s %s\n", ns_pid, tmp);
+		goto out;
+	}
+
+	ret = 0;
+out:
+	/* Wait child reaper last as it waits namespace processes itself */
+	for (i = 1; i >= 0; i--) {
+		kill(pid[i], SIGKILL);
+		waitpid(pid[i], &status, 0);
+	}
+	if (ret)
+		fail("Test failed");
+	else
+		pass();
+	return ret;
+}
diff --git a/test/zdtm/static/pidns02.desc b/test/zdtm/static/pidns02.desc
new file mode 100644
index 000000000..d20a6722c
--- /dev/null
+++ b/test/zdtm/static/pidns02.desc
@@ -0,0 +1 @@
+{'flavor': 'uns', 'flags': 'suid noauto', 'feature': 'ns_pid'}