[CRIU] [PATCH v2 05/11] uffdd: Implement --daemon mode

[Mike Rapoport]

From: Pavel Emelyanov <xemul at virtuozzo.com>

Right now the zdtm.py hacks around core code and waits for
a second for the socket to appear. Let's better make proper
--daemon mode for lazy-pages daemon and pidfile generation.

Signed-off-by: Pavel Emelyanov <xemul at virtuozzo.com>
Acked-by: Mike Rapoport <rppt at linux.vnet.ibm.com>
---
 criu/crtools.c         |  2 +-
 criu/include/crtools.h |  2 +-
 criu/uffd.c            | 47 ++++++++++++++++++++++++++++++++++++++++-------
 test/zdtm.py           | 12 +++---------
 4 files changed, 45 insertions(+), 18 deletions(-)

diff --git a/criu/crtools.c b/criu/crtools.c
index 72718cb..710059f 100644
--- a/criu/crtools.c
+++ b/criu/crtools.c
@@ -751,7 +751,7 @@ int main(int argc, char *argv[], char *envp[])
 	}
 
 	if (!strcmp(argv[optind], "lazy-pages"))
-		return cr_lazy_pages() != 0;
+		return cr_lazy_pages(opts.daemon_mode) != 0;
 
 	if (!strcmp(argv[optind], "check"))
 		return cr_check() != 0;
diff --git a/criu/include/crtools.h b/criu/include/crtools.h
index 0e26716..efd84ae 100644
--- a/criu/include/crtools.h
+++ b/criu/include/crtools.h
@@ -22,7 +22,7 @@ extern int convert_to_elf(char *elf_path, int fd_core);
 extern int cr_check(void);
 extern int cr_exec(int pid, char **opts);
 extern int cr_dedup(void);
-extern int cr_lazy_pages(void);
+extern int cr_lazy_pages(bool daemon);
 
 extern int check_add_feature(char *arg);
 extern void pr_check_features(const char *offset, const char *sep, int width);
diff --git a/criu/uffd.c b/criu/uffd.c
index 1d629a3..85d9025 100644
--- a/criu/uffd.c
+++ b/criu/uffd.c
@@ -15,12 +15,13 @@
 #include <sys/un.h>
 #include <sys/socket.h>
 #include <sys/epoll.h>
+#include <sys/wait.h>
 
 #include "linux/userfaultfd.h"
 
 #include "int.h"
 #include "page.h"
-#include "log.h"
+#include "criu-log.h"
 #include "criu-plugin.h"
 #include "pagemap.h"
 #include "files-reg.h"
@@ -840,12 +841,9 @@ static int epoll_add_fd(int epollfd, int fd)
 	return 0;
 }
 
-static int prepare_uffds(int epollfd)
+static int prepare_lazy_socket(void)
 {
-	int i;
 	int listen;
-	int client;
-	socklen_t len;
 	struct sockaddr_un saddr;
 
 	if (prepare_sock_addr(&saddr))
@@ -857,6 +855,16 @@ static int prepare_uffds(int epollfd)
 		return -1;
 	}
 
+	return listen;
+}
+
+static int prepare_uffds(int listen, int epollfd)
+{
+	int i;
+	int client;
+	socklen_t len;
+	struct sockaddr_un saddr;
+
 	/* accept new client request */
 	len = sizeof(struct sockaddr_un);
 	if ((client = accept(listen, (struct sockaddr *) &saddr, &len)) < 0) {
@@ -887,10 +895,11 @@ close_uffd:
 	return -1;
 }
 
-int cr_lazy_pages()
+int cr_lazy_pages(bool daemon)
 {
 	struct epoll_event *events;
 	int epollfd;
+	int lazy_sk;
 	int ret;
 
 	if (check_for_uffd())
@@ -901,11 +910,35 @@ int cr_lazy_pages()
 	if (lazy_pages_prepare_pstree())
 		return -1;
 
+	lazy_sk = prepare_lazy_socket();
+	if (lazy_sk < 0)
+		return -1;
+
+	if (daemon) {
+		ret = cr_daemon(1, 0, &lazy_sk, -1);
+		if (ret == -1) {
+			pr_err("Can't run in the background\n");
+			return -1;
+		}
+		if (ret > 0) { /* parent task, daemon started */
+			if (opts.pidfile) {
+				if (write_pidfile(ret) == -1) {
+					pr_perror("Can't write pidfile");
+					kill(ret, SIGKILL);
+					waitpid(ret, NULL, 0);
+					return -1;
+				}
+			}
+
+			return 0;
+		}
+	}
+
 	epollfd = prepare_epoll(task_entries->nr_tasks, &events);
 	if (epollfd < 0)
 		return -1;
 
-	if (prepare_uffds(epollfd))
+	if (prepare_uffds(lazy_sk, epollfd))
 		return -1;
 
 	if (connect_to_page_server())
diff --git a/test/zdtm.py b/test/zdtm.py
index 0d8503f..3bd9010 100755
--- a/test/zdtm.py
+++ b/test/zdtm.py
@@ -679,8 +679,6 @@ class criu_cli:
 			print "Forcing %s fault" % fault
 			env = dict(os.environ, CRIU_FAULT = fault)
 		cr = subprocess.Popen(strace + [criu_bin, action] + args, env = env, preexec_fn = preexec)
-		if action == "lazy-pages":
-			return cr
 		return cr.wait()
 
 
@@ -839,8 +837,6 @@ class criu:
 		__ddir = self.__ddir()
 
 		ret = self.__criu.run(action, s_args, self.__fault, strace, preexec)
-		if action == "lazy-pages":
-			return ret
 
 		grep_errors(os.path.join(__ddir, log))
 		if ret != 0:
@@ -927,11 +923,9 @@ class criu:
 			r_opts.append('--external')
 			r_opts.append('mnt[zdtm]:%s' % criu_dir)
 
-		lazy_pages_p = None
 		if self.__lazy_pages:
-			lazy_pages_p = self.__criu_act("lazy-pages", opts = [])
+			self.__criu_act("lazy-pages", opts = ["--daemon", "--pidfile", "lp.pid"])
 			r_opts += ["--lazy-pages"]
-			time.sleep(1)  # FIXME wait user fault fd socket
 
 		if self.__leave_stopped:
 			r_opts += ['--leave-stopped']
@@ -942,8 +936,8 @@ class criu:
 			pstree_check_stopped(self.__test.getpid())
 			pstree_signal(self.__test.getpid(), signal.SIGCONT)
 
-		if lazy_pages_p and lazy_pages_p.wait():
-			raise test_fail_exc("CRIU lazy-pages")
+		if self.__lazy_pages:
+			wait_pid_die(int(rpidfile(self.__ddir() + "/lp.pid")), "lazy pages daemon")
 
 	@staticmethod
 	def check(feature):
-- 
1.9.1