[CRIU] [PATCH 09/10] epoll: Ignore inaccessible targets

[Cyrill Gorcunov]

Not all targets can be restored by now,
so simply ignore them on dump this should
not be a common case.

Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
---
 criu/eventpoll.c      | 57 +++++++++++++++++++++++++++++++++++++++++----------
 criu/include/fdinfo.h |  1 +
 criu/proc_parse.c     |  1 +
 3 files changed, 48 insertions(+), 11 deletions(-)

diff --git a/criu/eventpoll.c b/criu/eventpoll.c
index 0515b736603a..670cb06f95bd 100644
--- a/criu/eventpoll.c
+++ b/criu/eventpoll.c
@@ -151,6 +151,7 @@ int dump_eventpoll(void)
 	struct kid_elem *kid;
 
 	list_for_each_entry(dinfo, &eventpoll_fds, list) {
+		unsigned long nr_valid = 0;
 		kcmp_epoll_slot_t slot = {
 			.efd	= dinfo->fd,
 			.toff	= 0,
@@ -167,22 +168,56 @@ int dump_eventpoll(void)
 				kid = fd_kid_epoll_lookup(dinfo->pid,
 							  te->epl.gen_id,
 							  &slot);
-				if (!kid || kid->pid != dinfo->pid) {
-					pr_err("Target %d not found for pid %d "
-					       "(or pid mismatsh %d)\n",
-					       te->epl.e.tfd, dinfo->pid,
-					       kid ? kid->pid : -1);
-					goto out;
+				if (!kid || kid->pid != dinfo->pid ||
+				    kid->idx != te->epl.e.tfd) {
+					pr_warn("Target %d not found for pid %d "
+						"(or pid mismatsh %d), ignoring\n",
+						te->epl.e.tfd, dinfo->pid,
+						kid ? kid->pid : -1);
+					te->epl.valid = 0;
+				} else {
+					pr_debug("Target %d for pid %d matched fd %d\n",
+						 te->epl.e.tfd, dinfo->pid, kid->idx);
+					nr_valid++;
+				}
+			} else {
+				char path[PATH_MAX];
+
+				snprintf(path, sizeof(path), "/proc/%d/fd/%d",
+					 dinfo->pid, slot.tfd);
+				if (access(path, F_OK)) {
+					pr_warn("Target %d not found for pid %d, ignoring\n",
+						te->epl.e.tfd, dinfo->pid);
+					te->epl.valid = 0;
+				} else {
+					pr_debug("Target %d for pid %d is accessible\n",
+						 te->epl.e.tfd, dinfo->pid);
+					nr_valid++;
 				}
-
-				pr_debug("Target %d for pid %d matched fd %d\n",
-					 te->epl.e.tfd, dinfo->pid, kid->idx);
 			}
+		}
+
+		if (nr_valid != dinfo->efe.n_tfd) {
+			size_t i = 0;
 
-			if (pb_write_one(img_from_set(glob_imgset, CR_FD_EVENTPOLL_FILE),
-					 &dinfo->efe, PB_EVENTPOLL_FILE))
+			EventpollTfdEntry **tfd = xmalloc(sizeof(struct EventpollTfdEntry *) * nr_valid);
+			if (!tfd)
 				goto out;
+
+			list_for_each_entry(te, &dinfo->ep_list, epl.node) {
+				if (te->epl.valid)
+					tfd[i++] = &te->epl.e;
+			}
+
+			xfree(dinfo->efe.tfd);
+			dinfo->efe.tfd = tfd;
+			dinfo->efe.n_tfd = nr_valid;
 		}
+
+		pr_info_eventpoll("Dumping ", &dinfo->efe);
+		if (pb_write_one(img_from_set(glob_imgset, CR_FD_EVENTPOLL_FILE),
+				 &dinfo->efe, PB_EVENTPOLL_FILE))
+			goto out;
 	}
 
 	ret = 0;
diff --git a/criu/include/fdinfo.h b/criu/include/fdinfo.h
index be516efce5d6..c9af47eeadc5 100644
--- a/criu/include/fdinfo.h
+++ b/criu/include/fdinfo.h
@@ -30,6 +30,7 @@ struct eventpoll_tfd_entry {
 	struct list_head node;
 	unsigned int gen_id;
 	int use_kcmp;
+	int valid;
 };
 
 union fdinfo_entries {
diff --git a/criu/proc_parse.c b/criu/proc_parse.c
index a96123679aa2..f2255d42e6f7 100644
--- a/criu/proc_parse.c
+++ b/criu/proc_parse.c
@@ -1744,6 +1744,7 @@ static int parse_fdinfo_pid_s(int pid, int fd, int type,
 			e = xmalloc(sizeof(union fdinfo_entries));
 			if (!e)
 				goto out;
+			e->epl.valid = 1;
 
 			eventpoll_tfd_entry__init(&e->epl.e);
 
-- 
2.7.4