[CRIU] [PATCH RFC 09/30] files: Allow to receive further fds

[Kirill Tkhai]

Allow to be received more sockets, than expected,
by this transport socket.

This will be used in next patch.

Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
---
 criu/files.c         |   37 +++++++++++++++++++++++++++++++++++--
 criu/include/files.h |    2 ++
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/criu/files.c b/criu/files.c
index a7c5bbe..8ecc253 100644
--- a/criu/files.c
+++ b/criu/files.c
@@ -956,20 +956,51 @@ static int open_transport_fd(int pid, struct fdinfo_list_entry *fle)
 	return -1;
 }
 
+static bool insane_fle(struct fdinfo_list_entry *alien_fle)
+{
+	struct fdinfo_list_entry *fle;
+
+	list_for_each_entry(fle, &rsti(current)->used, used_list)
+		if (alien_fle == fle)
+			return false;
+	pr_err("Insane fle=%p, pid=%d\n", alien_fle, current->pid.virt);
+	return true;
+}
+
+static int recv_further_fle(struct fdinfo_list_entry *fle, int fd)
+{
+	BUG_ON(fle->received);
+	fle->received = 1;
+	if (close(fle->fe->fd) < 0) {
+		pr_perror("Can't close transport fd\n");
+		return -1;
+	}
+	return reopen_fd_as(fle->fe->fd, fd);
+}
+
 int recv_fd_from_peer(struct fdinfo_list_entry *fle)
 {
 	struct fdinfo_list_entry *tmp;
 	int fd, ret;
 
+	if (fle->received)
+		return fle->fe->fd;
+again:
 	ret = recv_fds(fle->fe->fd, &fd, 1, NULL, (unsigned long *)&tmp);
 	if (ret)
 		return -1;
 
 	if (tmp != fle) {
-		pr_err("Received wrong fle\n");
-		return -1;
+		pr_info("Further fle=%p, pid=%d\n", tmp, fle->pid);
+		if (insane_fle(fle))
+			return -1;
+		if (recv_further_fle(tmp, fd))
+			return -1;
+		goto again;
 	}
 	close(fle->fe->fd);
+	BUG_ON(fle->received);
+	fle->received = 1;
 
 	return fd;
 }
@@ -1014,6 +1045,8 @@ static int send_fd_to_self(int fd, struct fdinfo_list_entry *fle)
 		return -1;
 	}
 
+	fle->received = 1;
+
 	return 0;
 }
 
diff --git a/criu/include/files.h b/criu/include/files.h
index 26d971e..631895c 100644
--- a/criu/include/files.h
+++ b/criu/include/files.h
@@ -72,12 +72,14 @@ struct fdinfo_list_entry {
 	int			pid;
 	futex_t			real_pid;
 	FdinfoEntry		*fe;
+	u8			received:1;
 };
 
 static inline void fle_init(struct fdinfo_list_entry *fle, int pid, FdinfoEntry *fe)
 {
 	fle->pid = pid;
 	fle->fe = fe;
+	fle->received = 0;
 }
 
 /* reports whether fd_a takes prio over fd_b */