[CRIU] [PATCH v5 02/33] files: Send/receive fds with pointers on their struct fdinfo_list_entry in receiver

[Kirill Tkhai]

For moving to a single transport socket scheme, we need to be able to differ
fds in receive queue from each other. Add a fle pointer as identifier for that.

v2: Rebase on compel
Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
---
 criu/files.c         |   21 +++++++++++++++++++--
 criu/include/files.h |    1 +
 criu/pipes.c         |    2 +-
 criu/sk-unix.c       |    2 +-
 criu/tty.c           |    2 +-
 5 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/criu/files.c b/criu/files.c
index b3714336a..5d681a50d 100644
--- a/criu/files.c
+++ b/criu/files.c
@@ -957,6 +957,23 @@ static int open_transport_fd(int pid, struct fdinfo_list_entry *fle)
 	return -1;
 }
 
+int recv_fd_from_peer(struct fdinfo_list_entry *fle)
+{
+	struct fdinfo_list_entry *tmp;
+	int fd, ret;
+
+	ret = recv_fds(fle->fe->fd, &fd, 1, (void *)&tmp, sizeof(struct fdinfo_list_entry *));
+	if (ret)
+		return -1;
+
+	if (tmp != fle) {
+		pr_err("Received wrong fle\n");
+		return -1;
+	}
+
+	return fd;
+}
+
 int send_fd_to_peer(int fd, struct fdinfo_list_entry *fle, int sock)
 {
 	struct sockaddr_un saddr;
@@ -967,7 +984,7 @@ int send_fd_to_peer(int fd, struct fdinfo_list_entry *fle, int sock)
 	transport_name_gen(&saddr, &len,
 			futex_get(&fle->real_pid), fle->fe->fd);
 	pr_info("\t\tSend fd %d to %s\n", fd, saddr.sun_path + 1);
-	return send_fd(sock, &saddr, len, fd);
+	return send_fds(sock, &saddr, len, &fd, 1, (void *)&fle, sizeof(struct fdinfo_list_entry *));
 }
 
 static int send_fd_to_self(int fd, struct fdinfo_list_entry *fle, int sock)
@@ -1077,7 +1094,7 @@ static int receive_fd(int pid, struct fdinfo_list_entry *fle)
 
 	pr_info("\tReceive fd for %d\n", fle->fe->fd);
 
-	tmp = recv_fd(fle->fe->fd);
+	tmp = recv_fd_from_peer(fle);
 	if (tmp < 0) {
 		pr_err("Can't get fd %d\n", tmp);
 		return -1;
diff --git a/criu/include/files.h b/criu/include/files.h
index 229c0d2e6..4f40e71f2 100644
--- a/criu/include/files.h
+++ b/criu/include/files.h
@@ -148,6 +148,7 @@ extern int file_desc_add(struct file_desc *d, u32 id, struct file_desc_ops *ops)
 extern struct fdinfo_list_entry *file_master(struct file_desc *d);
 extern struct file_desc *find_file_desc_raw(int type, u32 id);
 
+extern int recv_fd_from_peer(struct fdinfo_list_entry *fle);
 extern int send_fd_to_peer(int fd, struct fdinfo_list_entry *fle, int sock);
 extern int restore_fown(int fd, FownEntry *fown);
 extern int rst_file_params(int fd, FownEntry *fown, int flags);
diff --git a/criu/pipes.c b/criu/pipes.c
index 9fc87bd91..31f436eb2 100644
--- a/criu/pipes.c
+++ b/criu/pipes.c
@@ -237,7 +237,7 @@ static int recv_pipe_fd(struct pipe_info *pi)
 
 	pr_info("\tWaiting fd for %d\n", fd);
 
-	tmp = recv_fd(fd);
+	tmp = recv_fd_from_peer(fle);
 	if (tmp < 0) {
 		pr_err("Can't get fd %d\n", tmp);
 		return -1;
diff --git a/criu/sk-unix.c b/criu/sk-unix.c
index 5cbe07a83..47c4b5574 100644
--- a/criu/sk-unix.c
+++ b/criu/sk-unix.c
@@ -1097,7 +1097,7 @@ static int open_unixsk_pair_slave(struct unix_sk_info *ui)
 	pr_info("Opening pair slave (id %#x ino %#x peer %#x) on %d\n",
 			ui->ue->id, ui->ue->ino, ui->ue->peer, fle->fe->fd);
 
-	sk = recv_fd(fle->fe->fd);
+	sk = recv_fd_from_peer(fle);
 	if (sk < 0) {
 		pr_err("Can't recv pair slave\n");
 		return -1;
diff --git a/criu/tty.c b/criu/tty.c
index 0f3d1c9b2..6c85fde09 100644
--- a/criu/tty.c
+++ b/criu/tty.c
@@ -923,7 +923,7 @@ static int receive_tty(struct tty_info *info)
 	fle = file_master(&info->d);
 	pr_info("\tWaiting tty fd %d (pid %d)\n", fle->fe->fd, fle->pid);
 
-	fd = recv_fd(fle->fe->fd);
+	fd = recv_fd_from_peer(fle);
 	close(fle->fe->fd);
 	if (fd < 0) {
 		pr_err("Can't get fd %d\n", fd);