files: Sanitize helpers for scattering two-headed files

Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/files.c

@@ -885,7 +885,7 @@ static int plant_fd(struct fdinfo_list_entry *fle, int fd)
 	return reopen_fd_as(fle->fe->fd, fd);
 }
 
-int recv_fd_from_peer(struct fdinfo_list_entry *fle)
+static int recv_fd_from_peer(struct fdinfo_list_entry *fle)
 {
 	struct fdinfo_list_entry *tmp;
 	int fd, ret, tsock;
@@ -913,7 +913,7 @@ int recv_fd_from_peer(struct fdinfo_list_entry *fle)
 	return 0;
 }
 
-int send_fd_to_peer(int fd, struct fdinfo_list_entry *fle)
+static int send_fd_to_peer(int fd, struct fdinfo_list_entry *fle)
 {
 	struct sockaddr_un saddr;
 	int len, sock, ret;
@@ -928,6 +928,25 @@ int send_fd_to_peer(int fd, struct fdinfo_list_entry *fle)
 	return set_fds_event(fle->pid);
 }
 
+/*
+ * Helpers to scatter file_desc across users for those files, that
+ * create two descriptors from a single system call at once (e.g.
+ * ... or better i.e. -- pipes, socketpairs and ttys)
+ */
+int recv_desc_from_peer(struct file_desc *d, int *fd)
+{
+	struct fdinfo_list_entry *fle;
+
+	fle = file_master(d);
+	*fd = fle->fe->fd;
+	return recv_fd_from_peer(fle);
+}
+
+int send_desc_to_peer(int fd, struct file_desc *d)
+{
+	return send_fd_to_peer(fd, file_master(d));
+}
+
 static int send_fd_to_self(int fd, struct fdinfo_list_entry *fle)
 {
 	int dfd = fle->fe->fd;

criu/include/files.h

@@ -148,8 +148,8 @@ 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);
+extern int recv_desc_from_peer(struct file_desc *d, int *fd);
+extern int send_desc_to_peer(int fd, struct file_desc *d);
 extern int restore_fown(int fd, FownEntry *fown);
 extern int rst_file_params(int fd, FownEntry *fown, int flags);
 

criu/pipes.c

@@ -229,21 +229,14 @@ static int reopen_pipe(int fd, int flags)
 
 static int recv_pipe_fd(struct pipe_info *pi, int *new_fd)
 {
-	struct fdinfo_list_entry *fle;
 	int tmp, fd, ret;
 
-	fle = file_master(&pi->d);
-	fd = fle->fe->fd;
-
-	pr_info("\tWaiting fd for %d\n", fd);
-
-	ret = recv_fd_from_peer(fle);
+	ret = recv_desc_from_peer(&pi->d, &tmp);
 	if (ret != 0) {
 		if (ret != 1)
-			pr_err("Can't get fd %d\n", fd);
+			pr_err("Can't get fd %d\n", tmp);
 		return ret;
 	}
-	tmp = fd;
 
 	if (pi->reopen)
 		fd = reopen_pipe(tmp, pi->pe->flags);
@@ -304,13 +297,9 @@ int open_pipe(struct file_desc *d, int *new_fd)
 		return -1;
 
 	list_for_each_entry(p, &pi->pipe_list, pipe_list) {
-		struct fdinfo_list_entry *fle;
-		int fd;
-
-		fle = file_master(&p->d);
-		fd = pfd[p->pe->flags & O_WRONLY];
+		int fd = pfd[p->pe->flags & O_WRONLY];
 
-		if (send_fd_to_peer(fd, fle)) {
+		if (send_desc_to_peer(fd, &p->d)) {
 			pr_perror("Can't send file descriptor");
 			return -1;
 		}

criu/sk-unix.c

@@ -1085,7 +1085,6 @@ static int open_unixsk_pair_master(struct unix_sk_info *ui, int *new_fd)
 {
 	int sk[2];
 	struct unix_sk_info *peer = ui->peer;
-	struct fdinfo_list_entry *fle;
 
 	pr_info("Opening pair master (id %#x ino %#x peer %#x)\n",
 			ui->ue->id, ui->ue->ino, ui->ue->peer);
@@ -1106,8 +1105,7 @@ static int open_unixsk_pair_master(struct unix_sk_info *ui, int *new_fd)
 	if (restore_sk_common(sk[0], ui))
 		return -1;
 
-	fle = file_master(&peer->d);
-	if (send_fd_to_peer(sk[1], fle)) {
+	if (send_desc_to_peer(sk[1], &peer->d)) {
 		pr_err("Can't send pair slave\n");
 		return -1;
 	}
@@ -1120,21 +1118,14 @@ static int open_unixsk_pair_master(struct unix_sk_info *ui, int *new_fd)
 
 static int open_unixsk_pair_slave(struct unix_sk_info *ui, int *new_fd)
 {
-	struct fdinfo_list_entry *fle;
 	int sk, ret;
 
-	fle = file_master(&ui->d);
-
-	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);
-
-	ret = recv_fd_from_peer(fle);
+	ret = recv_desc_from_peer(&ui->d, &sk);
 	if (ret != 0) {
 		if (ret != 1)
 			pr_err("Can't recv pair slave\n");
 		return ret;
 	}
-	sk = fle->fe->fd;
 
 	if (bind_unix_sk(sk, ui))
 		return -1;

criu/tty.c

@@ -893,7 +893,6 @@ static void pty_restore_queued_data(struct tty_info *info, int fd)
 static int pty_open_slaves(struct tty_info *info)
 {
 	int fd = -1, ret = -1;
-	struct fdinfo_list_entry *fle;
 	struct tty_info *slave;
 
 	list_for_each_entry(slave, &info->sibling, sibling) {
@@ -908,12 +907,10 @@ static int pty_open_slaves(struct tty_info *info)
 		if (restore_tty_params(fd, slave))
 			goto err;
 
-		fle = file_master(&slave->d);
-
-		pr_debug("send slave %#x fd %d connected on %s (pid %d)\n",
-			 slave->tfe->id, fd, path_from_reg(slave->reg_d), fle->pid);
+		pr_debug("send slave %#x fd %d connected on %s\n",
+			 slave->tfe->id, fd, path_from_reg(slave->reg_d));
 
-		if (send_fd_to_peer(fd, fle)) {
+		if (send_desc_to_peer(fd, &slave->d)) {
 			pr_err("Can't send file descriptor\n");
 			goto err;
 		}
@@ -931,14 +928,9 @@ err:
 
 static int receive_tty(struct tty_info *info, int *new_fd)
 {
-	struct fdinfo_list_entry *fle;
 	int fd, ret;
 
-	fle = file_master(&info->d);
-	pr_info("\tWaiting tty fd %d (pid %d)\n", fle->fe->fd, fle->pid);
-
-	fd = fle->fe->fd;
-	ret = recv_fd_from_peer(fle);
+	ret = recv_desc_from_peer(&info->d, &fd);
 	if (ret != 0) {
 		if (ret != 1)
 			pr_err("Can't get fd %d\n", fd);