unix: Collect unix sockets early on restore

Same as prev 2 patches now for the unix sockets. They are still in per-pid image files, but
this is going to change soon (I hope).
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-restore.c

@@ -424,6 +424,10 @@ static int prepare_shared(int ps_fd)
 		if (ret <= 0)
 			break;
 
+		ret = collect_unix_sockets(e.pid);
+		if (ret < 0)
+			return -1;
+
 		ret = prepare_shmem_pid(e.pid);
 		if (ret < 0)
 			break;

include/sockets.h

@@ -12,6 +12,7 @@ extern int dump_socket(struct fd_parms *p, int lfd,
 
 extern int collect_sockets(void);
 extern int collect_inet_sockets(void);
+extern int collect_unix_sockets(int pid);
 extern int prepare_sockets(int pid);
 struct fdinfo_entry;
 extern int open_inet_sk(struct fdinfo_entry *fe);

sockets.c

@@ -1071,7 +1071,7 @@ err:
 	return -1;
 }
 
-static int bind_unix_sk(int sk, const struct unix_sk_entry *ue, int img_fd)
+static int bind_unix_sk(int sk, const struct unix_sk_entry *ue, char *name)
 {
 	struct sockaddr_un addr;
 
@@ -1082,9 +1082,7 @@ static int bind_unix_sk(int sk, const struct unix_sk_entry *ue, int img_fd)
 
 	memset(&addr, 0, sizeof(addr));
 	addr.sun_family = AF_UNIX;
-
-	if (read_img_buf(img_fd, &addr.sun_path, ue->namelen) < 0)
-		return -1;
+	memcpy(&addr.sun_path, name, ue->namelen);
 
 	if (addr.sun_path[0] != '\0')
 		unlink(addr.sun_path);
@@ -1094,13 +1092,12 @@ static int bind_unix_sk(int sk, const struct unix_sk_entry *ue, int img_fd)
 			ue->id, ue->type);
 }
 
-static int open_unix_sk_dgram(int sk, const struct unix_sk_entry *ue,
-		int img_fd)
+static int open_unix_sk_dgram(int sk, const struct unix_sk_entry *ue, char *name)
 {
 	int ret = 0;
 
 	if (ue->namelen)
-		ret = bind_unix_sk(sk, ue, img_fd);
+		ret = bind_unix_sk(sk, ue, name);
 	else if (ue->peer) {
 		struct sockaddr_un addr;
 		int addrlen;
@@ -1122,13 +1119,12 @@ static int open_unix_sk_dgram(int sk, const struct unix_sk_entry *ue,
 	return ret;
 }
 
-static int open_unix_sk_stream(int sk, const struct unix_sk_entry *ue,
-		int img_fd)
+static int open_unix_sk_stream(int sk, const struct unix_sk_entry *ue, char *name)
 {
 	int ret;
 
 	if (ue->state == TCP_LISTEN) {
-		ret = bind_unix_sk(sk, ue, img_fd);
+		ret = bind_unix_sk(sk, ue, name);
 		if (ret < 0)
 			goto out;
 
@@ -1161,7 +1157,7 @@ out:
 	return ret;
 }
 
-static int open_unix_sk(const struct unix_sk_entry *ue, int *img_fd)
+static int open_unix_sk(const struct unix_sk_entry *ue, char *name)
 {
 	int sk;
 
@@ -1175,11 +1171,11 @@ static int open_unix_sk(const struct unix_sk_entry *ue, int *img_fd)
 
 	switch (ue->type) {
 	case SOCK_STREAM:
-		if (open_unix_sk_stream(sk, ue, *img_fd))
+		if (open_unix_sk_stream(sk, ue, name))
 			goto err;
 		break;
 	case SOCK_DGRAM:
-		if (open_unix_sk_dgram(sk, ue, *img_fd))
+		if (open_unix_sk_dgram(sk, ue, name))
 			goto err;
 		break;
 	default:
@@ -1187,9 +1183,6 @@ static int open_unix_sk(const struct unix_sk_entry *ue, int *img_fd)
 		goto err;
 	}
 
-	if (move_img_fd(img_fd, ue->fd))
-		return -1;
-
 	return reopen_fd_as(ue->fd, sk);
 
 err:
@@ -1197,30 +1190,35 @@ err:
 	return -1;
 }
 
+struct unix_sk_info {
+	struct unix_sk_entry ue;
+	struct list_head list;
+	char *name;
+	int pid;
+};
+
+static LIST_HEAD(unix_sockets);
+
 static int prepare_unix_sockets(int pid)
 {
-	int usk_fd, ret = -1;
+	int ret = 0;
 	struct sk_packets_pool unix_pool = {
 		.packets_list = LIST_HEAD_INIT(unix_pool.packets_list),
 	};
+	struct unix_sk_info *ui, *n;
 
-	usk_fd = open_image_ro(CR_FD_UNIXSK, pid);
-	if (usk_fd < 0)
-		return -1;
-
-	while (1) {
-		struct unix_sk_entry ue;
-
-		ret = read_img_eof(usk_fd, &ue);
-		if (ret <= 0)
-			break;
+	list_for_each_entry_safe(ui, n, &unix_sockets, list) {
+		if (ui->pid != pid)
+			continue;
 
-		ret = open_unix_sk(&ue, &usk_fd);
+		ret = open_unix_sk(&ui->ue, ui->name);
 		if (ret)
 			break;
+
+		list_del(&ui->list);
+		xfree(ui->name);
+		xfree(ui);
 	}
-err:
-	close(usk_fd);
 
 	if (ret)
 		return ret;
@@ -1524,3 +1522,52 @@ void show_sk_queues(int fd, struct cr_options *o)
 	}
 	pr_img_tail(CR_FD_SK_QUEUES);
 }
+
+int collect_unix_sockets(int pid)
+{
+	int fd, ret;
+
+	pr_info("Reading unix sockets in\n");
+
+	fd = open_image_ro(CR_FD_UNIXSK, pid);
+	if (fd < 0) {
+		if (errno == ENOENT)
+			return 0;
+		else
+			return -1;
+	}
+
+	while (1) {
+		struct unix_sk_info *ui;
+
+		ui = xmalloc(sizeof(*ui));
+		ret = -1;
+		if (ui == NULL)
+			break;
+
+		ret = read_img_eof(fd, &ui->ue);
+		if (ret <= 0) {
+			xfree(ui);
+			break;
+		}
+
+		if (ui->ue.namelen) {
+			ui->name = xmalloc(ui->ue.namelen);
+			ret = -1;
+			if (ui->name == NULL)
+				break;
+
+			ret = read_img_buf(fd, ui->name, ui->ue.namelen);
+			if (ret < 0)
+				break;
+		} else
+			ui->name = NULL;
+
+		ui->pid = pid;
+		pr_info(" `- Got %u peer %u\n", ui->ue.id, ui->ue.peer);
+		list_add_tail(&ui->list, &unix_sockets);
+	}
+
+	close(fd);
+	return ret;
+}