files: Rework select_ps_list fdsec ops callback

For unlinked opened and mmaped files we'd need to
care about remaps, for this the callback with both
file_desc and fdinfo_list_entry will be required.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

eventpoll.c

@@ -144,16 +144,17 @@ static int eventpoll_post_open(struct file_desc *d, int fd)
 	return 0;
 }
 
-static struct list_head *eventpoll_select_list(struct file_desc *d, struct rst_info *ri)
+static void eventpoll_collect_fd(struct file_desc *d,
+		struct fdinfo_list_entry *fle, struct rst_info *ri)
 {
-	return &ri->eventpoll;
+	list_add_tail(&fle->ps_list, &ri->eventpoll);
 }
 
 static struct file_desc_ops desc_ops = {
 	.type = FD_TYPES__EVENTPOLL,
 	.open = eventpoll_open,
 	.post_open = eventpoll_post_open,
-	.select_ps_list = eventpoll_select_list,
+	.collect_fd = eventpoll_collect_fd,
 };
 
 static int collect_one_epoll_tfd(void *o, ProtobufCMessage *msg)

files.c

@@ -533,14 +533,6 @@ int rst_file_params(int fd, FownEntry *fown, int flags)
 	return 0;
 }
 
-static struct list_head *select_ps_list(struct file_desc *desc, struct rst_info *ri)
-{
-	if (desc->ops->select_ps_list)
-		return desc->ops->select_ps_list(desc, ri);
-	else
-		return &ri->fds;
-}
-
 static int collect_fd(int pid, FdinfoEntry *e, struct rst_info *rst_info)
 {
 	struct fdinfo_list_entry *le, *new_le;
@@ -567,9 +559,13 @@ static int collect_fd(int pid, FdinfoEntry *e, struct rst_info *rst_info)
 		if (pid_rst_prio(new_le->pid, le->pid))
 			break;
 
+	if (fdesc->ops->collect_fd)
+		fdesc->ops->collect_fd(fdesc, new_le, rst_info);
+	else
+		collect_gen_fd(new_le, rst_info);
+
 	list_add_tail(&new_le->desc_list, &le->desc_list);
 	new_le->desc = fdesc;
-	list_add_tail(&new_le->ps_list, select_ps_list(fdesc, rst_info));
 
 	return 0;
 }

include/files.h

@@ -8,6 +8,7 @@
 #include "list.h"
 #include "image.h"
 #include "pid.h"
+#include "rst_info.h"
 
 #include "protobuf/fdinfo.pb-c.h"
 #include "protobuf/fown.pb-c.h"
@@ -96,12 +97,19 @@ struct file_desc_ops {
 	 */
 	int			(*want_transport)(FdinfoEntry *fe, struct file_desc *d);
 	/*
-	 * Helps determining sequence of different file types restore.
-	 * See the prepare_fds for details.
+	 * Called to collect a new fd before adding it on desc. Clients
+	 * may chose to collect it to some specific rst_info list. See
+	 * prepare_fds() for details.
 	 */
-	struct list_head *	(*select_ps_list)(struct file_desc *, struct rst_info *);
+	void			(*collect_fd)(struct file_desc *, struct fdinfo_list_entry *,
+						struct rst_info *);
 };
 
+static inline void collect_gen_fd(struct fdinfo_list_entry *fle, struct rst_info *ri)
+{
+	list_add_tail(&fle->ps_list, &ri->fds);
+}
+
 struct file_desc {
 	u32			id;		/* File id, unique */
 	struct hlist_node	hash;		/* Descriptor hashing and lookup */

tty.c

@@ -667,17 +667,22 @@ static int tty_transport(FdinfoEntry *fe, struct file_desc *d)
 	return !info->create;
 }
 
-static struct list_head *tty_select_pslist(struct file_desc *d, struct rst_info *ri)
+static void tty_collect_fd(struct file_desc *d, struct fdinfo_list_entry *fle,
+		struct rst_info *ri)
 {
+	struct list_head *tgt;
+
 	/*
 	 * Unix98 pty slave peers requires the master peers being
 	 * opened before them
 	 */
 
 	if (pty_is_master(container_of(d, struct tty_info, d)))
-		return &ri->fds;
+		tgt = &ri->fds;
 	else
-		return &ri->tty_slaves;
+		tgt = &ri->tty_slaves;
+
+	list_add_tail(&fle->ps_list, tgt);
 }
 
 static struct file_desc_ops tty_desc_ops = {
@@ -685,7 +690,7 @@ static struct file_desc_ops tty_desc_ops = {
 	.open		= tty_open,
 	.post_open	= tty_restore_ctl_terminal,
 	.want_transport = tty_transport,
-	.select_ps_list	= tty_select_pslist,
+	.collect_fd	= tty_collect_fd,
 };
 
 static struct pstree_item *find_first_sid(int sid)