[CRIU] [PATCH 12/15] files: new "used" files introduced

[Stanislav Kinsburskiy]

This list contains all per-process used file fdinfo's, sorted by fd number.
Will be used to safely create new artificial file descriptors.

Signed-off-by: Stanislav Kinsburskiy <skinsbursky at virtuozzo.com>
---
 eventpoll.c        |    1 +
 files.c            |    1 +
 include/files.h    |   14 ++++++++++++++
 include/rst_info.h |    1 +
 tty.c              |    1 +
 5 files changed, 18 insertions(+)

diff --git a/eventpoll.c b/eventpoll.c
index c414c35..8d3a001 100644
--- a/eventpoll.c
+++ b/eventpoll.c
@@ -185,6 +185,7 @@ static void eventpoll_collect_fd(struct file_desc *d,
 		struct fdinfo_list_entry *fle, struct rst_info *ri)
 {
 	list_add_tail(&fle->ps_list, &ri->eventpoll);
+	collect_used_fd(fle, ri);
 }
 
 static struct file_desc_ops desc_ops = {
diff --git a/files.c b/files.c
index 2208cc3..667f70c 100644
--- a/files.c
+++ b/files.c
@@ -686,6 +686,7 @@ int prepare_fd_pid(struct pstree_item *item)
 	pid_t pid = item->pid.virt;
 	struct rst_info *rst_info = rsti(item);
 
+	INIT_LIST_HEAD(&rst_info->used);
 	INIT_LIST_HEAD(&rst_info->fds);
 	INIT_LIST_HEAD(&rst_info->eventpoll);
 	INIT_LIST_HEAD(&rst_info->tty_slaves);
diff --git a/include/files.h b/include/files.h
index db7e108..fdfd641 100644
--- a/include/files.h
+++ b/include/files.h
@@ -67,6 +67,7 @@ struct fdinfo_list_entry {
 	struct list_head	desc_list;	/* To chain on  @fd_info_head */
 	struct file_desc	*desc;		/* Associated file descriptor */
 	struct list_head	ps_list;	/* To chain  per-task files */
+	struct list_head	used_list;	/* To chain per-task used fds */
 	int			pid;
 	futex_t			real_pid;
 	FdinfoEntry		*fe;
@@ -108,9 +109,22 @@ struct file_desc_ops {
 	char *			(*name)(struct file_desc *, char *b, size_t s);
 };
 
+static inline void collect_used_fd(struct fdinfo_list_entry *new_fle, struct rst_info *ri)
+{
+	struct fdinfo_list_entry *fle;
+
+	list_for_each_entry(fle, &ri->used, used_list) {
+		if (new_fle->fe->fd < fle->fe->fd)
+			break;
+	}
+
+	list_add_tail(&new_fle->used_list, &fle->used_list);
+}
+
 static inline void collect_gen_fd(struct fdinfo_list_entry *fle, struct rst_info *ri)
 {
 	list_add_tail(&fle->ps_list, &ri->fds);
+	collect_used_fd(fle, ri);
 }
 
 struct file_desc {
diff --git a/include/rst_info.h b/include/rst_info.h
index 74e01ee..f72025b 100644
--- a/include/rst_info.h
+++ b/include/rst_info.h
@@ -27,6 +27,7 @@ struct fdt {
 struct _MmEntry;
 
 struct rst_info {
+	struct list_head	used;
 	struct list_head	fds;
 	struct list_head	eventpoll;
 	struct list_head	tty_slaves;
diff --git a/tty.c b/tty.c
index 1286742..e441f80 100644
--- a/tty.c
+++ b/tty.c
@@ -1006,6 +1006,7 @@ static void tty_collect_fd(struct file_desc *d, struct fdinfo_list_entry *fle,
 		tgt = &ri->tty_slaves;
 
 	list_add_tail(&fle->ps_list, tgt);
+	collect_used_fd(fle, ri);
 }
 
 static struct file_desc_ops tty_desc_ops = {