[PATCH v9 02/24] tools lib: Introduce fdarray clone function

[Alexey Bayduraev]

Introduce a function to create a copy of an existing file descriptor in
the fdarray structure. The function returns the position of the copied fd.

Acked-by: Namhyung Kim <namhyung@xxxxxxxxx>
Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@xxxxxxxxxxxxxxx>
---
 tools/lib/api/fd/array.c | 17 +++++++++++++++++
 tools/lib/api/fd/array.h |  1 +
 2 files changed, 18 insertions(+)

diff --git a/tools/lib/api/fd/array.c b/tools/lib/api/fd/array.c
index 5e6cb9debe37..de8bcbaea3f1 100644
--- a/tools/lib/api/fd/array.c
+++ b/tools/lib/api/fd/array.c
@@ -88,6 +88,23 @@ int fdarray__add(struct fdarray *fda, int fd, short revents, enum fdarray_flags
 	return pos;
 }
 
+int fdarray__clone(struct fdarray *fda, int pos, struct fdarray *base)
+{
+	struct pollfd *entry;
+	int npos;
+
+	if (pos >= base->nr)
+		return -EINVAL;
+
+	entry = &base->entries[pos];
+
+	npos = fdarray__add(fda, entry->fd, entry->events, base->priv[pos].flags);
+	if (npos >= 0)
+		fda->priv[npos] = base->priv[pos];
+
+	return npos;
+}
+
 int fdarray__filter(struct fdarray *fda, short revents,
 		    void (*entry_destructor)(struct fdarray *fda, int fd, void *arg),
 		    void *arg)
diff --git a/tools/lib/api/fd/array.h b/tools/lib/api/fd/array.h
index 7fcf21a33c0c..4a03da7f1fc1 100644
--- a/tools/lib/api/fd/array.h
+++ b/tools/lib/api/fd/array.h
@@ -42,6 +42,7 @@ struct fdarray *fdarray__new(int nr_alloc, int nr_autogrow);
 void fdarray__delete(struct fdarray *fda);
 
 int fdarray__add(struct fdarray *fda, int fd, short revents, enum fdarray_flags flags);
+int fdarray__clone(struct fdarray *fda, int pos, struct fdarray *base);
 int fdarray__poll(struct fdarray *fda, int timeout);
 int fdarray__filter(struct fdarray *fda, short revents,
 		    void (*entry_destructor)(struct fdarray *fda, int fd, void *arg),
-- 
2.19.0