[Xcb] [PATCH] Perform safety check before trying to load glyph cursor

[mgraesslin at kde.org]

From: Martin Gräßlin <mgraesslin at kde.org>

The passed in cursor name to xcb_cursor_load_cursor might not match
one of the predefined font cursor values. Without the check the
call to create glyph cursor will fail with a BadValue error, but
the library returns the id allocated for the xcb_cursor_t. A user
of the library gets a value which looks like a valid cursor, but
when using it for e.g. a cursor value in xcb_create_window it raises
a BadCursor error.
---
 cursor/load_cursor.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/cursor/load_cursor.c b/cursor/load_cursor.c
index 914950a..9edd061 100644
--- a/cursor/load_cursor.c
+++ b/cursor/load_cursor.c
@@ -207,6 +207,8 @@ xcb_cursor_t xcb_cursor_load_cursor(xcb_cursor_context_t *c, const char *name) {
     if (fd == -1 || core_char > -1) {
         if (core_char == -1)
             core_char = cursor_shape_to_id(name);
+        if (core_char == -1)
+            return XCB_CURSOR_NONE;
 
         cid = xcb_generate_id(c->conn);
         xcb_create_glyph_cursor(c->conn, cid, c->cursor_font, c->cursor_font, core_char, core_char + 1, 0, 0, 0, 65535, 65535, 65535);
-- 
2.1.4