Add fsetxattr(), fremovexattr(), open_by_handle_at(), and "virtiofsd demo"

Mostly assorted fixes, a new FDGET operation (get a copy of the
target file descriptor via pidfd_getfd()) and a new "FD" flag that
means we have to do that on direct tag reference.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/cooker/call.c b/cooker/call.c
index dd37fe9..dbdc52b 100644
--- a/cooker/call.c
+++ b/cooker/call.c
@@ -72,7 +72,9 @@ static union value parse_metadata(struct gluten_ctx *g, struct field *f,
 		if (tag_offset.type == OFFSET_NULL)
 			die("   tag not found");
 
-		if ((*base_offset)->type == OFFSET_NULL || (f->flags & WBUF)) {
+		if (f->flags & FD) {
+			emit_fdget(g, tag_offset, offset);
+		} else if ((*base_offset)->type == OFFSET_NULL || (f->flags & WBUF)) {
 			**base_offset = tag_offset;
 		} else if (f->flags & MASK || add) {
 			emit_bitwise(g, f->type, BITWISE_OR, offset, offset,
@@ -374,6 +376,7 @@ bool arg_needs_temp(struct field *f, int pos, JSON_Value *jvalue,
 
 		return false;
 	case FDPATH:
+	case FDMOUNT:
 	case STRING:
 		return false;
 	case STRUCT:
@@ -433,7 +436,8 @@ static void parse_call(struct gluten_ctx *g, struct context_desc *cdesc,
 	struct gluten_offset offset[6] = { 0 }, ret_offset = { 0 };
 	bool is_ptr[6] = { false };
 	/* Minimum requirements for argument specification:
-	 * - if argument can be FDPATH, exactly one value for that position
+	 * - if argument can be FDPATH/FDMOUNT, exactly one value for that
+	 *   position
 	 * - if argument is a size field, value is optional
 	 * - otherwise, every argument needs to be specified
 	 */
@@ -459,7 +463,7 @@ static void parse_call(struct gluten_ctx *g, struct context_desc *cdesc,
 			arg_check[a->pos].multi_field = true;
 		arg_check[a->pos].found = true;
 
-		if (a->f.type == FDPATH)
+		if (a->f.type == FDPATH || a->f.type == FDMOUNT)
 			arg_check[a->pos].needs_fd = true;
 
 		if (a->f.size)