cooker, seitan: simple working example

parser:
  - add OP_BLOCK and OP_RETURN to the parser
seitan:
  - fix op_cmp in seitan, it was jmp when comparison was true

Working example:
demo.json:
[
  {
    "match": [ /* qemu-pr-helper and similar */
      { "connect": { "addr": { "family": "unix", "path": "/tmp/test.sock" } } }
    ],
    "return": 0
  }
]

Create gluten and the bpf filter:
$ seitan-cooker demo.hjson demo.gluten demo.bpf

Launch the seitan eater with the target program:
$ seitan-eater -i demo.bpf -- strace -e connect tests-utils/test-syscalls connect

Start seitan with gluten:
$ seitan -i demo.gluten -p $(pgrep seitan-eater)

Seitan mocks the connect syscall and `connect` returns successfully:
$ seitan-eater -i demo.bpf -- strace -e connect tests-utils/test-syscalls connect
Test syscall: connect
connect(4, {sa_family=AF_UNIX, sun_path="/tmp/test.sock"}, 108) = 0

1 files changed, 4 insertions, 4 deletions

diff --git a/cooker/parse.c b/cooker/parse.c
index 09b1e46..acb6810 100644
--- a/cooker/parse.c
+++ b/cooker/parse.c
@@ -38,14 +38,14 @@ static void handle_limit(struct gluten_ctx *g, JSON_Value *value)
 
 static void handle_return(struct gluten_ctx *g, JSON_Value *value)
 {
-	(void)g;
-	(void)value;
+	union value v = { .v_u64 = json_value_get_number(value) };
+
+	emit_return(g, emit_data(g, U64, sizeof(v.v_u64), &v));
 }
 
 static void handle_block(struct gluten_ctx *g, JSON_Value *value)
 {
-	(void)g;
-	(void)value;
+	emit_block(g, json_value_get_number(value));
 }
 
 static void handle_context(struct gluten_ctx *g, JSON_Value *value)