From 1c1a9da7a4f9c4c1990192e14763ebf423d812a9 Mon Sep 17 00:00:00 2001
From: Alice Frosi <afrosi@redhat.com>
Date: Wed, 7 Jun 2023 16:54:53 +0200
Subject: seitan, cooker: refactor op_return

Refactor OP_RETURN:
  - merged OP_BLOCK and OP_CONT into OP_RETURN
  - add desc field for op_return
  - updated the demo files
---
 cooker/emit.c  | 36 ++++++++++++++++--------------------
 cooker/emit.h  |  4 ++--
 cooker/parse.c | 34 +++++++++++++++++++++++++++-------
 3 files changed, 45 insertions(+), 29 deletions(-)

(limited to 'cooker')

diff --git a/cooker/emit.c b/cooker/emit.c
index 7b1b14d..506a561 100644
--- a/cooker/emit.c
+++ b/cooker/emit.c
@@ -304,36 +304,32 @@ void emit_cmp_field(struct gluten_ctx *g, enum op_cmp_type cmp,
 /**
  * emit_return() - Emit OP_RETURN instruction: return value
  * @g:		gluten context
- * @v:		Pointer to return value
+ * @v:		offset of the return value
+ * @error:	error value
+ * @cont 	if the filtered syscall needs to be executed
  */
-void emit_return(struct gluten_ctx *g, struct gluten_offset v)
+void emit_return(struct gluten_ctx *g, struct gluten_offset v, int32_t error,
+		 bool cont)
 {
 	struct op *op = (struct op *)gluten_ptr(&g->g, g->ip);
 	struct op_return *ret = &op->op.ret;
+	struct gluten_offset o;
+	struct return_desc *desc;
 
 	op->type = OP_RETURN;
-	ret->val = v;
-
-	debug("   %i: OP_RETURN:",  g->ip.offset);
 
-	if (++g->ip.offset > INST_MAX)
-		die("Too many instructions");
-}
+	o = gluten_ro_alloc(g, sizeof(struct return_desc));
+	desc = (struct return_desc *)gluten_ptr(&g->g, o);
 
-/**
- * emit_block() - Emit OP_BLOCK instruction: return error value
- * @g:		gluten context
- * @error:	Error value
- */
-void emit_block(struct gluten_ctx *g, int32_t error)
-{
-	struct op *op = (struct op *)gluten_ptr(&g->g, g->ip);
-	struct op_block *block = &op->op.block;
+	desc->val = v;
+	desc->error = error;
+	desc->cont = cont;
 
-	op->type = OP_BLOCK;
-	block->error = error;
+	ret->desc = o;
 
-	debug("   %i: OP_BLOCK: %d", g->ip.offset, error);
+	debug("   %i: OP_RETURN:",  g->ip.offset);
+	debug("  \t val=(%s %d) errno=%d cont=%s", gluten_offset_name[v.type],
+	      v.offset, error, cont ? "true" : "false");
 
 	if (++g->ip.offset > INST_MAX)
 		die("Too many instructions");
diff --git a/cooker/emit.h b/cooker/emit.h
index 18618ee..81f947e 100644
--- a/cooker/emit.h
+++ b/cooker/emit.h
@@ -24,8 +24,8 @@ void emit_cmp_field(struct gluten_ctx *g, enum op_cmp_type cmp,
 		    struct field *field,
 		    struct gluten_offset base, struct gluten_offset match,
 		    enum jump_type jmp);
-void emit_return(struct gluten_ctx *g, struct gluten_offset v);
-void emit_block(struct gluten_ctx *g, int32_t error);
+void emit_return(struct gluten_ctx *g, struct gluten_offset v, int32_t error,
+                 bool cont);
 void emit_copy(struct gluten_ctx *g,
 	       struct gluten_offset dst, struct gluten_offset src, size_t size);
 void emit_copy_field(struct gluten_ctx *g, struct field *field,
diff --git a/cooker/parse.c b/cooker/parse.c
index 81ad159..353947e 100644
--- a/cooker/parse.c
+++ b/cooker/parse.c
@@ -6,6 +6,7 @@
  *
  * Copyright 2023 Red Hat GmbH
  * Author: Stefano Brivio <sbrivio@redhat.com>
+ *         Alice Frosi <afrosi@redhat.com>
  */
 
 #include "parson.h"
@@ -73,14 +74,34 @@ static void handle_limit(struct gluten_ctx *g, JSON_Value *value)
 
 static void handle_return(struct gluten_ctx *g, JSON_Value *value)
 {
-	union value v = { .v_u64 = json_value_get_number(value) };
+	JSON_Object *obj = json_value_get_object(value);
+	JSON_Value *jvalue;
+	union value v = { .v_u64 = 0 };
+	int32_t error = 0;
+	bool cont = false;
 
-	emit_return(g, emit_data(g, U64, sizeof(v.v_u64), &v));
-}
+	debug("  Parsing \"return\"");
 
-static void handle_block(struct gluten_ctx *g, JSON_Value *value)
-{
-	emit_block(g, json_value_get_number(value));
+	jvalue = json_object_get_value(obj, "error");
+        if (json_value_get_type(jvalue) == JSONNumber) {
+		error = json_value_get_number(jvalue);
+	}
+
+	jvalue = json_object_get_value(obj, "value");
+        if (json_value_get_type(jvalue) == JSONNumber) {
+		v.v_u64 = json_value_get_number(jvalue);
+	}
+
+	jvalue = json_object_get_value(obj, "continue");
+        if (json_value_get_type(jvalue) == JSONBoolean) {
+		cont = json_value_get_boolean(jvalue);
+	}
+	if (cont && (v.v_u64 != 0 || error != 0))
+		die("  if continue is true, error and value needs to be zero");
+
+	debug("  emit return: val=%ld errno=%d cont=%s", v.v_u64, error,
+	      cont ? "true" : "false");
+	emit_return(g, emit_data(g, U64, sizeof(v.v_u64), &v), error, cont);
 }
 
 static void handle_context(struct gluten_ctx *g, JSON_Value *value)
@@ -103,7 +124,6 @@ struct rule_parser {
 	{ "fd",		handle_fd },
 	{ "limit",	handle_limit },
 	{ "return",	handle_return },
-	{ "block",	handle_block },
 	{ "context",	handle_context },
 	{ NULL, NULL },
 };
-- 
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