Adjust to VDP API Changes from VC#4035

Ref https://github.com/varnishcache/varnish-cache/pull/4035

README.rst

@@ -204,14 +204,14 @@ VOID xvdp.arg(STRING)
 The ``.arg()`` method sets a command-line argument to be used with a
 program.
 
-Restricted to: ``vcl_init``, ``vcl_deliver``.
+Restricted to: ``vcl_init``, ``vcl_deliver``, ``vcl_backend_fetch``.
 
 Invocations of ``.arg()`` in ``vcl_init`` set arguments to be used
-globally in the VCL instance. Invocations in ``vcl_deliver`` set
-arguments to be used for a single client response, overriding any
-arguments that may have been set in ``vcl_init`` For example, you can
-call ``.arg()`` in ``vcl_deliver`` if the arguments to be used are not
-known until runtime.
+globally in the VCL instance. Invocations in ``vcl_deliver`` /
+``vcl_backend_fetch`` are valid for a single resp.body / bereq.body,
+overriding any arguments that may have been set in ``vcl_init`` For
+example, you can call ``.arg()`` in ``vcl_deliver`` if the arguments
+to be used are not known until runtime.
 
 The parameter in ``.arg()`` MAY be empty (if you need the empty string
 as a CLI argument), but MAY NOT be NULL (for example, it may not be
@@ -277,12 +277,12 @@ VOID xvdp.setenv(STRING var, STRING value, BOOL overwrite)
 Set the environment variable ``var`` to ``value`` in the invoked
 process.
 
-Restricted to: ``vcl_init``, ``vcl_deliver``.
+Restricted to: ``vcl_init``, ``vcl_deliver``, ``vcl_backend_fetch``.
 
 Settings in ``vcl_init`` are global for the VCL instance, while
-settings in ``vcl_deliver`` are valid for a single client response
-(for use cases where the environment settings are not known until
-runtime).
+settings in ``vcl_deliver`` / ``vcl_backend_fetch`` are valid for a
+single resp.body / bereq.body (for use cases where the environment
+settings are not known until runtime).
 
 Currently, any invocation of ``.setenv()`` in ``vcl_deliver`` cancels
 all environment settings specified in ``vcl_init`` for the current

src/vdfp_pipe.c

@@ -174,9 +174,10 @@ mk_dup(int oldfd, int newfd)
 }
 
 static int v_matchproto_(vdp_init_f)
-vdp_init(VRT_CTX, struct vdp_ctx *vc, void **priv, struct objcore *objcore)
+vdp_init(VRT_CTX, struct vdp_ctx *vc, void **priv,
+    struct objcore *objcore, struct req *req,
+    struct http *hd, intmax_t *cl)
 {
-	struct req *req;
 	struct vdp_state *state;
 	struct vdp_entry *vdpe;
 	struct vdp_map map_entry, *map;
@@ -188,18 +189,19 @@ vdp_init(VRT_CTX, struct vdp_ctx *vc, void **priv, struct objcore *objcore)
 	char **argv;
 
 	CHECK_OBJ_NOTNULL(vc, VDP_CTX_MAGIC);
-	req = vc->req;
-	CHECK_OBJ_NOTNULL(req, REQ_MAGIC);
-	AN(req->vcl);
 	AN(priv);
-	AZ(*priv);
 	CHECK_OBJ_ORNULL(objcore, OBJCORE_MAGIC);
+	CHECK_OBJ_ORNULL(req, REQ_MAGIC);
+	CHECK_OBJ_NOTNULL(hd, HTTP_MAGIC);
+	AN(cl);
+
+	AZ(*priv);
 
 	vdpe = VTAILQ_LAST(&vc->vdp, vdp_entry_s);
 	CHECK_OBJ_NOTNULL(vdpe, VDP_ENTRY_MAGIC);
 	AN(vdpe->vdp);
 	map_entry.vdp = vdpe->vdp;
-	map_entry.vcl = req->vcl;
+	map_entry.vcl = ctx->vcl;
 	map = VRBT_FIND(vdp_tree, &tree_h, &map_entry);
 	CHECK_OBJ_NOTNULL(map, PIPE_VDP_MAP_MAGIC);
 	CHECK_OBJ_NOTNULL(map->obj, PIPE_VDP_MAGIC);
@@ -309,7 +311,8 @@ vdp_init(VRT_CTX, struct vdp_ctx *vc, void **priv, struct objcore *objcore)
 	state->fds[STDIN_FILENO].fd = in[1];
 	state->fds[STDOUT_FILENO].fd = out[0];
 	state->fds[STDERR_FILENO].fd = err[0];
-	http_Unset(req->resp, H_Content_Length);
+	http_Unset(hd, H_Content_Length);
+	*cl = -1;
 	return (0);
 }
 
@@ -800,6 +803,9 @@ get_task(VRT_CTX, struct VPFX(pipe_vdp) *obj, const char *method)
 	return (task);
 }
 
+#define VDP_VALID_METHOD						\
+	(VCL_MET_INIT | VCL_MET_DELIVER | VCL_MET_BACKEND_FETCH)
+
 VCL_VOID
 vmod_vdp_arg(VRT_CTX, struct VPFX(pipe_vdp) *obj, VCL_STRING arg)
 {
@@ -810,7 +816,7 @@ vmod_vdp_arg(VRT_CTX, struct VPFX(pipe_vdp) *obj, VCL_STRING arg)
 	CHECK_OBJ_NOTNULL(ctx->ws, WS_MAGIC);
 	CHECK_OBJ_NOTNULL(obj, PIPE_VDP_MAGIC);
 
-	AN(ctx->method & (VCL_MET_INIT | VCL_MET_DELIVER));
+	AN(ctx->method & VDP_VALID_METHOD);
 
 	if (arg == NULL) {
 		VDPFAIL(ctx, "%s.arg(): arg is NULL", obj->name);
@@ -893,7 +899,7 @@ vmod_vdp_setenv(VRT_CTX, struct VPFX(pipe_vdp) *obj, VCL_STRING var,
 	CHECK_OBJ_NOTNULL(ctx->ws, WS_MAGIC);
 	CHECK_OBJ_NOTNULL(obj, PIPE_VDP_MAGIC);
 
-	AN(ctx->method & (VCL_MET_INIT | VCL_MET_DELIVER));
+	AN(ctx->method & VDP_VALID_METHOD);
 
 	if (var == NULL || *var == '\0') {
 		VDPFAIL(ctx, "%s.setenv(): var is empty", obj->name);

src/vdfp_pipe.vcc

@@ -185,14 +185,14 @@ $Method VOID .arg(STRING)
 The ``.arg()`` method sets a command-line argument to be used with a
 program.
 
-$Restrict vcl_init vcl_deliver
+$Restrict vcl_init vcl_deliver vcl_backend_fetch
 
 Invocations of ``.arg()`` in ``vcl_init`` set arguments to be used
-globally in the VCL instance. Invocations in ``vcl_deliver`` set
-arguments to be used for a single client response, overriding any
-arguments that may have been set in ``vcl_init`` For example, you can
-call ``.arg()`` in ``vcl_deliver`` if the arguments to be used are not
-known until runtime.
+globally in the VCL instance. Invocations in ``vcl_deliver`` /
+``vcl_backend_fetch`` are valid for a single resp.body / bereq.body,
+overriding any arguments that may have been set in ``vcl_init`` For
+example, you can call ``.arg()`` in ``vcl_deliver`` if the arguments
+to be used are not known until runtime.
 
 The parameter in ``.arg()`` MAY be empty (if you need the empty string
 as a CLI argument), but MAY NOT be NULL (for example, it may not be
@@ -251,12 +251,12 @@ $Method VOID .setenv(STRING var, STRING value, BOOL overwrite=1)
 Set the environment variable ``var`` to ``value`` in the invoked
 process.
 
-$Restrict vcl_init vcl_deliver
+$Restrict vcl_init vcl_deliver vcl_backend_fetch
 
 Settings in ``vcl_init`` are global for the VCL instance, while
-settings in ``vcl_deliver`` are valid for a single client response
-(for use cases where the environment settings are not known until
-runtime).
+settings in ``vcl_deliver`` / ``vcl_backend_fetch`` are valid for a
+single resp.body / bereq.body (for use cases where the environment
+settings are not known until runtime).
 
 Currently, any invocation of ``.setenv()`` in ``vcl_deliver`` cancels
 all environment settings specified in ``vcl_init`` for the current