[master] 84708f9fb Add simplified VEXT loading as -E<name>

[Nils Goroll]

commit 84708f9fb2cc8b4feaa9fd0a0a5dca79af130d2d
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Fri Nov 28 17:14:20 2025 +0100

    Add simplified VEXT loading as -E<name>
    
    Similar to how vmods can be loaded by their base name, we now support loading
    extensions using, for example, -Estd:
    
    If a path is specified (-E argument contains "/"), it is taken literally as
    before. Otherwise, the -E argument is expanded to libvmod_%s.so and a search in
    vmod_path is conducted.

diff --git a/bin/varnishd/mgt/mgt_vext.c b/bin/varnishd/mgt/mgt_vext.c
index 30c0b2661..c2f61f576 100644
--- a/bin/varnishd/mgt/mgt_vext.c
+++ b/bin/varnishd/mgt/mgt_vext.c
@@ -45,6 +45,7 @@
 #include "vas.h"
 #include "miniobj.h"
 #include "vav.h"
+#include "vfil.h"
 #include "vqueue.h"
 #include "vrnd.h"
 #include "vsb.h"
@@ -65,10 +66,25 @@ struct vext {
 static VTAILQ_HEAD(,vext) vext_list =
     VTAILQ_HEAD_INITIALIZER(vext_list);
 
+static int
+vext_tryopen(void *priv, const char *fn)
+{
+	struct vext *vp;
+
+	CAST_OBJ_NOTNULL(vp, priv, VEXT_MAGIC);
+	vp->fd = open(fn, O_RDONLY);
+	if (vp->fd < 0)
+		return (1);
+	return (0);
+}
+
 void
 vext_argument(const char *arg)
 {
 	struct vext *vp;
+	char fn[1024];
+	char *fno = NULL;
+	struct vfil_path *vmod_path = NULL;
 
 	fprintf(stderr, "EEE <%s>\n", arg);
 	ALLOC_OBJ(vp, VEXT_MAGIC);
@@ -79,11 +95,20 @@ vext_argument(const char *arg)
 		ARGV_ERR("\tParse failure in argument: %s\n\t%s\n",
 		    arg, vp->argv[0]);
 	VTAILQ_INSERT_TAIL(&vext_list, vp, list);
-	fprintf(stderr, "eee <%s>\n", vp->argv[1]);
-	vp->fd = open(vp->argv[1], O_RDONLY);
-	if (vp->fd < 0)
+
+	if (strchr(vp->argv[1], '/'))
+		bstrcpy(fn, vp->argv[1]);
+	else
+		bprintf(fn, "libvmod_%s.so", vp->argv[1]);
+
+	VFIL_setpath(&vmod_path, mgt_vmod_path);
+	if (VFIL_searchpath(vmod_path, vext_tryopen, vp, fn, &fno)) {
 		ARGV_ERR("\tCannot open %s\n\t%s\n",
-		    vp->argv[1], strerror(errno));
+		    fn, strerror(errno));
+	}
+
+	fprintf(stderr, "eee <%s>\n", fno);
+	free(fno);
 }
 
 void
@@ -115,7 +140,7 @@ vext_copyin(struct vsb *vi)
 		if (p != NULL)
 			p++;
 		else
-			p = vp->argv[0];
+			p = vp->argv[1];
 		VSB_printf(vi, ",-E%s", p);
 		VSB_printf(vp->vsb, "vext_cache/%s,", p);
 		for (i = 0; i < 8; i++) {
diff --git a/bin/varnishtest/tests/x00000.vtc b/bin/varnishtest/tests/x00000.vtc
index 7069f4c2c..5baea5986 100644
--- a/bin/varnishtest/tests/x00000.vtc
+++ b/bin/varnishtest/tests/x00000.vtc
@@ -2,7 +2,7 @@ varnishtest "Test VMOD import from VEXT"
 
 feature topbuild
 
-server s1 {
+server s1 -repeat 2 {
 	rxreq
 	txresp
 } -start
@@ -23,3 +23,26 @@ client c1 {
 	rxresp
 	expect resp.http.foobar ~ [0-9]
 } -run
+
+varnish v1 -stop
+
+varnish v2 \
+	-arg "-Estd" \
+	-vcl+backend {
+		import std;
+
+		sub vcl_deliver {
+			set resp.http.foobar = std.random(10,99);
+		}
+	} -start
+
+client c2 -connect ${v2_sock} {
+	txreq
+	rxresp
+	expect resp.http.foobar ~ [0-9]
+} -run
+
+varnish v2 -stop
+
+shell -err -match {Error:.*Cannot open libvmod_std.so} \
+	"varnishd -pvmod_path=/nonexistent -Estd -b none -a ${tmpdir}/vtc.sock"