diff --git a/cgit.c b/cgit.c
index 6be3754..dd40893 100644
--- a/cgit.c
+++ b/cgit.c
@@ -463,6 +463,7 @@ static int prepare_repo_cmd(struct cgit_context *ctx)
 		cgit_print_docend();
 		return 1;
 	}
+	cgit_prepare_repo_env(ctx->repo);
 	return 0;
 }
 
diff --git a/cgit.h b/cgit.h
index caa9d8e..df7ee5d 100644
--- a/cgit.h
+++ b/cgit.h
@@ -319,9 +319,11 @@ extern const char *cgit_repobasename(const char *reponame);
 
 extern int cgit_parse_snapshots_mask(const char *str);
 
-extern int cgit_open_filter(struct cgit_filter *filter, struct cgit_repo * repo);
+extern int cgit_open_filter(struct cgit_filter *filter);
 extern int cgit_close_filter(struct cgit_filter *filter);
 
+extern void cgit_prepare_repo_env(struct cgit_repo * repo);
+
 extern int readfile(const char *path, char **buf, size_t *size);
 
 extern char *expand_macros(const char *txt);
diff --git a/shared.c b/shared.c
index be2ae59..4adeaa8 100644
--- a/shared.c
+++ b/shared.c
@@ -374,7 +374,8 @@ typedef struct {
 	char * value;
 } cgit_env_var;
 
-static void prepare_env(struct cgit_repo * repo) {
+void cgit_prepare_repo_env(struct cgit_repo * repo)
+{
 	cgit_env_var env_vars[] = {
 		{ .name = "CGIT_REPO_URL", .value = repo->url },
 		{ .name = "CGIT_REPO_NAME", .value = repo->name },
@@ -395,7 +396,7 @@ static void prepare_env(struct cgit_repo * repo) {
 			fprintf(stderr, warn, p->name, p->value);
 }
 
-int cgit_open_filter(struct cgit_filter *filter, struct cgit_repo * repo)
+int cgit_open_filter(struct cgit_filter *filter)
 {
 
 	filter->old_stdout = chk_positive(dup(STDOUT_FILENO),
@@ -406,8 +407,6 @@ int cgit_open_filter(struct cgit_filter *filter, struct cgit_repo * repo)
 		close(filter->pipe_fh[1]);
 		chk_non_negative(dup2(filter->pipe_fh[0], STDIN_FILENO),
 			"Unable to use pipe as STDIN");
-		if (repo)
-			prepare_env(repo);
 		execvp(filter->cmd, filter->argv);
 		die("Unable to exec subprocess %s: %s (%d)", filter->cmd,
 			strerror(errno), errno);
diff --git a/ui-commit.c b/ui-commit.c
index a69dec6..536a8e8 100644
--- a/ui-commit.c
+++ b/ui-commit.c
@@ -106,7 +106,7 @@ void cgit_print_commit(char *hex, const char *prefix)
 	html("</table>\n");
 	html("<div class='commit-subject'>");
 	if (ctx.repo->commit_filter)
-		cgit_open_filter(ctx.repo->commit_filter, ctx.repo);
+		cgit_open_filter(ctx.repo->commit_filter);
 	html_txt(info->subject);
 	if (ctx.repo->commit_filter)
 		cgit_close_filter(ctx.repo->commit_filter);
@@ -114,7 +114,7 @@ void cgit_print_commit(char *hex, const char *prefix)
 	html("</div>");
 	html("<div class='commit-msg'>");
 	if (ctx.repo->commit_filter)
-		cgit_open_filter(ctx.repo->commit_filter, ctx.repo);
+		cgit_open_filter(ctx.repo->commit_filter);
 	html_txt(info->msg);
 	if (ctx.repo->commit_filter)
 		cgit_close_filter(ctx.repo->commit_filter);
@@ -123,7 +123,7 @@ void cgit_print_commit(char *hex, const char *prefix)
 		html("<div class='notes-header'>Notes</div>");
 		html("<div class='notes'>");
 		if (ctx.repo->commit_filter)
-			cgit_open_filter(ctx.repo->commit_filter, ctx.repo);
+			cgit_open_filter(ctx.repo->commit_filter);
 		html_txt(notes.buf);
 		if (ctx.repo->commit_filter)
 			cgit_close_filter(ctx.repo->commit_filter);
diff --git a/ui-repolist.c b/ui-repolist.c
index dce2eac..25c36ce 100644
--- a/ui-repolist.c
+++ b/ui-repolist.c
@@ -300,7 +300,7 @@ void cgit_print_site_readme()
 	if (!ctx.cfg.root_readme)
 		return;
 	if (ctx.cfg.about_filter)
-		cgit_open_filter(ctx.cfg.about_filter, NULL);
+		cgit_open_filter(ctx.cfg.about_filter);
 	html_include(ctx.cfg.root_readme);
 	if (ctx.cfg.about_filter)
 		cgit_close_filter(ctx.cfg.about_filter);
diff --git a/ui-snapshot.c b/ui-snapshot.c
index 126779d..07cc944 100644
--- a/ui-snapshot.c
+++ b/ui-snapshot.c
@@ -19,7 +19,7 @@ static int write_compressed_tar_archive(struct archiver_args *args,const char *f
 	f.argv = malloc(2 * sizeof(char *));
 	f.argv[0] = f.cmd;
 	f.argv[1] = NULL;
-	cgit_open_filter(&f, NULL);
+	cgit_open_filter(&f);
 	rv = write_tar_archive(args);
 	cgit_close_filter(&f);
 	return rv;
diff --git a/ui-summary.c b/ui-summary.c
index 1e9a1b6..5be2545 100644
--- a/ui-summary.c
+++ b/ui-summary.c
@@ -113,7 +113,7 @@ void cgit_print_repo_readme(char *path)
 	 */
 	html("<div id='summary'>");
 	if (ctx.repo->about_filter)
-		cgit_open_filter(ctx.repo->about_filter, ctx.repo);
+		cgit_open_filter(ctx.repo->about_filter);
 	if (ref)
 		cgit_print_file(tmp, ref);
 	else
diff --git a/ui-tree.c b/ui-tree.c
index 2d8d2f3..442b6be 100644
--- a/ui-tree.c
+++ b/ui-tree.c
@@ -45,7 +45,7 @@ static void print_text_buffer(const char *name, char *buf, unsigned long size)
 	if (ctx.repo->source_filter) {
 		html("<td class='lines'><pre><code>");
 		ctx.repo->source_filter->argv[1] = xstrdup(name);
-		cgit_open_filter(ctx.repo->source_filter, ctx.repo);
+		cgit_open_filter(ctx.repo->source_filter);
 		html_raw(buf, size);
 		cgit_close_filter(ctx.repo->source_filter);
 		free(ctx.repo->source_filter->argv[1]);