[PATCH v2 4/5] upload-pack: read uploadpack.lazyFetchTrusted

[Christian Couder <christian.couder@gmail.com>]

Previous commits created and prepared the path_allowlist_apply()
function.

Let's reuse this function for a new "uploadpack.lazyFetchTrusted"
configuration variable.

It allows us to:

  - read an allowlist from that config variable,
  - check if the current repo is in that list, and
  - return the result from a new upload_pack_lazy_fetch_trusted()
    function.

The new function will be used in a following commit.

Note that the new config variable should be read only from protected
configuration files.

Signed-off-by: Christian Couder <christian.couder@gmail.com>
---
 upload-pack.c | 37 +++++++++++++++++++++++++++++++++++++
 upload-pack.h |  3 +++
 2 files changed, 40 insertions(+)

diff --git a/upload-pack.c b/upload-pack.c
index a52856d869..29e700e43b 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -34,6 +34,8 @@
 #include "json-writer.h"
 #include "strmap.h"
 #include "promisor-remote.h"
+#include "setup.h"
+#include "abspath.h"
 
 /* Remember to update object flag allocation in object.h */
 #define THEY_HAVE	(1u << 11)
@@ -1378,6 +1380,41 @@ static int upload_pack_config(const char *var, const char *value,
 	return parse_hide_refs_config(var, value, "uploadpack", &data->hidden_refs);
 }
 
+struct lazy_fetch_trusted {
+	int trusted;
+	char *repo_path;
+};
+
+static int upload_pack_protected_lazy_fetch_config(const char *var, const char *value,
+						   const struct config_context *ctx UNUSED,
+						   void *cb_data)
+{
+	struct lazy_fetch_trusted *data = cb_data;
+
+	if (!strcmp("uploadpack.lazyfetchtrusted", var)) {
+		path_allowlist_apply(var, value, data->repo_path,
+				     &data->trusted, false);
+		return 0;
+	}
+
+	return 0;
+}
+
+bool upload_pack_lazy_fetch_trusted(struct repository *r)
+{
+	struct lazy_fetch_trusted data = { 0 };
+
+	data.repo_path = real_pathdup(r->worktree ? r->worktree : r->gitdir, 0);
+	if (!data.repo_path)
+		return false;
+
+	git_protected_config(upload_pack_protected_lazy_fetch_config, &data);
+
+	free(data.repo_path);
+
+	return !!data.trusted;
+}
+
 static int upload_pack_protected_config(const char *var, const char *value,
 					const struct config_context *ctx UNUSED,
 					void *cb_data)
diff --git a/upload-pack.h b/upload-pack.h
index d6ee25ea98..b2212992c3 100644
--- a/upload-pack.h
+++ b/upload-pack.h
@@ -12,4 +12,7 @@ struct strbuf;
 int upload_pack_advertise(struct repository *r,
 			  struct strbuf *value);
 
+/* Is this repo trusted for lazy fetching? */
+bool upload_pack_lazy_fetch_trusted(struct repository *r);
+
 #endif /* UPLOAD_PACK_H */
-- 
2.55.0.565.gc116661202