auth: have cgit calculate login address

This way we're sure to use virtual root, or any other strangeness
encountered.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

cgit.c

@@ -611,7 +611,8 @@ static inline void open_auth_filter(struct cgit_context *ctx, const char *functi
 		ctx->env.https ? ctx->env.https : "",
 		ctx->qry.repo ? ctx->qry.repo : "",
 		ctx->qry.page ? ctx->qry.page : "",
-		ctx->qry.url ? ctx->qry.url : "");
+		ctx->qry.url ? ctx->qry.url : "",
+		cgit_loginurl());
 }
 
 /* We intentionally keep this rather small, instead of looping and

cgitrc.5.txt

@@ -645,7 +645,7 @@ source filter::
 	filtered contents is expected on standard output.
 
 auth filter::
-	The authentication filter receives 11 parameters:
+	The authentication filter receives 12 parameters:
 	  - filter action, explained below, which specifies which action the
 	    filter is called for
 	  - http cookie
@@ -656,8 +656,9 @@ auth filter::
 	  - cgit repo
 	  - cgit page
 	  - cgit url
+	  - cgit login url
 	When the filter action is "body", this filter must write to output the
-	HTML for displaying the login form, which POSTs to "/?p=login". When
+	HTML for displaying the login form, which POSTs to the login url. When
 	the filter action is "authenticate-cookie", this filter must validate
 	the http cookie and return a 0 if it is invalid or 1 if it is invalid,
 	in the exit code / close function. If the filter action is

filter.c

@@ -417,7 +417,7 @@ struct cgit_filter *cgit_new_filter(const char *cmd, filter_type filtertype)
 
 	switch (filtertype) {
 		case AUTH:
-			argument_count = 11;
+			argument_count = 12;
 			break;
 
 		case EMAIL:

filters/simple-authentication.lua

@@ -122,12 +122,7 @@ function filter_open(...)
 	cgit["repo"] = select(9, ...)
 	cgit["page"] = select(10, ...)
 	cgit["url"] = select(11, ...)
-
-	cgit["login"] = ""
-	for _ in cgit["url"]:gfind("/") do
-		cgit["login"] = cgit["login"] .. "../"
-	end
-	cgit["login"] = cgit["login"] .. "?p=login"
+	cgit["login"] = select(12, ...)
 
 end
 

ui-shared.c

@@ -73,6 +73,14 @@ const char *cgit_rooturl()
 		return ctx.cfg.script_name;
 }
 
+const char *cgit_loginurl()
+{
+	static const char *login_url = 0;
+	if (!login_url)
+		login_url = fmtalloc("%s?p=login", cgit_rooturl());
+	return login_url;
+}
+
 char *cgit_repourl(const char *reponame)
 {
 	if (ctx.cfg.virtual_root)

ui-shared.h

@@ -4,6 +4,7 @@
 extern const char *cgit_httpscheme();
 extern const char *cgit_hosturl();
 extern const char *cgit_rooturl();
+extern const char *cgit_loginurl();
 extern char *cgit_repourl(const char *reponame);
 extern char *cgit_fileurl(const char *reponame, const char *pagename,
 			  const char *filename, const char *query);