Be prepared for empty repositories

Before this patch, cgit would segfault on repositories with no refs.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

2 files changed, 9 insertions, 4 deletions

diff --git a/cgit.c b/cgit.c
index 8795085..cefeddf 100644
--- a/cgit.c
+++ b/cgit.c
@@ -146,163 +146,167 @@ static void querystring_cb(const char *name, const char *value)
 		ctx.qry.ofs = atoi(value);
 	} else if (!strcmp(name, "path")) {
 		ctx.qry.path = trim_end(value, '/');
 	} else if (!strcmp(name, "name")) {
 		ctx.qry.name = xstrdup(value);
 	} else if (!strcmp(name, "mimetype")) {
 		ctx.qry.mimetype = xstrdup(value);
 	}
 }
 
 static void prepare_context(struct cgit_context *ctx)
 {
 	memset(ctx, 0, sizeof(ctx));
 	ctx->cfg.agefile = "info/web/last-modified";
 	ctx->cfg.nocache = 0;
 	ctx->cfg.cache_size = 0;
 	ctx->cfg.cache_dynamic_ttl = 5;
 	ctx->cfg.cache_max_create_time = 5;
 	ctx->cfg.cache_repo_ttl = 5;
 	ctx->cfg.cache_root = CGIT_CACHE_ROOT;
 	ctx->cfg.cache_root_ttl = 5;
 	ctx->cfg.cache_static_ttl = -1;
 	ctx->cfg.css = "/cgit.css";
 	ctx->cfg.logo = "/git-logo.png";
 	ctx->cfg.max_repo_count = 50;
 	ctx->cfg.max_commit_count = 50;
 	ctx->cfg.max_lock_attempts = 5;
 	ctx->cfg.max_msg_len = 60;
 	ctx->cfg.max_repodesc_len = 60;
 	ctx->cfg.module_link = "./?repo=%s&page=commit&id=%s";
 	ctx->cfg.renamelimit = -1;
 	ctx->cfg.robots = "index, nofollow";
 	ctx->cfg.root_title = "Git repository browser";
 	ctx->cfg.root_desc = "a fast webinterface for the git dscm";
 	ctx->cfg.script_name = CGIT_SCRIPT_NAME;
 	ctx->page.mimetype = "text/html";
 	ctx->page.charset = PAGE_ENCODING;
 	ctx->page.filename = NULL;
 	ctx->page.modified = time(NULL);
 	ctx->page.expires = ctx->page.modified;
 }
 
 struct refmatch {
 	char *req_ref;
 	char *first_ref;
 	int match;
 };
 
 int find_current_ref(const char *refname, const unsigned char *sha1,
 		     int flags, void *cb_data)
 {
 	struct refmatch *info;
 
 	info = (struct refmatch *)cb_data;
 	if (!strcmp(refname, info->req_ref))
 		info->match = 1;
 	if (!info->first_ref)
 		info->first_ref = xstrdup(refname);
 	return info->match;
 }
 
 char *find_default_branch(struct cgit_repo *repo)
 {
 	struct refmatch info;
+	char *ref;
 
 	info.req_ref = repo->defbranch;
 	info.first_ref = NULL;
 	info.match = 0;
 	for_each_branch_ref(find_current_ref, &info);
 	if (info.match)
-		return info.req_ref;
+		ref = info.req_ref;
 	else
-		return info.first_ref;
+		ref = info.first_ref;
+	if (ref)
+		ref = xstrdup(ref);
+	return ref;
 }
 
 static int prepare_repo_cmd(struct cgit_context *ctx)
 {
 	char *tmp;
 	unsigned char sha1[20];
 	int nongit = 0;
 
 	setenv("GIT_DIR", ctx->repo->path, 1);
 	setup_git_directory_gently(&nongit);
 	if (nongit) {
 		ctx->page.title = fmt("%s - %s", ctx->cfg.root_title,
 				      "config error");
 		tmp = fmt("Not a git repository: '%s'", ctx->repo->path);
 		ctx->repo = NULL;
 		cgit_print_http_headers(ctx);
 		cgit_print_docstart(ctx);
 		cgit_print_pageheader(ctx);
 		cgit_print_error(tmp);
 		cgit_print_docend();
 		return 1;
 	}
 	ctx->page.title = fmt("%s - %s", ctx->repo->name, ctx->repo->desc);
 
 	if (!ctx->qry.head) {
-		ctx->qry.head = xstrdup(find_default_branch(ctx->repo));
+		ctx->qry.head = find_default_branch(ctx->repo);
 		ctx->repo->defbranch = ctx->qry.head;
 	}
 
 	if (!ctx->qry.head) {
 		cgit_print_http_headers(ctx);
 		cgit_print_docstart(ctx);
 		cgit_print_pageheader(ctx);
 		cgit_print_error("Repository seems to be empty");
 		cgit_print_docend();
 		return 1;
 	}
 
 	if (get_sha1(ctx->qry.head, sha1)) {
 		tmp = xstrdup(ctx->qry.head);
 		ctx->qry.head = ctx->repo->defbranch;
 		cgit_print_http_headers(ctx);
 		cgit_print_docstart(ctx);
 		cgit_print_pageheader(ctx);
 		cgit_print_error(fmt("Invalid branch: %s", tmp));
 		cgit_print_docend();
 		return 1;
 	}
 	return 0;
 }
 
 static void process_request(void *cbdata)
 {
 	struct cgit_context *ctx = cbdata;
 	struct cgit_cmd *cmd;
 
 	cmd = cgit_get_cmd(ctx);
 	if (!cmd) {
 		ctx->page.title = "cgit error";
 		ctx->repo = NULL;
 		cgit_print_http_headers(ctx);
 		cgit_print_docstart(ctx);
 		cgit_print_pageheader(ctx);
 		cgit_print_error("Invalid request");
 		cgit_print_docend();
 		return;
 	}
 
 	if (cmd->want_repo && !ctx->repo) {
 		cgit_print_http_headers(ctx);
 		cgit_print_docstart(ctx);
 		cgit_print_pageheader(ctx);
 		cgit_print_error(fmt("No repository selected"));
 		cgit_print_docend();
 		return;
 	}
 
 	if (ctx->repo && prepare_repo_cmd(ctx))
 		return;
 
 	if (cmd->want_layout) {
 		cgit_print_http_headers(ctx);
 		cgit_print_docstart(ctx);
 		cgit_print_pageheader(ctx);
 	}
 
 	cmd->fn(ctx);
 
 	if (cmd->want_layout)
 		cgit_print_docend();
diff --git a/ui-shared.c b/ui-shared.c
index 209af6e..4280a70 100644
--- a/ui-shared.c
+++ b/ui-shared.c
@@ -457,129 +457,130 @@ void cgit_print_docend()
 		htmlf(" by cgit %s", cgit_version);
 		html("</div>\n");
 	}
 	html("</body>\n</html>\n");
 }
 
 int print_branch_option(const char *refname, const unsigned char *sha1,
 			int flags, void *cb_data)
 {
 	char *name = (char *)refname;
 	html_option(name, name, ctx.qry.head);
 	return 0;
 }
 
 int print_archive_ref(const char *refname, const unsigned char *sha1,
 		       int flags, void *cb_data)
 {
 	struct tag *tag;
 	struct taginfo *info;
 	struct object *obj;
 	char buf[256], *url;
 	unsigned char fileid[20];
 	int *header = (int *)cb_data;
 
 	if (prefixcmp(refname, "refs/archives"))
 		return 0;
 	strncpy(buf, refname+14, sizeof(buf));
 	obj = parse_object(sha1);
 	if (!obj)
 		return 1;
 	if (obj->type == OBJ_TAG) {
 		tag = lookup_tag(sha1);
 		if (!tag || parse_tag(tag) || !(info = cgit_parse_tag(tag)))
 			return 0;
 		hashcpy(fileid, tag->tagged->sha1);
 	} else if (obj->type != OBJ_BLOB) {
 		return 0;
 	} else {
 		hashcpy(fileid, sha1);
 	}
 	if (!*header) {
 		html("<h1>download</h1>\n");
 		*header = 1;
 	}
 	url = cgit_pageurl(ctx.qry.repo, "blob",
 			   fmt("id=%s&amp;path=%s", sha1_to_hex(fileid),
 			       buf));
 	html_link_open(url, NULL, "menu");
 	html_txt(strlpart(buf, 20));
 	html_link_close();
 	return 0;
 }
 
 void add_hidden_formfields(int incl_head, int incl_search, char *page)
 {
 	char *url;
 
 	if (!ctx.cfg.virtual_root) {
 		url = fmt("%s/%s", ctx.qry.repo, page);
 		if (ctx.qry.path)
 			url = fmt("%s/%s", url, ctx.qry.path);
 		html_hidden("url", url);
 	}
 
-	if (incl_head && strcmp(ctx.qry.head, ctx.repo->defbranch))
+	if (incl_head && ctx.qry.head && ctx.repo->defbranch &&
+	    strcmp(ctx.qry.head, ctx.repo->defbranch))
 		html_hidden("h", ctx.qry.head);
 
 	if (ctx.qry.sha1)
 		html_hidden("id", ctx.qry.sha1);
 	if (ctx.qry.sha2)
 		html_hidden("id2", ctx.qry.sha2);
 
 	if (incl_search) {
 		if (ctx.qry.grep)
 			html_hidden("qt", ctx.qry.grep);
 		if (ctx.qry.search)
 			html_hidden("q", ctx.qry.search);
 	}
 }
 
 char *hc(struct cgit_cmd *cmd, const char *page)
 {
 	return (strcmp(cmd->name, page) ? NULL : "active");
 }
 
 void cgit_print_pageheader(struct cgit_context *ctx)
 {
 	struct cgit_cmd *cmd = cgit_get_cmd(ctx);
 
 	html("<table id='header'>\n");
 	html("<tr>\n");
 	html("<td class='logo' rowspan='2'><a href='");
 	if (ctx->cfg.logo_link)
 		html_attr(ctx->cfg.logo_link);
 	else
 		html_attr(cgit_rooturl());
 	html("'><img src='");
 	html_attr(ctx->cfg.logo);
 	html("' alt='cgit logo'/></a></td>\n");
 
 	html("<td class='main'>");
 	if (ctx->repo) {
 		cgit_index_link("index", NULL, NULL, NULL, 0);
 		html(" : ");
 		reporevlink(NULL, ctx->repo->name, NULL, hc(cmd, "summary"),
 			    ctx->qry.head, NULL, NULL);
 		html("</td><td class='form'>");
 		html("<form method='get' action=''>\n");
 		add_hidden_formfields(0, 1, ctx->qry.page);
 		html("<select name='h' onchange='this.form.submit();'>\n");
 		for_each_branch_ref(print_branch_option, ctx->qry.head);
 		html("</select> ");
 		html("<input type='submit' name='' value='switch'/>");
 		html("</form>");
 	} else
 		html_txt(ctx->cfg.root_title);
 	html("</td></tr>\n");
 
 	html("<tr><td class='sub'>");
 	if (ctx->repo) {
 		html_txt(ctx->repo->desc);
 		html("</td><td class='sub right'>");
 		html_txt(ctx->repo->owner);
 	} else {
 		if (ctx->cfg.root_desc)
 			html_txt(ctx->cfg.root_desc);
 		else if (ctx->cfg.index_info)
 			html_include(ctx->cfg.index_info);
 	}