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);
         }