ui-shared.c: fix segfault when repo is empty

PATH_INFO="/$REPONAME/commit/?id=1" QUERY_STRING="id=1" ./cgit.cgi
triggers segfault when the repository is empty and therefore
ctx.qry.head is unset

Signed-off-by: Florian Pritz <bluewind@xssn.at>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/ui-shared.c b/ui-shared.c
index 4049a2b..8a7cc32 100644
--- a/ui-shared.c
+++ b/ui-shared.c
@@ -153,293 +153,293 @@ static void site_url(char *page, char *search, int ofs)
                 html("q=");
                 html_attr(search);
                 delim = "&";
         }
         if (ofs) {
                 html(delim);
                 htmlf("ofs=%d", ofs);
         }
 }
 
 static void site_link(char *page, char *name, char *title, char *class,
                       char *search, int ofs)
 {
         html("<a");
         if (title) {
                 html(" title='");
                 html_attr(title);
                 html("'");
         }
         if (class) {
                 html(" class='");
                 html_attr(class);
                 html("'");
         }
         html(" href='");
         site_url(page, search, ofs);
         html("'>");
         html_txt(name);
         html("</a>");
 }
 
 void cgit_index_link(char *name, char *title, char *class, char *pattern,
                      int ofs)
 {
         site_link(NULL, name, title, class, pattern, ofs);
 }
 
 static char *repolink(char *title, char *class, char *page, char *head,
                       char *path)
 {
         char *delim = "?";
 
         html("<a");
         if (title) {
                 html(" title='");
                 html_attr(title);
                 html("'");
         }
         if (class) {
                 html(" class='");
                 html_attr(class);
                 html("'");
         }
         html(" href='");
         if (ctx.cfg.virtual_root) {
                 html_url_path(ctx.cfg.virtual_root);
                 if (ctx.cfg.virtual_root[strlen(ctx.cfg.virtual_root) - 1] != '/')
                         html("/");
                 html_url_path(ctx.repo->url);
                 if (ctx.repo->url[strlen(ctx.repo->url) - 1] != '/')
                         html("/");
                 if (page) {
                         html_url_path(page);
                         html("/");
                         if (path)
                                 html_url_path(path);
                 }
         } else {
                 html(ctx.cfg.script_name);
                 html("?url=");
                 html_url_arg(ctx.repo->url);
                 if (ctx.repo->url[strlen(ctx.repo->url) - 1] != '/')
                         html("/");
                 if (page) {
                         html_url_arg(page);
                         html("/");
                         if (path)
                                 html_url_arg(path);
                 }
                 delim = "&amp;";
         }
         if (head && strcmp(head, ctx.repo->defbranch)) {
                 html(delim);
                 html("h=");
                 html_url_arg(head);
                 delim = "&amp;";
         }
         return fmt("%s", delim);
 }
 
 static void reporevlink(char *page, char *name, char *title, char *class,
                         char *head, char *rev, char *path)
 {
         char *delim;
 
         delim = repolink(title, class, page, head, path);
-        if (rev && strcmp(rev, ctx.qry.head)) {
+        if (rev && ctx.qry.head != NULL && strcmp(rev, ctx.qry.head)) {
                 html(delim);
                 html("id=");
                 html_url_arg(rev);
         }
         html("'>");
         html_txt(name);
         html("</a>");
 }
 
 void cgit_summary_link(char *name, char *title, char *class, char *head)
 {
         reporevlink(NULL, name, title, class, head, NULL, NULL);
 }
 
 void cgit_tag_link(char *name, char *title, char *class, char *head,
                    char *rev)
 {
         reporevlink("tag", name, title, class, head, rev, NULL);
 }
 
 void cgit_tree_link(char *name, char *title, char *class, char *head,
                     char *rev, char *path)
 {
         reporevlink("tree", name, title, class, head, rev, path);
 }
 
 void cgit_plain_link(char *name, char *title, char *class, char *head,
                      char *rev, char *path)
 {
         reporevlink("plain", name, title, class, head, rev, path);
 }
 
 void cgit_log_link(char *name, char *title, char *class, char *head,
                    char *rev, char *path, int ofs, char *grep, char *pattern,
                    int showmsg)
 {
         char *delim;
 
         delim = repolink(title, class, "log", head, path);
         if (rev && strcmp(rev, ctx.qry.head)) {
                 html(delim);
                 html("id=");
                 html_url_arg(rev);
                 delim = "&";
         }
         if (grep && pattern) {
                 html(delim);
                 html("qt=");
                 html_url_arg(grep);
                 delim = "&";
                 html(delim);
                 html("q=");
                 html_url_arg(pattern);
         }
         if (ofs > 0) {
                 html(delim);
                 html("ofs=");
                 htmlf("%d", ofs);
                 delim = "&";
         }
         if (showmsg) {
                 html(delim);
                 html("showmsg=1");
         }
         html("'>");
         html_txt(name);
         html("</a>");
 }
 
 void cgit_commit_link(char *name, char *title, char *class, char *head,
                       char *rev)
 {
         if (strlen(name) > ctx.cfg.max_msg_len && ctx.cfg.max_msg_len >= 15) {
                 name[ctx.cfg.max_msg_len] = '\0';
                 name[ctx.cfg.max_msg_len - 1] = '.';
                 name[ctx.cfg.max_msg_len - 2] = '.';
                 name[ctx.cfg.max_msg_len - 3] = '.';
         }
         reporevlink("commit", name, title, class, head, rev, NULL);
 }
 
 void cgit_refs_link(char *name, char *title, char *class, char *head,
                     char *rev, char *path)
 {
         reporevlink("refs", name, title, class, head, rev, path);
 }
 
 void cgit_snapshot_link(char *name, char *title, char *class, char *head,
                         char *rev, char *archivename)
 {
         reporevlink("snapshot", name, title, class, head, rev, archivename);
 }
 
 void cgit_diff_link(char *name, char *title, char *class, char *head,
                     char *new_rev, char *old_rev, char *path)
 {
         char *delim;
 
         delim = repolink(title, class, "diff", head, path);
-        if (new_rev && strcmp(new_rev, ctx.qry.head)) {
+        if (new_rev && ctx.qry.head != NULL && strcmp(new_rev, ctx.qry.head)) {
                 html(delim);
                 html("id=");
                 html_url_arg(new_rev);
                 delim = "&amp;";
         }
         if (old_rev) {
                 html(delim);
                 html("id2=");
                 html_url_arg(old_rev);
         }
         html("'>");
         html_txt(name);
         html("</a>");
 }
 
 void cgit_patch_link(char *name, char *title, char *class, char *head,
                      char *rev)
 {
         reporevlink("patch", name, title, class, head, rev, NULL);
 }
 
 void cgit_stats_link(char *name, char *title, char *class, char *head,
                      char *path)
 {
         reporevlink("stats", name, title, class, head, NULL, path);
 }
 
 void cgit_object_link(struct object *obj)
 {
         char *page, *shortrev, *fullrev, *name;
 
         fullrev = sha1_to_hex(obj->sha1);
         shortrev = xstrdup(fullrev);
         shortrev[10] = '\0';
         if (obj->type == OBJ_COMMIT) {
                 cgit_commit_link(fmt("commit %s...", shortrev), NULL, NULL,
                                  ctx.qry.head, fullrev);
                 return;
         } else if (obj->type == OBJ_TREE)
                 page = "tree";
         else if (obj->type == OBJ_TAG)
                 page = "tag";
         else
                 page = "blob";
         name = fmt("%s %s...", typename(obj->type), shortrev);
         reporevlink(page, name, NULL, NULL, ctx.qry.head, fullrev, NULL);
 }
 
 void cgit_print_date(time_t secs, char *format, int local_time)
 {
         char buf[64];
         struct tm *time;
 
         if (!secs)
                 return;
         if(local_time)
                 time = localtime(&secs);
         else
                 time = gmtime(&secs);
         strftime(buf, sizeof(buf)-1, format, time);
         html_txt(buf);
 }
 
 void cgit_print_age(time_t t, time_t max_relative, char *format)
 {
         time_t now, secs;
 
         if (!t)
                 return;
         time(&now);
         secs = now - t;
 
         if (secs > max_relative && max_relative >= 0) {
                 cgit_print_date(t, format, ctx.cfg.local_time);
                 return;
         }
 
         if (secs < TM_HOUR * 2) {
                 htmlf("<span class='age-mins'>%.0f min.</span>",
                       secs * 1.0 / TM_MIN);
                 return;
         }
         if (secs < TM_DAY * 2) {
                 htmlf("<span class='age-hours'>%.0f hours</span>",
                       secs * 1.0 / TM_HOUR);
                 return;
         }
         if (secs < TM_WEEK * 2) {
                 htmlf("<span class='age-days'>%.0f days</span>",
                       secs * 1.0 / TM_DAY);
                 return;
         }
         if (secs < TM_MONTH * 2) {
                 htmlf("<span class='age-weeks'>%.0f weeks</span>",
                       secs * 1.0 / TM_WEEK);
                 return;