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
@@ -217,65 +217,65 @@ static char *repolink(char *title, char *class, char *page, char *head,
 			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 = "&";
 	}
 	if (head && strcmp(head, ctx.repo->defbranch)) {
 		html(delim);
 		html("h=");
 		html_url_arg(head);
 		delim = "&";
 	}
 	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);
 }
 
@@ -317,65 +317,65 @@ void cgit_log_link(char *name, char *title, char *class, char *head,
 }
 
 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);