Fetch the supplementary groups properly. Closes #1.

src/main.zig

@@ -19,12 +19,13 @@ const c = @cImport({
     @cInclude("unistd.h");
     @cInclude("grp.h");
     @cInclude("crypt.h");
+    @cInclude("string.h");
 });
 
 fn getGroups(alloc: mem.Allocator, passwd: c.passwd) ![]c.gid_t {
     var ngr: c_int = 0;
     _ = c.getgrouplist(passwd.pw_name, passwd.pw_gid, null, &ngr);
-    const groups = try alloc.alloc(c.gid_t, @intCast(usize, ngr));
+    const groups = try alloc.alloc(c.gid_t, @intCast(ngr));
     _ = c.getgrouplist(passwd.pw_name, passwd.pw_gid, groups.ptr, &ngr);
     return groups;
 }
@@ -55,10 +56,12 @@ pub fn main() !u8 {
         const gr = c.getgrgid(gr_id).*;
         if (gr.gr_gid == wheel.gr_gid) {
             const pass = mem.span(c.getpass("#: "));
-            if (cstr.cmp(shadow.sp_pwdp, c.crypt(pass, shadow.sp_pwdp)) == 0) {
+            if (c.strcmp(shadow.sp_pwdp, c.crypt(pass, shadow.sp_pwdp)) == 0) {
                 crypto.utils.secureZero(u8, pass);
                 _ = c.setuid(0);
                 _ = c.setgid(0);
+                const rootGroups = try getGroups(gpa, c.getpwuid(0).*);
+                _ = c.setgroups(rootGroups.len, rootGroups.ptr);
                 var argl = ArrayList([]const u8).init(gpa);
                 for (os.argv[1..]) |arg| {
                     try argl.append(mem.span(arg));