group names are sentinel-terminated

src/DB.zig

@@ -315,7 +315,7 @@ fn getGroup(self: *const DB, group: PackedGroup, buf: []u8) error{BufferTooSmall
 
     return CGroup{
         .gid = group.gid(),
-        .name = buf[buf_offset .. buf_offset + name.len].ptr,
+        .name = buf[buf_offset .. buf_offset + name.len :0].ptr,
         .members = member_ptrs.ptr,
     };
 }
@@ -347,7 +347,7 @@ fn pushStr(str: []const u8, buf: []u8, offset: *usize) [*:0]const u8 {
     mem.copy(u8, buf[start..], str);
     buf[start + str.len] = 0;
     offset.* += str.len + 1;
-    return @ptrCast([*:0]const u8, &buf[start]);
+    return buf[start .. start + str.len :0].ptr;
 }
 
 fn getUser(self: *const DB, user: PackedUser, buf: []u8) error{BufferTooSmall}!CUser {

src/Group.zig

@@ -128,14 +128,11 @@ pub fn strlenZ(self: *const Group) usize {
     return count;
 }
 
-// Name type should be 0-terminated, members should be null-terminated, but
-// sentinel is not part of the type (but is always there). Adding sentinel
-// crashes zig compiler in pre-0.10. https://github.com/ziglang/zig/issues/7517
 pub const CGroup = extern struct {
     gid: u32,
-    // should be [*:0]const u8
+    name: [*:0]const u8,
-    name: [*]const u8,
     // Should be [*:null]align(1) const ?[*:0]const u8
+    // https://github.com/ziglang/zig/issues/7517
     members: [*]align(1) const ?[*:0]const u8,
 };
 

src/libnss.zig

@@ -275,10 +275,27 @@ test "getgrgid_r and getgrnam_r" {
     );
     try testing.expectEqual(@as(c_int, 0), errno);
     try testVidmantasGroup(group);
+
+    group = undefined;
+    try testing.expectEqual(
+        c.NSS_STATUS_SUCCESS,
+        _nss_turbo_getgrnam_r("vidmantas", &group, &buffer, buffer.len, &errno),
+    );
+    try testing.expectEqual(@as(c_int, 0), errno);
+    try testVidmantasGroup(group);
+
+    group = undefined;
+    try testing.expectEqual(
+        c.NSS_STATUS_NOTFOUND,
+        _nss_turbo_getgrnam_r("does not exist", &group, &buffer, buffer.len, &errno),
+    );
+    try testing.expectEqual(@enumToInt(os.E.NOENT), @intCast(u16, errno));
 }
 
 fn testVidmantasGroup(g: CGroup) !void {
     try testing.expectEqual(@as(u32, 128), g.gid);
+    try testing.expectEqualStrings("vidmantas", mem.sliceTo(g.name, 0));
     const members = g.members;
     try testing.expect(members[0] != null);
+    try testing.expectEqualStrings("vidmantas", mem.sliceTo(members[0].?, 0));
 }