remove debug code

src/DB.zig

@@ -279,7 +279,7 @@ pub fn fromBytes(buf: []align(8) const u8) InvalidHeader!DB {
     return result;
 }
 
-pub fn packCGroupNoMembers(group: PackedGroup, buf: []u8) error{BufferTooSmall}!CGroup {
+pub fn packCGroupNoMembers(group: *const PackedGroup, buf: []u8) error{BufferTooSmall}!CGroup {
     // first word in buf will be a pointer to null. that probably can be
     // simplified by writing (0)**word_size to the buffer, but let's pretend
     // type safety for a moment.
@@ -301,48 +301,53 @@ pub fn packCGroupNoMembers(group: PackedGroup, buf: []u8) error{BufferTooSmall}!
     };
 }
 
-const GroupMembersIter = struct {
-    it: compress.DeltaDecompressionIterator,
-};
-
-pub fn groupMembersIter(vit: *compress.VarintSliceIterator) GroupMembersIter {
-    return GroupMembersIter{
-        .it = compress.deltaDecompressionIterator(vit),
-    };
-}
-
+// The pointer to `arr` gets changed on second iteration, and I don't know why.
+// Leaving this for better times.
+//const GroupMembersIter = struct {
+//    vit: compress.VarintSliceIterator,
+//    it: compress.DeltaDecompressionIterator,
+//    total: usize,
+//    arr: []const u8,
+//
+//    pub fn nextMust(self: *GroupMembersIter) ?u64 {
+//        return self.it.nextMust();
+//    }
+//};
+//
 //pub fn groupMembersIter(members_slice: []const u8) GroupMembersIter {
+//    std.debug.print("members_slice.ptr={*}\n", .{members_slice.ptr});
 //    var vit = compress.varintSliceIteratorMust(members_slice);
+//    var it = compress.deltaDecompressionIterator(&vit);
 //    return GroupMembersIter{
-//        .it = compress.deltaDecompressionIterator(&vit),
+//        .arr = members_slice,
+//        .vit = vit,
+//        .it = it,
+//        .total = vit.remaining,
 //    };
 //}
 
 // dumps PackedGroup to []u8 and returns a CGroup.
-pub fn packCGroup(self: *const DB, group: PackedGroup, buf: []u8) error{BufferTooSmall}!CGroup {
+pub fn packCGroup(self: *const DB, group: *const PackedGroup, buf: []u8) error{BufferTooSmall}!CGroup {
     const members_slice = self.groupmembers[group.members_offset..];
     var vit = compress.varintSliceIteratorMust(members_slice);
     const num_members = vit.remaining;
 
     const ptr_end = @sizeOf(?[*:0]const u8) * (num_members + 1);
-    if (ptr_end > buf.len) return error.BufferTooSmall;
+    if (ptr_end > buf.len)
+        return error.BufferTooSmall;
     var member_ptrs = mem.bytesAsSlice(?[*:0]const u8, buf[0..ptr_end]);
     member_ptrs[member_ptrs.len - 1] = null;
     var buf_offset: usize = ptr_end;
 
     var it = compress.deltaDecompressionIterator(&vit);
-    var members = groupMembersIter(&vit);
-    _ = members;
-    _ = it;
 
     var i: usize = 0;
-    std.debug.print("\n", .{});
     while (it.nextMust()) |member_offset| : (i += 1) {
-        std.debug.print("got offset: {d}\n", .{member_offset});
         const entry = PackedUser.fromBytes(self.users[member_offset << 3 ..]);
         const start = buf_offset;
         const name = entry.user.name();
-        if (buf_offset + name.len + 1 > buf.len) return error.BufferTooSmall;
+        if (buf_offset + name.len + 1 > buf.len)
+            return error.BufferTooSmall;
         mem.copy(u8, buf[buf_offset..], name);
         buf_offset += name.len;
         buf[buf_offset] = 0;
@@ -394,9 +399,9 @@ pub fn getgrnam(
 ) error{BufferTooSmall}!?CGroup {
     const group = self.getGroupByName(name) orelse return null;
     if (omit_members)
-        return try packCGroupNoMembers(group, buf)
+        return try packCGroupNoMembers(&group, buf)
     else
-        return try self.packCGroup(group, buf);
+        return try self.packCGroup(&group, buf);
 }
 
 // get a CGroup entry by it's gid.
@@ -408,9 +413,9 @@ pub fn getgrgid(
 ) error{BufferTooSmall}!?CGroup {
     const group = self.getGroupByGid(gid) orelse return null;
     if (omit_members)
-        return try packCGroupNoMembers(group, buf)
+        return try packCGroupNoMembers(&group, buf)
     else
-        return try self.packCGroup(group, buf);
+        return try self.packCGroup(&group, buf);
 }
 
 fn pushStr(str: []const u8, buf: []u8, offset: *usize) [*:0]const u8 {

src/compress.zig

@@ -112,6 +112,7 @@ pub const VarintSliceIterator = struct {
         if (self.remaining == 0)
             return null;
         const value = try uvarint(self.arr[self.idx..]);
+        //std.debug.print("ptr={*} idx={d:<10} arr.ptr={*}\n", .{ self, self.idx, self.arr.ptr });
         self.idx += value.bytes_read;
         self.remaining -= 1;
         return value.value;
@@ -334,3 +335,33 @@ test "overflow" {
         try testing.expectError(error.Overflow, uvarint(t));
     }
 }
+
+const compress = @This();
+
+const GroupMembersIter = struct {
+    vit: compress.VarintSliceIterator,
+    it: compress.DeltaDecompressionIterator,
+    total: usize,
+};
+
+pub fn groupMembersIter(members_slice: []const u8) GroupMembersIter {
+    var vit = compress.varintSliceIteratorMust(members_slice);
+    var it = compress.deltaDecompressionIterator(&vit);
+    return GroupMembersIter{
+        .vit = vit,
+        .it = it,
+        .total = vit.remaining,
+    };
+}
+
+test "compress: trying to repro pointer change of DB.groupMembersIter" {
+    const members_slice = &[_]u8{ 4, 0, 60, 2, 2, 2, 64, 2 };
+
+    var members = groupMembersIter(members_slice);
+
+    var i: usize = 0;
+    while (members.it.nextMust()) |member_offset| : (i += 1) {
+        _ = member_offset;
+        //std.debug.print("member_offset: {d}\n", .{member_offset});
+    }
+}

src/libnss.zig

@@ -342,9 +342,9 @@ fn getgrent_r(
     };
 
     const cgroup1 = if (state.omit_members)
-        DB.packCGroupNoMembers(group, buffer[0..buflen])
+        DB.packCGroupNoMembers(&group, buffer[0..buflen])
     else
-        state.file.db.packCGroup(group, buffer[0..buflen]);
+        state.file.db.packCGroup(&group, buffer[0..buflen]);
 
     if (cgroup1) |cgroup| {
         result.* = cgroup;