IOS/ES: Fix the implementation of ES_DeleteTicket

* It should take a ticket view, not a title ID.
* It's missing a lot of checks.
* It's not deleting tickets properly.
* It's not deleting only the ticket it needs to delete.
* It should not return -1017 when the ticket doesn't exist.
* It's not returning the proper error code when a read/write fails.
* It's not cleaning up the ticket directory if there is nothing left.

This commit fixes its implementation.

Source/Core/Core/IOS/ES/Formats.cpp

@@ -300,6 +300,21 @@ std::vector<u8> TicketReader::GetTitleKey() const
   return key;
 }
 
+void TicketReader::DeleteTicket(u64 ticket_id_to_delete)
+{
+  std::vector<u8> new_ticket;
+  const size_t num_tickets = GetNumberOfTickets();
+  for (size_t i = 0; i < num_tickets; ++i)
+  {
+    const auto ticket_start = m_bytes.cbegin() + sizeof(Ticket) * i;
+    const u64 ticket_id = Common::swap64(&*ticket_start + offsetof(Ticket, ticket_id));
+    if (ticket_id != ticket_id_to_delete)
+      new_ticket.insert(new_ticket.end(), ticket_start, ticket_start + sizeof(Ticket));
+  }
+
+  m_bytes = std::move(new_ticket);
+}
+
 s32 TicketReader::Unpersonalise()
 {
   const auto ticket_begin = m_bytes.begin();

Source/Core/Core/IOS/ES/Formats.h

@@ -193,6 +193,9 @@ public:
   u64 GetTitleId() const;
   std::vector<u8> GetTitleKey() const;
 
+  // Deletes a ticket with the given ticket ID from the internal buffer.
+  void DeleteTicket(u64 ticket_id);
+
   // Decrypts the title key field for a "personalised" ticket -- one that is device-specific
   // and has a title key that must be decrypted first.
   s32 Unpersonalise();

Source/Core/Core/IOS/ES/TitleManagement.cpp

@@ -6,6 +6,7 @@
 
 #include <algorithm>
 #include <cinttypes>
+#include <cstddef>
 #include <utility>
 #include <vector>
 
@@ -335,15 +336,45 @@ IPCCommandResult ES::DeleteTitle(const IOCtlVRequest& request)
 
 IPCCommandResult ES::DeleteTicket(const IOCtlVRequest& request)
 {
-  if (!request.HasNumberOfValidVectors(1, 0))
+  if (!request.HasNumberOfValidVectors(1, 0) ||
+      request.in_vectors[0].size != sizeof(IOS::ES::TicketView))
+  {
+    return GetDefaultReply(ES_EINVAL);
+  }
+
+  const u64 title_id =
+      Memory::Read_U64(request.in_vectors[0].address + offsetof(IOS::ES::TicketView, title_id));
+
+  if (!CanDeleteTitle(title_id))
     return GetDefaultReply(ES_EINVAL);
 
-  u64 TitleID = Memory::Read_U64(request.in_vectors[0].address);
-  INFO_LOG(IOS_ES, "IOCTL_ES_DELETETICKET: title: %08x/%08x", (u32)(TitleID >> 32), (u32)TitleID);
+  auto ticket = DiscIO::FindSignedTicket(title_id);
+  if (!ticket.IsValid())
+    return GetDefaultReply(FS_ENOENT);
 
-  // Presumably return -1017 when delete fails
-  if (!File::Delete(Common::GetTicketFileName(TitleID, Common::FROM_SESSION_ROOT)))
-    return GetDefaultReply(ES_EINVAL);
+  const u64 ticket_id =
+      Memory::Read_U64(request.in_vectors[0].address + offsetof(IOS::ES::TicketView, ticket_id));
+  ticket.DeleteTicket(ticket_id);
+
+  const std::vector<u8>& new_ticket = ticket.GetRawTicket();
+  const std::string ticket_path = Common::GetTicketFileName(title_id, Common::FROM_SESSION_ROOT);
+  {
+    File::IOFile ticket_file(ticket_path, "wb");
+    if (!ticket_file || !ticket_file.WriteBytes(new_ticket.data(), new_ticket.size()))
+      return GetDefaultReply(ES_EIO);
+  }
+
+  // Delete the ticket file if it is now empty.
+  if (new_ticket.empty())
+    File::Delete(ticket_path);
+
+  // Delete the ticket directory if it is now empty.
+  const std::string ticket_parent_dir =
+      Common::RootUserPath(Common::FROM_CONFIGURED_ROOT) +
+      StringFromFormat("/ticket/%08x", static_cast<u32>(title_id >> 32));
+  const auto ticket_parent_dir_entries = File::ScanDirectoryTree(ticket_parent_dir, false);
+  if (ticket_parent_dir_entries.children.empty())
+    File::DeleteDir(ticket_parent_dir);
 
   return GetDefaultReply(IPC_SUCCESS);
 }