ncch_container: Apply IPS patch after allocating .bss

This allows an IPS patch to edit .bss. This is useful for game patches
that need to add code, as putting things in .bss allows adding new code
*without* editing .code and thus without having to relocate everything.

src/core/file_sys/ncch_container.cpp

@@ -539,26 +539,28 @@ Loader::ResultStatus NCCHContainer::LoadSectionExeFS(const char* name, std::vect
                 }
             }
 
-            std::string override_ips = filepath + ".exefsdir/code.ips";
-
-            if (FileUtil::Exists(override_ips) && strcmp(name, ".code") == 0) {
-                FileUtil::IOFile ips_file(override_ips, "rb");
-                std::size_t ips_file_size = ips_file.GetSize();
-                std::vector<u8> ips(ips_file_size);
-
-                if (ips_file.IsOpen() &&
-                    ips_file.ReadBytes(&ips[0], ips_file_size) == ips_file_size) {
-                    LOG_INFO(Service_FS, "File {} patching code.bin", override_ips);
-                    ApplyIPS(ips, buffer);
-                }
-            }
-
             return Loader::ResultStatus::Success;
         }
     }
     return Loader::ResultStatus::ErrorNotUsed;
 }
 
+bool NCCHContainer::ApplyIPSPatch(std::vector<u8>& code) const {
+    const std::string override_ips = filepath + ".exefsdir/code.ips";
+
+    FileUtil::IOFile ips_file{override_ips, "rb"};
+    if (!ips_file)
+        return false;
+
+    std::vector<u8> ips(ips_file.GetSize());
+    if (ips_file.ReadBytes(ips.data(), ips.size()) != ips.size())
+        return false;
+
+    LOG_INFO(Service_FS, "File {} patching code.bin", override_ips);
+    ApplyIPS(ips, code);
+    return true;
+}
+
 Loader::ResultStatus NCCHContainer::LoadOverrideExeFSSection(const char* name,
                                                              std::vector<u8>& buffer) {
     std::string override_name;

src/core/file_sys/ncch_container.h

@@ -271,6 +271,13 @@ public:
      */
     Loader::ResultStatus ReadExtdataId(u64& extdata_id);
 
+    /**
+     * Apply an IPS patch for .code (if it exists).
+     * This should only be called after allocating .bss.
+     * @return bool true if a patch was applied, false otherwise
+     */
+    bool ApplyIPSPatch(std::vector<u8>& code) const;
+
     /**
      * Checks whether the NCCH container contains an ExeFS
      * @return bool check result

src/core/loader/ncch.cpp

@@ -100,6 +100,9 @@ ResultStatus AppLoader_NCCH::LoadExec(std::shared_ptr<Kernel::Process>& process)
             overlay_ncch->exheader_header.codeset_info.data.num_max_pages * Memory::PAGE_SIZE +
             bss_page_size;
 
+        // Apply any IPS patch now that the entire codeset (including .bss) has been allocated
+        overlay_ncch->ApplyIPSPatch(code);
+
         codeset->entrypoint = codeset->CodeSegment().addr;
         codeset->memory = std::move(code);