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npdm: parse the Switch 2 ACID layout

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Switch 2 ACID blocks have a 0x300-byte signature/key area (Switch 1:
0x200), so the ACID header starts 0x100 bytes later. Without this the
FAC offset was garbage and loading failed with ErrorBadFileAccessControl.
Also read FAC/FAH relative to their ACID/ACI block, as the format (and
the existing KAC read) does.
This commit is contained in:
Takoroka 2026-10-27 12:00:22 -04:00
commit b2f11310f5
1 changed files with 19 additions and 2 deletions
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21
src/core/file_sys/program_metadata.cpp
View file

@ -5,6 +5,7 @@
// SPDX-License-Identifier: GPL-2.0-or-later
#include <cstddef>
#include <cstring>
#include <vector>
#include "common/logging.h"
@ -33,13 +34,29 @@ Loader::ResultStatus ProgramMetadata::Load(VirtualFile file) {
return Loader::ResultStatus::ErrorBadACIDHeader;
}
// Switch 2 ACID blocks have a 0x300-byte signature/key area instead of 0x200, so the
// header starts 0x100 bytes later. Offsets inside the header are unchanged.
if (std::memcmp(acid_header.magic.data(), "ACID", 4) != 0) {
constexpr std::size_t acid_sig_size_v1 = 0x200;
constexpr std::size_t acid_sig_size_v2 = 0x300;
constexpr std::size_t acid_body_size = sizeof(AcidHeader) - acid_sig_size_v1;
auto* const body = reinterpret_cast<u8*>(&acid_header) + acid_sig_size_v1;
if (file->ReadBytes(body, acid_body_size, npdm_header.acid_offset + acid_sig_size_v2) !=
acid_body_size ||
std::memcmp(acid_header.magic.data(), "ACID", 4) != 0) {
return Loader::ResultStatus::ErrorBadACIDHeader;
}
LOG_INFO(Loader, "NPDM uses the Switch 2 ACID layout");
}
if (sizeof(AciHeader) != file->ReadObject(&aci_header, npdm_header.aci_offset)) {
return Loader::ResultStatus::ErrorBadACIHeader;
}
// Load acid_file_access per-component instead of the entire struct, since this struct does not
// reflect the layout of the real data.
std::size_t current_offset = acid_header.fac_offset;
// FAC/FAH offsets are relative to the start of the ACID/ACI block, like the KAC offsets.
std::size_t current_offset = npdm_header.acid_offset + acid_header.fac_offset;
if (sizeof(FileAccessControl::version) != file->ReadBytes(&acid_file_access.version,
sizeof(FileAccessControl::version),
current_offset)) {
@ -57,7 +74,7 @@ Loader::ResultStatus ProgramMetadata::Load(VirtualFile file) {
}
// Load aci_file_access per-component instead of the entire struct, same as acid_file_access
current_offset = aci_header.fah_offset;
current_offset = npdm_header.aci_offset + aci_header.fah_offset;
if (sizeof(FileAccessHeader::version) != file->ReadBytes(&aci_file_access.version,
sizeof(FileAccessHeader::version),
current_offset)) {