Nintendo Switch Brew

NCM services

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Revision as of 19:39, 7 September 2017 by Hexkyz (talk | contribs) (Updating names)

NCM contains services for internal file path and content management.

Location Resolver services

lr

Cmd Name Arguments Notes
0 GetLocationResolver StorageID
1 GetRegisteredLocationResolver None
2 CheckStorage StorageID
3 GetAddOnContentLocationResolver None

ILocationResolver

Cmd Name Arguments Notes
0 GetProgramNcaPath u64 TID + C descriptor Used for NCA-type1.
1 SetProgramNcaPath u64 TID + X descriptor ContentPath Used for NCA-type1.
2 GetUserControlNcaPath u64 TID + C descriptor Used for NCA-type3 (gamecard only?).
3 GetDocHtmlNcaPath u64 TID + C descriptor Used for NCA-type4.
4 GetControlNcaPath u64 TID + C descriptor Used for NCA-type3. Stubbed, only returns error 0x608.
5 SetControlNcaPath u64 TID + X descriptor ContentPath Used for NCA-type3.
6 SetDocHtmlNcaPath u64 TID + X descriptor ContentPath Used for NCA-type4.
7 GetInfoHtmlNcaPath u64 TID + C descriptor Used for NCA-type5.
8 SetInfoHtmlNcaPath u64 TID + X descriptor ContentPath Used for NCA-type5.
9 ClearLocationResolver None Clears all NCA paths set.

These get-commands load the ContentPath from linked-lists in memory using the input titleID. The set-commands add a new entry to the list, if a matching entry is found it's removed first. ClearLocationResolver frees all entries in all of these linked-lists. The ContentPath is only used with memcpy() here with size=0x300, nothing more.

The set commands always return 0. When the get-commands fail to find an entry for the specified titleID, 0x408 is returned for GetProgramNcaPath, while the rest of the commands return 0xA08.

IRegisteredLocationResolver

Cmd Name Arguments Notes
0 GetPatchType0NcaPath u64 TID + C descriptor Used for NCA-type1.
1 SetPatchType0NcaPath u64 TID + X descriptor ContentPath
2 RegisterPatchTitle0 u64 TID
3 SetPatchTitle0NcaPath u64 TID + X descriptor ContentPath
4 GetPatchType1NcaPath u64 TID + C descriptor
5 SetPatchType1NcaPath u64 TID + X descriptor ContentPath
6 RegisterPatchTitle1 u64 TID
7 SetPatchTitle1NcaPath u64 TID + X descriptor ContentPath

IAddOnContentLocationResolver

Cmd Name Arguments Notes
0 GetAddOnContentNcaPath u64 TID + C descriptor
1 RegisterAddOnContent StorageID + u64 TID
2 ClearAddOnContentLocationResolver None Clears all registered titles here.

Content Manager services

ncm

Cmd Name Notes
0
1
2
3
4 GetIContentStorage Takes a StorageID.
5 GetIContentMetaDatabase Takes a StorageID.
8
9 InitializeStorageForMediaId
10 UninitializeStorageForMediaId
11 InitializeDatabaseForMediaId
12 UninitializeDatabaseForMediaId

All of the above cmds takes a u8 as input.

IContentStorage

Cmd Name Notes
0 #GetRootEntry
1 Takes two 0x10-sized entries, and a u64.
2 Takes a 0x10-sized entry.
3 Takes a 0x10-sized entry, returns a bool/u8.
4 Takes a 0x10-sized entry, a u64-offset, and type-5 array.
5 Takes two 0x10-sized entries.
6 DeleteContent? Takes a 0x10-sized entry.
7 IsNcaEntryValid Takes a 0x10-sized entry, returns a bool.
8 MakeNcaRegisteredPath Takes a type-0x1A string and a 0x10-sized entry.
9 MakeNcaPlaceholderPath Takes a type-0x1A string and a 0x10-sized entry.
10 Void.
11 Takes a type-6 buffer, each entry 0x10 bytes, and returns a u32.
12 #GetNumberOfEntries
13 #GetEntries
14 #GetEntrySize
15 Void.
16 Takes three 0x10-sized entries.
17 Takes a 0x10-sized entry and a u64.
18 #ReadEntryRaw
19 Takes a 0x10-sized entry and returns another 0x10-sized entry.
20 #GetNcaTitleInfo
21 Takes a 0x10-sized entry, a u64, and a type5 buffer.
22 GetFreeSpace
23 GetTotalSpace

GetRootEntry

Returns an entry of 16 completely random-looking bytes. It is not possible to read this entry.

Changes on reboot?

GetNumberOfEntries

Writes the total number of entries which can be read by GetEntries, to cmdreply <SFCO_offset>+0x10.

GetEntries

Takes an output buffer, u32 offset and gets all entries starting at that offset. Returns number of entries read.

Each entry is a #NcaID.

The total read entries is exactly the same as the number of "<hex>.nca" directories in the storage FS(or at least under the "registered" directory?).

GetEntrySize

Takes a #NcaID as input.

Returns the total size readable by ReadEntryRaw. This is the same as the size-field in the NAX0 "<NcaID>.nca/00" file.

ReadEntryRaw

Takes an output buffer, a #NcaID as input, and a u64 file offset.

Returns encrypted looking data from the content in the NAX0. Doesn't match the encrypted raw data in the NAX0 "<NcaID>.nca/00" file. Seems to be at least one crypto layer below the initial NAX0 layer, since the data doesn't change after NAX0 recreation.

Manually modifying the content in the NAX0(starting at offset 0x4000) results in different output data being returned by this cmd. Changing any data within the first 0x10-bytes results in the entire 0x10-byte block changing. Likewise for offset 0x4010 size 0x1, entire 0x10-byte block at 0x4010 changes. Changing the first 0x20-bytes at 0x4000 to zeros has the same combined changed output, as when offset 0x4000 size 0x10 and offset 0x4010 size 0x10 were changed to zeros separately. Output BlockA and BlockB are completely different, where the raw NAX0 data for those blocks are all-zero.

Overwriting the entire raw NAX0 content with zeros results in output data which doesn't seem to have any duplicate blocks/data. When changing the previously mentioned raw content for the first 8 blocks to last-block-byte = 1<<i, where i is 0-7, none of the changed output blocks match any output blocks from the previously mentioned output(all-zero raw content).

This implies that that an AES mode is being used which isn't CTR, where changing data in one block doesn't affect other blocks.

See GetEntrySize for the total size readable with this.

GetNcaTitleInfo

Takes a #NcaID and returns the following 0x10-sized entry.

With some NcaIDs this may return 0 with an all-zero output entry. This seems to be the case for most/all (?) NandSystem NcaIds? This seems to be only usable with NcaIds which have type 1 or 4.

Offset Size Description
0x0 0x8 Big-endian titleID
0x8 0x8 Unknown. Usually zero?

IContentMetaDatabase

Cmd Name Notes
0 InsertContentEntry? Takes a 0x10-sized entry, a type-5 buffer and a u64.
1 Takes a 0x10-sized entry, a type-6 buffer and a u64. Returns a u64.
2 Takes a 0x10-sized entry.
3 UpdateContentEntry Takes a meta record entry and a u8. Returns a NcaID.
4 Takes a type-6 buffer, each entry being 24 bytes, 0x10-sized entry and a u32. Returns a u32.
5 Iterate Takes a type-6 buffer, each entry being 16 bytes, a 0x10-sized entry, and a u32. Returns a u32.
6 #GetTitleIdInfo
7 #GetTitleList Takes a type-6 buffer, each entry being 24 bytes, and a u8/bool. Returns two u32's.
8 Takes a 0x10-sized entry. Returns a bool/u8.
9 Takes a type-5 buffer, each entry being 16 bytes. Returns a bool/u8.
10 Takes a 0x10-sized entry. Returns a u64.
11 Takes a 0x10-sized entry. Returns a u32.
12 Takes a 0x10-sized entry. Returns a u64.
13 Void.
14 Takes a type-6 byte buffer, and a type-5 buffer with each entry being 16 bytes.
15 EndIteration Void.
16 Takes two 0x10-sized entries. Returns a bool/u8.
17 #GetUpdateTitleList
18 Takes a 0x10-sized entry. Returns a bool/u8.
19 Takes a 0x10-sized entry. Returns a u32.

GetTitleIdInfo

Takes a u64 title-id as input, returns same title-id together with info struct. 

struct title_info {
  u32  version;
  u8   type;
  u8   pad[3];
};

GetTitleList

Each 24-byte entries is as follows: 

 u64    title_id_update;
 struct title_info info;
 u64    title_id;


GetUpdateTitleList

Takes a type-6 output buffer, each entry being 0x10-byte bytes, a u32 entryoffset and a 0x10-sized entry. Returns a u32 for total_read_entries.

The input entry is the output entry from #GetTitleIdInfo starting at the TID. The output 0x10-bytes entries are the same as the output from #GetTitleIdInfo starting at the TID. However, "pad[0]" is used for something else it seems?(0 for everything except for TID 010000000000081B, where it's 1)

See NCA#Meta_records.

This reads the titlelist stored in the specified title, normally a title with title-type 3, which is sysupdate-title 0100000000000816. Returns 0 with total_read_entries=0 when used with other title(s).

NcaID

This is a 0x10-byte entry. This is originally from the hex portion of "<hex>.nca" directory-names from this storage FS(like SD).

The NcaID is the same as the first 0x10-bytes from the calculated SHA256 hash, from hashing the entire output from ReadEntryRaw.

Enums

Title Types

Value Description
0x01 System Programs (System Modules or System Applets)
0x02 System Data Archives
0x03 System Update
0x04 Firmware package A
0x05 Firmware package B
0x80 Regular application
0x81 Update title
0x82 Add-on content
0x83 Delta title

ncm:v

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