Filesystem services

Services

Filesystem service "fs:USER"

You can at most have 32 FS archive handles.

Command Header	Available since system version	Description	Required exheader access info bitmask
0x000100C6	?	Dummy1	None
0x040100C4	?	Control	None
0x08010002	?	Initialize	None
0x080201C2	?	OpenFile	None
0x08030204	?	OpenFileDirectly	None
0x08040142	?	DeleteFile	None
0x08050244	?	RenameFile	None
0x08060142	?	DeleteDirectory	None
0x08070142	?	DeleteDirectoryRecursively	None
0x08080202	?	CreateFile	None
0x08090182	?	CreateDirectory	None
0x080A0244	?	RenameDirectory	None
0x080B0102	?	OpenDirectory	None
0x080C00C2	?	OpenArchive	Each archive ID code has separate access info bitmasks, if it has any
0x080D0144	?	ControlArchive	None
0x080E0080	?	CloseArchive	None
0x080F0180	?	Obsoleted_2_0_FormatThisUserSaveData	None
0x08100200	?	Obsoleted_3_0_CreateSystemSaveData	0x4, for when the input saveID doesn't match the exheader saveID
0x08110040	?	Obsoleted_3_0_DeleteSystemSaveData	0x1004, for when the input saveID doesn't match the exheader saveID
0x08120080	?	GetFreeBytes	None
0x08130000	?	GetCardType	0x1017
0x08140000	?	GetSdmcArchiveResource	None
0x08150000	?	GetNandArchiveResource	0x1007
0x08160000	?	GetSdmcFatfsError	0x2
0x08170000	?	IsSdmcDetected	None
0x08180000	?	IsSdmcWritable	None
0x08190042	?	GetSdmcCid	0x2
0x081A0042	?	GetNandCid	0x2
0x081B0000	?	GetSdmcSpeedInfo	0x2
0x081C0000	?	GetNandSpeedInfo	0x2
0x081D0042	?	GetSdmcLog	0x2
0x081E0042	?	GetNandLog	0x2
0x081F0000	?	ClearSdmcLog	0x2
0x08200000	?	ClearNandLog	0x2
0x08210000	?	CardSlotIsInserted	0x1017
0x08220000	?	CardSlotPowerOn	0x2
0x08230000	?	CardSlotPowerOff	0x2
0x08240000	?	CardSlotGetCardIFPowerStatus	0x2
0x08250040	?	CardNorDirectCommand	0x2
0x08260080	?	CardNorDirectCommandWithAddress	0x2
0x08270082	?	CardNorDirectRead	0x2
0x082800C2	?	CardNorDirectReadWithAddress	0x2
0x08290082	?	CardNorDirectWrite	0x2
0x082A00C2	?	CardNorDirectWriteWithAddress	0x2
0x082B00C2	?	CardNorDirectRead_4xIO	0x2
0x082C0082	?	CardNorDirectCpuWriteWithoutVerify	0x2
0x082D0040	?	CardNorDirectSectorEraseWithoutVerify	0x2
0x082E0040	?	GetProductInfo	0x1005
0x082F0040	?	GetProgramLaunchInfo	0x1005
0x08300182	?	Obsoleted_3_0_CreateExtSaveData	0xC, for when the input extdataID doesn't match the exheader extdataID
0x08310180	?	Obsoleted_3_0_CreateSharedExtSaveData	0x1005
0x08320102	?	Obsoleted_3_0_ReadExtSaveDataIcon	0x100D, for when the input extdataID doesn't match the exheader extdataID
0x08330082	?	Obsoleted_3_0_EnumerateExtSaveData	0x1005
0x08340082	?	Obsoleted_3_0_EnumerateSharedExtSaveData	0x1005
0x08350080	?	Obsoleted_3_0_DeleteExtSaveData	0x100D, for when the input extdataID doesn't match the exheader extdataID
0x08360080	?	Obsoleted_3_0_DeleteSharedExtSaveData	0x1005
0x08370040	?	SetCardSpiBaudRate	0x2
0x08380040	?	SetCardSpiBusMode	0x2
0x08390000	?	SendInitializeInfoTo9	None
0x083A0100	?	GetSpecialContentIndex	0x1005
0x083B00C2	?	GetLegacyRomHeader	0x1015
0x083C00C2	?	GetLegacyBannerData	0x1015
0x083D0100	?	CheckAuthorityToAccessExtSaveData	0x44
0x083E00C2	?	QueryTotalQuotaSize	None
0x083F00C0	?	Obsoleted_3_0_GetExtDataBlockSize	None
0x08400040	?	AbnegateAccessRight	?
0x08410000	?	DeleteSdmcRoot	0x1005
0x08420040	?	DeleteAllExtSaveDataOnNand	0x1005
0x08430000	?	InitializeCtrFileSystem	None
0x08440000	?	CreateSeed	0x2
0x084500C2	?	GetFormatInfo	?
0x08460102	?	GetLegacyRomHeader2	0x1015
0x08470180	?	Obsoleted_2_0_FormatCtrCardUserSaveData	0x6
0x08480042	?	GetSdmcCtrRootPath	0x100D
0x08490040	?	GetArchiveResource	?
0x084A0002	?	ExportIntegrityVerificationSeed	0x4000
0x084B0002	?	ImportIntegrityVerificationSeed	0x4000
0x084C0242	?	FormatSaveData	0x6, in some cases this write isn't needed however
0x084D0102	?	GetLegacySubBannerData	0x1015
0x084E0342	?	UpdateSha256Context	0x5
0x084F0102	?	ReadSpecialFile	None
0x08500040	?	GetSpecialFileSize	None
0x08510242	3.0.0-5	CreateExtSaveData	Shared extdata: 0x101005. Regular extdata in certain cases: 0xC
0x08520100	3.0.0-5	DeleteExtSaveData	Shared extdata: 0x101005. Regular extdata in certain cases: 0x10100D
0x08530142	3.0.0-5	ReadExtSaveDataIcon	0x10100D (this doesn't apply in certain cases, however)
0x085400C0	3.0.0-5	GetExtDataBlockSize	0x10100D (this doesn't apply in certain cases, however)
0x08550102	3.0.0-5	EnumerateExtSaveData	0x101005
0x08560240	3.0.0-5	CreateSystemSaveData	0x4 (this doesn't apply in certain cases, however)
0x08570080	3.0.0-5	DeleteSystemSaveData	0x1004 (this doesn't apply in certain cases, however)
0x08580000	3.0.0-5	StartDeviceMoveAsSource	0x2004
0x08590200	3.0.0-5	StartDeviceMoveAsDestination	0x2004
0x085A00C0	3.0.0-5	SetArchivePriority	None
0x085B0080	3.0.0-5	GetArchivePriority	None
0x085C00C0	3.0.0-5	SetCtrCardLatencyParameter	0xE
0x085D01C0	3.0.0-5	SetFsCompatibilityInfo	0x100001
0x085E0040	3.0.0-5	ResetCardCompatibilityParameter	0xE
0x085F0040	3.0.0-5	SwitchCleanupInvalidSaveData	0x12004
0x08600042	3.0.0-5	EnumerateSystemSaveData	0x2004
0x08610042	3.0.0-5	InitializeWithSdkVersion	None
0x08620040	3.0.0-5	SetPriority	None
0x08630000	3.0.0-5	GetPriority	None
0x08640000	3.0.0-5	Obsoleted_4_0_GetNandInfo	Stubbed, this returns an error
0x08650140	4.0.0-7	SetSaveDataSecureValue	0x121004 (in certain cases this doesn't apply, however)
0x086600C0	4.0.0-7	GetSaveDataSecureValue	0x121004 (in certain cases this doesn't apply, however)
0x086700C4	4.0.0-7	ControlSecureSave	0x121004
0x08680000	4.0.0-7	GetMediaType	None
0x08690000	4.0.0-7	Obsoleted_4_0_GetNandEraseCount	Stubbed, this returns an error.
0x086A0082	4.0.0-7	ReadNandReport	None
0x086B00C2	?	SetOtherSaveDataSecureValue	00121004
0x086C00C2	?	GetOtherSaveDataSecureValue	00121004
0x086D0040	?	?	00020004
0x086E00C0	Related to Secure Value? Used in Pokemon Sun/Moon.	SetThisSaveDataSecureValue	None?
0x086F0040	Related to Secure Value? Used in Pokemon Sun/Moon.	GetThisSaveDataSecureValue	0xE
0x087000C2	?	?	None?
0x08710100	?	?	0xC
0x087201C0	?	?	00080004
0x087300C0	?	?	00080004
0x08740000	?	?	00080004
0x08750140	?	?	None?
0x087600C0	?	?	None?
0x08770100	?	?	?
0x087800C0	?	?	?
0x087900C2	?	Same as GetLegacyBannerData, except for the last parameter this passes u8 value 0x1 instead of 0x0, for the FSPXI command.	0x00101015
0x087A0180	9.6.0-X	AddSeed	0x00200000
0x087B0080	9.6.0-X	GetSeed	0x00200000
0x087C0080	9.6.0-X	DeleteSeed	0x00200000
0x087D0000	9.6.0-X	GetNumSeeds	0x00200000
0x087E0042	9.6.0-X	Eventually calls same code as command <0x087A....>. Writes a list of titleIDs to the outbuf, this is for titles with content-lock-seed(s) stored in SEEDDB. (u32 total_titleids_probably, ((Size<<4) | 12), outbufptr)	0x00200000
0x087F....	9.6.0-X	?	0x00200000
0x0880....	9.6.0-X	Eventually calls same code as command <0x087A....>.	0x00200000
0x8810080	9.6.0-X	Eventually calls same code as command <0x087A....>.	0x00200000
0x0882....	9.6.0-X	Eventually calls same code as command <0x087A....>.	0x00200000
0x08830000	9.6.0-X	Writes an output value to cmdreply[2].	0x00200000
0x08840042	9.6.0-X	Eventually calls same code as command <0x087A....>.	0x00200000
0x0885....	9.6.0-X	?	0x00200000
0x088600C0	11.1.0-X	CheckUpdatedDat	0x00080000

Note: The question marks from Dummy1 to GetSpecialFileSize on the "available since system version" field are mainly there because I think that most of these are necessary for the main system to function, so theoretically that would mean that since the creation of the 3DS these were available, or since launch if that makes more sense. But because of the peculiar nature of some of the functions, they will remain question marks until they can be confirmed 100%.

When access rights are required for a command, at least one of the bits in the process access info specified in the above table for the command must be set. Error 0xD9004676 is returned when a process attempts to use a command which it doesn't have access rights for the command. The exheader access info field is all zero's for most applications. Note that the permissions listed in the above table is for system-version v2.x, therefore permission bit(s) added with newer FIRM may be missing from this.

Each session for fs:USER has separate permissions, initially these are set to all zero's for new fs:USER sessions. The permissions/etc for fs:USER sessions are initialized via FS:Initialize(loaded from the user process exheader).

Filesystem service "fs:LDR"

This service is identical to fs:USER, except FS:OpenArchive archive 0x2345678E can only be accessed with fs:LDR.

ProgramRegistry service "fs:REG"

Command Header	Description
0x000100C6	Dummy1
0x040103C0	Register
0x04020040	Unregister
0x040300C0	GetProgramInfo
0x04040100	LoadProgram
0x04050080	UnloadProgram
0x04060080	CheckHostLoadId

Only two sessions can be opened for this service at a time, hence no other processes can use this due to pm-module and loader using this.

File and directory access

Files

File session handles obtained via FS:OpenFile and FS:OpenFileDirectly can be used to access files through a service-like interface, despite not being an actual service registered using SRV:RegisterService. To use this service-like interface, simply call the SendSyncRequest SVC with a file session handle, using the IPC buffer in thread-local storage for parameters and responses, just like you would with a proper service.

Command Header	Description
0x000100C6	Dummy1
0x040100C4	Control
0x08010100	OpenSubFile
0x080200C2	Read
0x08030102	Write
0x08040000	GetSize
0x08050080	SetSize
0x08060000	GetAttributes
0x08070040	SetAttributes
0x08080000	Close
0x08090000	Flush
0x080A0040	SetPriority
0x080B0000	GetPriority
0x080C0000	OpenLinkFile
0x0C010100	GetAvailable

Directories

Directory session handles obtained via FS:OpenDirectory are usable via a service-like interface, following the exact same procedure described above for file sessions.

Command Header	Available since system version	Description
0x000100C6	1.0.0-0	Dummy1
0x040100C4	1.0.0-0	Control
0x08010042	1.0.0-0	Read
0x08020000	1.0.0-0	Close
0x08030040	?	SetPriority
0x08040000	?	GetPriority

Archives

ArchiveId	Description	Accessible via FS	Accessible via FSPXI	Only accessible by Process9 internally	Requires binary Lowpath	Required exheader FS access info bitmask
0x00000003	SelfNCCH (including RomFS)	Yes	No	No	No	None
0x00000004	SaveData (the saveID/mediatype for this is loaded from data originally from the user process' exheader)	Yes	No	No	No	None
0x00000006	ExtSaveData	Yes	No	No	Yes	0x100D, when the input extdataID isn't listed in the exheader.
0x00000007	Shared ExtSaveData	Yes	No	No	Yes	None
0x00000008	SystemSaveData	Yes	No	No	Yes	0x4, when the input saveID doesn't match the exheader system-saveID.
0x00000009	SDMC	Yes	Yes	No	No	0x8E
0x0000000A	SDMC Write-Only	Yes	No	No	No	0x808E
0x12345678	ExtSaveData for BOSS	Yes	No	No	Yes	0x44
0x12345679	CARD SPI FS	Yes	Yes	No	No	0x16
0x1234567B	ExtSaveData, and ExtSaveData for BOSS	No	Yes	No	Yes
0x1234567C	SystemSaveData	No	Yes	No	Yes
0x1234567D	NAND RW	Yes	Yes	No	No	0x800
0x1234567E	NAND RO	Yes	Yes	No	No	0x200
0x1234567F	NAND RO Write FS	No	Yes	No	No	?
0x12345680	Unknown. There's code for this in spider v9.9, but that code isn't actually used.	Yes	?	No	Yes	?
0x12345681	Unknown. Accessed by FS service.	?	?	No	?	?
0x12345682	Unknown. There's code for this in spider v9.9, but that code isn't actually used.	Yes	?	No	Yes	?
0x2345678A	Used for accessing general NCCH data. With FSPXI this also allows savedata access.	Yes	Yes	No	Yes	0x1005
0x2345678B	?	No	No	Yes	Yes
0x2345678C	Used internally to access /dbs files?	No	No	Yes	Yes
0x2345678D	?	No	No	Yes	No
0x2345678E	FSPXI: Similar to archive 0x2345678A. For fs:LDR(used by the "loader" FIRM ARM11-process), only ExeFS. Not accessible with fs:USER.	Yes	Yes	No	Yes	None, see description.
0x567890AB	NAND CTR FS	No	Yes	No	No	?
0x567890AC	TWL PHOTO	Yes	Yes	No	No	?
0x567890AD	TWLS (DSi Sound stores recordings here). This is mapped to the FAT12 image stored in the file at Twln/shared2/0000.	No	Yes	No	No	?
0x567890AE	NAND TWL FS	Yes	Yes	No	No	0x100
0x567890AF	NAND W FS	Yes	Yes	No	No	0x100
0x567890B0	?	No	Yes	No	No
0x567890B1	Gamecard SaveData (for check). This is a wrapper for UserSaveDataForCheck: the OpenArchive code for that is called with archive-lowpath TID=0/mediatype=2(gamecard).	Yes	No	No	No	0x6
0x567890B2	UserSaveData (for check). This is the same as the regular SaveData archive, except with this the savedata ID and mediatype is loaded from the input archive lowpath.	Yes	No	No	Yes	0x6
0x567890B4	Similar to 0x567890B2 but can only access Accessible Save specified in exheader?	Yes	No	No	Yes	?

Archives listed as not requiring a binary lowpath, use lowpath type empty.

The above permission bitmasks are from v2.x, see the above Services section for how these are handled.

Archives CTR NAND, NAND RO Write FS, TWL NAND, NAND W FS, and CARD SPI FS require the corresponding process exheader access control mount flag to be set, in the exheader for any of the currently running ARM11 processes, for FSPXI. The access rights checked by FS module for archive mounting with fs:USER, are stored in the process' exheader accessinfo.

The CARDSPI archive allows access to the gamecard CARD1 raw savedata flash(aka "cardspi:/" in Process9), the file lowpath must be WCHAR "/". The "NAND W FS" archive allows access to the raw NAND image(aka "wnand:/" in Process9), the file lowpath must be WCHAR "/".

Filenames and Paths

PathType:

Value	Description
-1	Returned internally by Process9, when errors occur it seems(in particular when no nul-terminator was found in the input path). The data ptr is set to NULL.
0x0	INVALID - Specifies an invalid path
0x1	EMPTY - Specifies an empty path
0x2	BINARY - Non-text based path. Meaning is per-archive
0x3	ASCII - Text-based path with 7-bit ASCII characters padded to 8-bits each (signed char)
0x4	UTF16 - Text-based path with UTF-16 characters

In IPC requests, sizes of ASCII and UTF16 paths must include space for the null-terminator.

Binary LowPath

The format of the data that a binary LowPath points to is custom per archive.

SelfNCCH File Path Data Format

Index word	Description
0	Type: 0x0: RomFS 0x1: error 0xD9004676 0x2: ExeFS 0x3: Error 0xE0E046BE. 0x4: FS-module crashes on this 0x5: Update RomFS?
1-2	File name for ExeFS ("icon"/"banner"/"logo"). ".code" is not allowed

Note that ExeFS files only support reading from offset=0 and with size=file_size.

SystemSaveData Archive Path Data Format

FS

Index word	Description
0	Mediatype (must be zero for NAND)
1	saveid

The file/directory lowpath is a text lowpath in the savegame filesystem.

FSPXI

Index word	Description
0	u8 Mediatype (must be zero for NAND)

The file lowpath is a binary lowpath containing the u64 saveid, however the high word of the saveid is always zero. The mounted file is the cleartext savegame image. Up to 32 SystemSaveData image files can be opened under a single mounted FSPXI archive.

UserSaveDataForCheck Archive Path Data Format

Index word	Description
0	Mediatype (must be non-zero)
1	Lower word saveid
2	Upper word saveid

The file/directory lowpath for this FS archive is a text path in the savegame filesystem.

0x567890B4 Archive Path Data Format

Index word	Description
0	Mediatype
1	Lower_word_saveid >> 8 ?
2	Unknown. Game calculate this using formula 0xFFFFFF00 | unknown_b

ExtSaveData Archive Path Data Format

Index word	Description
0	Mediatype
1	Lower word saveid
2	Upper word saveid

For FS, the file/directory lowpath is a text path in the extdata filesystem. For FSPXI, the file lowpath is a text path relative to the "/extdata/<ExtdataIDHigh>/<ExtdataIDLow>" directory on SD/NAND, for the cleartext extdata image to mount.

0x2345678A Archive Path Data Format

Index word	Description
0	Lower word programID
1	Upper word programID
2	(Mediatype & 0xFF) | (uninitialized_data? & 0xFFFFFF00)
3	Number of something? Hardcoded per-archive, 0 for ExeFS, 200 for area:, 100 for rate:, 40 for eula:, etc.

File lowpath:

Index word	Description
0	0 for NCCH data, 1 for savedata. The latter is only valid for FSPXI. Value 2 is allowed via archive 0x3, it's unknown what this is.
1	TMD content index / NCSD partition index.
2	Type: 0=romfs(0 for non-NCCH as well), 1=exefs ".code"(?), 2=exefs "icon"/"banner"/"logo", 3=unknown, 4=unknown, 5=unknown.
3-4	Filename for ExeFS.

The 0x14-byte lowpath is all-zero for accessing the title's main RomFS.

RomFS

Archives 0x3 and 0x2345678E both allow for accessing the level-3 IVFC images for RomFS access. The main CXI RomFS is accessible via an all-zero 0xc-byte binary file-lowpath. The update RomFS can be accessed with the first u32 in the binary file-lowpath being set to 0x5. The user must handle parsing the filesystem used in the exposed image itself.

With FSPXI the returned data for RomFS is the entire RomFS section from the NCCH, starting at the IVFC header.

The 0x3 archive is an interface for the 0x2345678E archive with the current process programID+mediatype. The file lowpath is 3-words. These words are written to 0x2345678E-archive file_lowpath+0, with the rest of that lowpath set to all-zero(lowpath is different from archive 0x2345678A). File lowpath:

Index word	Description
0	See above. The only values which FS-module doesn't allow to be used here are: 0x1: Error 0xE0E046BE. 0x3: Error 0xE0E046BE. 0x4: FS-module executes svcBreak when using this.
1-2	See above. Not validated by FS-module.

SEEDDB

With 9.6.0-X new System_SaveData with saveID 0001000F was added, this seems to be handled by FS-module itself, probably via the new service-cmds added to fsuser. Home Menu and NIM module have access to those commands.

The SEEDDB savedata contains the title-unique seed-data used for the new NCCH keyY generation added with FIRM 9.6.0-X.

Common Types

MediaType

Value	Description
0	NAND
1	SD
2	Game Card

SystemMediaType

Value	Description
0	CTR NAND
1	TWL NAND
2	SD
3	TWL Photo

OpenFlags

Bit	Description
0	Read
1	Write
2	Create

Attributes

Offset	Size	Description
0x0	0x1	Is Directory
0x1	0x1	Is Hidden
0x2	0x1	Is Archive
0x3	0x1	Is Read-Only

WriteOption

Offset	Size	Description
0x0	0x1	Flush
0x1	0x1	Update Time Stamp
0x2	0x1	Reserved
0x3	0x1	Reserved

DirectoryEntry

Offset	Size	Description
0x0	0x20C	UTF-16 Entry Name
0x20C	0xA	8.3 short filename name
0x216	0x4	8.3 short filename extension
0x21A	0x1	Always 1
0x21B	0x1	Reserved
0x21C	0x4	Attributes
0x220	0x8	Entry Size

ArchiveResource

Offset	Size	Description
0x0	0x4	Sector byte-size
0x4	0x4	Cluster byte-size
0x8	0x4	Partition capacity in clusters
0xC	0x4	Available free space in clusters

ProgramInfo

Offset	Size	Description
0x0	0x8	Program ID
0x8	0x1	Media Type
0x9	0x7	Padding

ProductInfo

Offset	Size	Description
0x0	0x10	Product Code
0x10	0x2	Company Code
0x12	0x2	Remaster Version

IntegrityVerificationSeed

Offset	Size	Description
0x0	0x10	AES-CBC MAC over a SHA256 hash, which hashes the first 0x110-bytes of the cleartext SEED.
0x10	0x120	The nand/private/movable.sed, encrypted with AES-CBC using the above MAC for the counter.

ExtSaveDataInfo

Offset	Size	Description
0x0	0x1	Media Type
0x1	0x1	Unknown
0x2	0x2	Reserved
0x4	0x8	Save ID
0xC	0x4	Reserved

SystemSaveDataInfo

Offset	Size	Description
0x0	0x1	Media Type
0x1	0x1	Unknown
0x2	0x2	Reserved
0x4	0x4	Save ID

SecureValueSlot

Value	Description
0x1000	SD Application

CardSpiBaudRate

Value	Description
0x0	512KHz
0x1	1MHz
0x2	2MHz
0x3	4MHz
0x4	8MHz
0x5	16MHz

CardSpiBusMode

Value	Description
0x0	1-bit
0x1	4-bit

SpecialContentType

Value	Description
0x1	Update
0x2	Manual
0x3	DLP Child

DeviceMoveContext

Offset	Size	Description
0x0	0x10	IVs
0x10	0x10	Encrypt Parameter

Errors

See Filesystem_services_PXI.