mount.nbt.8 - nbtfsutils - Rivoreo Source Code Repositories

 '\" t

 .TH mount.nbt 8

 .SH NAME
 mount.nbt - Mount a Named Binary Tag File System
 .SH SYNOPSIS
 .nf
 mount.nbt [-o \fI<fs-option>\fR[,\fI...\fR]] [-fnrvwh] \fI<nbt-file>\fR \fI<mount-point>\fR
 .fi
 .SH DESCRIPTION
 This tool is a FUSE-based file system implementation for accessing NBT formatted data, which is used by Minecraft to store various data about the game. Running this tool mounts a file system from the file specified by \fI<nbt-file>\fR; both standalone NBT file (usually have suffix \fI.dat\fR) and Minecraft Region file (usually have suffix \fI.mcr\fR or \fI.mca\fR) are supported.
 .SH OPTIONS
 .sp

 .B
 .IP -f
 Operate in foreground. Useful for debugging.

 .B
 .IP -h
 Print a brief usage message.

 .B
 .IP -n
 Ignored.

 .B
 .IP "-o \fI<fs-option>\fR[,\fI...\fR]"
 Pass gereric mount options, FUSE-specific options, and/or NBT-specific options, in a comma-separated list. See \fBmount(8)\fR and \fBfuse(8)\fR for gereric mount options and FUSE-specific options.
 .sp
 NBT-specific options are:
 .RS
 .TP
 .B ro
 Mount the file system read-only, useful to mount from a file that can't be written to, or to prevent accidentally changing it; but see \fBwritefile\fR option below.
 .TP
 .B rw
 Revert any \fBro\fR option that may be specified early.
 .TP
 .B region
 Specify the \fI<nbt-file>\fR is a Minecraft Region file instead of a standalone NBT file.
 .TP
 .B typeprefix
 Use node type prefix for node names when listing compound nodes as a directory. This option affects directory listing only, existing nodes can always be accessed either with or without the type prefix.
 .TP
 .B umask=\fI<mask>\fR
 Set file mode mask using an octal number for NBT nodes, default 0.
 .TP
 .B writefile=\fI<path>\fR
 Set an alternative path for writing NBT data; the original \fI<nbt-file>\fR won't be written to if this is specified. Will have no effect when file system is mounted read-only.
 .TP
 .B compression={gzip|zlib}
 Set compression format for writing NBT data; default \fBgzip\fR for standalone NBT file, \fBzlib\fR for Minecraft Region file. Will have no effect when file system is mounted read-only.
 .RE

 .B
 .IP -r
 Mount the file system read-only. Same as specifying \fB-o ro\fR.

 .B
 .IP -v
 Be Verbose during mounting.

 .B
 .IP -V
 Display version, copyright and licensing information of this tool. The program will exit afterward.

 .B
 .IP -w
 Mount the file system read-write. Same as specifying \fB-o rw\fR.

 .SH NODE TYPES
 .PP
 NBT specification defined several types for a tag, they are mapped into file types as followings:

 .TS
 box;
 l l l.
 NBT Tag Type	File Type	Type Prefix Name
 TAG_Byte	Regular	int8, byte
 TAG_Short	Regular	int16
 TAG_Int	Regular	int32
 TAG_Long	Regular	int64
 TAG_Float	Regular	float32, float, single
 TAG_Double	Regular	float64, double
 TAG_Byte_Array	Regular	int8array, bytearray
 TAG_String	Regular	string
 TAG_List	Directory	list
 TAG_Compound	Directory	compound
 TAG_Int_Array	Directory	int32array
 TAG_Long_Array	Directory	int64array
 .TE

 .SH ACCESSING NODES
 .SS Referencing Nodes Under Compound
 For nodes directly under a \fBcompound\fR, they can be accessed using their name; a \fBtype prefix\fR can also be prepended to an name to reference a node, as \fItypeprefix\fR:\fIname\fR.
 For example an \fBint64\fR node named \fBRandomSeed\fR under a \fBcompound\fR named \fBData\fR, the following 2 pathes would referencing the exactly same node:
 .RS
 Data/int64:RandomSeed
 .br
 compound:Data/RandomSeed
 .RE
 Turning on mount option \fBtypeprefix\fR will having this \fBtype prefix\fR be automatically prepended to node names, when listing a \fBcompound\fR using \fBreaddir(3)\fR; this could be useful to preserve the type information when copying a \fBcompound\fR node recursively (such as using \fBtar(1)\fR), so it is possible for the copied nodes be restored into another NBT later.
 .SS Referencing Nodes Under List
 Nodes under a \fBlist\fR are accessed using index numbers starting with 0; they will also have same type, a pseudo file \fB.type\fR is available under any \fBlist\fR to indicate node type the list contains.
 .SS Accessing Individual Node
 Any node which the file type is regular file can be read and written directly using \fBread(2)\fR and \fBwrite(2)\fR; they can also be \fBtruncate(2)\fRed to empty, but number typed (
 .B int8
 ,
 .B int16
 ,
 .B int32
 ,
 .B int64
 ,
 .B float32
 and
 .B float64
 ) nodes will turn its value into 0 after that.
 Nodes with type \fBint8array\fR or \fBstring\fR support \fBlseek(2)\fR and unlimited \fBtruncate(2)\fR operations.
 Reading from a \fBstring\fR node will have an additional line feed character (\\n) appended to the end automatically; similarly, writing to a \fBstring\fR node will have the ending line feed character stripped if exist.
 .PP
 \fBlist\fR and \fBcompound\fR nodes can contain other nodes, accessing them according to above rules.
 .PP
 \fBint32array\fR and \fBint64array\fR nodes are represented as directories, the array elements are accessed using an index number starting with 0, as regular files under the directory.
 Creating a new regular file with appreciate index number under the directory extends the array, and any element between the old tail index and new index will appear automatically as well; newly added elements will initialized to 0.
 An array can also be shrunk by removing (\fBunlink(2)\fR) the tail element, one element at a time; as a design limitation, only the tail element can be removed.
 On supported platforms, the array nodes may also be read directly (using \fBread(2)\fR); in this case seeking is supported only when aligned to element size, which is 4 or 8 for \fBint32array\fR or \fBint64array\fR respectively. The data stream read directly from an array will be the binary representation of the array elements in \fBhost byte order\fR.

 .SH ADDING AND REMOVING NODES
 .SS Under Compound
 Nodes under a \fBcompound\fR can be removed by using \fBunlink(2)\fR or \fBrmdir(2)\fR, according to their represented file type; usual file system restrictions on directory apply, meaning they can not be removed unless empty.
 .PP
 Unlike referencing an existing node, creating a new node under a \fBcompound\fR must use a type prefixed name.
 .SS Under List
 Like \fBcompound\fR, nodes under a \fBlist\fR may be removed by using either \fBunlink(2)\fR or \fBrmdir(2)\fR; if a non-tail node was removed, the index number of later nodes will be shifted backward by 1, which could be surprising when trying to remove multiple nodes.
 .PP
 New node may be added only to the tail of a \fBlist\fR, there is currently not possible to insert a node in middle of a list. Newly created node will have the type specified by the list type, indicated by the \fB.type\fR pseude file.
 .PP
 The list type may also be changed by writing a \fBtype prefix name\fR into \fB.type\fR, but only when the list is empty.
 .SS Special Requirement For Creating List Node
 A \fBlist\fR node may be created under either \fBcompound\fR or \fBlist\fR using \fBmkdir(2)\fR according to rules above, but please note newly created list will have an invalid list type; no node can be created under such list, and if a file system is unmounted with it, writing NBT data will fail, causing all modifications to be lost!
 Any newly created list must be initiailized with a supported list type, by writing the type prefix name to its \fB.type\fR pseude file.

 .SH CAVEATS
 .PP
 Data is commited to underlying \fI<nbt-file>\fR only upon unmounting; if anything went wrong during this process, the error message will be sent to \fBsyslog(3)\fR, and the file system will be unmounted without saving some or all data.
 .PP
 When modifying a Minecraft Region file, it is currently not possible to extend a modified chunk beyond the space available for the chunk in that Region file; although this rarely happen unless a considerable amount of additional data was copied into a chunk. If this happens, such chunk will not be saved.

 .SH EXAMPLES
 .PP
 The following examples took place in an Unix shell (\fBsh(1)\fR).
 .LP
 Mount a standalone NBT file \fI/tmp/level.dat\fR at \fI/mnt/nbt\fR, prepare to write a new NBT file at \fI/tmp/new-level.dat\fR:
 .sp
 .in +2
 .nf
 mount -o writefile=/tmp/new-level.dat /tmp/level.dat /mnt/nbt
 .fi
 .in -2
 .sp
 .LP
 Mount a Minecraft Region file \fI/tmp/r.0.-1.mcr\fR at \fI/mnt/region\fR, with \fBtype prefix\fR turned on for node name listing:
 .sp
 .in +2
 .nf
 mount -o region,typeprefix /tmp/r.0.-1.mcr /mnt/region
 .fi
 .in -2
 .sp
 .LP
 Working in a \fBcompound\fR, create and write a new \fBstring\fR node named \fIid\fR:
 .sp
 .in +2
 .nf
 echo Villager > string:id
 .fi
 .in -2
 .LP
 Working in a \fBcompound\fR, create a new \fBlist\fR node \fIPos\fR with list type set to \fBfloat64\fR, then create and write first node in the list:
 .sp
 .in +2
 .nf
 mkdir list:Pos
 echo float64 > Pos/.type
 echo 31.5 > Pos/0
 .fi
 .in -2
 .sp

 .SH "SEE ALSO"
 .PP
 fuse(8), fusermount(8), mount(8)
 .PP
 Named Binary Tag specification by Mojang
	'\" t

	.TH mount.nbt 8

	.SH NAME
	mount.nbt - Mount a Named Binary Tag File System
	.SH SYNOPSIS
	.nf
	mount.nbt [-o \fI<fs-option>\fR[,\fI...\fR]] [-fnrvwh] \fI<nbt-file>\fR \fI<mount-point>\fR
	.fi
	.SH DESCRIPTION
	This tool is a FUSE-based file system implementation for accessing NBT formatted data, which is used by Minecraft to store various data about the game. Running this tool mounts a file system from the file specified by \fI<nbt-file>\fR; both standalone NBT file (usually have suffix \fI.dat\fR) and Minecraft Region file (usually have suffix \fI.mcr\fR or \fI.mca\fR) are supported.
	.SH OPTIONS
	.sp

	.B
	.IP -f
	Operate in foreground. Useful for debugging.

	.B
	.IP -h
	Print a brief usage message.

	.B
	.IP -n
	Ignored.

	.B
	.IP "-o \fI<fs-option>\fR[,\fI...\fR]"
	Pass gereric mount options, FUSE-specific options, and/or NBT-specific options, in a comma-separated list. See \fBmount(8)\fR and \fBfuse(8)\fR for gereric mount options and FUSE-specific options.
	.sp
	NBT-specific options are:
	.RS
	.TP
	.B ro
	Mount the file system read-only, useful to mount from a file that can't be written to, or to prevent accidentally changing it; but see \fBwritefile\fR option below.
	.TP
	.B rw
	Revert any \fBro\fR option that may be specified early.
	.TP
	.B region
	Specify the \fI<nbt-file>\fR is a Minecraft Region file instead of a standalone NBT file.
	.TP
	.B typeprefix
	Use node type prefix for node names when listing compound nodes as a directory. This option affects directory listing only, existing nodes can always be accessed either with or without the type prefix.
	.TP
	.B umask=\fI<mask>\fR
	Set file mode mask using an octal number for NBT nodes, default 0.
	.TP
	.B writefile=\fI<path>\fR
	Set an alternative path for writing NBT data; the original \fI<nbt-file>\fR won't be written to if this is specified. Will have no effect when file system is mounted read-only.
	.TP
	.B compression={gzip\|zlib}
	Set compression format for writing NBT data; default \fBgzip\fR for standalone NBT file, \fBzlib\fR for Minecraft Region file. Will have no effect when file system is mounted read-only.
	.RE

	.B
	.IP -r
	Mount the file system read-only. Same as specifying \fB-o ro\fR.

	.B
	.IP -v
	Be Verbose during mounting.

	.B
	.IP -V
	Display version, copyright and licensing information of this tool. The program will exit afterward.

	.B
	.IP -w
	Mount the file system read-write. Same as specifying \fB-o rw\fR.

	.SH NODE TYPES
	.PP
	NBT specification defined several types for a tag, they are mapped into file types as followings:

	.TS
	box;
	l l l.
	NBT Tag Type File Type Type Prefix Name
	TAG_Byte Regular int8, byte
	TAG_Short Regular int16
	TAG_Int Regular int32
	TAG_Long Regular int64
	TAG_Float Regular float32, float, single
	TAG_Double Regular float64, double
	TAG_Byte_Array Regular int8array, bytearray
	TAG_String Regular string
	TAG_List Directory list
	TAG_Compound Directory compound
	TAG_Int_Array Directory int32array
	TAG_Long_Array Directory int64array
	.TE

	.SH ACCESSING NODES
	.SS Referencing Nodes Under Compound
	For nodes directly under a \fBcompound\fR, they can be accessed using their name; a \fBtype prefix\fR can also be prepended to an name to reference a node, as \fItypeprefix\fR:\fIname\fR.
	For example an \fBint64\fR node named \fBRandomSeed\fR under a \fBcompound\fR named \fBData\fR, the following 2 pathes would referencing the exactly same node:
	.RS
	Data/int64:RandomSeed
	.br
	compound:Data/RandomSeed
	.RE
	Turning on mount option \fBtypeprefix\fR will having this \fBtype prefix\fR be automatically prepended to node names, when listing a \fBcompound\fR using \fBreaddir(3)\fR; this could be useful to preserve the type information when copying a \fBcompound\fR node recursively (such as using \fBtar(1)\fR), so it is possible for the copied nodes be restored into another NBT later.
	.SS Referencing Nodes Under List
	Nodes under a \fBlist\fR are accessed using index numbers starting with 0; they will also have same type, a pseudo file \fB.type\fR is available under any \fBlist\fR to indicate node type the list contains.
	.SS Accessing Individual Node
	Any node which the file type is regular file can be read and written directly using \fBread(2)\fR and \fBwrite(2)\fR; they can also be \fBtruncate(2)\fRed to empty, but number typed (
	.B int8
	,
	.B int16
	,
	.B int32
	,
	.B int64
	,
	.B float32
	and
	.B float64
	) nodes will turn its value into 0 after that.
	Nodes with type \fBint8array\fR or \fBstring\fR support \fBlseek(2)\fR and unlimited \fBtruncate(2)\fR operations.
	Reading from a \fBstring\fR node will have an additional line feed character (\\n) appended to the end automatically; similarly, writing to a \fBstring\fR node will have the ending line feed character stripped if exist.
	.PP
	\fBlist\fR and \fBcompound\fR nodes can contain other nodes, accessing them according to above rules.
	.PP
	\fBint32array\fR and \fBint64array\fR nodes are represented as directories, the array elements are accessed using an index number starting with 0, as regular files under the directory.
	Creating a new regular file with appreciate index number under the directory extends the array, and any element between the old tail index and new index will appear automatically as well; newly added elements will initialized to 0.
	An array can also be shrunk by removing (\fBunlink(2)\fR) the tail element, one element at a time; as a design limitation, only the tail element can be removed.
	On supported platforms, the array nodes may also be read directly (using \fBread(2)\fR); in this case seeking is supported only when aligned to element size, which is 4 or 8 for \fBint32array\fR or \fBint64array\fR respectively. The data stream read directly from an array will be the binary representation of the array elements in \fBhost byte order\fR.

	.SH ADDING AND REMOVING NODES
	.SS Under Compound
	Nodes under a \fBcompound\fR can be removed by using \fBunlink(2)\fR or \fBrmdir(2)\fR, according to their represented file type; usual file system restrictions on directory apply, meaning they can not be removed unless empty.
	.PP
	Unlike referencing an existing node, creating a new node under a \fBcompound\fR must use a type prefixed name.
	.SS Under List
	Like \fBcompound\fR, nodes under a \fBlist\fR may be removed by using either \fBunlink(2)\fR or \fBrmdir(2)\fR; if a non-tail node was removed, the index number of later nodes will be shifted backward by 1, which could be surprising when trying to remove multiple nodes.
	.PP
	New node may be added only to the tail of a \fBlist\fR, there is currently not possible to insert a node in middle of a list. Newly created node will have the type specified by the list type, indicated by the \fB.type\fR pseude file.
	.PP
	The list type may also be changed by writing a \fBtype prefix name\fR into \fB.type\fR, but only when the list is empty.
	.SS Special Requirement For Creating List Node
	A \fBlist\fR node may be created under either \fBcompound\fR or \fBlist\fR using \fBmkdir(2)\fR according to rules above, but please note newly created list will have an invalid list type; no node can be created under such list, and if a file system is unmounted with it, writing NBT data will fail, causing all modifications to be lost!
	Any newly created list must be initiailized with a supported list type, by writing the type prefix name to its \fB.type\fR pseude file.

	.SH CAVEATS
	.PP
	Data is commited to underlying \fI<nbt-file>\fR only upon unmounting; if anything went wrong during this process, the error message will be sent to \fBsyslog(3)\fR, and the file system will be unmounted without saving some or all data.
	.PP
	When modifying a Minecraft Region file, it is currently not possible to extend a modified chunk beyond the space available for the chunk in that Region file; although this rarely happen unless a considerable amount of additional data was copied into a chunk. If this happens, such chunk will not be saved.

	.SH EXAMPLES
	.PP
	The following examples took place in an Unix shell (\fBsh(1)\fR).
	.LP
	Mount a standalone NBT file \fI/tmp/level.dat\fR at \fI/mnt/nbt\fR, prepare to write a new NBT file at \fI/tmp/new-level.dat\fR:
	.sp
	.in +2
	.nf
	mount -o writefile=/tmp/new-level.dat /tmp/level.dat /mnt/nbt
	.fi
	.in -2
	.sp
	.LP
	Mount a Minecraft Region file \fI/tmp/r.0.-1.mcr\fR at \fI/mnt/region\fR, with \fBtype prefix\fR turned on for node name listing:
	.sp
	.in +2
	.nf
	mount -o region,typeprefix /tmp/r.0.-1.mcr /mnt/region
	.fi
	.in -2
	.sp
	.LP
	Working in a \fBcompound\fR, create and write a new \fBstring\fR node named \fIid\fR:
	.sp
	.in +2
	.nf
	echo Villager > string:id
	.fi
	.in -2
	.LP
	Working in a \fBcompound\fR, create a new \fBlist\fR node \fIPos\fR with list type set to \fBfloat64\fR, then create and write first node in the list:
	.sp
	.in +2
	.nf
	mkdir list:Pos
	echo float64 > Pos/.type
	echo 31.5 > Pos/0
	.fi
	.in -2
	.sp

	.SH "SEE ALSO"
	.PP
	fuse(8), fusermount(8), mount(8)
	.PP
	Named Binary Tag specification by Mojang