freebsd-dev/lib/libdisk/libdisk.3

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.\" Copyright (c) 1996 Joerg Wunsch
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.Dd March 15, 1996
.Dt LIBDISK 3
.Os
.Sh NAME
.Nm Open_Disk ,
.Nm Clone_Disk ,
.Nm Free_Disk ,
.Nm Debug_Disk ,
.Nm Set_Bios_Geom ,
.Nm Delete_Chunk ,
.Nm Collapse_Disk ,
.Nm Collapse_Chunk ,
.Nm Create_Chunk ,
.Nm All_FreeBSD ,
.Nm CheckRules ,
.Nm Disk_Names ,
.Nm Set_Boot_Mgr ,
.Nm Set_Boot_Blocks ,
.Nm Write_Disk ,
.Nm Cyl_Aligned ,
.Nm Next_Cyl_Aligned ,
.Nm Prev_Cyl_Aligned ,
.Nm Track_Aligned ,
.Nm Next_Track_Aligned ,
.Nm Prev_Track_Aligned ,
.Nm Create_Chunk_DWIM ,
.Nm MakeDev ,
.Nm MakeDevDisk ,
.Nm ShowChunkFlags ,
.Nm ChunkCanBeRoot ,
.Nm chunk_n ,
.Nm slice_type_name
.Nd library interface to slice and partition labels
.Sh LIBRARY
.Lb libdisk
.Sh SYNOPSIS
.Fd #include <sys/types.h>
.Fd #include <libdisk.h>
.Pp
.Vt extern const char *chunk_n[] ;
.Ft const char *
.Fn slice_type_name "int type" "int subtype"
.Ft struct disk *
.Fn Open_Disk "const char *devname"
.Ft struct disk *
.Fn Clone_Disk "struct disk *disk"
.Ft void
.Fn Free_Disk "struct disk *disk"
.Ft void
.Fn Debug_Disk "struct disk *disk"
.Ft void
.Fn Set_Bios_Geom "struct disk *disk" "u_long cyl" "u_long heads" "u_long sects"
.Ft int
.Fn Delete_Chunk "struct disk *disk" "struct chunk *"
.Ft void
.Fn Collapse_Disk "struct disk *disk"
.Ft int
.Fn Collapse_Chunk "struct disk *disk" "struct chunk *chunk"
.Ft int
.Fn Create_Chunk "struct disk *disk" "u_long offset" "u_long size" "chunk_e type" "int subtype" "u_long flags"
.Ft void
.Fn All_FreeBSD "struct disk *d" "int force_all"
.Ft char *
.Fn CheckRules "struct disk *"
.Ft char **
.Fn Disk_Names "void"
.Ft void
.Fn Set_Boot_Mgr "struct disk *d" "const u_char *bootmgr" "const size_t bootmgr_size"
.Ft void
.Fn Set_Boot_Blocks "struct disk *d" "const u_char *boot1" "const u_char *boot2"
.Ft int
.Fn Write_Disk "struct disk *d"
.Ft int
.Fn Cyl_Aligned "struct disk *d" "u_long offset"
.Ft u_long
.Fn Next_Cyl_Aligned "struct disk *d" "u_long offset"
.Ft u_long
.Fn Prev_Cyl_Aligned "struct disk *d" "u_long offset"
.Ft int
.Fn Track_Aligned "struct disk *d" "u_long offset"
.Ft u_long
.Fn Next_Track_Aligned "struct disk *d" "u_long offset"
.Ft u_long
.Fn Prev_Track_Aligned "struct disk *d" "u_long offset"
.Ft struct chunk *
.Fn Create_Chunk_DWIM "struct disk *d" "struct chunk *parent" "u_long size" "chunk_e type" "int subtype" "u_long flags"
.Ft int
.Fn MakeDev "struct chunk *c" "const char *path"
.Ft int
.Fn MakeDevDisk "struct disk *d" "const char *path"
.Ft char *
.Fn ShowChunkFlags "struct chunk *c"
.Ft char *
.Fn ChunkCanBeRoot "struct chunk *c"
.Sh DESCRIPTION
.Nm Libdisk
provides an interface to the low-level disk slice and partition labels.
Most functions operate with arguments of the types
.Ql struct disk ,
or
.Ql struct chunk .
.Pp
While both types are mostly opaque to the programmer, the internal
structure is mentioned below for the sake of completeness.
.Bd -literal -offset indent
struct disk {
	char		*name;
	u_long		flags;
	u_long		bios_cyl;
	u_long		bios_hd;
	u_long		bios_sect;
	u_char		*bootmgr;
	u_char		*boot1;
	u_char		*boot2;
	struct chunk	*chunks;
};
.Ed
The only flag value by now is
.Ql DISK_ON_TRACK ,
meaning that this disk is handled by the On-Track Disk Manager.
.Pp
.Bd -literal -offset indent
struct chunk {
	struct chunk	*next;
	struct chunk	*part;
	struct disk	*disk;
	long		offset;
	u_long		size;
	u_long		end;
	char		*name;
	char		*oname;
	chunk_e		type;
	int		subtype;
	u_long		flags;
	void		(*private_free)(void*);
	void		*(*private_clone)(void*);
	void		*private_data;
};
.Ed
The
.Ql type
field can be one of the following values:
.Ql whole, unknown, fat, freebsd, extended, part, unused .
.Pp
These are the valid
.Ql flag
values for a
.Ql struct chunk .
.Bl -tag -offset indent -width CHUNK_BSD_COMPATXX
.It CHUNK_PAST_1024
This chunk cannot be booted from because it extends past cylinder 1024.
.It CHUNK_BSD_COMPAT
This chunk is in the BSD-compatibility, and has a short name too, i.e.
.Ql wd0s4f -> wd0f .
.It CHUNK_ALIGN
This chunk should be aligned.
.It CHUNK_IS_ROOT
This
.Ql part
is a rootfs, allocate partition
.Sq a .
.It CHUNK_ACTIVE
This is the active slice in the MBR.
.It CHUNK_FORCE_ALL
Force a dedicated disk for 
.Fx ,
bypassing all BIOS geometry considerations.
.El
.Pp
The
.Ql private_data ,
.Ql private_free ,
and
.Ql private_clone
fields are for data private to the application, and the management
thereof.  If the functions are not provided, no storage management is
done, cloning will just copy the pointer and freeing will just forget
it.
.Pp
.Fn Open_Disk
will open the named disk, and return populated tree.
.Pp
.Fn Clone_Disk
clones a copy of a tree.  Useful for
.Dq Undo
functionality.
.Pp
.Fn Free_Disk
frees a tree made with
.Fn Open_Disk
or
.Fn Clone_Disk .
.Pp
.Fn Debug_Disk
prints the content of the tree to stdout.
.Pp
.Fn Set_Bios_Geom
sets the geometry the bios uses.
.Pp
.Fn Delete_Chunk
frees a chunk of disk_space.
.Pp
.Fn Collapse_Disk
and
.Fn Collapse_Chunk
are experimental, do not use.
.Pp
.Fn Create_Chunk
creates a chunk with the specified parameters.
.Pp
.Fn All_FreeBSD
makes one
.Fx
chunk covering the entire disk; if
.Ql force_all
is set, bypass all BIOS geometry considerations.
.Pp
.Fn CheckRules
returns
.Ql char*
to warnings about broken design rules in this disklayout.
.Pp
.Fn Disk_Names
returns
.Ql char**
with all disk's names (wd0, wd1 ...).  You must free each pointer, as
well as the array by hand.
.Pp
.Fn Set_Boot_Mgr
sets this boot-manager for use on this disk.  Gets written when
.Fn Write_Disk
is called.
.Pp
.Fn Set_Boot_Blocks
sets the boot-blocks for use on this disk.  Gets written when
.Fn Write_Disk
is called.
.Pp
.Fn Write_Disk
writes all the MBRs, disklabels, bootblocks and boot managers.
.Pp
.Fn Cyl_Aligned
checks if
.Ql offset
is aligned on a cylinder according to the BIOS geometry.
.Pp
.Fn Next_Cyl_Aligned
rounds
.Ql offset
up to next cylinder according to the BIOS geometry.
.Pp
.Fn Prev_Cyl_Aligned
rounds
.Ql offset
down to previous cylinder according to the BIOS geometry.
.Pp
.Fn Track_Aligned
checks if
.Ql offset
is aligned on a track according to the BIOS geometry.
.Pp
.Fn Next_Track_Aligned
rounds
.Ql offset
up to next track according to the BIOS geometry.
.Pp
.Fn Prev_Track_Aligned
checks if
.Ql offset
is aligned on a track according to the BIOS geometry.
.Pp
.Fn Create_Chunk_DWIM
creates a partition inside the given parent of the given size, and
returns a pointer to it.  The first unused chunk big enough is used.
.Pp
.Fn MakeDev
makes the device nodes for this chunk.
.Pp
.Fn MakeDevDisk
makes the device nodes for all chunks on this disk.
.Pp
.Fn ShowChunkFlags
returns a string to show flags.
.Pp
.Fn ChunkCanBeRoot
returns NULL if chunk can be
.Ql / .
.Pp
Chunk name strings can be accessed directly using the external array
.Va chunk_n .
.Pp
.Fn slice_type_name
returns the name strings associated with the specified 
.Ql type .
.Ql subtype .
If
.Fn slice_type_name
returns "unknown" for slices it isn't familiar with.
.Sh AUTHORS
.An -nosplit
The
.Nm libdisk
library was written by
.An Poul-Henning Kamp .
.Pp
This manual page was written by
.An J\(:org Wunsch .