.\"	$NetBSD: puffs_path.3,v 1.3.10.1 2009/02/24 03:45:56 snj Exp $
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.Dd December 27, 2007
.Dt PUFFS_PATH 3
.Os
.Sh NAME
.Nm puffs_path
.Nd puffs pathbuilding routines
.Sh LIBRARY
.Lb libpuffs
.Sh SYNOPSIS
.In puffs.h
.Ft int
.Fo pu_pathbuild_fn
.Fa "struct puffs_usermount *pu" "const struct puffs_pathobj *po_dir"
.Fa "const struct puffs_pathobj *po_comp" "size_t offset"
.Fa "struct puffs_pathobj *po_new"
.Fc
.Ft int
.Fo pu_pathtransform_fn
.Fa "struct puffs_usermount *pu" "const struct puffs_pathobj *po_base"
.Fa "const struct puffs_cn *pcn" "struct puffs_pathobj *po_new"
.Fc
.Ft int
.Fo pu_pathcmp_fn
.Fa "struct puffs_usermount *pu" "struct puffs_pathobj *po1"
.Fa "struct puffs_pathobj *po2" "size_t checklen" "int checkprefix"
.Fc
.Ft void
.Fn pu_pathfree_fn "struct puffs_usermount *pu" "struct puffs_pathobj *po"
.Ft int
.Fo pu_namemod_fn
.Fa "struct puffs_usermount *pu" "struct puffs_pathobj *po_dir"
.Fa "struct puffs_cn *pcn"
.Fc
.Ft struct puffs_pathobj *
.Fn puffs_getrootpathobj "struct puffs_usermount *pu"
.Sh DESCRIPTION
The puffs library has the ability to provide full pathnames for backends
which require them.
Normal file systems should be constructed without the file system
node tied to a file name and should not used routines described herein.
An example of a file system where the backend requires filenames is
.Xr mount_psshfs 8 .
.Pp
The features described here are enabled by passing
.Dv PUFFS_FLAG_BUILDPATH
to
.Fn puffs_init .
This facility requires to use puffs nodes to store the contents of the
pathname.
Either the address of the operation cookie must directly be that of the
puffs node, or
.Fn puffs_set_cmap
must be used to set a mapping function from the cookie to the puffs
node associated with the cookie.
Finally, the root node for the file system must be set using
.Fn puffs_setroot
and the root path object retrieved using
.Fn puffs_getrootpathobj
and initialized.
.Pp
There are two different places a filename can be retrieved from.
It is available for each puffs node after the node has been registered
with the framework, i.e.
.Em after
the routine creating the node returns.
In other words, there is a window between the node is created and
when the pathname is available and multithreaded file systems must
take this into account.
The second place where a pathname is available is from the componentname
.Vt struct puffs_pcn
in operations which are passed one.
These can be retrieved using the convenience macros
.Fn PNPATH
and
.Fn PCNPATH
for node and componentname, respectively.
The type of object they return is
.Vt void * .
.Pp
By default the framework manages "regular" filenames, which consist
of directory names separated by "/" and a final component.
If the file system wishes to use pathnames of this format, all it
has to do it enable the feature.
Everything else, including bookkeeping for node and directory renames,
is done by the library.
The callback routines described next provide the ability to build
non-standard pathnames.
A
.Fn pu_foo_fn
callback is set using the
.Fn puffs_set_foo
routine.
.Pp
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.Sh SEE ALSO
.Xr puffs 3 ,
.Xr puffs_node 3 ,
.Xr mount_psshfs 8 ,
.Xr mount_sysctlfs 8