mirror of
https://git.hardenedbsd.org/hardenedbsd/HardenedBSD.git
synced 2024-12-25 03:54:17 +01:00
175 lines
3.6 KiB
Groff
175 lines
3.6 KiB
Groff
.\" Author: Juli Mallett <jmallett@FreeBSD.org>
|
|
.\" Date: June 04, 2003
|
|
.\" Description:
|
|
.\" Manual page for libufs functions:
|
|
.\" cgget(3)
|
|
.\" cgput(3)
|
|
.\" cgread(3)
|
|
.\" cgread1(3)
|
|
.\" cgwrite(3)
|
|
.\" cgwrite1(3)
|
|
.\"
|
|
.\" This file is in the public domain.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd January 19, 2018
|
|
.Dt CGREAD 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm cgget , cgput , cgread , cgread1 , cgwrite , cgwrite1
|
|
.Nd read/write cylinder groups of UFS disks
|
|
.Sh LIBRARY
|
|
.Lb libufs
|
|
.Sh SYNOPSIS
|
|
.In sys/param.h
|
|
.In sys/mount.h
|
|
.In ufs/ufs/ufsmount.h
|
|
.In ufs/ufs/dinode.h
|
|
.In ufs/ffs/fs.h
|
|
.In libufs.h
|
|
.Ft int
|
|
.Fn cgget "struct uufsd *disk" "int cg" "struct cg *cgp"
|
|
.Ft int
|
|
.Fn cgput "struct uufsd *disk" "struct cg *cgp"
|
|
.Ft int
|
|
.Fn cgread "struct uufsd *disk"
|
|
.Ft int
|
|
.Fn cgread1 "struct uufsd *disk" "int cg"
|
|
.Ft int
|
|
.Fn cgwrite "struct uufsd *disk"
|
|
.Ft int
|
|
.Fn cgwrite1 "struct uufsd *disk" "int cg"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn cgget ,
|
|
.Fn cgread ,
|
|
and
|
|
.Fn cgread1
|
|
functions provide cylinder group reads for
|
|
.Xr libufs 3
|
|
consumers.
|
|
The
|
|
.Fn cgput ,
|
|
.Fn cgwrite ,
|
|
and
|
|
.Fn cgwrite1
|
|
functions provide cylinder group writes for
|
|
.Xr libufs 3
|
|
consumers.
|
|
.Pp
|
|
The
|
|
.Fn cgget
|
|
function reads the cylinder group specified by
|
|
.Fa cg
|
|
into the buffer pointed to by
|
|
.Fa cgp
|
|
from the disk referenced by the user-land UFS-disk structure.
|
|
The
|
|
.Fn cgget
|
|
function is the only cylinder group read function that is safe to use
|
|
in threaded applications.
|
|
.Pp
|
|
The
|
|
.Fn cgput
|
|
function writes the cylinder group specified by
|
|
.Va cgp
|
|
to the disk referenced by the user-land UFS-disk structure.
|
|
The
|
|
.Fn cgput
|
|
function is the only cylinder group write function that is safe to use
|
|
in threaded applications.
|
|
Note that the
|
|
.Fn cgput
|
|
function needs to be called only if the cylinder group has been
|
|
modified and the on-disk copy needs to be updated.
|
|
.Pp
|
|
The
|
|
.Fn cgread1
|
|
function reads from the cylinder group specified by
|
|
.Fa cg
|
|
into the
|
|
.Va d_cg
|
|
cylinder-group structure in a user-land UFS-disk structure.
|
|
It sets the
|
|
.Va d_lcg
|
|
field to the cylinder group number
|
|
.Fa cg .
|
|
.Pp
|
|
The
|
|
.Fn cgread
|
|
function operates on sequential cylinder groups.
|
|
Calling the
|
|
.Fn cgread
|
|
function is equivalent to calling
|
|
.Fn cgread1
|
|
with a cylinder group specifier equivalent to the value of the current
|
|
.Va d_ccg
|
|
field, and then incrementing the
|
|
.Va d_ccg
|
|
field.
|
|
.Pp
|
|
The
|
|
.Fn cgwrite
|
|
function stores on disk the cylinder group held in the
|
|
.Va d_cg
|
|
cylinder-group structure in a user-land UFS-disk structure.
|
|
.Pp
|
|
The
|
|
.Fn cgwrite1
|
|
function provides no additional functionality over the
|
|
.Fn cgwrite
|
|
function as there is only one place that a given cylinder group
|
|
can correctly be written.
|
|
If the caller gets the
|
|
.Fa cg
|
|
parameter wrong, the function fails with the error
|
|
.Er EDOOFUS .
|
|
This function remains only to provide backward compatibility.
|
|
.Sh RETURN VALUES
|
|
The
|
|
.Fn cgread
|
|
function returns 0 if there are no more cylinder groups to read,
|
|
1 if there are more cylinder groups, and \-1 on error.
|
|
The
|
|
.Fn cgread1
|
|
function returns 1 on success and \-1 on error.
|
|
The other functions return 0 on success and \-1 on error.
|
|
.Sh ERRORS
|
|
The
|
|
.Fn cgget ,
|
|
.Fn cgread ,
|
|
and
|
|
.Fn cgread1
|
|
functions may fail and set
|
|
.Va errno
|
|
for any of the errors specified for the library function
|
|
.Xr bread 3 .
|
|
.Pp
|
|
The
|
|
.Fn cgput ,
|
|
.Fn cgwrite ,
|
|
and
|
|
.Fn cgwrite1
|
|
functions may fail and set
|
|
.Va errno
|
|
for any of the errors specified for the library function
|
|
.Xr bwrite 3 .
|
|
Additionally the
|
|
.Fn cgwrite1
|
|
will return the
|
|
.Er EDOOFUS
|
|
error if the cylinder group specified does not match the
|
|
cylinder group that it is requesting to write.
|
|
.Sh SEE ALSO
|
|
.Xr bread 3 ,
|
|
.Xr bwrite 3 ,
|
|
.Xr libufs 3
|
|
.Sh HISTORY
|
|
These functions first appeared as part of
|
|
.Xr libufs 3
|
|
in
|
|
.Fx 5.1 .
|
|
.Sh AUTHORS
|
|
.An Juli Mallett Aq Mt jmallett@FreeBSD.org
|