heimdal/lib/kafs/kafs.3

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.Dd May  1, 2006
.Os HEIMDAL
.Dt KAFS 3
.Sh NAME
.Nm k_hasafs ,
.Nm k_hasafs_recheck ,
.Nm k_pioctl ,
.Nm k_unlog ,
.Nm k_setpag ,
.Nm k_afs_cell_of_file ,
.Nm kafs_set_verbose ,
.Nm kafs_settoken_rxkad ,
.Nm kafs_settoken ,
.Nm krb_afslog ,
.Nm krb_afslog_uid ,
.Nm kafs_settoken5 ,
.Nm krb5_afslog ,
.Nm krb5_afslog_uid
.Nd AFS library
.Sh LIBRARY
AFS cache manager access library (libkafs, -lkafs)
.Sh SYNOPSIS
.In kafs.h
.Ft int
.Fn k_afs_cell_of_file "const char *path" "char *cell" "int len"
.Ft int
.Fn k_hasafs "void"
.Ft int
.Fn k_hasafs_recheck "void"
.Ft int
.Fn k_pioctl "char *a_path" "int o_opcode" "struct ViceIoctl *a_paramsP" "int a_followSymlinks"
.Ft int
.Fn k_setpag "void"
.Ft int
.Fn k_unlog "void"
.Ft void
.Fn kafs_set_verbose "void (*func)(void *, const char *, int)" "void *"
.Ft int
.Fn kafs_settoken_rxkad "const char *cell" "struct ClearToken *token" "void *ticket" "size_t ticket_len"
.Ft int
.Fn kafs_settoken "const char *cell" "uid_t uid" "CREDENTIALS *c"
.Fn krb_afslog "char *cell" "char *realm"
.Ft int
.Fn krb_afslog_uid "char *cell" "char *realm" "uid_t uid"
.Ft krb5_error_code
.Fn krb5_afslog_uid "krb5_context context" "krb5_ccache id" "const char *cell" "krb5_const_realm realm" "uid_t uid"
.Ft int
.Fn kafs_settoken5 "const char *cell" "uid_t uid" "krb5_creds *c"
.Ft krb5_error_code
.Fn krb5_afslog "krb5_context context" "krb5_ccache id" "const char *cell" "krb5_const_realm realm"
.Sh DESCRIPTION
.Fn k_hasafs
initializes some library internal structures, and tests for the
presence of AFS in the kernel, none of the other functions should be
called before
.Fn k_hasafs
is called, or if it fails.
.Pp
.Fn k_hasafs_recheck
forces a recheck if a AFS client has started since last time
.Fn k_hasafs
or
.Fn k_hasafs_recheck
was called.
.Pp
.Fn kafs_set_verbose
set a log function that will be called each time the kafs library does
something important so that the application using libkafs can output
verbose logging.
Calling the function
.Fa kafs_set_verbose
with the function argument set to
.Dv NULL
will stop libkafs from calling the logging function (if set).
.Pp
.Fn kafs_settoken_rxkad
set
.Li rxkad
with the
.Fa token
and
.Fa ticket
(that have the length
.Fa ticket_len )
for a given
.Fa cell .
.Pp
.Fn kafs_settoken
and
.Fn kafs_settoken5
work the same way as
.Fn kafs_settoken_rxkad
but internally converts the Kerberos 4 or 5 credential to a afs
cleartoken and ticket.
.Pp
.Fn krb_afslog ,
and
.Fn krb_afslog_uid
obtains new tokens (and possibly tickets) for the specified
.Fa cell
and
.Fa realm .
If
.Fa cell
is
.Dv NULL ,
the local cell is used. If
.Fa realm
is
.Dv NULL ,
the function tries to guess what realm to use. Unless you  have some good knowledge of what cell or realm to use, you should pass
.Dv NULL .
.Fn krb_afslog
will use the real user-id for the
.Dv ViceId
field in the token,
.Fn krb_afslog_uid
will use
.Fa uid .
.Pp
.Fn krb5_afslog ,
and
.Fn krb5_afslog_uid
are the Kerberos 5 equivalents of
.Fn krb_afslog ,
and
.Fn krb_afslog_uid .
.Pp
.Fn krb5_afslog ,
.Fn kafs_settoken5
can be configured to behave differently via a 
.Nm krb5_appdefault
option
.Li afs-use-524
in
.Pa krb5.conf .
Possible values for
.Li afs-use-524
are:
.Bl -tag -width local
.It yes
use the 524 server in the realm to convert the ticket
.It no
use the Kerberos 5 ticket directly, can be used with if the afs cell
support 2b token.
.It local, 2b
convert the Kerberos 5 credential to a 2b token locally (the same work
as a 2b 524 server should have done).
.El
.Pp
Example:
.Pp
.Bd -literal
[appdefaults]
	SU.SE = { afs-use-524 = local }
	PDC.KTH.SE = { afs-use-524 = yes }
	afs-use-524 = yes
.Ed
.Pp
libkafs will use the
.Li libkafs
as application name when running the
.Nm krb5_appdefault
function call.
.Pp
The (uppercased) cell name is used as the realm to the
.Nm krb5_appdefault function.
.Pp
.\" The extra arguments are the ubiquitous context, and the cache id where
.\" to store any obtained tickets. Since AFS servers normally can't handle
.\" Kerberos 5 tickets directly, these functions will first obtain version
.\" 5 tickets for the requested cells, and then convert them to version 4
.\" tickets, that can be stashed in the kernel. To convert tickets the
.\" .Fn krb524_convert_creds_kdc
.\" function will be used.
.\" .Pp
.Fn k_afs_cell_of_file
will in
.Fa cell
return the cell of a specified file, no more than
.Fa len
characters is put in
.Fa cell .
.Pp
.Fn k_pioctl
does a
.Fn pioctl
system call with the specified arguments. This function is equivalent to
.Fn lpioctl .
.Pp
.Fn k_setpag
initializes a new PAG.
.Pp
.Fn k_unlog
removes destroys all tokens in the current PAG.
.Sh RETURN VALUES
.Fn k_hasafs
returns 1 if AFS is present in the kernel, 0 otherwise.
.Fn krb_afslog
and
.Fn krb_afslog_uid
returns 0 on success, or a Kerberos error number on failure.
.Fn k_afs_cell_of_file ,
.Fn k_pioctl ,
.Fn k_setpag ,
and
.Fn k_unlog
all return the value of the underlaying system call, 0 on success.
.Sh ENVIRONMENT
The following environment variable affect the mode of operation of
.Nm kafs :
.Bl -tag -width AFS_SYSCALL
.It Ev AFS_SYSCALL
Normally,
.Nm kafs
will try to figure out the correct system call(s) that are used by AFS
by itself.  If it does not manage to do that, or does it incorrectly,
you can set this variable to the system call number or list of system
call numbers that should be used.
.El
.Sh EXAMPLES
The following code from
.Nm login
will obtain a new PAG and tokens for the local cell and the cell of
the users home directory.
.Bd -literal
if (k_hasafs()) {
	char cell[64];
	k_setpag();
	if(k_afs_cell_of_file(pwd->pw_dir, cell, sizeof(cell)) == 0)
		krb_afslog(cell, NULL);
	krb_afslog(NULL, NULL);
}
.Ed
.Sh ERRORS
If any of these functions (apart from
.Fn k_hasafs )
is called without AFS being present in the kernel, the process will
usually (depending on the operating system) receive a SIGSYS signal.
.Sh SEE ALSO
.Xr krb5_appdefault 3 ,
.Xr krb5.conf 5
.Rs
.%A Transarc Corporation
.%J AFS-3 Programmer's Reference
.%T File Server/Cache Manager Interface
.%D 1991
.Re
.Sh BUGS
.Ev AFS_SYSCALL
has no effect under AIX.