.\"	$Id: kafs.3,v 1.8 2002/08/28 20:04:31 joda Exp $
.\"
.Dd May 7, 1997
.Os KTH-KRB
.Dt KAFS 3
.Sh NAME
.Nm k_hasafs ,
.Nm k_pioctl ,
.Nm k_unlog ,
.Nm k_setpag ,
.Nm k_afs_cell_of_file ,
.Nm krb_afslog ,
.Nm krb_afslog_uid
.\" .Nm krb5_afslog ,
.\" .Nm krb5_afslog_uid
.Nd AFS library
.Sh LIBRARY
AFS cache manager access library (libkafs, -lkafs)
.Sh SYNOPSIS
.Fd #include <kafs.h>
.Ft int
.Fn k_afs_cell_of_file "const char *path" "char *cell" "int len"
.Ft int
.Fn k_hasafs
.Ft int
.Fn k_pioctl "char *a_path" "int o_opcode" "struct ViceIoctl *a_paramsP" "int a_followSymlinks"
.Ft int
.Fn k_setpag
.Ft int
.Fn k_unlog
.Ft int
.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 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 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 .
.\" 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
syscall 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 beeing present in the kernel, the process will
usually (depending on the operating system) receive a SIGSYS signal.
.Sh SEE ALSO
.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.