KAFS(3)

NAME
k_hasafs, k_pioctl, k_unlog, k_setpag, k_afs_cell_of_file, krb_afslog, krb_afslog_uid - AFS library

LIBRARY
AFS cache manager access library (libkafs, -lkafs)

SYNOPSIS
#include <kafs.h>
int
k_afs_cell_of_file(const char *path, char *cell, int len);
int
k_hasafs();
int
k_pioctl(char *a_path, int o_opcode, struct ViceIoctl *a_paramsP, int a_followSymlinks);
int
k_setpag();
int
k_unlog();
int
krb_afslog(char *cell, char *realm);
int
krb_afslog_uid(char *cell, char *realm, uid_t uid);

DESCRIPTION
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 k_hasafs() is called, or if it fails.

krb_afslog(), and krb_afslog_uid() obtains new tokens (and possibly tickets) for the specified cell and realm. If cell is NULL, the local cell is used. If realm is 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 NULL. krb_afslog() will use the real user-id for the ViceId field in the token, krb_afslog_uid() will use uid.

k_afs_cell_of_file() will in cell return the cell of a specified file, no more than len characters is put in cell.

k_pioctl() does a pioctl() syscall with the specified arguments. This function is equivalent to lpioctl().

k_setpag() initializes a new PAG.

k_unlog() removes destroys all tokens in the current PAG.

RETURN VALUES
k_hasafs() returns 1 if AFS is present in the kernel, 0 otherwise. krb_afslog() and krb_afslog_uid() returns 0 on success, or a kerberos error number on failure. k_afs_cell_of_file(), k_pioctl(), k_setpag(), and k_unlog() all return the value of the underlaying system call, 0 on success.

ENVIRONMENT
The following environment variable affect the mode of operation of kafs:

AFS_SYSCALL
    Normally, 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.

EXAMPLES
The following code from login will obtain a new PAG and tokens for the local cell and the cell of the users home directory.

    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);
    }

ERRORS
If any of these functions (apart from k_hasafs()) is called without AFS beeing present in the kernel, the process will usually (depending on the operating system) receive a SIGSYS signal.

SEE ALSO
Transarc Corporation, AFS-3 Programmer's Reference, File Server/Cache Manager Interface, 1991.

BUGS
AFS_SYSCALL has no effect under AIX.