Table of Contents

## Name

Xau library: XauFileName, XauReadAuth, XauLockAuth, XauUnlockAuth, XauWriteAuth, XauDisposeAuth, XauGetAuthByAddr, XauGetBestAuthByAddr - X authority database routines

## Synopsis

#include <X11/Xauth.h>

    typedef struct xauth {
        unsigned short    family;
        unsigned short    address_length;
        char    *address;
        unsigned short    number_length;
        char    *number;
        unsigned short    name_length;
        char    *name;
        unsigned short    data_length;
        char    *data;
    } Xauth;
    char *XauFileName ()
    Xauth *XauReadAuth (auth_file)
        FILE *auth_file;
    int XauWriteAuth (auth_file, auth)
        FILE *auth_file;
        Xauth *auth;
    Xauth *XauGetAuthByAddr (kAfamily,
    address_length, address,
    number_length, number)
        unsigned short family;
        unsigned short address_length;
        char *address;
        unsigned short number_length;
        char *number;
    Xauth *XauGetBestAuthByAddr (kAfamily,
    address_length, address,
    number_length, number,
    types_length, types, type_lengths)
        unsigned short family;
        unsigned short address_length;
        char *address;
        unsigned short number_length;
        char *number;
        int types_length;
        char **types;
        int *type_lengths;
    int XauLockAuth (file_name, retries, timeout, dead)
        char *file_name;
        int retries;
        int timeout;
        long dead;
    int XauUnlockAuth (file_name)
        char *file_name;
    XauDisposeAuth (auth)
        Xauth *auth;

    DescriptionXauFileName generates the default authorization file name by
    first checking the XAUTHORITY environment variable if set, else it returns
    $HOME/.Xauthority.  This name is statically allocated and should not be freed.

    XauReadAuth reads the next entry from auth_file.  The entry is not statically
    allocated and should be freed by calling XauDisposeAuth.
    XuWriteAuth writes
    an authorization entry to auth_file.  It returns 1 on success, 0 on failure.

    XauGetAuthByAddr searches for an entry which matches the given network
    address/display number pair.  The entry is not statically allocated and
    should be freed by calling XauDisposeAuth.
    XauGetBestAuthByAddr is similar
    to XauGetAuthByAddr, except that a list of acceptable authentication methods
    is specified.  Xau will choose the file entry which matches the earliest
    entry in this list (e.g., the most secure authentication method).  The types
    argument is an array of strings, one string for each authentication method.
     types_length specifies how many elements are in the types array. types_lengths
    is an array of integers representing the length of each string.
    XauLockAuth
    does the work necessary to synchronously update an authorization file.
    First it makes two file names, one with ``-c'' appended to file_name, the other
    with ``-l'' appended.  If the ``-c'' file already exists and is more than dead seconds
    old, XauLockAuth removes it and the associated ``-l'' file.  To prevent possible
    synchronization troubles with NFS, a dead value of zero forces the files
    to be removed.  XauLockAuth makes retries attempts to create and link the
    file names, pausing timeout seconds between each attempt.  XauLockAuth returns
    a collection of values depending on the results:
        LOCK_ERROR    A system error occurred, either a file_name
            which is too long, or an unexpected failure from
            a system call.  errno may prove useful.
        LOCK_TIMEOUT    retries attempts failed
        LOCK_SUCCESS    The lock succeeded.

XauUnlockAuth undoes the work of XauLockAuth by unlinking both the ``-c'' and ``-l'' file names.

XauDisposeAuth frees storage allocated to hold an authorization entry.

## See Also

xauth(1) , xdm(1)

## Author

Keith Packard, MIT X Consortium

Table of Contents

- Name
- Synopsis
- Description
- See Also
- Author