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.TH Xau __libmansuffix__ __xorgversion__

.SH NAME

Xau library: XauFileName, XauReadAuth, XauLockAuth, XauUnlockAuth,

XauWriteAuth, XauDisposeAuth,

XauGetAuthByAddr, XauGetBestAuthByAddr \- X authority database routines

.SH SYNOPSIS

.ft CW

.nf

#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;

.HP

char *XauFileName (void);

.HP

Xauth *XauReadAuth (FILE *\fIauth_file\fP\^);

.HP

int XauWriteAuth (FILE *\fIauth_file\fP, Xauth *\fIauth\fP\^);

.HP

Xauth *XauGetAuthByAddr (unsigned short \fIfamily\fP\^, unsigned short

\fIaddress_length\fP\^, const char *\fIaddress\fP\^, unsigned short

\fInumber_length\fP\^, const char *\fInumber\fP\^, unsigned short

\fIname_length\fP\^, const char *\fIname\fP\^);

.HP

Xauth *XauGetBestAuthByAddr (unsigned short \fIfamily\fP\^, unsigned short

\fIaddress_length\fP\^, const char *\fIaddress\fP\^, unsigned short

\fInumber_length\fP\^, const char *\fInumber\fP\^, int \fItypes_length\fP\^,

char **\fItypes\fR\^, const int *\fItype_lengths\fR\^);

.HP

int XauLockAuth (const char *\fIfile_name\fP\^, int \fIretries\fP\^, int

\fItimeout\fP\^, long \fIdead\fP\^);

.HP

int XauUnlockAuth (const char *\fIfile_name\fP\^);

.HP

int XauDisposeAuth (Xauth *\fIauth\fP\^);

.fi

.ft

.SH DESCRIPTION

.PP

\fBXauFileName\fP 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.

.PP

\fBXauReadAuth\fP reads the next entry from \fIauth_file\fP.  The entry is

\fBnot\fP statically allocated and should be freed by calling

\fIXauDisposeAuth\fP.

.PP

\fBXauWriteAuth\fP writes an authorization entry to \fIauth_file\fP.  It

returns 1 on success, 0 on failure.

.PP

\fBXauGetAuthByAddr\fP searches for an entry which matches the given network

address/display number pair.  The entry is \fBnot\fP statically allocated

and should be freed by calling \fIXauDisposeAuth\fP.

.PP

\fBXauGetBestAuthByAddr\fP is similar to \fBXauGetAuthByAddr\fP, 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 \fItypes\fP argument is an array of

strings, one string for each authentication method.  \fItypes_length\fP

specifies how many elements are in the \fItypes\fP array.

\fItypes_lengths\fP is an array of integers representing the length

of each string.

.PP

\fBXauLockAuth\fP does the work necessary to synchronously update an

authorization file.  First it makes two file names, one with ``-c'' appended

to \fIfile_name\fP, the other with ``-l'' appended.  If the ``-c'' file

already exists and is more than \fIdead\fP seconds old, \fIXauLockAuth\fP

removes it and the associated ``-l'' file.  To prevent possible

synchronization troubles with NFS, a \fIdead\fP value of zero forces the

files to be removed.  \fIXauLockAuth\fP makes \fIretries\fP attempts to

create and link the file names, pausing \fItimeout\fP seconds between each

attempt.  \fIXauLockAuth\fP returns a collection of values depending on the

results:

.TP

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.

.TP

LOCK_TIMEOUT

\fIretries\fP attempts failed

.TP

LOCK_SUCCESS

The lock succeeded.

.PP

\fBXauUnlockAuth\fP undoes the work of \fIXauLockAuth\fP by unlinking both

the ``-c'' and ``-l'' file names.

.PP

\fBXauDisposeAuth\fP frees storage allocated to hold an authorization entry.

.SH "SEE ALSO"

xauth(1), xdm(1)

.SH AUTHOR

Keith Packard, MIT X Consortium