Xau(3)
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 (void);
Xauth *XauReadAuth (FILE *auth_file);
int XauWriteAuth (FILE *auth_file, Xauth *auth);
Xauth *XauGetAuthByAddr (unsigned short family, unsigned short
address_length, const char *address, unsigned short
number_length, const char *number, unsigned short
name_length, const char *name);
Xauth *XauGetBestAuthByAddr (unsigned short family, unsigned short
address_length, const char *address, unsigned short
number_length, const char *number, int types_length,
char **types, const int *type_lengths);
int XauLockAuth (const char *file_name, int retries, int
timeout, long dead);
int XauUnlockAuth (const char *file_name);
int XauDisposeAuth (Xauth *auth);
DESCRIPTION
XauFileName 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.
XauWriteAuth 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
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