aklog - Obtain tokens for authentication to AFS
aklog [-d] [-hosts] [-zsubs] [-noprdb] [-noauth] [-linked]
[-force] [-524] [-setpag]
[[-cell | -c] <cell> [-k <Kerberos realm>]]+
aklog [-d] [-hosts] [-zsubs] [-noprdb] [-noauth] [-linked]
[-force] [-524] [-setpag] [-path | -p] <path>+
The aklog program authenticates to a cell in AFS by obtaining AFS
tokens using a Kerberos 5 ticket. If aklog is invoked with no command-
line arguments, it will obtain tokens for the workstation’s local cell.
It may be invoked with an arbitrary number of cells and pathnames to
obtain tokens for multiple cells. aklog knows how to expand cell name
abbreviations, so cells can be referred to by enough letters to make
the cell name unique among the cells the workstation knows about.
aklog obtains tokens by obtaining a Kerberos service ticket for the AFS
service and then storing it as a token. By default, it obtains that
ticket from the realm corresponding to that cell (the uppercase version
of the cell name), but a different realm for a particular cell can be
specified with -k. -k cannot be used in -path mode (see below).
When a Kerberos 5 cross-realm trust is used, aklog looks up the AFS ID
corresponding to the name (Kerberos principal) of the person invoking
the command, and if the user doesn’t exist and the
system:authuser@FOREIGN.REALM PTS group exists, then it attempts
automatic registration of the user with the foreign cell. The user is
then added to the system:authuser@FOREIGN.REALM PTS group if
registration is successful. Automatic registration in the foreign cell
will fail if the group quota for the system:authuser@FOREIGN.REALM
group is less than one. Each automatic registration decrements the
group quota by one.
When using aklog, be aware that AFS uses the Kerberos v4 principal
naming format, not the Kerberos v5 format, when referring to principals
in PTS ACLs, UserList, and similar locations. AFS will internally map
Kerberos v5 principal names to the Kerberos v4 syntax by removing any
portion of the instance after the first period (generally the domain
name of a host principal), changing any "/" to ".", and changing an
initial principal part of "host" to "rcmd". In other words, to create
a PTS entry for the Kerberos v5 principal "user/admin", refer to it as
"user.admin", and for the principal "host/shell.example.com", refer to
it as "rcmd.shell".
Normally, aklog generates native K5 tokens. This flag tells aklog
to instead use the krb524 translation service to generate K4 or
rxkad2b tokens, which may be necessary for AFS cells that don’t
support native K5 tokens. Support for native K5 tokens were added
in OpenAFS 1.2.8.
-cell <cell>, -c <cell>
This flag tells aklog that the next argument is the name of a cell
to authenticate to. It normally isn’t necessary; aklog normally
determines whether an argument is a cell or a path name based on
whether it contains "/" or is "." or "..". The cell may be
followed by -k to specify the corresponding Kerberos realm.
-d Turns on printing of debugging information. This option is not
intended for general users.
Normally, aklog will not replace tokens with new tokens that appear
to be identical. If this flag is given, it will skip that check.
Prints all the server addresses which may act as a single point of
failure in accessing the specified directory path. Each element of
the path is examined, and as new volumes are traversed, if they are
not replicated, the server’s IP address containing the volume will
be displayed. The output is of the form:
This option is only useful in combination with paths as arguments
rather than cells.
-k <Kerberos realm>
This flag is valid only immediately after the name of the cell. It
tells aklog to use that Kerberos realm when authenticating to the
preceding cell. By default, aklog will use the realm (per the
local Kerberos configuration) of the first database server in the
cell, so this flag normally won’t be necessary.
If the AFS cell is linked to a DCE cell, get tokens for both.
Don’t actually authenticate, just do everything else aklog does up
to setting tokens.
Ordinarily, aklog looks up the AFS ID corresponding to the name of
the person invoking the command, and if the user doesn’t exist, the
cell is a foreign one, the system:authuser@FOREIGN.REALM PTS group
exists, and has a positive group quota, then it attempts automatic
registration of the user with the foreign cell. Specifying this
flag turns off this functionality. This may be desirable if the
protection database is unavailable for some reason and tokens are
desired anyway, or if one wants to disable user registration.
-path <pathname>, -p <pathname>
This flag tells aklog that the next argument is a path in AFS.
aklog will walk that path and obtain tokens for every cell needed
to access all of the directories. Normally, this flag isn’t
necessary; aklog assumes an argument is a path if it contains "/"
or is "." or "..".
When setting tokens, attempt to put the parent process in a new
PAG. This is usually used as part of the login process but can be
used any time to create a new AFS authentication context. Note
that this in some cases relies on dangerous and tricky
manipulations of kernel records and will not work on all platforms
or with all Linux kernels.
Prints out the Zephyr subscription information to get alerts
regarding all of the file servers required to access a particular
path. The output is of the form:
where <instance> is the instance of a class "filsrv" Zephyr
If this file exists in the user’s home directory, it should contain
a list of AFS cells to which to authenticate, one per line. If
aklog is invoked without any options, it will attempt to obtain
tokens in every cell listed in this file if it exists, rather than
only obtaining tokens for the local cell.
The exit status of aklog will be one of the following:
0 Success -- No error occurred.
1 Usage -- Bad command syntax; accompanied by a usage message.
2 Something failed -- More than one cell or pathname was given on the
command line and at least one failure occurred. A more specific
error status is returned when only one directive is given.
3 AFS -- Unable to get AFS configuration or unable to get information
about a specific cell.
4 Kerberos -- Unable to get tickets for authentication.
5 Token -- Unable to get tokens.
6 Bad pathname -- The path given was not a directory or lstat(2)
failed on some component of the pathname.
7 Miscellaneous -- An internal failure occurred. For example, aklog
returns this if it runs out of memory.
To get tokens for the local cell:
To get tokens for the "athena.mit.edu" cell:
% aklog athena.mit.edu
% aklog athena
The latter will work if you local cache manager already knows about the
To get tokens adequate to read /afs/athena.mit.edu/user/p/potato:
% aklog /afs/athena.mit.edu/user/p/potato
To get tokens for "testcell.mit.edu" that is in a test Kerberos realm:
% aklog testcell.mit.edu -k TESTREALM.MIT.EDU
kinit(1), tokens(1), unlog(1)
Manpage originally written by Emanuel Jay Berkenbilt (MIT-Project
Athena). Extensively modified by Russ Allbery <firstname.lastname@example.org>.
Original manpage is copyright 1990, 1991 Massachusetts Institute of
Technology. All rights reserved.
Copyright 2006 Russ Allbery <email@example.com>.
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