openafs/doc/man-pages/pod5/uss.pod

=head1 NAME

uss - Provides instructions for the uss add command

=head1 DESCRIPTION

The uss template file defines the components of an AFS user account that
the B<uss add> command (or B<add> instruction in a B<uss> bulk input file)
creates. Use the B<-template> argument to the B<uss add> or B<uss bulk>
command to identify the template file.

=head2 Summary of Template File Instructions

The template file can include the following instructions, each on its own
line. A more detailed description of each instruction's syntax follows
this list.

=over 4

=item A

Imposes restrictions on user passwords and authentication attempts.

=item D

Creates a directory.

=item E

Creates a single-line file.

=item F

Creates a file by copying a prototype.

=item G

Defines a directory that is one of a set of parent directories into which
the B<uss> command interpreter evenly distributes newly created home
directories.

=item L

Creates a hard link.

=item S

Creates a symbolic link.

=item V

Creates a volume, mounts it in the file space and sets the ACL on the
mount point.

=item X

Executes a command.

=back

If the template file is empty (zero-length), the B<uss add> command or
C<add> instruction in a bulk input file only creates an entry in the
Protection and Authentication Databases, naming them according to the name
specified with the B<uss add> command's B<-user> argument, or in the bulk
input file C<add> instruction's I<username> field.

=head2 The A Instruction for Setting the Default Treatment of Volumes

The C<A> instruction in a uss template file enhances cell security by
imposing the following restrictions on users' password choice and
authentication attempts. For further information on these limits, see the
I<IBM AFS Administration Guide> and the B<kas setfields> reference page.

=over 4

=item *

Limiting the user's password lifetime. When the lifetime expires, the user
can no longer authenticate using that password, and must change it.

=item *

Prohibiting the reuse of the user's 20 most recently used passwords.

=item *

Limiting the number of consecutive times that a user can provide an
incorrect password during authentication, and for how long the
Authentication Server refuses further authentication attempts after the
limit is exceeded (referred to as an I<account lockout>). For regular user
accounts in most cells, the recommended limit is nine and lockout time is
25 minutes.

=back

The instruction has the following syntax:

   A <username> <lifetime> <reuse> <failures> <locktime>

where

=over 4

=item A

Indicates a security-enhancing instruction. It must be a capital letter.

=item <username>

Names the Authentication Database entry on which to impose security
restrictions. Specify the value $USER to read in the username from the
B<uss add> command's B<-user> argument, or from the I<username> field of
an C<add> instruction in a bulk input file.

=item <lifetime>

Sets the number of days after the user's password is changed that it
remains valid. When the password becomes invalid (expires), the user is
unable to authenticate, but has 30 more days in which to issue the
B<kpasswd> command to change the password (after that, only an
administrator can change it).

Specify an integer from the range C<1> through C<254> to specify the
number of days until expiration, the value C<0> to indicate that the
password never expires, or the value $PWEXPIRES to read in the number
of days from the B<uss add> or B<uss bulk> command's B<-pwexpires>
argument. If the C<A> instruction does not appear in the template file,
the default is for the user's password never to expire.

=item <reuse>

Determines whether or not the user can change his or her password (using
the B<kpasswd> or B<kas setpassword> command) to one that is similar to
any of the last twenty passwords. The acceptable values are C<reuse> to
allow reuse and C<noreuse> to prohibit it.  If the C<A> instruction does
not appear in the template file, the default is to allow password reuse.

=item <failures>

Sets the number of consecutive times the user can provide an incorrect
password during authentication (using the B<klog> command or a login
utility that grants AFS tokens). When the user exceeds the limit, the
Authentication Server rejects further authentication attempts for the
amount of time specified in the <locktime> field.

Specify an integer from the range C<1> through C<254> to specify the
number of failures permitted, or the value C<0> to indicate that there is
no limit to the number of unsuccessful attempts.  If the C<A> instruction
does not appear in the template file, the default is to allow an unlimited
number of failures.

=item <locktime>

Specifies how long the Authentication Server refuses authentication
attempts from a user who has exceeded the failure limit set in the
<failures> field.

Specify a number of hours and minutes (I<hh:mm>) or minutes only (I<mm>),
from the range C<01> (one minute) through C<36:00> (36 hours). The
Authentication Server automatically reduces any larger value to C<36:00>
and also rounds up any non-zero value to the next higher multiple of 8.5
minutes. A value of C<0> (zero) sets an infinite lockout time; an
administrator must always issue the B<kas unlock> command to unlock the
account.

=back

=head2 The D Instruction for Creating a Directory

The C<D> instruction in a uss template file creates a directory. Its
intended use is to create a subdirectory in the user home directory
created by the C<V> instruction in the template file.

Any number of C<D> instructions can appear in the template file. If any
variables in the instruction take their values from the C<V> instruction
(notably, the $MTPT variable), the instruction must follow the C<V>
instruction in the file.

Although it is possible to use the C<D> instruction to create a directory
on the local disk of the machine where the B<uss> command is issued, it is
not recommended. The preferred method for automated creation of
directories on a local disk is the B<package> program. Two complications
arise if the <pathname> field refers to a local disk directory:

=over 4

=item *

The B<uss> command prints a warning message because it cannot associate an
access control list (ACL) with a local disk directory. It creates the
directory nonetheless, and some syntactically correct value must appear in
the instruction's <ACL> field.

=item *

To designate any user other than the issuer as the new directory's owner,
the issuer must log onto the machine as the local superuser C<root>. For
local disk directories, only the local superuser C<root> is allowed to
issue the UNIX B<chown> command that the B<uss> command interpreter
invokes to change the owner from the default value (the directory's
creator, which in this case is the issuer of the B<uss> command). The
issuer must then also use the B<-admin> argument to the B<uss add> or
B<uss bulk> command to authenticate as a privileged AFS administrator,
which is required for creating the Authentication Database and Protection
Database entries that the B<uss> command interpreter always creates for a
new account.

=back

The instruction has the following syntax:

   D <pathname> <mode> <owner> <ACL>

where

=over 4

=item D

Indicates a directory creation instruction. It must be a capital letter.

=item <pathname>

Specifies the directory's full pathname. It can include variables.

Specify the read/write path to the directory, to avoid the failure that
results from attempting to create a new directory in a read-only
volume. By convention, the read/write path is indicated by placing a
period before the cell name at the pathname's second level (for example,
F</afs/.abc.com>). For further discussion of the concept of read/write and
read-only paths through the filespace, see the reference page for the B<fs
mkmount> command.

=item <mode>

Sets the directory's UNIX mode bits. Acceptable values are the standard
three- or four-digit numbers corresponding to combinations of
permissions. Examples: C<755> corresponds to C<rwxr-xr-x>, and C<644> to
C<rw-r--r-->. The first (owner) C<x> bit must be turned on to enable
access to a directory.

=item <owner>

Specifies the username or UNIX user ID (UID) of the user to be designated
the directory's owner in the output from the UNIX C<ls -ld> command. If
the directory resides in AFS, place the $UID variable in this field. If
the directory resides on the local disk, this field must be the username
or UID of the B<uss> command's issuer, unless the issuer is logged in as
the local superuser C<root>.

=item <ACL>

Sets the ACL on the new directory. It must appear even if the new
directory resides on the local disk rather than in AFS, but is ignored in
that case. Provide one or more paired values, each pair consisting of an
AFS username or group name and the desired permissions, in that order.
Separate the two parts of the pair, and each pair, with a space. The B<fs
setacl> reference page describes the available permissions.

For an AFS directory, grant all permissions to the directory's owner at
least. Usually that is the new user, in which case the appropriate value
is C<$USER all>.

It is not possible to grant any permissions to the issuer of the B<uss>
command. As the last step in account creation, the B<uss> command
interpreter automatically deletes that person from any ACLs set during the
creation process.

=back

=head2 The E Instruction for Creating a Single-line File

The C<E> instruction in a uss template file creates a file by echoing a
specified character string into it. Its intended use is to create files in
the user home directory created by the C<V> instruction in the template
file, or in a subdirectory created by a C<D> instruction.

Any number of C<E> instructions can appear in the template file. If the
file resides in a directory created by a C<D> instruction, the C<E>
instruction must follow the C<D> instruction in the file.

The C<E> and C<F> instructions have complementary advantages. The
character string echoed into the file by an C<E> instruction can be
customized for each user, because it can include the standard variables
for which the B<uss> command interpreter substitutes the values specified
by arguments to the B<uss add> command or fields in a bulk input file
B<add> instruction. In contrast, a file created using the C<F> instruction
cannot include variables and so has the same content for all
users. However, a file created by an C<E> instruction can be a single line
only, because no carriage returns (newline characters) are allowed in the
character string.

Although it is possible to use the C<E> instruction to create a file on
the local disk of the machine where the B<uss> command is issued, it is
not recommended. The preferred method for automated creation of files on a
local disk is the B<package> program.  The main complication is that
designating any user other than the issuer as the new file's owner
requires logging onto the machine as the local superuser C<root>. For
local disk files, only the local superuser C<root> is allowed to issue the
UNIX B<chown> command that the B<uss> command interpreter invokes to
change the owner from the default value (the file's creator, which in this
case is the issuer of the B<uss> command). The issuer must then also use
the B<-admin> argument to the B<uss add> or B<uss bulk> command to
authenticate as a privileged AFS administrator, which is required for
creating the Authentication Database and Protection Database entries that
the B<uss> command interpreter always creates for a new account.

The instruction has the following syntax:

   E <pathname> <mode> <owner> "<contents>"

where

=over 4

=item E

Indicates a file creation instruction. It must be a capital letter.

=item <pathname>

Specifies the file's full pathname. It can include variables.

Specify the read/write path to the file, to avoid the failure that results
from attempting to create a new file in a read-only volume. By convention,
the read/write path is indicated by placing a period before the cell name
at the pathname's second level (for example, F</afs/.abc.com>). For
further discussion of the concept of read/write and read-only paths
through the filespace, see the reference page for the B<fs mkmount>
command.

=item <mode>

Sets the file's UNIX mode bits. Acceptable values are the standard three-
or four-digit numbers corresponding to combinations of
permissions. Examples: C<755> corresponds to C<rwxr-xr-x>, and C<644> to
C<rw-r--r-->.

=item <owner>

Specifies the username or UNIX user ID (UID) of the user to be designated
the file's owner in the output from the UNIX C<ls -l> command. If the file
resides in AFS, place the $UID variable in this field. If the file
resides on the local disk, specify the username or UID of the B<uss>
command's issuer; otherwise, the account creation operation halts
immediately.

=item <contents>

Specifies the one-line character string to write into the new file.
Surround it with double quotes if it contains one or more spaces. It
cannot contain the newline character, but can contain any of the standard
variables, which the command interpreter resolves as it creates the file.

=back

=head2 The F Instruction for Creating a File from a Prototype

The C<F> instruction in a uss template file creates a file by copying the
contents of an existing file (the <prototype>) into it. Its intended use
is to create files in the user home directory created by the C<V>
instruction in the template file, or in a subdirectory created by a C<D>
instruction.

Any number of C<F> instructions can appear in the template file. If the
file resides in a directory created by a C<D> instruction, the C<F>
instruction must follow the C<D> instruction in the file.

The C<E> and C<F> instructions have complementary advantages. A file
created using the C<F> instruction has the same content for all users,
whereas a file created by an C<E> instruction can be customized for each
user if it includes variables.  However, a file created by an C<E>
instruction can be a single line only, whereas the prototype file copied
by an C<F> instruction can be any length.

Although it is possible to use the C<F> instruction to create a file on
the local disk of the machine where the B<uss> command is issued, it is
not recommended. The preferred method for automated creation of files on a
local disk is the B<package> program.  The main complication is that
designating any user other than the issuer as the new file's owner
requires logging onto the machine as the local superuser C<root>. For
local disk files, only the local superuser C<root> is allowed to issue the
UNIX B<chown> command that the B<uss> command interpreter invokes to
change the owner from the default value (the file's creator, which in this
case is the issuer of the B<uss> command). The issuer must then also use
the B<-admin> argument to the B<uss add> or B<uss bulk> command to
authenticate as a privileged AFS administrator, which is required for
creating the Authentication Database and Protection Database entries that
the B<uss> command interpreter always creates for a new account.

The instruction has the following syntax:

   F <pathname> <mode> <owner> <prototype_file>

where

=over 4

=item F

Indicates a file creation instruction. It must be a capital letter.

=item <pathname>

Specifies the full pathname of the file to create, including the
filename. It can include variables.

Specify the read/write path to the file, to avoid the failure that results
from attempting to create a new file in a read-only volume. By convention,
the read/write path is indicated by placing a period before the cell name
at the pathname's second level (for example, F</afs/.abc.com>). For
further discussion of the concept of read/write and read-only paths
through the filespace, see the reference page for the B<fs mkmount>
command.

=item <mode>

Sets the file's UNIX mode bits. Acceptable values are the standard three-
or four-digit numbers corresponding to combinations of
permissions. Examples: C<755> corresponds to C<rwxr-xr-x>, and C<644> to
C<rw-r--r-->.

=item <owner>

Specifies the username or UNIX user ID (UID) of the user to be designated
the file's owner in the output from the UNIX C<ls -l> command. If the file
resides in AFS, place the $UID variable in this field. If the file
resides on the local disk, specify the username or UID of the B<uss>
command's issuer; otherwise, the account creation operation halts
immediately.

=item <prototype_file>

Names the AFS or local disk directory that houses the prototype file to
copy. The prototype file's name must match the final element in the
<pathname> field.

=back

=head2 The G Instruction for Even Distribution of Home Directories

The C<G> instruction in a uss template file creates a directory as one of
the set of directories from which the B<uss> command interpreter selects
when choosing a new user home directory's parent directory. More
specifically, when the $AUTO variable appears in the <mount_point>
field of a C<V> instruction, the command interpreter substitutes for it
the directory defined by a C<G> instruction that currently has the fewest
entries.

The instruction's intended use is to distribute user accounts evenly among
several directories, rather than using directories that reflect divisions
such as departmental affiliation. Distributing home directories in this
fashion is useful mainly in very large cells where storing all user home
directories under a single parent directory potentially slows directory
lookup, or where a workplace-based division results in unevenly sized
directories such that some users consistently experience slower directory
lookup than others. See the chapter on B<uss> in the I<IBM AFS
Administration Guide> for more information.

Any number of C<G> instructions can appear in the template file. If the
C<V> instruction includes the $AUTO variable, it must appear after all
of the C<G> instructions in the file.

The instruction has the following syntax:

   G <directory>

where

=over 4

=item G

Indicates an instruction that creates a directory to be considered as a
value for the $AUTO variable. It must be a capital letter.

=item <directory>

Specifies the directory's name as either a complete pathname or only the
directory name. The choice determines the appropriate format for the
<mount_point> field of a C<V> instruction, as discussed in the following
example.

Specify the read/write path to the directory, to avoid the failure that
results from attempting to create a new mount point in a read-only volume
when the $AUTO variable is used in a C<V> instruction's <mount_point>
field. By convention, the read/write path is indicated by placing a period
before the cell name at the pathname's second level (for example,
F</afs/.abc.com>). For further discussion of the concept of read/write and
read-only paths through the filespace, see the reference page for the B<fs
mkmount> command.

=back

=head2 The L and S Instructions for Creating a Link

The C<L> instruction in a uss template file creates a hard link between
two files, as achieved by the standard UNIX B<ln> command. The C<S>
instruction creates a symbolic link between two files, as achieved by the
standard UNIX C<ln -s> command. A full explanation of links is beyond the
scope of this document, but the basic effect is to create a second name
for an existing file, enabling access via either name. Creating a link
does not create a second copy of the file.

AFS allows hard links only if the linked files reside in the same
directory, because it becomes difficult to determine which access control
list (ACL) applies to the file if the two copies reside in directories
with different ACLs. AFS allows symbolic links between two files that
reside in different directories, or even different volumes. The File
Server uses the ACL associated with the actual file rather than the link.

Any number of C<L> and C<S> instructions can appear in the template
file. If the existing file or link is to reside in a directory created by
a C<D> instruction, or if the existing file was created by an C<E> or C<F>
instruction, the C<L> or C<S> instruction must follow the C<D>, C<E>, or
C<F> instruction.

The instructions share the following syntax:

   L <existing_file> <link>
   S <existing_file> <link>

where

=over 4

=item L

Indicates a hard link creation instruction. It must be a capital letter.

=item S

Indicates a symbolic link creation instruction. It must be a capital
letter.

=item <existing_file>

Specifies the complete pathname of the existing file.

=item <link>

Specifies the complete pathname of the second name for the file.

Specify the read/write path to the link, to avoid the failure that results
from attempting to create a new link in a read-only volume. By convention,
the read/write path is indicated by placing a period before the cell name
at the pathname's second level (for example, F</afs/.abc.com>). For
further discussion of the concept of read/write and read-only paths
through the filespace, see the reference page for the B<fs mkmount>
command.

=back

=head2 The V Instruction for Creating and Mounting a Volume

The C<V> instruction in a uss template file creates a volume on a
specified file server machine and partition and creates an entry for it in
the Volume Location Database (VLDB). It mounts the volume at a location in
the AFS file space that becomes the user's home directory, then designates
the directory's owner and sets its access control list (ACL).

Only one C<V> instruction can appear in the template file, and one must
appear if the template file contains any instructions at all (is not
empty). All other instructions are optional, except that the template must
include C<G> instructions if the $AUTO variable appears in it. (The
C<V> instruction is not necessarily the first line in the template. If the
template includes the $AUTO variable, then the C<G> instructions which
provide values for the variable must precede it in the file.)

The instruction has the following syntax:

   V <vname> <server> <partition> <quota> <mount_point> <owner> <ACL>

where

=over 4

=item V

Indicates a volume creation instruction. It must be a capital letter.

=item <name>

Specifies the volume's name. To follow the convention for AFS user volume
names, specify the value C<user.$USER>.  Provide a value for the $USER
variable via the B<uss add> command's B<-user> argument or the <username>
field in the bulk input file B<add> instruction.

=item <server>

Names the file server machine on which to create the new user's volume. It
is best to provide the fully-qualified hostname (for example,
C<fs1.abc.com>), but an abbreviated form is acceptable provided that the
cell's naming service is available to resolve it at the time the volume is
created. To read in the value from the B<uss add> command's B<-server>
argument, specify the value $SERVER.

=item <partition>

Specifies the partition on which to create the user's volume; it must be
on the file server machine named in the <server> field.  Identify the
partition by its complete name (for example, F</vicepa>) or use or use one
of the following abbreviations.

   /vicepa     =     vicepa      =      a      =      0
   /vicepb     =     vicepb      =      b      =      1

After F</vicepz> (for which the index is 25) comes 

   /vicepaa    =     vicepaa     =      aa     =      26
   /vicepab    =     vicepab     =      ab     =      27

and so on through 

   /vicepiv    =     vicepiv     =      iv     =      255

To read in the value from the B<uss add> command's B<-partition> argument,
specify the value $PART.

=item <quota>

Sets the maximum number of kilobyte blocks the volume can occupy on the
file server machine's disk. Specify an integer constant if all volumes
have the same quota (C<1024> equals a megabyte), or use one of the number
variables ($1 through $9) to assign different values to different volumes.

=item <mount_point>

Creates a mount point for the volume, which serves as the volume's root
directory. Include the $USER variable as part of the pathname to follow
the convention that user home directory names include the username.

Specify the read/write path to the mount point, to avoid the failure that
results from attempting to create a new mount point in a read-only
volume. By convention, the read/write path is indicated by placing a
period before the cell name at the pathname's second level (for example,
F</afs/.abc.com>). If the $AUTO variable appears in this field, the
directories named by each C<G> instruction possibly already indicate the
read/write path. For further discussion of the concept of read/write and
read-only paths through the filespace, see the reference page for the B<fs
mkmount> command.

=item <owner>

Specifies the username or UNIX user ID (UID) of the user to be designated
the mount point's owner in the output from the UNIX C<ls -ld> command. To
follow the convention for home directory ownership, place the value
$UID in this field.

=item <ACL>

Sets the ACL on the new directory. Provide one or more paired values, each
pair consisting of an AFS username or group name and the desired
permissions, in that order. Separate the two parts of the pair, and each
pair, with a space. The B<fs setacl> reference page describes the
available permissions.

Grant all permissions to the new user at least. The appropriate
value is C<$USER all>.

AFS automatically grants the system:administrators group all permissions
as well. It is not possible to grant any permissions to the issuer of the
B<uss> command. As the last step in account creation, the B<uss> command
interpreter automatically deletes that user from any ACLs set during the
creation process.

=back

=head2 The X Instruction for Running a Command

The C<X> instruction in a uss template file runs the indicated command,
which can be a standard UNIX or AFS command. It can include any variables
from the template file, which the B<uss> command interpreter resolves
before passing the command on to the appropriate other command
interpreter. It must be a single line only, however (cannot contain
carriage returns or newline characters).

Any number of C<X> instructions can appear in the template file. If an
instruction manipulates an element created by another instruction, it must
follow that instruction in the file.

The instruction has the following syntax:

   X "<command>"

where

=over 4

=item X

Indicates a command execution instruction. It must be a capital letter.

=item <command>

Specifies the command to run. Surround it with double quotes as shown if
it contains one or more spaces. It can contain any variables from the
template file, but not newline characters.

=back

=head1 EXAMPLES

The following example A instruction sets a password lifetime of 254 days,
prohibits password reuse, limits the number of consecutive failed
authentication attempts to nine and sets the corresponding locktime to
25:30 minutes (which is a multiple of 8.5 minutes). The username is read
in from the B<-user> argument to the B<uss add> command or from the
I<username> field in each C<add> instruction in a bulk input file.

   A $USER 254 noreuse 9 25:30

The following example C<D> instruction creates a directory called
F<public> in a new user's home directory, designates the user as the
directory's owner, and grants him or her all ACL permissions.

   D $MTPT/public 0755 $UID $USER all 

The following example C<E> instruction creates a file in the current
working directory called F<I<username>.etcp>. The contents are an entry
suitable for incorporating into the cell's global F</etc/password> file.

   E  $USER.etcp  0644 root "$USER:X:$UID:10:$NAME:$MTPT:/bin/csh"

The following example C<F> instruction, appropriate for the ABC
Corporation cell, copies a prototype F<.login> file into the user's home
directory.

   F $MTPT/.login 0644 $UID /afs/abc.com/common/uss/skel/.login 

In the following example, the State University cell's administrators
have decided to distribute user home directories evenly into three
directories. They define three C<G> instructions:

   G usr1
   G usr2
   G usr3

and then put the following value in the <mount_point> field of the C<V>
instruction:

   /afs/stateu.edu/$AUTO/$USER

Alternatively, if they include the entire directory pathname in the C<G>
instruction:

   G /afs/stateu.edu/usr1
   G /afs/stateu.edu/usr2
   G /afs/stateu.edu/usr3

then the <mount_point> field of the C<V> instruction specifies only the
following:

   $AUTO/$USER

The following example C<L> instruction creates a hard link between the
files F<mail> and F<mbox> in the user's home directory.

   L $MTPT/mbox $MTPT/mail

The following example C<S> instruction, appropriate for the ABC
Corporation cell, links the file F<Mail/outgoing> in the user's home
directory to the file F</afs/abc.com/common/mail/outgoing>.

   S /afs/abc.com/common/mail/outgoing $MTPT/Mail/outgoing

The following example C<V> instruction creates a volume called
C<user.I<username>> on the F</vicepa> partition of the specified file
server machine, assigning it a quota of 3000 kilobyte blocks. The mount
point is under F</afs/abc.com/usr> and matches the username (the value of
the $USER variable). The user owns the home directory and has all
access rights to it. The instruction appears on two lines only for
legibility; it must appear on a single line in the template file.

   V user.$USER $SERVER.abc.com /vicepa 3000 \
           /afs/abc.com/usr/$USER $UID $USER all 

The following example C<X> instruction mounts the backup version of the
user's volume at the F<OldFiles> subdirectory.

   X "fs mkm /afs/abc.com/usr/$USER/OldFiles   user.$USER.backup"

=head1 SEE ALSO

L<uss_bulk(5)>,
L<fs_mkmount(1)>,
L<uss_add(8)>

=head1 COPYRIGHT

IBM Corporation 2000. <http://www.ibm.com/> All Rights Reserved.

This documentation is covered by the IBM Public License Version 1.0.  It was
converted from HTML to POD by software written by Chas Williams and Russ
Allbery, based on work by Alf Wachsmann and Elizabeth Cassell.