login(1) login(1)
NAME [Toc] [Back]
login - sign on; start terminal session
SYNOPSIS [Toc] [Back]
login [name [env-var] ...]
DESCRIPTION [Toc] [Back]
The login command is used at the beginning of each terminal session to
properly identify a prospective user. login can be invoked as a user
command or by the system as an incoming connection is established.
login can also be invoked by the system when a previous user shell
terminates but the terminal does not disconnect.
If login is invoked as a command, it must replace the initial command
interpreter (the user's login shell). This is accomplished with the
shell command
exec login
The user's login name is requested, if it is not specified on the
command line, and the corresponding password is obtained, if required,
with the following prompts:
login:
Password:
Terminal echo is turned off (where possible) during password entry to
prevent written records of the password. If the account does not have
a password, and the authentication profile for the account requires
one, login invokes pam_chauthtok() to establish one for the account.
On a trusted system, login displays the last successful and
unsuccessful login times and terminal devices.
As a security precaution, some installations use an option that
requires a second "dialup" password. This occurs only for dialup
connections, and is requested with the prompt:
dialup password:
Both passwords must be correct for a successful login (see dialups(4)
for details on dialup security).
If password aging is activated, the user's password may have expired.
pam_chauthtok() is invoked to change the password. In an untrusted
environment, the user is required to re-login after a successful
password change (see passwd(1)).
After three unsuccessful login attempts, a HANGUP signal is issued.
If a login is not successfully completed within a certain period of
time (for example, one minute), the terminal is silently disconnected.
Hewlett-Packard Company - 1 - HP-UX 11i Version 2: August 2003
login(1) login(1)
After a successful login, the accounting files are updated, user and
group IDs, group access list, and working directory are initialized,
and the user's command interpreter (shell) is determined from
corresponding user entries in the files /etc/passwd and
/etc/logingroup (see passwd(4) and group(4)). If /etc/passwd does not
specify a shell for the user name, /usr/bin/sh is used by default.
login then forks the appropriate shell by using the last component of
the shell path name preceded by a - (for example, -sh or -ksh). When
the command interpreter is invoked with its name preceded by a minus
in this manner, the shell performs its own initialization, including
execution of profile, login, or other initialization scripts.
For example, if the user login shell is the Korn or POSIX shell (see
ksh(1) or sh-posix(1), respectively), the shell executes the profile
files /etc/profile and $HOME/.profile if they exist (and possibly
others as well). Depending on what these profile files contain,
messages regarding mail in the user's mail file or any messages the
user may have received since the user's last login may be displayed.
If the command name field is *, a chroot() to the directory named in
the directory field of the entry is performed. At that point, login
is re-executed at the new level, which must have its own root
structure, including a /usr/bin/login command and an /etc/passwd file.
For the normal user, the basic environment variables (see environ(5))
are initialized to:
HOME=login_directory
LOGNAME=login_name
MAIL=/var/mail/login_name
PATH=:/usr/bin
SHELL=login_shell
login_directory, login_name, and login_shell are taken from the
corresponding fields of the passwd file entry (see passwd(4)).
For superuser, PATH is set to:
PATH=:/usr/sbin:/usr/bin:/sbin
In the case of a remote login, the environment variable TERM is also
set to the remote user's terminal type.
The environment can be expanded or modified by supplying additional
arguments to login, either at execution time or when login requests
the user's login name. The arguments can take either the form value
or varname=value, where varname is a new or existing environment
variable name and value is a value to be assigned to the variable.
An argument in the first form (without an equals sign) is placed in
the environment as if it were entered in the form
Hewlett-Packard Company - 2 - HP-UX 11i Version 2: August 2003
login(1) login(1)
Ln=value
where n is a number starting at 0 that is incremented each time a new
variable name is required.
An argument in the second form (with an equals sign) is placed into
the environment without modification.
If the variable name (Ln or varname) already appears in the
environment, the new value replaces the older one.
There are two exceptions. The variables PATH and SHELL cannot be
changed. This prevents users logged in with restricted shell
environments from spawning secondary shells that are not restricted.
Both login and getty understand simple single-character quoting
conventions. Typing a backslash in front of a character quotes it and
allows the inclusion of such things as spaces and tabs.
If /var/adm/btmp is present, all unsuccessful login attempts are
logged to that file. This feature is disabled if the file is not
present. The lastb command, (see last(1)), displays a summary of bad
login attempts for users with read access to btmp.
If the /etc/securetty file is present, login security is in effect,
i.e., root is allowed to log in successfully only on the ttys listed
in this file. Restricted ttys are listed by device name, one per
line. Valid tty names are dependent on the installation. An example
is
console
tty01
ttya1
etc.
Note that this feature does not inhibit a normal user from using the
su command (see su(1)).
HP-UX Smart Card Login [Toc] [Back]
If the user account is configured to use a Smart Card, the user
password is stored in the card. This password has characteristics
identical to a normal password stored on the system.
In order to login using a Smart Card account, the card must be
inserted into the Smart Card reader. The user is prompted for a PIN
(personal identification number) instead of a password during
authentication. The prompts are:
login:
Enter PIN:
Hewlett-Packard Company - 3 - HP-UX 11i Version 2: August 2003
login(1) login(1)
The password is retrieved automatically from the Smart Card when a
valid PIN is entered. Therefore, it is not necessary to know the
password, only the PIN.
The card is locked if an incorrect PIN is entered three consecutive
times. It may be unlocked only by the card issuer.
SECURITY FEATURES [Toc] [Back]
On a standard system, login prohibits a user from logging in if any of
the following is true:
+ The password for the account has expired and the user cannot
successfully change the password.
+ The password for the account has expired and the password was not
changed within the specified number of days after the expiration
(see shadow(4)).
+ The account lifetime has passed (see shadow(4)).
On a trusted system, login prohibits a user from logging in if any of
the following is true:
+ The password for the account has expired and the user cannot
successfully change the password.
+ The password lifetime for the account has passed.
+ The time between the last login and the current time exceeds the
time allowed for login intervals.
+ The administrative lock on the account has been set.
+ The maximum number of unsuccessful login attempts for the account
has been exceeded.
+ The maximum number of unsuccessful login attempts for the
terminal has been exceeded.
+ The administrative lock on the terminal has been set.
+ The terminal has an authorized user list and the user is not on
it.
+ The terminal has time of day restrictions and the current time is
not within the allowable period.
On a trusted system, login allows superuser to log in on the console
unless /etc/securetty exists and does not contain console.
Hewlett-Packard Company - 4 - HP-UX 11i Version 2: August 2003
login(1) login(1)
Refer to the /etc/default/security file in the security(4) manpage for
detailed information on configurable parameters that affect the
behavior of this command. Currently supported parameters are:
ABORT_LOGIN_ON_MISSING_HOMEDIR [Toc] [Back]
NOLOGIN [Toc] [Back]
NUMBER_OF_LOGINS_ALLOWED [Toc] [Back]
EXTERNAL INFLUENCES [Toc] [Back]
Environment Variables
HOME User's home directory.
MAIL Where to look for mail.
PATH Path to be searched for commands.
SHELL Which command interpreter is being used.
TERM User's terminal type.
varname User-specified named variables.
Ln User-specified unnamed variables.
DIAGNOSTICS [Toc] [Back]
The following diagnostics appear if the associated condition occurs:
.rhosts is a soft link
The personal equivalence file is a symbolic link.
Bad .rhosts ownership [Toc] [Back]
The personal equivalence file is not owned by the local user or
by a user with appropriate privileges.
Bad group id [Toc] [Back]
setgid() failed (see setuid(2)).
Bad user id [Toc] [Back]
setuid() failed (see setuid(2)).
Cannot open password file [Toc] [Back]
Consult the system administrator.
Locuser too long [Toc] [Back]
The indicated string was too long for login's internal buffer.
Login incorrect [Toc] [Back]
Hewlett-Packard Company - 5 - HP-UX 11i Version 2: August 2003
login(1) login(1)
User name and password cannot be matched.
No /usr/bin/login or /etc/login on root
Attempted to log in to a subdirectory root that does not have a
subroot login command. That is, the passwd file entry had shell
path *, but the system cannot find a login command under the
given home directory.
No directory [Toc] [Back]
Consult system administrator.
No Root Directory [Toc] [Back]
Attempted to log in to a subdirectory root that does not exist.
That is, the passwd file entry had shell path *, but the system
cannot chroot() to the given home directory.
No shell [Toc] [Back]
The user shell (/usr/bin/sh if shell name is null in /etc/passwd)
could not be started with the exec command. Consult system
administrator.
No utmp entry. You must exec "login" from the lowest level "sh"
Attempted to execute login as a command without using the shell's
exec internal command or from other than the initial shell. The
current shell is terminated.
Remuser too long [Toc] [Back]
The indicated string was too long for login's internal buffer.
Terminal type too long [Toc] [Back]
The indicated string was too long for login's internal buffer.
Unable to change to directory name
Cannot chdir to the user's home directory.
Your password has expired. Choose a new one
Password aging is enabled and the user's password has expired.
WARNINGS [Toc] [Back]
If /etc/group is linked to /etc/logingroup, and group membership for
the user trying to log in is managed by the Network Information
Service (NIS), and no NIS server is able to respond, login waits until
Hewlett-Packard Company - 6 - HP-UX 11i Version 2: August 2003
login(1) login(1)
a server does respond.
DEPENDENCIES [Toc] [Back]
Pluggable Authentication Modules (PAM)
PAM is an Open Group standard for user authentication, password
modification, and validation of accounts. In particular,
pam_authenticate() is invoked to perform all functions related to
login. This includes retrieving the password, validating the account,
and displaying error messages. pam_chauthtok() is invoked during
password expiration or establishment.
HP Process Resource Manager [Toc] [Back]
If the optional HP Process Resource Manager (PRM) software is
installed and configured, the login shell is launched in the user's
initial process resource group. If the user's initial group is not
defined, the shell runs in the user default group (PRMID=1). See
prmconfig(1) for a description of how to configure HP PRM, and
prmconf(4) for a description of how the user's initial process
resource group is determined.
AUTHOR [Toc] [Back]
login was developed by AT&T and HP.
FILES [Toc] [Back]
$HOME/.profile Personal profile (individual user initialization)
$HOME/.rhosts Personal equivalence file for the remote login
server.
/etc/d_passwd Dialup security encrypted passwords.
/etc/dialups Lines which require dialup security.
/etc/hosts.equiv System list of equivalent hosts allowing logins
without passwords.
/etc/logingroup Group file - defines group access lists.
/etc/motd Message-of-the-day.
/etc/passwd Password file - defines users, passwords, and
primary groups.
/etc/profile System profile (initialization for all users).
/etc/securetty List of valid ttys for root login.
/etc/shadow Shadow Password file.
/etc/utmp Users currently logged-in.
/tcb/files/auth/*/* The trusted system password database.
/var/adm/btmp History of bad login attempts.
/var/adm/wtmp History of logins, logouts, and date changes.
/var/mail/login_name Mailbox for user. login_name
/etc/default/security Security defaults configuration file.
SEE ALSO [Toc] [Back]
csh(1), groups(1), ksh(1), last(1), mail(1), newgrp(1), passwd(1),
sh(1), sh-posix(1), su(1), getty(1M), initgroups(3C), dialups(4),
group(4), passwd(4), profile(4), security(4), shadow(4), utmp(4),
environ(5).
Hewlett-Packard Company - 7 - HP-UX 11i Version 2: August 2003
login(1) login(1)
HP Process Resource Manager [Toc] [Back]
prmconfig(1), prmconf(4) in HP Process Resource Manager Users Guide.
Pluggable Authentication Modules (PAM) [Toc] [Back]
pam_acct_mgmt(3), pam_authenticate(3), pam_chauthtok(3).
HP-UX Smart Card Login [Toc] [Back]
scpin(1), scsync(1).
Hewlett-Packard Company - 8 - HP-UX 11i Version 2: August 2003 [ Back ] |
