Difference between revisions of "Automatic login to virtual console"

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(With systemd: add instructions to disable getty@.service before enabling autologin@.service)
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[[Category:Security]]
 
[[Category:Security]]
 
[[es:Automatic login to virtual console]]
 
[[es:Automatic login to virtual console]]
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[[fr:Connexion automatique a la console]]
 
[[it:Automatic login to virtual console]]
 
[[it:Automatic login to virtual console]]
{{Article summary start}}
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[[ja:仮想端末に自動ログイン]]
{{Article summary text|Describes how to automatically log in to a virtual console.}}
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[[ru:Automatic login to virtual console]]
{{Article summary heading|Related}}
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{{Related articles start}}
{{Article summary wiki|Display Manager}}
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{{Related|Display manager}}
{{Article summary wiki|Start X at Login}}
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{{Related|Nodm}}
{{Article summary end}}
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{{Related|Silent boot}}
 +
{{Related|Start X at login}}
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{{Related articles end}}
  
This article describes how to automatically log in to a ''virtual console'' at the end of the [[boot process]]. This article only covers console log-ins; methods for starting an [[Xorg|X server]] are described in [[Start X at Boot]].
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This article describes how to automatically log in to a [[Wikipedia:Virtual console|virtual console]] at the end of the [[boot process]]. This article only covers console log-ins; see [[Start X at login]] for information about automatic login into [[Xorg]].
  
__TOC__
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== Configuration ==
== With default init ==
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=== Using agetty ===
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Configuration relies on systemd [[Systemd#Editing provided units|drop-in files]] to override the default parameters passed to ''agetty''.
This is the preferred (i.e. clean) method. Edit {{ic|/etc/inittab}} like this:
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{{hc|/etc/inittab|
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c1:2345:respawn:/sbin/agetty -a ''USERNAME'' -8 -s 38400 tty1 linux
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c2:2345:respawn:/sbin/agetty -8 -s 38400 tty2 linux
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c3:2345:respawn:/sbin/agetty -8 -s 38400 tty3 linux
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c4:2345:respawn:/sbin/agetty -8 -s 38400 tty4 linux
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c5:2345:respawn:/sbin/agetty -8 -s 38400 tty5 linux
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c6:2345:respawn:/sbin/agetty -8 -s 38400 tty6 linux
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}}
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to automatically log in {{ic|''USERNAME''}} to the first console (tty1).
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If you want your username to be used automatically without skipping the password prompt:
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Configuration differs for virtual versus serial consoles. In most cases, you want to set up automatic login on a virtual console, (whose device name is {{ic|tty''N''}}, where {{ic|''N''}} is a number). The configuration of automatic login for serial consoles will be slightly different. Device names of the serial consoles look like {{ic|ttyS''N''}}, where {{ic|''N''}} is a number.
  
c1:2345:respawn:/sbin/agetty -a ''USERNAME'' -o "-- \u" -8 -s 38400 tty1 linux
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=== Virtual console ===
  
=== Using mingetty ===
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[[systemd#Editing provided units|Edit the provided unit]] either manually by creating the following drop-in snippet, or by running {{ic|systemctl edit getty@tty1}} and pasting its content:
{{Note|Although a {{pkg|mingetty}} derivative, {{AUR|fgetty}} does not support the {{ic|--autologin}} parameter.}}
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Alternatively, you can install the {{pkg|mingetty}} package from the [[Official Repositories|official repositories]]. Mingetty is designed to be a minimal [[getty]] and allows automatic log-ins:
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{{hc|/etc/systemd/system/getty@tty1.service.d/override.conf|2=
{{hc|/etc/inittab|
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[Service]
c1:2345:respawn:/sbin/mingetty --autologin ''USERNAME'' tty1 linux
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ExecStart=
c2:2345:respawn:/sbin/agetty -8 -s 38400 tty2 linux
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ExecStart=-/usr/bin/agetty --autologin ''username'' --noclear %I $TERM
c3:2345:respawn:/sbin/agetty -8 -s 38400 tty3 linux
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c4:2345:respawn:/sbin/agetty -8 -s 38400 tty4 linux
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c5:2345:respawn:/sbin/agetty -8 -s 38400 tty5 linux
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c6:2345:respawn:/sbin/agetty -8 -s 38400 tty6 linux
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}}
 
}}
  
Using the above methods, you will get a re-login loop when trying to log out. If you wish to only login at boot, use the following:
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{{Tip|The option {{ic|1=Type=idle}} found in the default {{ic|getty@.service}} will delay the service startup until all jobs (state change requests to units) are completed in order to avoid polluting the login prompt with boot-up messages. When [[Start X at login|starting X automatically]], it may be useful to start {{ic|getty@tty1.service}} immediately by adding {{ic|1=Type=simple}} into the [[drop-in snippet]]. Both the init system and ''startx'' can be [[Silent boot|silenced]] to avoid the interleaving of their messages during boot-up.}}
{{hc|/etc/inittab|
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c2:2345:respawn:/sbin/agetty -8 -s 38400 tty2 linux
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c3:2345:respawn:/sbin/agetty -8 -s 38400 tty3 linux
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c4:2345:respawn:/sbin/agetty -8 -s 38400 tty4 linux
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c5:2345:respawn:/sbin/agetty -8 -s 38400 tty5 linux
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c6:2345:respawn:/sbin/agetty -8 -s 38400 tty6 linux
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a1:2345:wait:/sbin/mingetty --autologin ''USERNAME'' tty1 linux
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c1:2345:respawn:/sbin/agetty -8 -s 38400 tty1 linux
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}}
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=== Using a C login program ===
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If you want to use a ''tty'' other than ''tty1'', see [[Systemd FAQ#How_do_I_change_the_default_number_of_gettys.3F|systemd FAQ]].
  
As an alternative, a C login program can be written:
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=== Serial console ===
  
{{hc|autologin.c|
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Create the following file (and leading directories):
#include <unistd.h>
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int main(void) {
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{{hc|/etc/systemd/system/serial-getty@ttyS0.service.d/autologin.conf|2=
  execlp("login", "login", "-f", "''USERNAME''", NULL);
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[Service]
}
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ExecStart=
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ExecStart=-/usr/bin/agetty --autologin ''username'' -s %I 115200,38400,9600 vt102
 
}}
 
}}
  
Here, the C function {{Ic|execlp}} executes the command {{Ic|login -f ''USERNAME''}}.
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==See also==
 
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The program must be compiled and copied to an appropriate location:
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$ gcc -o autologin autologin.c
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# cp autologin /usr/local/sbin/
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Finally, tell {{ic|/etc/inittab}} to use it:
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{{hc|/etc/inittab|
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c1:2345:respawn:/sbin/agetty -n -l /usr/local/sbin/autologin -s 38400 tty1 linux
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c2:2345:respawn:/sbin/agetty -8 -s 38400 tty2 linux
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c3:2345:respawn:/sbin/agetty -8 -s 38400 tty3 linux
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c4:2345:respawn:/sbin/agetty -8 -s 38400 tty4 linux
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c5:2345:respawn:/sbin/agetty -8 -s 38400 tty5 linux
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c6:2345:respawn:/sbin/agetty -8 -s 38400 tty6 linux
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}}
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== With systemd ==
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Create a new service file similar to {{ic|getty@.service}} by copying it to {{ic|/etc/systemd/system/}}:
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# cp /usr/lib/systemd/system/getty@.service /etc/systemd/system/autologin@.service
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{{Note|{{ic|/etc/systemd/system/}} takes precedence over {{ic|/usr/lib/systemd/system/}}.}}
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Once created you can link the new {{ic|autologin@.service}} to your chosen tty, e.g. {{ic|tty1}}, {{ic|tty2}}, [...] {{ic|tty8}}, etc, by specifying it as an alias in the {{ic|[Install]}} section of the unit file. Also, change the value of {{ic|ExecStart}} in {{ic|autologin@.service}}, to end up with something like this:
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{{hc|/etc/systemd/system/autologin@.service|
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2=[Service]
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[...]
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ExecStart&#61;-/sbin/agetty --noclear -a ''USERNAME'' %I 38400
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[...]
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[Install]
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Alias=getty.target.wants/getty@''tty1''.service
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}}
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{{Tip|It is possible to change {{ic|1=Type=idle}} to {{ic|1=Type=simple}} and avoid delaying the execution of agetty until all jobs (state change requests to units) are completed. This option is more useful when [[Start X at Login|starting X automatically]]. See {{ic|man systemd.service}} for more info. {{Note|{{ic|1=Type=simple}} can cause systemd boot-up messages to pollute the login prompt.}}}}
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For security reasons, you may also want to change {{ic|1=Restart=always}} to {{ic|1=Restart=no}}.
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Finally, you need to disable the old getty@.service for the specified TTY and enable the new autologin@.service for the same TTY:
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# systemctl daemon-reload
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# systemctl disable getty@tty1.service
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# systemctl enable autologin@tty1.service
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# systemctl start autologin@tty1.service
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{{Warning|If you are currently in an X session on the same TTY configured in the service file, starting autologin@tty''X''.service will kill your X server.}}
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To avoid errors related to display-manager.service in dmesg, you should set the default target to multi-user instead of graphical:
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* [[Systemd#Change_default_target_to_boot_into|Change default runlevel/target to boot into]]
# systemctl enable multi-user.target
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(See also: [[Systemd#Change_default_runlevel.2Ftarget_to_boot_into|Change default runlevel/target to boot into]].)
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Latest revision as of 15:43, 23 July 2016

This article describes how to automatically log in to a virtual console at the end of the boot process. This article only covers console log-ins; see Start X at login for information about automatic login into Xorg.

Configuration

Configuration relies on systemd drop-in files to override the default parameters passed to agetty.

Configuration differs for virtual versus serial consoles. In most cases, you want to set up automatic login on a virtual console, (whose device name is ttyN, where N is a number). The configuration of automatic login for serial consoles will be slightly different. Device names of the serial consoles look like ttySN, where N is a number.

Virtual console

Edit the provided unit either manually by creating the following drop-in snippet, or by running systemctl edit getty@tty1 and pasting its content:

/etc/systemd/system/getty@tty1.service.d/override.conf
[Service]
ExecStart=
ExecStart=-/usr/bin/agetty --autologin username --noclear %I $TERM
Tip: The option Type=idle found in the default getty@.service will delay the service startup until all jobs (state change requests to units) are completed in order to avoid polluting the login prompt with boot-up messages. When starting X automatically, it may be useful to start getty@tty1.service immediately by adding Type=simple into the drop-in snippet. Both the init system and startx can be silenced to avoid the interleaving of their messages during boot-up.

If you want to use a tty other than tty1, see systemd FAQ.

Serial console

Create the following file (and leading directories):

/etc/systemd/system/serial-getty@ttyS0.service.d/autologin.conf
[Service]
ExecStart=
ExecStart=-/usr/bin/agetty --autologin username -s %I 115200,38400,9600 vt102

See also