SRCDS

Script to manage one or multiple instances of Source Dedicated Servers (SRCDS), such as CS:GO or TF2. Written in Dash (Debian Almquist Shell) to offer POSIX compliance.

1.0 Notes

This script was tested on Debian 11 Bullseye. It already works, but some features are not available yet.

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2.0 Installation

In the following examples, we will use /home/gameserver/srcds as script path and /home/gameserver/srcds/instances (you can change that in conf/main.conf) for the gameservers. Thus, login with root permissions, manually download the code and move its content there:

mkdir -p /home/gameserver/srcds
cd /home/gameserver/srcds
wget https://github.com/etkaar/srcds/archive/refs/heads/main.tar.gz
tar -xzf main.tar.gz --strip-components=1
rm main.tar.gz
chmod 0700 app.sh

Then, create a lower privileged user:

useradd gameserver --no-create-home --home-dir /home/gameserver --shell /usr/sbin/nologin

Update ownership:

chown -R gameserver:gameserver /home/gameserver

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3.0 Security

Gameservers are running within a screen session. This makes it possible to both read from and write to the gameserver console.

In order to make them available for easy reattachments by root (screen -r) or another higher privileged user, these screens are started by this very user. However, privileges are still always dropped for the actual gameserver process, which is started by a lower privileged user (see conf/main.conf) without shell access:

cd "$INSTANCE_PATH" && \
screen -L -d -m -S "$SCREEN_NAME" \
setpriv --reuid="$CVAR_USER" --regid="$CVAR_GROUP" --clear-groups --reset-env -- $CMD_START && \
cd "$ABSPATH"

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4.0 Configuration

conf/main.conf

# You usually want to use a lower privileged user
# account to run the server. Don't use root.
User gameserver
Group gameserver
ForcedUserShell /usr/sbin/nologin

# Time granted for a graceful shutdown (after that,
# process is going to be killed)
GracefulShutdownTimeout 10

# Wait time between stop and restart
RestartWaitTimeBetween 5

# Prefix for the screen name (prefix-{INSTANCE-ID})
ScreenNamePrefix "srcds-"

# Instances are stored into this directory,
# e.g. /home/gameserver/srcds/instances/srv01 for an instance with id 'srv01'
InstancesPath /home/gameserver/srcds/instances

# Multiple instances are possible,
# see <conf/instances.conf>.

conf/instances.conf

# Instance ID       Server App ID[1]     IPv4 Address          Port        Map             Max. Players     Status[2]          Priority
example             232330               127.0.0.1             27015       cs_office       64               always-online      default

# [1] Server App IDs
#   232330 (Counter-Strike: Source)
#   232290 (Day of Defeat: Source)
#   232250 (Team Fortress 2)
#   ...
#
# See 'Linux Dedicated Server' in
# https://developer.valvesoftware.com/wiki/Dedicated_Servers_List

# [2] Status
#   always-online: Gameserver is always restarted (gameserver crash, restart of the dedicated server, ...).

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5.0 Commands

5.1 Status

Find out if an instance is currently running or not:

/home/gameserver/srcds/app.sh example status

5.2 Install Instance

Install instance (= gameserver), which was previously defined in conf/instances.conf:

/home/gameserver/srcds/app.sh example install

5.3 Install Instance

Update instance:

/home/gameserver/srcds/app.sh example update

5.4 Start Instance

/home/gameserver/srcds/app.sh example start

5.5 Stop Instance

/home/gameserver/srcds/app.sh example stop