AdBlocking on Sailfish OS via /etc/hosts

Table of Contents

Caveat
Android App Support

There are some apps in Openrepos which do not seem to work anymore for SFOS 4.x. But you don't really need an app, all you need is a systemd timer & service and a simplistic shell script.

Gain command line access to your phone and become root.

> cd /etc/systemd/system
> nano hosts.timer hosts.service
> systemctl daemon-reload
> systemctl enable hosts.timer

hosts.timer:

ini
[Unit]
Description=Update /etc/hosts

[Timer]
WakeSystem=false
OnCalendar=Sat *-*-* 16:00:00
RandomizedDelaySec=1h
AccuracySec=1h
Persistent=true

[Install]
WantedBy=timers.target

So once a week on Saturday at roughly 16:00. Adjust to your liking.
See man systemd.timer for further options.

hosts.service:

ini
[Unit]
Description=Update /etc/hosts

[Service]
# Un/comment as required:
#ExecStart=/home/defaultuser/.local/bin/hosts
ExecStart=/home/nemo/.local/bin/hosts

~/.local/bin/hosts:

sh
#!/bin/sh

# see https://github.com/StevenBlack/hosts/ for alternatives
url="https://raw.githubusercontent.com/StevenBlack/hosts/master/hosts"

cd /etc || exit 1

curl --retry 20 --retry-all-errors --retry-connrefused --retry-delay 5 "$url" \
| grep '^0\.0\.0\.0' > hosts.new || exit 1
sed -i '/0\.0\.0\.0 0\.0\.0\.0/d' hosts.new

[ -f hosts.editable ] || exit 1
cat hosts.editable hosts.new > hosts.tmp && mv hosts.tmp hosts && rm hosts.new

The script removes some useless fluff and then combines this data with hosts.editable into the new hosts file.
/etc/hosts is only overwritten when all this succeeds.

Make sure that

~/.local/bin/hosts is marked executable: chmod +x ~/.local/bin/hosts
The file /etc/hosts.editable exists and contains the default contents of /etc/hosts (before any manipulation). Here it is:
```
127.0.0.1   localhost.localdomain     localhost
::1         localhost6.localdomain6   localhost6
```

Caveat

It seems that a full reboot is required for the new hosts file to take effect for the sailfish-browser.

Android App Support

It also works for Android Apps, ~~explained here:~~

~~> mv /system/etc/hosts /system/etc/hosts.old~~
~~> echo 'lxc.mount.entry = /etc/hosts system/etc/hosts none bind,create=file 0 0' \~~
~~>> /var/lib/lxc/aliendalvik/extra_config~~

As of 4.5., a new method needs to be used:

devel-su

Patch /usr/libexec/appsupport/prepare-aliendalvik.sh. After …"$CONTAINER_CONFIG_PATH/10-bsp_config" put

echo “lxc.mount.entry = /etc/hosts system/etc/hosts none bind,create=file 0 0” >> “$CONTAINER_CONFIG_PATH/10-bsp_config”

Verify:

appsupport-attach cat /etc/hosts

Here the same as a .patch file (not tested):

diff
--- /usr/libexec/appsupport/prepare-aliendalvik.org.sh  2023-01-25 20:52:12.000000000 +0000
+++ /usr/libexec/appsupport/prepare-aliendalvik.sh      2023-02-11 23:47:29.737036812 +0000
@@ -121,6 +121,7 @@
 /usr/libexec/appsupport/alien-generate-rootfs-config.sh "$CONTAINER_CONFIG_PATH/40-rootfs_config"

 /usr/libexec/appsupport/appsupport-generate-config --type lxc --user-id "$ALIEN_USER_ID" --instance "$INSTANCE_NAME" --base-uid "$ALIEN_BASE_UID" "$CONTAINER_CONFIG_PATH/10-bsp_config" || exit 32
+echo "lxc.mount.entry = /etc/hosts system/etc/hosts none bind,create=file 0 0" >> "$CONTAINER_CONFIG_PATH/10-bsp_config"

 /usr/libexec/appsupport/alien-generate-net-config.sh $PRIVILEGED "$CONTAINER_CONFIG_PATH/30-net_config"