Author: Micski

Tracker3 core dumps on FreeBSD with GNOME.

If you have a FreeBSD desktop computer with the GNOME desktop environment, or similar open source desktop computer, you might have noticed random Tracker3 core dumps on the file system.

$ find . -name '*.core'
./bin/tracker3.core
./projects/tracker3.core

You might also have noticed messages about Tracker3 error, exit and core dumps in system logs.

$ dmesg
pid 2416 (tracker3), jid 0, uid 1001: exited on signal 10 (no core dump - other error)
pid 2451 (tracker3), jid 0, uid 1001: exited on signal 10 (no core dump - other error)
pid 2848 (tracker3), jid 0, uid 1001: exited on signal 10 (core dumped)

What is Tracker3?

A first approach to learning, what Tracker3 is, would be to open its manual page. Unfortunately, as often seen with utilities like this, they do not include a manual by default.

$ man tracker3
No manual entry for "tracker3"

A search for “tracker3 official website” on search engines does not give a clean answer. The utility seems to not have a website nor a coding home listed on search engines. Again, a sign of poor coding and project management skills.

Thanks to Freshports, more about the utility can be learned. Here, it is described as a system utility, that index and harvest meta data for GNOME utilities, such as the file management utility Nautilus. A rather useless feature, in my oppinion. Its undocumented operation is a privacy concern. It might even scan files across datasets and partitions, which could be privacy concern.

Tracker is a powerful desktop-neutral first class object database, tag/metadata
database, search tool and indexer.

Tracker is also extremely fast and super efficient with your systems memory when
compared with some other competing frameworks and is by far the fastest and most
memory efficient Nautilus search and Deskbar backends currently availble.

It consists of a common object database that allows entities to have an almost
infinte number of properties, metadata (both embedded/harvested as well as user
definable), a comprehensive database of keywords/tags and links to other
entities.

Freshports does have a reference to a page, which seems to be about Tracker3 by GNOME, but aligned with their poor views on privacy and security, the site either does not work or blocks privacy VPNs.

<Code>AccessDenied</Code>

It does not come with a manual by default. However, according to FreeBSD Manual Pages, there are no known manual for it. I even tried compiling it with option for installing its manual pages. It was not installed.

===> The following configuration options are available for tracker3-3.5.3_3:
DOCS=on: Build and/or install documentation
MAN=off: Install manual pages

It is a dependency of Nautilus, which does not have an option for disabling this.

Removing Tracker3 from GNOME and FreeBSD.

If a system utility, that index and harvest the file system for filenames and metadata in the background, is not needed or unwanted, it might be a logic approach, that Tracker3 is removed with the package manager. However, as seen in the output, it does not seem, that GNOME wanted that to be an option.

# pkg remove tracker3
Checking integrity... done (0 conflicting)
Deinstallation has been requested for the following 7 packages (of 0 packages in the universe):
Installed packages to be REMOVED:
evince: 43.1_11
gnome-lite: 42_5
gnome-terminal: 3.44.2_3
gnome-tweaks: 40.10_4
nautilus: 42.2_3
sushi: 42.0_5
tracker3: 3.5.3_3
Number of packages to be removed: 7
The operation will free 38 MiB.
Proceed with deinstalling packages? [y/N]: 

Tracker3 in GNOME is a privacy concern.

Tracker3 is deeply embedded in GNOME. Tracker3 comes enabled without consent from the user. It is a forced installation, that comes with no clear information, warning nor documentation. It is difficult or impossible to disable or deinstall. It scans file systems, datasets and partitions. It stores metadata from files, that has been downloaded temporary. It stores metadata for files, that has been deleted. It stores metadata in internal database and hidden files. It does not have an interface to manage data. This is not a utility, that fits well with the UNIX philosophy. Tracker3 is a privacy concern.

Disabling Search and Tracker3 in GNOME.

Tracker3 can to some degree be disabled from within GNOME by going to the Settings menu and Search and then disabling Application Search. This also seems to reduce the amount of core dumps. However, I have been able to find any documentation about this.

Switching from GNOME to XFCE.

Switching desktop environment from GNOME to XFCE, or similar more simple, resource friendly and privacy focused desktop environment, could be a better over-all solution. The switch to XFCE should be fairly straight forward, because it is also based on X. Unfortunately, there is no guarantee, that XFCE will not implement the same or similar kind of file system metadata scanner at some point. A reason is, that some users and project contributors believe, that a desktop search feature is more important than privacy and security.

References.

• Tracker3 on Freshports.
• TSPARQL.
• TinySPARQL on GNOME.
• Desktop Search on Wikipedia.
• XFCE desktop environment.

Some text files has line breaks, that might look good on fixed width screens, but can not be used as paragraph in other editing software. The is cause by line breaks.

$ cat input.txt 
The computer was a powerful WOPR machine for game simulation.
You can play a nice game of chess or an exciting war game.

This one-liner will replace line breaks with space and then remove any double spaces. It will also make sure, that the file ends with a new line, so it meets the POSIX standard definition of a text file.

$ (tr '\n' ' ' < input.txt | sed 's/  */ /g'; echo) > output.txt

The result is one clean paragraph, that will scale to any screen width or be used in other editing software.

$ cat output.txt 
The computer was a powerful WOPR machine for game simulation. You can play a nice game of chess or an exciting war game.

Is it possible to reduce or disable swap memory on FreeBSD? In this example, 32 GB swap is enabled by using 16 GB on each of 2 SSDs. I would prefer this to be closer to 8 GB by using 4 GB on each of 2 SSDs.

Information about current swap devices.

Get information about currently active swap devices and sizes.

# swapinfo -h
Device              Size     Used    Avail Capacity
/dev/nda0p3          16G       0B      16G     0%
/dev/nda1p3          16G       0B      16G     0%
Total                32G       0B      32G     0%

Get information about partitions on disks and GEOM providers. Each device and partition has a unique identifier, that can be used to make changes.

# gpart show
=>        40  4000797280  nda0  GPT  (1.9T)
          40      532480     1  efi  (260M)
      532520        1024     2  freebsd-boot  (512K)
      533544         984        - free -  (492K)
      534528    33554432     3  freebsd-swap  (16G)
    34088960  3966707712     4  freebsd-zfs  (1.8T)
  4000796672         648        - free -  (324K)
=>        40  3907029088  nda1  GPT  (1.8T)
          40      532480     1  efi  (260M)
      532520        1024     2  freebsd-boot  (512K)
      533544         984        - free -  (492K)
      534528    33554432     3  freebsd-swap  (16G)
    34088960  3872940032     4  freebsd-zfs  (1.8T)
  3907028992         136        - free -  (68K)

The devices can be listed. This also shows the naming convention for the partitions.

# gpart status
nda0p1      OK  nda0
nda0p2      OK  nda0
nda0p3      OK  nda0
nda0p4      OK  nda0
nda1p1      OK  nda1
nda1p2      OK  nda1
nda1p3      OK  nda1
nda1p4      OK  nda1

Disabling swap on FreeBSD.

Move swapped pages out from swap devices and disable them.

# swapoff -a
swapoff: removing /dev/nda0p3 as swap device
swapoff: removing /dev/nda1p3 as swap device

If you want to re-enable swap, it is as easy as reverting that.

# swapon -a
swapon: adding /dev/nda0p3 as swap device
swapon: adding /dev/nda1p3 as swap device

Reducing swap partitions?

Is it possible to reduce the swap partition on each SSD and then have ZFS use the free space? Is it possible to split the partitions?

Deleting swap partitions?

Delete or comment out the swap partitions from the static information about file systems. This ensures, that they do not get re-mounted during boot.

# nano /etc/fstab
# Device                Mountpoint      FStype  Options         Dump    Pass#
/dev/gpt/efiboot0       /boot/efi       msdosfs rw              2       2
#/dev/nda0p3            none            swap    sw              0       0
#/dev/nda1p3            none            swap    sw              0       0
proc                    /proc           procfs  rw              0       0

Is it possible to delete the swap partition on each SSD and then have ZFS use the free space? The handbook does mention growing partitions, but it is not clear, if ZFS can in fact grow directly or it will be necessary to re-create partitions, format, import and encrypt.

Links

• Add swap
• 20.3. Resizing and Growing Disks in FreeBSD Handbook.

What is a Bourne shell?

The Bourne shell, also often referred to as /bin/sh or just sh, has been a default shell for users on FreeBSD for many major versions, while C shell was the default shell for root. From FreeBSD 14, the default shell for root is the Bourne shell.

Changing to Bourne shell on FreeBSD.

The shell for a user in FreeBSD can be changed with the chsh utility.

Configuring the Bourne shell in FreeBSD.

The Bourne shell in FreeBSD is configured by editing the global configuration file /etc/profile and/or the local user configuration file .shrc. These files contains commands, that will be executed, when the shell is started, such as when the user logs into the system.

In this example, the global configuration sets the blocksize for default file operations, ccache settings, the default editor, he default pager and a prompt. The prompt shows a “$” for a normal user and a “#” for root.

# nano /etc/profile
BLOCKSIZE=K
CCACHE=1
CCACHE_DIR=/var/cache/ccache
EDITOR=/usr/local/bin/nano
PAGER=less
VISUAL=$EDITOR
if [ "$(id -u)" -eq 0 ]; then
  PS1='# '
else
  PS1='$ '
fi
export BLOCKSIZE CCACHE CCACHE_DIR EDITOR PAGER PS1 VISUAL

If the user would like to add or change custom settings, then this can be set in the local user configuration file. If this is not relavant, the file should be deleted, because it does contain settings, that could interfere with the global settings.

$ rm .shrc
# rm .shrc

Testing.

The Bourne shell can now be tested. In this example, a user log in and switch to root.

$ whoami
jennifer
$ su -
Password: Pencil
# whoami
root
# echo $EDITOR
/usr/local/bin/nano

The different kinds of shells.

There are different kinds of shells, such as login shells and sub-shells. The sub-shells are also known as non-login shells. The difference is, that a login shell reads global configuration files, while sub-shells just inherits the settings from the original shell. In this example, the first shell will be a login-shell, while the second will be a sub-shell.

FreeBSD/amd64 (wopr) (ttyv0)

Login: stephen
Password: Pencil
 __      __________ ____________________ 
/  \    /  \_____  \\______   \______   \
\   \/\/   //   |   \|     ___/|       _/
 \        //    |    \    |    |    |   \
  \__/\  / \_______  /____|    |____|_  /
       \/          \/                 \/ 
Greetings, professor Falken. How about a nice game of chess?
$ sh
$ su stephen
$ logout
$ logout

More about shells.

• The different shells in FreeBSD.
• Configuring C shell on FreeBSD.
• FreeBSD Manual Pages – SH.

What is DOAS?

doas is a utility, that can permit users to execute commands as root or as another user. Groups as well as users can be permitted to do.

Installing DOAS on FreeBSD.

# pkg install doas

# man doas.conf

Configuring DOAS.

In this example, I will configure doas to permit members of the wheel group to use the FreeBSD service command script, that can start and stop services, such as an nginx web server, without a password. This is a safe and trivial command to disable password requirement for.

# nano /usr/local/etc/doas.conf
permit nopass :wheel as root cmd service

If I wanted to limit, which arguments, that can be passed to the command, I could specifiy this with the args feature.

# nano /usr/local/etc/doas.conf
permit nopass :wheel as root cmd service args nginx onestart

Testing.

$ doas service nginx onestart
nginx: the configuration file /usr/local/etc/nginx/nginx.conf syntax is ok
nginx: configuration file /usr/local/etc/nginx/nginx.conf test is successful
Starting nginx

Be aware, that doas requires, that the command is matched exactly. The following definition will not work.

# nano /usr/local/etc/doas.conf
permit nopass :wheel as root cmd /usr/sbin/service args nginx onestart
$ doas service nginx onestart
doas: Operation not permitted

Do not use sudo for FreeBSD. I tested sudo for FreeBSD and despite, that it is widely used in online procedures and documentation, I had to conclude, that it is somewhat poorly documented and simply does not work properly for FreeBSD.

# visudo
david ALL=(ALL) NOPASSWD: /usr/sbin/service nginx onestart

One thing, in particular, that did not work, was the ability for a member of the wheel group to execute a trivial safe command as root without the requirement for a password. sudo kept asking for password.

$ id
$ sudo service nginx onestart
Password:
sudo: a password is required

I recommend deinstalling sudo and instead using security/doas. This is also recommended on the FreeBSD Forums.

# rm /usr/local/etc/sudo.conf
# rm /usr/local/etc/sudoers
# pkg remove sudo

References

• DOAS for FreeBSD
• https://forums.freebsd.org/threads/how-to-allow-users-to-issue-sudo-command-and-be-root-and-skip-asking-for-password-when-sudo-command-is-issued.93474/