NFS on Fedora

NFS allows to share files and folders over network and is much much faster than samba while using way less resources. To setup a NFS server on Fedora 26 install: $ dnf install nfs-utils Shared directories are listed in the following configuration file: --- # Syntax # <path> <ipaddr>(<option>) /home/user/Public 192.168.0.0/255.255.255.0(ro,sync) More information can be found here: Fedora NFS administration guide. In the above example, the the directory ‘/home/user/Public’ can be accessed by every client in the same LAN with read-only permissions. In case SELinux is active and enforcing rules some further configuration might be required: …

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AMD Ryzen on Linux

Finally we have some new hardware worth writing of and also spending money on. I have been using an AMD Ryzen 7 1700X based build for some time now and so far I am really liking it, the CPU is marvelous considering the pricetag and felt like a worthwhile upgrade from the Xeon E3-1241v3 I was using before; it is basically twice the cores clocked at pretty much the same speed. Awesome. There are a couple of points worth spending some words on tho. …

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Handbrake, compile from source on Fedora 25

Handbrake cannot be installed from default repos nor rpmfusion, to get it on Fedora 25 there are two other options: use negativo17 third party repository; compile from source. The first option is, but that is my opinion, subpar because I don’t trust third party repositories; option two is what is left. Download the source code from git and install some dependencies: $ git clone https://github.com/HandBrake/HandBrake.git $ sudo dnf install dbus-glib-devel gstreamer1-devel gstreamer1-plugins-base-devel intltool libgudev1-devel libnotify-devel webkitgtk3-devel libgudev-devel dbus-glib-devel webkitgtk3-devel gstream-devel libnotify-devel gstreamer1-devel gstreamer1-plugins-base-devel lame-devel opus-devel fribidi-devel libass-devel libtheora-devel x264-devel nasm Like I do with every other program I like to keep as much up to date as possible, I have a small script to take care of compilation, installation and upgrade processes for me. …

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Gajim and OMEMO on Gentoo Linux

OMEMO is the new-ish state of the art end-to-end encryption XMPP protocol extension, Gajim support it via a plugin but making it work on Gentoo is not straightforward at all. Gajim’s OMEMO plugin requires python-axolotl package to work, since that is not present in Gentoo’s repositories it must be installed from source. Before doing so a couple of dependencies must be installed first: $ emerge -a dev-python/protobuf-python $ chmod o+w /usr/lib64/python3.4/site-packages/protobuf-3.2.0-py3.4.egg/EGG-INFO/namespace_packages.txt $ emerge -a dev-python/pillow dev-python/qrcode The chmod command fix some permission issue that arise when installing packages depending on protobuf-python if Python 3.4 support is enabled. Get and compile python-axolotl: …

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Monitor hard disk health status with smartd on Linux

This does not really works, read this: https://nagg.eu/monitor-hard-disk-smart-status-in-python/ First of all install smartmontools, it has the same name on pretty much every distro: $ emerge -a1 smartmontools Proceed to edit its configuration file, at the bottom of the file there is a quick explaination of all the available parameters: cat/etc/smartd.conf --- DEVICESCAN -H -R 1 -R 5 -R 7 -R 10 -R 11 -R 196 -R 197 -R 199 -R 200 -m user@domain.tld -n standby,10,q Parameter -H tells smartd to check the result of overall-health self-assesment test which is pretty much useless, -R is used to specify a single SMART attribute, if its value changes a mail is sent to user@domain.tld. To send emails a MTA must be installed, in centos that is sendmail, in gentoo it is not strictly necessary to have a full fledget MTA installed, nullmailer will suffice. If it is not already installed: …

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Compile LineageOS for Oneplus 3 on Fedora 25

Android community is one big cancerous clusterfuck, it is no wonder that finding a decent guide on how to compile Android from source written in a somewhat comprehensible english is pretty much mission impossible. Cyanogenmod Inc. shutting down their wiki and services overnight surely didn’t help either. Required packages on Fedora 25 are (rpmfusion repo must be previously installed): $ sudo dnf install screen java-1.8.0-openjdk-devel git schedtool ncurses-devel ncurses-libs ncurses-compat-libs ImageMagick-devel libstdc++-devel bison gnupg lzma For some reason the compilation process stores some temporary files in /tmp which, in Fedora 25, is mounted on a tmpfs ramdisk. In case the ramdisk runs out of space for some retarded reason the build process instead of halting will go on like nothing happens and produce borked binaries as output. To keep /tmp mounted on HDD run: …

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Manually backup/restore Android application's data

Android stores application’s data in /data/data directory, it can be accessed via adb only on a rooted phone. To make a backup copy the correspondent directory: $ adb root $ adb pull /data/data/eu.siacs.conversations Application’s data can also be extracted from a full system backup made with TWRP: $ tar -xvf data.ext4.win000 Restoring the backup is the tricky part since Android uses SELinux and every app has it’s own unix user. Before copying back on the phone the already backupped files reinstall the app from f-droid or whatever, then proceed as follow: …

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BTRFS RAID10 on Gentoo

Btrfs is fairly stable and with the latest kernels it is becoming even a better alternative to the most commonly used EXT4 and XFS filesystems. While not being always better or faster it brings to the table a huge amount of improvements that makes it by far the best filesystems for storage. XFS itself is moving in the very same direction and will probably have in the near future some of the features Btrfs already has (e.g. copy on write). No MDADM or partitioning is needed, to create a RAID10 with 4 HDD just type (where /dev/sd[X] is the disk whole disk, not a partition): …

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Ejabberd HTTP File Upload (XEP-0363)

XMPP module HTTP File Upload (formerly XEP-0363) provides a way to share files between XMPP clients, it works transparently and even in multi user chats. The sender uploads a file on an HTTP(S) server that will then generate an URI, this is sent to each one of the recipients that can then download it. The interesting bits about this XEP are various: File sharing now works even in multi-user chats (MUC), in any case the file is only uploaded a single time even if the recipients are more than one. Peer-to-peer file transfer, be it in-band (XEP-0234: Jingle File Transfer) or out-of-band (XEP-0065: SOCKS5 Bytestreams), is slow, unreliable, does not work in MUC and does not work if the recipient is offline. HTTP File Upload supports both client-server encryption (HTTPS) and end-to-end encryption when used in conjunction with OMEMO encryption (as per today this is supported by Conversations on Android and Gajim desktop client). 3.1. When using OMEMO encryption the files are stored encrypted on the server, this makes it impossibile for ejabberd to create a thumbnail if the file sent is a picture. To enable HTTP File Upload module with HTTPS enabled in ejabberd edit ejabberd.yml configuration file: > listen: - port: 5443 ip: "0.0.0.0" module: ejabberd_http request_handlers: "upload": mod_http_upload tls: true protocol_options: 'TLS_OPTIONS' dhfile: 'DH_FILE' ciphers: 'TLS_CIPHERS' modules: mod_http_upload: docroot: "/home/ejabberd/upload" # this must be a valid path, user ownership and SELinux flags must be set accordingly put_url: "https://@HOST@:5443/upload" access: local max_size: 25000000 #25 MByte thumbnail: false file_mode: "0644" dir_mode: "0744" mod_http_upload_quota: max_days: 2 shaper: soft_upload_quota: - 250: all # MiB hard_upload_quota: - 10000: all # MiB define_macro: 'TLS_CIPHERS': "ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256" 'TLS_OPTIONS': - "no_sslv2, no_sslv3, no_tlsv1" - "ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256" - "no_compression" 'DH_FILE': "/usr/local/etc/ejabberd/dhparams.pem" # generated with: openssl dhparam -out dhparams.pem 4096 Add an iptables rule to allow traffic coming from port TCP 5443: …

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Copy Linux sparse files over network

Sparse files are nice to use to store virtual machine’s virtual disks but can be a real pain in the ass to backup efficiently, especially over the network. Luckily rsync provides a way to intelligently copy sparse files both locally and over the network. The trick is use --sparse and --inplace options. Let’s say we have a sparse 60 GB qemu virtual disk with only around 7 GB used: $ ls -lh fedora24.qcow2 -rw------- 1 root root 61G Nov 8 19:11 fedora24.qcow2 $ du -h fedora24.qcow2 7.2G fedora24.qcow2 The first thing to note is that ls does not recognize sparse files while du does. The first time a file is copied use the --sparse option: …

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