Entries by Raymond P. Burkholder

• 8 Best GIMP Plugins and How to Install Them

On Debian Buster, even when cleaned of all older kernels, my /boot directory seems to be short of space now. I can't seem to update when just one kernel is present:

# ls -alt /boot total 42733 drwxr-xr-x 5 root root 1024 Jun 26 01:02 . -rw-r--r-- 1 root root 34752610 Jun 26 01:01 initrd.img-4.19.0-5-amd64 drwxr-xr-x 5 root root 1024 Jun 25 23:29 grub drwxr-xr-x 1 root root 234 Jun 3 18:06 .. -rw-r--r-- 1 root root 206223 May 15 16:07 config-4.19.0-5-amd64 -rw-r--r-- 1 root root 3370661 May 15 16:07 System.map-4.19.0-5-amd64 -rw-r--r-- 1 root root 5217520 May 15 16:07 vmlinuz-4.19.0-5-amd64 drwx------ 2 root root 12288 Jul 25 2018 lost+found drwx------ 3 root root 4096 Dec 31 1969 efi

My problem, is when adding or installing packages, I end up with:

Building cpio /boot/initrd.img-4.19.0-5-amd64.new initramfs
pigz: abort: write error on  (No space left on device)
E: mkinitramfs failure pigz 28
update-initramfs: failed for /boot/initrd.img-4.19.0-5-amd64 with 1.

The solution is to mv or remove initrd.img-4.19.0-5-amd64.

I can then rebuild the file with:

# update-initramfs -cvk `uname -r`

or removing the file prior to installing updates:

~/initramfs# rm /boot/initrd.img-4.19.0-5-amd64
~/initramfs# apt install -f
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 140 not upgraded.
1 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Setting up initramfs-tools (0.133) ...
update-initramfs: deferring update (trigger activated)
Processing triggers for initramfs-tools (0.133) ...

On watching the build, there must be a bunch of firmware files going in there. I wonder how to tone that down (mostly nuc8i7hvk01 special purpose display).

A bunch here -- will need to tone that down I think -- will need to go back to my installation notes to see why they are there:

# du -h --max-depth=1 /lib/firmware/amdgpu/
25M     /lib/firmware/amdgpu/

For simpler jobs, some commands to keep in mind:

• sudo apt-get autoclean
• sudo apt-get clean
• sudo apt-get autoremove
• sudo apt-get purge

I came across a Epson Perfection V39 and thought I'd try getting it to work on Linux Debian.

I have installed xsane, gscan2pdf and sane-utils.

When plugging into USB, /var/log/messages has:

Jun 25 23:16:04  usb 1-1: new full-speed USB device number 22 using xhci_hcd
Jun 25 23:16:05  usb 1-1: new high-speed USB device number 23 using xhci_hcd
Jun 25 23:16:05  usb 1-1: New USB device found, idVendor=04b8, idProduct=013d, bcdDevice= 1.00
Jun 25 23:16:05  usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Jun 25 23:16:05  usb 1-1: Product: Epson Perfection V39
Jun 25 23:16:05  usb 1-1: Manufacturer: EPSON
Jun 25 23:16:05  usb 1-1: SerialNumber: VCFY057184

I tried creating the following file:

# cat /etc/udev/hwdb.d/epson-v39.hwdb
# Epson Perfection V39
usb:v04B8p013D*
 libsane_matched=yes

and running 'systemd-hwdb update', but no luck

From a different perspective, Epson Drivers can be used to find the drivers. Put 'V39' only as the search criteria. One of the versions shown is 1.0.1, but v1.0.4 is actually available at v1.0.4. I wish there was a directory to browse as I found that one by trial and error on the url line.

However, skipping all that, this is the one that worked with xsane on Debian Buster: Image Scan! for Linux 1.0.1.

The scanner is seen:

iscan-gt-s650-bundle-1.0.1.x64.deb# scanimage -L
device `epkowa:interpreter:001:025' is a Epson (unknown model) flatbed scanner

As a side note, the 1.0.4 version provided a mechanism of seeing network based scanners such as an HP multifunction.

For future reference, find a scanner which is compatible: SANE - Supported Devices

• Grey Noise - At GreyNoise, we tell you all of the things not to be worried about. Think of us as "anti-threat intelligence".
• FTTH Parts List - fusion splicers, light meter, fault locator, enclosures
• Stack OverFlow JSON Hijacking
• Haacked JSON Hijacking
• TrustWave JSON Hijacking
• WebAssembly’s post-MVP future: A cartoon skill tree - from Mozilla

• Cassandra vs. MongoDB
• About Deletes and Tombstones in Cassandra
• Cassandra anti-patterns: Queues and queue-like datasets
• Is it possible to use a cassandra table as a basic queue
• Redis::JobQueue
• Transactionally Staged Job Drains in Postgres
• Scylla Summit 2017: Planning Your Queries for Maximum Performance
• High performance queues with Cassandra
• Counting Keys In Cassandra
• Cassandra anti-patterns: Queues and queue-like datasets

• Comparison of browser engines (CSS support) - from wikipedia

Some examples from my PC:

nuc8i7hvk01:~/$ sudo lshw -c cpu
  *-cpu
       description: CPU
       product: Intel(R) Core(TM) i7-8809G CPU @ 3.10GHz
       vendor: Intel Corp.
       physical id: 37
       bus info: cpu@0
       version: Intel(R) Core(TM) i7-8809G CPU @ 3.10GHz
       serial: To Be Filled By O.E.M.
       slot: U3E1
       size: 3941MHz
       capacity: 4200MHz
       width: 64 bits
       clock: 100MHz
       capabilities: lm fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp x86-64 constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb invpcid_single pti ssbd ibrs ibpb stibp tpr_shadow vnmi flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid mpx rdseed adx smap clflushopt intel_pt xsaveopt xsavec xgetbv1 xsaves dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp md_clear flush_l1d cpufreq
       configuration: cores=4 enabledcores=4 threads=8

nuc8i7hvk01:~/$ sudo lshw -c display
  *-display
       description: VGA compatible controller
       product: Polaris 22 XT [Radeon RX Vega M GH]
       vendor: Advanced Micro Devices, Inc. [AMD/ATI]
       physical id: 0
       bus info: pci@0000:01:00.0
       version: c0
       width: 64 bits
       clock: 33MHz
       capabilities: pm pciexpress msi vga_controller bus_master cap_list rom
       configuration: driver=amdgpu latency=0
       resources: iomemory:200-1ff iomemory:210-20f irq:132 memory:2000000000-20ffffffff memory:2100000000-21001fffff ioport:e000(size=256) memory:db500000-db53ffff memory:c0000-dffff

As a user with far too many FireFox open tabs, memory seems to disappear far too quickly. Knowing which of my many tabs contributes the most to the memory consumption would be helpful. But it seems as though Firefox doesn't make troubleshooting for that very easy. Here are a few tools which might help in narrowing my focus to determine granular memory consumption.

With recent versions of Firefox, there are some built-in tools which help to diagnose cpu and memory issues:

• about:performance - shows memory and cpu consumption
• about:memory?verbose - shows detailed memory consumption - not easily to digest
• about:cache?device=memory

Add-ons which provided in-tab memory consumption have been obsoleted. But one add-on which itemizes tabs: Tab Stats

Limiting the amount of RAM a program can use shows how on a Linux system to use cgroups to limit an application's memory footprint. The old 'ulimit' command is deprecated, and may not work.

Regarding the about:memory tool, more details can be found at Limit memory usage per Tab without blocking things? which points to about:memory and Memory.

Based upon How to Reduce Firefox Memory Usage using about:config it is possible to reduce memory caching with:

• 'about:config' in the address bar
• right click and create a 'new' -> 'integer'
• variable name is: browser.cache.memory.capacity (which is maximum RAM in KB) (further details at Browser.cache.memory.capacity) via About:config entries.

$ date
Thu May  9 09:47:03 MDT 2019
$ TZ=Z date -d '2 hours ago' +%FT%TZ
2019-05-09T13:47:04Z

I saw a pre-release of "Linux Observability with BPF" by David Calavera and Lorenzo Fontana. Well, I'd say it is a release prior to pre-release. Some good information it has, but teases the details.

This post is about what it takes to get the first example functional: the things I saw, didn't see, and kludges I put in place. With the understanding and first step in place, it can be cleaned up and additional progress can be now proceed.

I have a mixed Debian Buster/Testing/Sid workstation installation. A messy system due to the vagaries of getting Linux Stretch/Buster installed onto a new Intel NUC nuc8i7hvk01 when firmware and display drivers were just getting rolled out. Kernel updates have made progress. Given the inclination, a nice simple clean Buster rebuild will probably work this time around.

But enough of that. Here is what I needed to do for building a simple eBPF program, building a simple installer, and getting it to install, pass the verifier, and achieve a successful conclusion. Continue reading "eBPF Basics" »

It seems that in the last day or so, Mozilla forgot to renew an intermediate certificate in their FireFox browser. The result is that the browser has mass-disabled add-ons.

One temporary solution someone mentioned (which may only work on a Dev version, and/or Linux version):

Simple temporary fix is to browse to "about:config" and change the value for "xpinstall.signatures.required" to false. Well, that worked for me, anyway. When Mozilla fixes whatever the issue is, I'll set it back to true.

The 'studies based' alternate solution:

You can turn on the Studies option under Privacy & Security for a little while, then check about:studies and you should see one or two in there regarding the xpi verification/signing. Once you have those two studies, you can disable Studies again.

Mozilla has an Update Regarding Add-ons in Firefox, but does not apply to Firefox ESR (my Debian Linux install) or FireFox for Android.

Another link about resolution: Certificate issue causing add-ons to be disabled or fail to install

In this case, the three switches are special purpose appliances running Linux and containing a series of interchangeable network ports. In this session, I am going to sketch out some of the subsystems and open-source tools I've used to build a redundant/resilient router/firewall/monitoring solution on these appliances. In addition, I will describe how I was able to fully automate the build of the solution. The result being a fully documented and repeatable build. The design allows any one of the three switches to be rebuilt while the other two handle production. The end result is a template for building cost-effective, horizontally-scalable virtualization solutions.

Slide deck for the presentation has been posted at Cloud Monitors Cloud.

Raymond Burkholder is the founder of One Unified Net Limited. This has allowed him to take on a variety of challenges in network design, software development, and systems automation. His most recent stint was in Bermuda where he consulted on infrastructure for re-insurance companies, transitioned to handling day to day technical operations of an ISP, and moved on to optimizing the performance of the network, storage, monitoring, and virtualization infrastructure of a data center. He is now back in Canada taking a brief respite while looking for his next opportunity.

Raymond has a personal blog at https://blog.raymond.burkholder.net

Place 800

800 - 6 Ave. S.W.
Plus-15 Conference Room

There is $2 parking after 16:00 one block north-east of the meeting location, in the underground parkade at McDougall Centre.

5:30 PM, Tuesday, April 23, 2019

Snacks at 17:30. Meeting begins at 18:00.

Attendance is free for CUUG members, or $10 (cash only) at the door for non-CUUG members.

As a continuation of my other article incorporating CMake as a makefile generator, here are some references I used for getting a handle on how to build a set of CMakeLists.txt files to manage a project containing a library shared by two applications.

• cmake.org tutorial
• Reference Guide - direct from cmake.org
• CMake Community Wiki
• wxWiki - using CMake to include wxWidgets in projects - see below for sample
• stack overflow - Questions tagged [cmake] - the popular entries
• stack overflow - Multiple sub-projects depending on the same library - primary source for skeleton entries for a project with inter-dependent apps and libraries.
• stack overflow - CMake: Static library with multiple projects - Normally, when CMake projects have to cooperate, it's beneficial to make them part of the same buildsystem using add_subdirectory(). That way, CMake can track dependency between their targets, automatically resolve references to logical target names etc.
• Typical Linux Project using CMake - goes into detail for a project with libraries and applications, including external dependencis
• CMake Dependencies Done Right - mechanisms to evolve a CMake file - depend on defining a proper dependency tree for all libraries and executables
• stack overflow - CMake: Project structure with unit tests
• Basic CMake C++ project structure - includes an example of ExternalProject_Add - also with style notes in one of the answers
• stack overflow - CMake Setting up Release and Debug version and Flags 'cmake -DCMAKE_BUILD_TYPE=Release .. ', 'cmake -DCMAKE_BUILD_TYPE=Debug .. '
• How to configure a C/C++ project with Eclipse and CMake - manual mechanism when not using the wizard from the gui - talks about debug/release versions - something which isn't intuitively obvious when using the gui wizard for importing a CMake progject
• It's Time To Do CMake Right - Pablo Arias - Build Requirements vs Usage Requirements - defines public, private, interface plus additional concepts
• Mirko Kiefer's Blog - CMake by Example - a few twists on the simple CMake files with a focus on the 'install' concept

wxWidgets inclusion with CMake

project(myGreatProject)
cmake_minimum_required(VERSION 2.
aux_source_directory(. SRC_LIST)

set(wxWidgets_CONFIGURATION mswu)
find_package(wxWidgets COMPONENTS core base REQUIRED)
include(${wxWidgets_USE_FILE})

add_executable(${PROJECT_NAME} ${SRC_LIST})
target_link_libraries(${PROJECT_NAME} ${wxWidgets_LIBRARIES})

Random note:

${CMAKE_SOURCE_DIR}, ${CMAKE_BINARY_DIR}

• How to use GPG with YubiKey (bonus: WSL)
• Yubico - YubiKey 5C with NFC
• OpenBSD Journa - Using a Yubikey as smartcard for SSH public key authentication (referenced from Hacker News

I've been using NetBeans for quite some time as a GUI based IDE for building C++ projects. Recently, the project has been migrated over to Apache for management. In the transition time frame, NetBeans has progressed from 8.2 to 9.0 to the current 10.0 incarnation. The 8.2 version was the last which had an integral C++ development environment.

Via jumping through a few hoops, it is possible to run the c++ development environment in v10.0. The draw back is that what ever was available in 8.2 remains as 'current'. Which means the build environment is stuck at C++13.

By finding a development/beta version of 8.2 , I was able to obtain C++17 capability, but at a cost of stability of the IDE. Development of this branch has been discontinued since, I think, early 2018. I do not know if any behind-the-scenes work is happening somewhere.

So... it is time to try something else. Prior to NetBeans, I had been using Eclipse as an IDE. But, way back then, I had switched to NetBeans as Eclipse appeared to be lagging and unstable. The tables have turned. Eclipse appears to be progressing well now as a C++ IDE, far surpassing NetBean's capability.

For building, NetBeans generated makefiles directly. Eclipse can do the same. But Eclipse is also able to work with CMakeLists.txt files. Probably a boon as well as a bane, but as other projects are CMake based, I felt it might be worth a try to try.

So I dived in. I fought for a while to convert my make environment over to CMake. Boost libraries, with v1.69.0 can cause some troubles with CMake find_package abilities. The basic trick is to add the following for builds for v1.69 and possibly for v1.68:

set(CMAKE_CXX_COMPILER_ARCHITECTURE_ID, "x64")
set(Boost_ARCHITECTURE "-x64")

A primary issue undermining my successful transition was that I was using boost::log::trivial. No matter what I tried, it seems as though a CMake initiated make just wouldn't find the symbols. A message of the kind:

undefined reference to `boost::log::v2s_mt_posix::trivial::logger::get()'

The solution was simple. I had already performed the needed resolution in the old IDE. But forgot to migrate it to the new CMake file.

But as a note for posterity, adding the following to a c++ build line (which also incorporates the link step), will forward options to 'ld', the linker.

-Wl,--trace -Wl,--verbose

These options tell ld to emit additional troubleshooting information. But where to put these flags? I used the following to show the command expansions, which I could then copy and paste and change for testing (I found the flag in CMakeCache.txt):

build_dir$ cmake -DCMAKE_VERBOSE_MAKEFILE:BOOL=TRUE ..

The result was that I was indeed successfully resolving the boost_log library inclusion. But why wasn't it accessing the symbols?

The realization occurred after inspecting the library directly, and there is was, the symbol, in all its glory, different from the one for which the linker was originally searching (variations are discussed on StackOverFlow:

# nm -gC libboost_log-gcc8-mt-x64-1_69.so.1.69.0|grep trivial
0000000000099a80 T boost::log::v2_mt_posix::trivial::logger::get()

Well the solution is to place the following in to the CMakeLists.txt file:

target_compile_definitions(${PROJECT_NAME} PUBLIC BOOST_LOG_DYN_LINK )

This forces the c++ build to use the dynamic boost::log library rather than the static file. The symbol then changes to

`boost::log::v2_mt_posix::trivial::logger::get()'

which can fe found in the dynamic link file. And all is well.

As a side note, when using the CMAKE_VERBOSE_MAKEFILE expansion, with a few tweaks I was able to take a '/usr/bin/c++' invocation and run it instead as '/usr/bin/ld'. But this doesn't work very well due to many missing libraries, which the linking form of '/usr/bin/c++' automatically provides.

The link command is found in CMakeFiles/${program_name}.dir/link.txt along with other build products.