Search Results: "mt"

20 February 2024

Jonathan Dowland: Propaganda A Secret Wish

How can I not have done one of these for Propaganda already?
Propaganda: A Secret Wish, and 12"s of Duel and p:Machinery
Propaganda/A Secret Wish is criminally underrated. There seem to be a zillion variants of each track, which keeps completionists busy. Of the variants of Jewel/Duel/etc., I'm fond of the 03:10, almost instrumental mix of Jewel; preferring the lyrics to be exclusive to the more radio friendly Duel (04:42); I don't need them conflating (Jewel 06:21); but there are further depths I've yet to explore (Do Well cassette mix, the 20:07 The First Cut / Duel / Jewel (Cut Rough)/ Wonder / Bejewelled mega-mix...) I recently watched The Fall of the House of Usher which I think has Poe lodged in my brain, which is how this album popped back into my conciousness this morning, with the opening lines of Dream within a Dream. But are they Goth?

19 February 2024

Matthew Garrett: Debugging an odd inability to stream video

We have a cabin out in the forest, and when I say "out in the forest" I mean "in a national forest subject to regulation by the US Forest Service" which means there's an extremely thick book describing the things we're allowed to do and (somewhat longer) not allowed to do. It's also down in the bottom of a valley surrounded by tall trees (the whole "forest" bit). There used to be AT&T copper but all that infrastructure burned down in a big fire back in 2021 and AT&T no longer supply new copper links, and Starlink isn't viable because of the whole "bottom of a valley surrounded by tall trees" thing along with regulations that prohibit us from putting up a big pole with a dish on top. Thankfully there's LTE towers nearby, so I'm simply using cellular data. Unfortunately my provider rate limits connections to video streaming services in order to push them down to roughly SD resolution. The easy workaround is just to VPN back to somewhere else, which in my case is just a Wireguard link back to San Francisco.

This worked perfectly for most things, but some streaming services simply wouldn't work at all. Attempting to load the video would just spin forever. Running tcpdump at the local end of the VPN endpoint showed a connection being established, some packets being exchanged, and then nothing. The remote service appeared to just stop sending packets. Tcpdumping the remote end of the VPN showed the same thing. It wasn't until I looked at the traffic on the VPN endpoint's external interface that things began to become clear.

This probably needs some background. Most network infrastructure has a maximum allowable packet size, which is referred to as the Maximum Transmission Unit or MTU. For ethernet this defaults to 1500 bytes, and these days most links are able to handle packets of at least this size, so it's pretty typical to just assume that you'll be able to send a 1500 byte packet. But what's important to remember is that that doesn't mean you have 1500 bytes of packet payload - that 1500 bytes includes whatever protocol level headers are on there. For TCP/IP you're typically looking at spending around 40 bytes on the headers, leaving somewhere around 1460 bytes of usable payload. And if you're using a VPN, things get annoying. In this case the original packet becomes the payload of a new packet, which means it needs another set of TCP (or UDP) and IP headers, and probably also some VPN header. This still all needs to fit inside the MTU of the link the VPN packet is being sent over, so if the MTU of that is 1500, the effective MTU of the VPN interface has to be lower. For Wireguard, this works out to an effective MTU of 1420 bytes. That means simply sending a 1500 byte packet over a Wireguard (or any other VPN) link won't work - adding the additional headers gives you a total packet size of over 1500 bytes, and that won't fit into the underlying link's MTU of 1500.

And yet, things work. But how? Faced with a packet that's too big to fit into a link, there are two choices - break the packet up into multiple smaller packets ("fragmentation") or tell whoever's sending the packet to send smaller packets. Fragmentation seems like the obvious answer, so I'd encourage you to read Valerie Aurora's article on how fragmentation is more complicated than you think. tl;dr - if you can avoid fragmentation then you're going to have a better life. You can explicitly indicate that you don't want your packets to be fragmented by setting the Don't Fragment bit in your IP header, and then when your packet hits a link where your packet exceeds the link MTU it'll send back a packet telling the remote that it's too big, what the actual MTU is, and the remote will resend a smaller packet. This avoids all the hassle of handling fragments in exchange for the cost of a retransmit the first time the MTU is exceeded. It also typically works these days, which wasn't always the case - people had a nasty habit of dropping the ICMP packets telling the remote that the packet was too big, which broke everything.

What I saw when I tcpdumped on the remote VPN endpoint's external interface was that the connection was getting established, and then a 1500 byte packet would arrive (this is kind of the behaviour you'd expect for video - the connection handshaking involves a bunch of relatively small packets, and then once you start sending the video stream itself you start sending packets that are as large as possible in order to minimise overhead). This 1500 byte packet wouldn't fit down the Wireguard link, so the endpoint sent back an ICMP packet to the remote telling it to send smaller packets. The remote should then have sent a new, smaller packet - instead, about a second after sending the first 1500 byte packet, it sent that same 1500 byte packet. This is consistent with it ignoring the ICMP notification and just behaving as if the packet had been dropped.

All the services that were failing were failing in identical ways, and all were using Fastly as their CDN. I complained about this on social media and then somehow ended up in contact with the engineering team responsible for this sort of thing - I sent them a packet dump of the failure, they were able to reproduce it, and it got fixed. Hurray!

(Between me identifying the problem and it getting fixed I was able to work around it. The TCP header includes a Maximum Segment Size (MSS) field, which indicates the maximum size of the payload for this connection. iptables allows you to rewrite this, so on the VPN endpoint I simply rewrote the MSS to be small enough that the packets would fit inside the Wireguard MTU. This isn't a complete fix since it's done at the TCP level rather than the IP level - so any large UDP packets would still end up breaking)

I've no idea what the underlying issue was, and at the client end the failure was entirely opaque: the remote simply stopped sending me packets. The only reason I was able to debug this at all was because I controlled the other end of the VPN as well, and even then I wouldn't have been able to do anything about it other than being in the fortuitous situation of someone able to do something about it seeing my post. How many people go through their lives dealing with things just being broken and having no idea why, and how do we fix that?

(Edit: thanks to this comment, it sounds like the underlying issue was a kernel bug that Fastly developed a fix for - under certain configurations, the kernel fails to associate the MTU update with the egress interface and so it continues sending overly large packets)

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7 February 2024

Reproducible Builds: Reproducible Builds in January 2024

Welcome to the January 2024 report from the Reproducible Builds project. In these reports we outline the most important things that we have been up to over the past month. If you are interested in contributing to the project, please visit our Contribute page on our website.

How we executed a critical supply chain attack on PyTorch John Stawinski and Adnan Khan published a lengthy blog post detailing how they executed a supply-chain attack against PyTorch, a popular machine learning platform used by titans like Google, Meta, Boeing, and Lockheed Martin :
Our exploit path resulted in the ability to upload malicious PyTorch releases to GitHub, upload releases to [Amazon Web Services], potentially add code to the main repository branch, backdoor PyTorch dependencies the list goes on. In short, it was bad. Quite bad.
The attack pivoted on PyTorch s use of self-hosted runners as well as submitting a pull request to address a trivial typo in the project s README file to gain access to repository secrets and API keys that could subsequently be used for malicious purposes.

New Arch Linux forensic filesystem tool On our mailing list this month, long-time Reproducible Builds developer kpcyrd announced a new tool designed to forensically analyse Arch Linux filesystem images. Called archlinux-userland-fs-cmp, the tool is supposed to be used from a rescue image (any Linux) with an Arch install mounted to, [for example], /mnt. Crucially, however, at no point is any file from the mounted filesystem eval d or otherwise executed. Parsers are written in a memory safe language. More information about the tool can be found on their announcement message, as well as on the tool s homepage. A GIF of the tool in action is also available.

Issues with our SOURCE_DATE_EPOCH code? Chris Lamb started a thread on our mailing list summarising some potential problems with the source code snippet the Reproducible Builds project has been using to parse the SOURCE_DATE_EPOCH environment variable:
I m not 100% sure who originally wrote this code, but it was probably sometime in the ~2015 era, and it must be in a huge number of codebases by now. Anyway, Alejandro Colomar was working on the shadow security tool and pinged me regarding some potential issues with the code. You can see this conversation here.
Chris ends his message with a request that those with intimate or low-level knowledge of time_t, C types, overflows and the various parsing libraries in the C standard library (etc.) contribute with further info.

Distribution updates In Debian this month, Roland Clobus posted another detailed update of the status of reproducible ISO images on our mailing list. In particular, Roland helpfully summarised that all major desktops build reproducibly with bullseye, bookworm, trixie and sid provided they are built for a second time within the same DAK run (i.e. [within] 6 hours) . Additionally 7 of the 8 bookworm images from the official download link build reproducibly at any later time. In addition to this, three reviews of Debian packages were added, 17 were updated and 15 were removed this month adding to our knowledge about identified issues. Elsewhere, Bernhard posted another monthly update for his work elsewhere in openSUSE.

Community updates There were made a number of improvements to our website, including Bernhard M. Wiedemann fixing a number of typos of the term nondeterministic . [ ] and Jan Zerebecki adding a substantial and highly welcome section to our page about SOURCE_DATE_EPOCH to document its interaction with distribution rebuilds. [ ].
diffoscope is our in-depth and content-aware diff utility that can locate and diagnose reproducibility issues. This month, Chris Lamb made a number of changes such as uploading versions 254 and 255 to Debian but focusing on triaging and/or merging code from other contributors. This included adding support for comparing eXtensible ARchive (.XAR/.PKG) files courtesy of Seth Michael Larson [ ][ ], as well considerable work from Vekhir in order to fix compatibility between various and subtle incompatible versions of the progressbar libraries in Python [ ][ ][ ][ ]. Thanks!

Reproducibility testing framework The Reproducible Builds project operates a comprehensive testing framework (available at tests.reproducible-builds.org) in order to check packages and other artifacts for reproducibility. In January, a number of changes were made by Holger Levsen:
  • Debian-related changes:
    • Reduce the number of arm64 architecture workers from 24 to 16. [ ]
    • Use diffoscope from the Debian release being tested again. [ ]
    • Improve the handling when killing unwanted processes [ ][ ][ ] and be more verbose about it, too [ ].
    • Don t mark a job as failed if process marked as to-be-killed is already gone. [ ]
    • Display the architecture of builds that have been running for more than 48 hours. [ ]
    • Reboot arm64 nodes when they hit an OOM (out of memory) state. [ ]
  • Package rescheduling changes:
    • Reduce IRC notifications to 1 when rescheduling due to package status changes. [ ]
    • Correctly set SUDO_USER when rescheduling packages. [ ]
    • Automatically reschedule packages regressing to FTBFS (build failure) or FTBR (build success, but unreproducible). [ ]
  • OpenWrt-related changes:
    • Install the python3-dev and python3-pyelftools packages as they are now needed for the sunxi target. [ ][ ]
    • Also install the libpam0g-dev which is needed by some OpenWrt hardware targets. [ ]
  • Misc:
    • As it s January, set the real_year variable to 2024 [ ] and bump various copyright years as well [ ].
    • Fix a large (!) number of spelling mistakes in various scripts. [ ][ ][ ]
    • Prevent Squid and Systemd processes from being killed by the kernel s OOM killer. [ ]
    • Install the iptables tool everywhere, else our custom rc.local script fails. [ ]
    • Cleanup the /srv/workspace/pbuilder directory on boot. [ ]
    • Automatically restart Squid if it fails. [ ]
    • Limit the execution of chroot-installation jobs to a maximum of 4 concurrent runs. [ ][ ]
Significant amounts of node maintenance was performed by Holger Levsen (eg. [ ][ ][ ][ ][ ][ ][ ] etc.) and Vagrant Cascadian (eg. [ ][ ][ ][ ][ ][ ][ ][ ]). Indeed, Vagrant Cascadian handled an extended power outage for the network running the Debian armhf architecture test infrastructure. This provided the incentive to replace the UPS batteries and consolidate infrastructure to reduce future UPS load. [ ] Elsewhere in our infrastructure, however, Holger Levsen also adjusted the email configuration for @reproducible-builds.org to deal with a new SMTP email attack. [ ]

Upstream patches The Reproducible Builds project tries to detects, dissects and fix as many (currently) unreproducible packages as possible. We endeavour to send all of our patches upstream where appropriate. This month, we wrote a large number of such patches, including: Separate to this, Vagrant Cascadian followed up with the relevant maintainers when reproducibility fixes were not included in newly-uploaded versions of the mm-common package in Debian this was quickly fixed, however. [ ]

If you are interested in contributing to the Reproducible Builds project, please visit our Contribute page on our website. However, you can get in touch with us via:

Jonathan Dowland: carbon

I got a new work laptop this year: A Thinkpad X1 Carbon (Gen 11). It wasn't the one I wanted: I'd ordered an X1 Nano, which had a footprint very reminiscent to me of my beloved x40. Never mind! The Carbon is lovely. Despite ostensibly the same size as the T470s it's replacing, it's significantly more portable, and more capable. The two USB-A ports, as well as the full-size HDMI port, are welcome and useful (over the Nano). I used to keep notes on setting up Linux on different types of hardware, but I haven't really bothered now for years. Things Just Work. That's good! My old machine naming schemes are stretched beyond breaking point (and I've re-used my favourite hostname, qusp, one too many times) so I went for something new this time: Riffing on Carbon, I settled (for now) on carbyne, a carbon allotrope which is of interest to nanotechnologists (Seems appropriate)

31 January 2024

Bits from Debian: New Debian Developers and Maintainers (November and December 2023)

The following contributors got their Debian Developer accounts in the last two months: The following contributor was added as Debian Maintainer in the last two months: Congratulations!

30 January 2024

Antoine Beaupr : router archeology: the Soekris net5001

Roadkiller was a Soekris net5501 router I used as my main gateway between 2010 and 2016 (for r seau and t l phone). It was upgraded to FreeBSD 8.4-p12 (2014-06-06) and pkgng. It was retired in favor of octavia around 2016. Roughly 10 years later (2024-01-24), I found it in a drawer and, to my surprised, it booted. After wrangling with a RS-232 USB adapter, a null modem cable, and bit rates, I even logged in:
comBIOS ver. 1.33  20070103  Copyright (C) 2000-2007 Soekris Engineering.
net5501
0512 Mbyte Memory                        CPU Geode LX 500 Mhz 
Pri Mas  WDC WD800VE-00HDT0              LBA Xlt 1024-255-63  78 Gbyte
Slot   Vend Dev  ClassRev Cmd  Stat CL LT HT  Base1    Base2   Int 
-------------------------------------------------------------------
0:01:2 1022 2082 10100000 0006 0220 08 00 00 A0000000 00000000 10
0:06:0 1106 3053 02000096 0117 0210 08 40 00 0000E101 A0004000 11
0:07:0 1106 3053 02000096 0117 0210 08 40 00 0000E201 A0004100 05
0:08:0 1106 3053 02000096 0117 0210 08 40 00 0000E301 A0004200 09
0:09:0 1106 3053 02000096 0117 0210 08 40 00 0000E401 A0004300 12
0:20:0 1022 2090 06010003 0009 02A0 08 40 80 00006001 00006101 
0:20:2 1022 209A 01018001 0005 02A0 08 00 00 00000000 00000000 
0:21:0 1022 2094 0C031002 0006 0230 08 00 80 A0005000 00000000 15
0:21:1 1022 2095 0C032002 0006 0230 08 00 00 A0006000 00000000 15
 4 Seconds to automatic boot.   Press Ctrl-P for entering Monitor.
 
                                            
                                                  ______
                                                    ____  __ ___  ___ 
            Welcome to FreeBSD!                     __   '__/ _ \/ _ \
                                                    __       __/  __/
                                                                      
    1. Boot FreeBSD [default]                     _     _   \___ \___ 
    2. Boot FreeBSD with ACPI enabled             ____   _____ _____
    3. Boot FreeBSD in Safe Mode                    _ \ / ____   __ \
    4. Boot FreeBSD in single user mode             _)   (___         
    5. Boot FreeBSD with verbose logging            _ < \___ \        
    6. Escape to loader prompt                      _)  ____)    __   
    7. Reboot                                                         
                                                  ____/ _____/ _____/
                                            
                                            
                                            
    Select option, [Enter] for default      
    or [Space] to pause timer  5            
  
Copyright (c) 1992-2013 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
        The Regents of the University of California. All rights reserved.
FreeBSD is a registered trademark of The FreeBSD Foundation.
FreeBSD 8.4-RELEASE-p12 #5: Fri Jun  6 02:43:23 EDT 2014
    root@roadkiller.anarc.at:/usr/obj/usr/src/sys/ROADKILL i386
gcc version 4.2.2 20070831 prerelease [FreeBSD]
Timecounter "i8254" frequency 1193182 Hz quality 0
CPU: Geode(TM) Integrated Processor by AMD PCS (499.90-MHz 586-class CPU)
  Origin = "AuthenticAMD"  Id = 0x5a2  Family = 5  Model = a  Stepping = 2
  Features=0x88a93d<FPU,DE,PSE,TSC,MSR,CX8,SEP,PGE,CMOV,CLFLUSH,MMX>
  AMD Features=0xc0400000<MMX+,3DNow!+,3DNow!>
real memory  = 536870912 (512 MB)
avail memory = 506445824 (482 MB)
kbd1 at kbdmux0
K6-family MTRR support enabled (2 registers)
ACPI Error: A valid RSDP was not found (20101013/tbxfroot-309)
ACPI: Table initialisation failed: AE_NOT_FOUND
ACPI: Try disabling either ACPI or apic support.
cryptosoft0: <software crypto> on motherboard
pcib0 pcibus 0 on motherboard
pci0: <PCI bus> on pcib0
Geode LX: Soekris net5501 comBIOS ver. 1.33 20070103 Copyright (C) 2000-2007
pci0: <encrypt/decrypt, entertainment crypto> at device 1.2 (no driver attached)
vr0: <VIA VT6105M Rhine III 10/100BaseTX> port 0xe100-0xe1ff mem 0xa0004000-0xa00040ff irq 11 at device 6.0 on pci0
vr0: Quirks: 0x2
vr0: Revision: 0x96
miibus0: <MII bus> on vr0
ukphy0: <Generic IEEE 802.3u media interface> PHY 1 on miibus0
ukphy0:  none, 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto, auto-flow
vr0: Ethernet address: 00:00:24:cc:93:44
vr0: [ITHREAD]
vr1: <VIA VT6105M Rhine III 10/100BaseTX> port 0xe200-0xe2ff mem 0xa0004100-0xa00041ff irq 5 at device 7.0 on pci0
vr1: Quirks: 0x2
vr1: Revision: 0x96
miibus1: <MII bus> on vr1
ukphy1: <Generic IEEE 802.3u media interface> PHY 1 on miibus1
ukphy1:  none, 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto, auto-flow
vr1: Ethernet address: 00:00:24:cc:93:45
vr1: [ITHREAD]
vr2: <VIA VT6105M Rhine III 10/100BaseTX> port 0xe300-0xe3ff mem 0xa0004200-0xa00042ff irq 9 at device 8.0 on pci0
vr2: Quirks: 0x2
vr2: Revision: 0x96
miibus2: <MII bus> on vr2
ukphy2: <Generic IEEE 802.3u media interface> PHY 1 on miibus2
ukphy2:  none, 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto, auto-flow
vr2: Ethernet address: 00:00:24:cc:93:46
vr2: [ITHREAD]
vr3: <VIA VT6105M Rhine III 10/100BaseTX> port 0xe400-0xe4ff mem 0xa0004300-0xa00043ff irq 12 at device 9.0 on pci0
vr3: Quirks: 0x2
vr3: Revision: 0x96
miibus3: <MII bus> on vr3
ukphy3: <Generic IEEE 802.3u media interface> PHY 1 on miibus3
ukphy3:  none, 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto, auto-flow
vr3: Ethernet address: 00:00:24:cc:93:47
vr3: [ITHREAD]
isab0: <PCI-ISA bridge> at device 20.0 on pci0
isa0: <ISA bus> on isab0
atapci0: <AMD CS5536 UDMA100 controller> port 0x1f0-0x1f7,0x3f6,0x170-0x177,0x376,0xe000-0xe00f at device 20.2 on pci0
ata0: <ATA channel> at channel 0 on atapci0
ata0: [ITHREAD]
ata1: <ATA channel> at channel 1 on atapci0
ata1: [ITHREAD]
ohci0: <OHCI (generic) USB controller> mem 0xa0005000-0xa0005fff irq 15 at device 21.0 on pci0
ohci0: [ITHREAD]
usbus0 on ohci0
ehci0: <AMD CS5536 (Geode) USB 2.0 controller> mem 0xa0006000-0xa0006fff irq 15 at device 21.1 on pci0
ehci0: [ITHREAD]
usbus1: EHCI version 1.0
usbus1 on ehci0
cpu0 on motherboard
pmtimer0 on isa0
orm0: <ISA Option ROM> at iomem 0xc8000-0xd27ff pnpid ORM0000 on isa0
atkbdc0: <Keyboard controller (i8042)> at port 0x60,0x64 on isa0
atkbd0: <AT Keyboard> irq 1 on atkbdc0
kbd0 at atkbd0
atkbd0: [GIANT-LOCKED]
atkbd0: [ITHREAD]
atrtc0: <AT Real Time Clock> at port 0x70 irq 8 on isa0
ppc0: parallel port not found.
uart0: <16550 or compatible> at port 0x3f8-0x3ff irq 4 flags 0x10 on isa0
uart0: [FILTER]
uart0: console (19200,n,8,1)
uart1: <16550 or compatible> at port 0x2f8-0x2ff irq 3 on isa0
uart1: [FILTER]
Timecounter "TSC" frequency 499903982 Hz quality 800
Timecounters tick every 1.000 msec
IPsec: Initialized Security Association Processing.
usbus0: 12Mbps Full Speed USB v1.0
usbus1: 480Mbps High Speed USB v2.0
ad0: 76319MB <WDC WD800VE-00HDT0 09.07D09> at ata0-master UDMA100 
ugen0.1: <AMD> at usbus0
uhub0: <AMD OHCI root HUB, class 9/0, rev 1.00/1.00, addr 1> on usbus0
ugen1.1: <AMD> at usbus1
uhub1: <AMD EHCI root HUB, class 9/0, rev 2.00/1.00, addr 1> on usbus1
GEOM: ad0s1: geometry does not match label (255h,63s != 16h,63s).
uhub0: 4 ports with 4 removable, self powered
Root mount waiting for: usbus1
Root mount waiting for: usbus1
uhub1: 4 ports with 4 removable, self powered
Trying to mount root from ufs:/dev/ad0s1a
The last log rotation is from 2016:
[root@roadkiller /var/log]# stat /var/log/wtmp      
65 61783 -rw-r--r-- 1 root wheel 208219 1056 "Nov  1 05:00:01 2016" "Jan 18 22:29:16 2017" "Jan 18 22:29:16 2017" "Nov  1 05:00:01 2016" 16384 4 0 /var/log/wtmp
Interestingly, I switched between eicat and teksavvy on December 11th. Which year? Who knows!
Dec 11 16:38:40 roadkiller mpd: [eicatL0] LCP: authorization successful
Dec 11 16:41:15 roadkiller mpd: [teksavvyL0] LCP: authorization successful
Never realized those good old logs had a "oh dear forgot the year" issue (that's something like Y2K except just "Y", I guess). That was probably 2015, because the log dates from 2017, and the last entry is from November of the year after the above:
[root@roadkiller /var/log]# stat mpd.log 
65 47113 -rw-r--r-- 1 root wheel 193008 71939195 "Jan 18 22:39:18 2017" "Jan 18 22:39:59 2017" "Jan 18 22:39:59 2017" "Apr  2 10:41:37 2013" 16384 140640 0 mpd.log
It looks like the system was installed in 2010:
[root@roadkiller /var/log]# stat /
63 2 drwxr-xr-x 21 root wheel 2120 512 "Jan 18 22:34:43 2017" "Jan 18 22:28:12 2017" "Jan 18 22:28:12 2017" "Jul 18 22:25:00 2010" 16384 4 0 /
... so it lived for about 6 years, but still works after almost 14 years, which I find utterly amazing. Another amazing thing is that there's tuptime installed on that server! That is a software I thought I discovered later and then sponsored in Debian, but turns out I was already using it then!
[root@roadkiller /var]# tuptime 
System startups:        19   since   21:20:16 11/07/15
System shutdowns:       0 ok   -   18 bad
System uptime:          85.93 %   -   1 year, 11 days, 10 hours, 3 minutes and 36 seconds
System downtime:        14.07 %   -   61 days, 15 hours, 22 minutes and 45 seconds
System life:            1 year, 73 days, 1 hour, 26 minutes and 20 seconds
Largest uptime:         122 days, 9 hours, 17 minutes and 6 seconds   from   08:17:56 02/02/16
Shortest uptime:        5 minutes and 4 seconds   from   21:55:00 01/18/17
Average uptime:         19 days, 19 hours, 28 minutes and 37 seconds
Largest downtime:       57 days, 1 hour, 9 minutes and 59 seconds   from   20:45:01 11/22/16
Shortest downtime:      -1 years, 364 days, 23 hours, 58 minutes and 12 seconds   from   22:30:01 01/18/17
Average downtime:       3 days, 5 hours, 51 minutes and 43 seconds
Current uptime:         18 minutes and 23 seconds   since   22:28:13 01/18/17
Actual up/down times:
[root@roadkiller /var]# tuptime -t
No.        Startup Date                                         Uptime       Shutdown Date   End                                                  Downtime
1     21:20:16 11/07/15      1 day, 0 hours, 40 minutes and 12 seconds   22:00:28 11/08/15   BAD                                  2 minutes and 37 seconds
2     22:03:05 11/08/15      1 day, 9 hours, 41 minutes and 57 seconds   07:45:02 11/10/15   BAD                                  3 minutes and 24 seconds
3     07:48:26 11/10/15    20 days, 2 hours, 41 minutes and 34 seconds   10:30:00 11/30/15   BAD                        4 hours, 50 minutes and 21 seconds
4     15:20:21 11/30/15                      19 minutes and 40 seconds   15:40:01 11/30/15   BAD                                   6 minutes and 5 seconds
5     15:46:06 11/30/15                      53 minutes and 55 seconds   16:40:01 11/30/15   BAD                           1 hour, 1 minute and 38 seconds
6     17:41:39 11/30/15     6 days, 16 hours, 3 minutes and 22 seconds   09:45:01 12/07/15   BAD                4 days, 6 hours, 53 minutes and 11 seconds
7     16:38:12 12/11/15   50 days, 17 hours, 56 minutes and 49 seconds   10:35:01 01/31/16   BAD                                 10 minutes and 52 seconds
8     10:45:53 01/31/16     1 day, 21 hours, 28 minutes and 16 seconds   08:14:09 02/02/16   BAD                                  3 minutes and 48 seconds
9     08:17:56 02/02/16    122 days, 9 hours, 17 minutes and 6 seconds   18:35:02 06/03/16   BAD                                 10 minutes and 16 seconds
10    18:45:18 06/03/16   29 days, 17 hours, 14 minutes and 43 seconds   12:00:01 07/03/16   BAD                                 12 minutes and 34 seconds
11    12:12:35 07/03/16   31 days, 17 hours, 17 minutes and 26 seconds   05:30:01 08/04/16   BAD                                 14 minutes and 25 seconds
12    05:44:26 08/04/16     15 days, 1 hour, 55 minutes and 35 seconds   07:40:01 08/19/16   BAD                                  6 minutes and 51 seconds
13    07:46:52 08/19/16     7 days, 5 hours, 23 minutes and 10 seconds   13:10:02 08/26/16   BAD                                  3 minutes and 45 seconds
14    13:13:47 08/26/16   27 days, 21 hours, 36 minutes and 14 seconds   10:50:01 09/23/16   BAD                                  2 minutes and 14 seconds
15    10:52:15 09/23/16   60 days, 10 hours, 52 minutes and 46 seconds   20:45:01 11/22/16   BAD                 57 days, 1 hour, 9 minutes and 59 seconds
16    21:55:00 01/18/17                        5 minutes and 4 seconds   22:00:04 01/18/17   BAD                                 11 minutes and 15 seconds
17    22:11:19 01/18/17                       8 minutes and 42 seconds   22:20:01 01/18/17   BAD                                   1 minute and 20 seconds
18    22:21:21 01/18/17                       8 minutes and 40 seconds   22:30:01 01/18/17   BAD   -1 years, 364 days, 23 hours, 58 minutes and 12 seconds
19    22:28:13 01/18/17                      20 minutes and 17 seconds
The last few entries are actually the tests I'm running now, it seems this machine thinks we're now on 2017-01-18 at ~22:00, while we're actually 2024-01-24 at ~12:00 local:
Wed Jan 18 23:05:38 EST 2017
FreeBSD/i386 (roadkiller.anarc.at) (ttyu0)
login: root
Password:
Jan 18 23:07:10 roadkiller login: ROOT LOGIN (root) ON ttyu0
Last login: Wed Jan 18 22:29:16 on ttyu0
Copyright (c) 1992-2013 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
        The Regents of the University of California. All rights reserved.
FreeBSD 8.4-RELEASE-p12 (ROADKILL) #5: Fri Jun  6 02:43:23 EDT 2014
Reminders:
 * commit stuff in /etc
 * reload firewall (in screen!):
    pfctl -f /etc/pf.conf ; sleep 1
 * vim + syn on makes pf.conf more readable
 * monitoring the PPPoE uplink:
   tail -f /var/log/mpd.log
Current problems:
 * sometimes pf doesn't start properly on boot, if pppoe failed to come up, use
   this to resume:
     /etc/rc.d/pf start
   it will kill your shell, but fix NAT (2012-08-10)
 * babel fails to start on boot (2013-06-15):
     babeld -D -g 33123 tap0 vr3
 * DNS often fails, tried messing with unbound.conf (2014-10-05) and updating
   named.root (2016-01-28) and performance tweaks (ee63689)
 * asterisk and mpd4 are deprecated and should be uninstalled when we're sure
   their replacements (voipms + ata and mpd5) are working (2015-01-13)
 * if IPv6 fails, it's because netblocks are not being routed upstream. DHCPcd
   should do this, but doesn't start properly, use this to resume (2015-12-21):
     /usr/local/sbin/dhcpcd -6 --persistent --background --timeout 0 -C resolv.conf ng0
This machine is doomed to be replaced with the new omnia router, Indiegogo
campaign should ship in april 2016: http://igg.me/at/turris-omnia/x
(I really like the motd I left myself there. In theory, I guess this could just start connecting to the internet again if I still had the same PPPoE/ADSL link I had almost a decade ago; obviously, I do not.) Not sure how the system figured the 2017 time: the onboard clock itself believes we're in 1980, so clearly the CMOS battery has (understandably) failed:
> ?
comBIOS Monitor Commands
boot [drive][:partition] INT19 Boot
reboot                   cold boot
download                 download a file using XMODEM/CRC
flashupdate              update flash BIOS with downloaded file
time [HH:MM:SS]          show or set time
date [YYYY/MM/DD]        show or set date
d[b w d] [adr]           dump memory bytes/words/dwords
e[b w d] adr value [...] enter bytes/words/dwords
i[b w d] port            input from 8/16/32-bit port
o[b w d] port value      output to 8/16/32-bit port
run adr                  execute code at adr
cmosread [adr]           read CMOS RAM data
cmoswrite adr byte [...] write CMOS RAM data
cmoschecksum             update CMOS RAM Checksum
set parameter=value      set system parameter to value
show [parameter]         show one or all system parameters
?/help                   show this help
> show
ConSpeed = 19200
ConLock = Enabled
ConMute = Disabled
BIOSentry = Enabled
PCIROMS = Enabled
PXEBoot = Enabled
FLASH = Primary
BootDelay = 5
FastBoot = Disabled
BootPartition = Disabled
BootDrive = 80 81 F0 FF 
ShowPCI = Enabled
Reset = Hard
CpuSpeed = Default
> time
Current Date and Time is: 1980/01/01 00:56:47
Another bit of archeology: I had documented various outages with my ISP... back in 2003!
[root@roadkiller ~/bin]# cat ppp_stats/downtimes.txt
11/03/2003 18:24:49 218
12/03/2003 09:10:49 118
12/03/2003 10:05:57 680
12/03/2003 10:14:50 106
12/03/2003 10:16:53 6
12/03/2003 10:35:28 146
12/03/2003 10:57:26 393
12/03/2003 11:16:35 5
12/03/2003 11:16:54 11
13/03/2003 06:15:57 18928
13/03/2003 09:43:36 9730
13/03/2003 10:47:10 23
13/03/2003 10:58:35 5
16/03/2003 01:32:36 338
16/03/2003 02:00:33 120
16/03/2003 11:14:31 14007
19/03/2003 00:56:27 11179
19/03/2003 00:56:43 5
19/03/2003 00:56:53 0
19/03/2003 00:56:55 1
19/03/2003 00:57:09 1
19/03/2003 00:57:10 1
19/03/2003 00:57:24 1
19/03/2003 00:57:25 1
19/03/2003 00:57:39 1
19/03/2003 00:57:40 1
19/03/2003 00:57:44 3
19/03/2003 00:57:53 0
19/03/2003 00:57:55 0
19/03/2003 00:58:08 0
19/03/2003 00:58:10 0
19/03/2003 00:58:23 0
19/03/2003 00:58:25 0
19/03/2003 00:58:39 1
19/03/2003 00:58:42 2
19/03/2003 00:58:58 5
19/03/2003 00:59:35 2
19/03/2003 00:59:47 3
19/03/2003 01:00:34 3
19/03/2003 01:00:39 0
19/03/2003 01:00:54 0
19/03/2003 01:01:11 2
19/03/2003 01:01:25 1
19/03/2003 01:01:48 1
19/03/2003 01:02:03 1
19/03/2003 01:02:10 2
19/03/2003 01:02:20 3
19/03/2003 01:02:44 3
19/03/2003 01:03:45 3
19/03/2003 01:04:39 2
19/03/2003 01:05:40 2
19/03/2003 01:06:35 2
19/03/2003 01:07:36 2
19/03/2003 01:08:31 2
19/03/2003 01:08:38 2
19/03/2003 01:10:07 3
19/03/2003 01:11:05 2
19/03/2003 01:12:03 3
19/03/2003 01:13:01 3
19/03/2003 01:13:58 2
19/03/2003 01:14:59 5
19/03/2003 01:15:54 2
19/03/2003 01:16:55 2
19/03/2003 01:17:50 2
19/03/2003 01:18:51 3
19/03/2003 01:19:46 2
19/03/2003 01:20:46 2
19/03/2003 01:21:42 3
19/03/2003 01:22:42 3
19/03/2003 01:23:37 2
19/03/2003 01:24:38 3
19/03/2003 01:25:33 2
19/03/2003 01:26:33 2
19/03/2003 01:27:30 3
19/03/2003 01:28:55 2
19/03/2003 01:29:56 2
19/03/2003 01:30:50 2
19/03/2003 01:31:42 3
19/03/2003 01:32:36 3
19/03/2003 01:33:27 2
19/03/2003 01:34:21 2
19/03/2003 01:35:22 2
19/03/2003 01:36:17 3
19/03/2003 01:37:18 2
19/03/2003 01:38:13 3
19/03/2003 01:39:39 2
19/03/2003 01:40:39 2
19/03/2003 01:41:35 3
19/03/2003 01:42:35 3
19/03/2003 01:43:31 3
19/03/2003 01:44:31 3
19/03/2003 01:45:53 3
19/03/2003 01:46:48 3
19/03/2003 01:47:48 2
19/03/2003 01:48:44 3
19/03/2003 01:49:44 2
19/03/2003 01:50:40 3
19/03/2003 01:51:39 1
19/03/2003 11:04:33 19   
19/03/2003 18:39:36 2833 
19/03/2003 18:54:05 825  
19/03/2003 19:04:00 454  
19/03/2003 19:08:11 210  
19/03/2003 19:41:44 272  
19/03/2003 21:18:41 208  
24/03/2003 04:51:16 6
27/03/2003 04:51:20 5
30/03/2003 04:51:25 5
31/03/2003 08:30:31 255  
03/04/2003 08:30:36 5
06/04/2003 01:16:00 621  
06/04/2003 22:18:08 17   
06/04/2003 22:32:44 13   
09/04/2003 22:33:12 28   
12/04/2003 22:33:17 6
15/04/2003 22:33:22 5
17/04/2003 15:03:43 18   
20/04/2003 15:03:48 5
23/04/2003 15:04:04 16   
23/04/2003 21:08:30 339  
23/04/2003 21:18:08 13   
23/04/2003 23:34:20 253  
26/04/2003 23:34:45 25   
29/04/2003 23:34:49 5
02/05/2003 13:10:01 185  
05/05/2003 13:10:06 5
08/05/2003 13:10:11 5
09/05/2003 14:00:36 63928
09/05/2003 16:58:52 2
11/05/2003 23:08:48 2
14/05/2003 23:08:53 6
17/05/2003 23:08:58 5
20/05/2003 23:09:03 5
23/05/2003 23:09:08 5
26/05/2003 23:09:14 5
29/05/2003 23:00:10 3
29/05/2003 23:03:01 10   
01/06/2003 23:03:05 4
04/06/2003 23:03:10 5
07/06/2003 23:03:38 28   
10/06/2003 23:03:50 12   
13/06/2003 23:03:55 6
14/06/2003 07:42:20 3
14/06/2003 14:37:08 3
15/06/2003 20:08:34 3
18/06/2003 20:08:39 6
21/06/2003 20:08:45 6
22/06/2003 03:05:19 138  
22/06/2003 04:06:28 3
25/06/2003 04:06:58 31   
28/06/2003 04:07:02 4
01/07/2003 04:07:06 4
04/07/2003 04:07:11 5
07/07/2003 04:07:16 5
12/07/2003 04:55:20 6
12/07/2003 19:09:51 1158 
12/07/2003 22:14:49 8025 
15/07/2003 22:14:54 6
16/07/2003 05:43:06 18   
19/07/2003 05:43:12 6
22/07/2003 05:43:17 5
23/07/2003 18:18:55 183  
23/07/2003 18:19:55 9
23/07/2003 18:29:15 158  
23/07/2003 19:48:44 4604 
23/07/2003 20:16:27 3
23/07/2003 20:37:29 1079 
23/07/2003 20:43:12 342  
23/07/2003 22:25:51 6158
Fascinating. I suspect the (IDE!) hard drive might be failing as I saw two new files created in /var that I didn't remember seeing before:
-rw-r--r--   1 root    wheel        0 Jan 18 22:55 3@T3
-rw-r--r--   1 root    wheel        0 Jan 18 22:55 DY5
So I shutdown the machine, possibly for the last time:
Waiting (max 60 seconds) for system process  bufdaemon' to stop...done
Waiting (max 60 seconds) for system process  syncer' to stop...
Syncing disks, vnodes remaining...3 3 0 1 1 0 0 done
All buffers synced.
Uptime: 36m43s
usbus0: Controller shutdown
uhub0: at usbus0, port 1, addr 1 (disconnected)
usbus0: Controller shutdown complete
usbus1: Controller shutdown
uhub1: at usbus1, port 1, addr 1 (disconnected)
usbus1: Controller shutdown complete
The operating system has halted.
Please press any key to reboot.
I'll finally note this was the last FreeBSD server I personally operated. I also used FreeBSD to setup the core routers at Koumbit but those were replaced with Debian recently as well. Thanks Soekris, that was some sturdy hardware. Hopefully this new Protectli router will live up to that "decade plus" challenge. Not sure what the fate of this device will be: I'll bring it to the next Montreal Debian & Stuff to see if anyone's interested, contact me if you can't show up and want this thing.

25 January 2024

Jonathan Dowland: I'm going to FOSDEM 2024

I'm attending FOSDEM 2024. Perhaps I'll see you there! For the first time, I'm giving some talks, both in the Free Java Devroom (UB5.132) on Saturday 3rd. They are

19 January 2024

Russell Coker: 2.5Gbit Ethernet

I just decided to upgrade the core of my home network from 1Gbit to 2.5Gbit. I didn t really need to do this, it was only about 5 years ago that I upgrade from 100Mbit to 1Gbit. but it s cheap and seemed interesting. I decided to do it because a 2.5Gbit switch was listed as cheap on Ozbargain Computing [1], that was $40.94 delivered. If you are in Australia and like computers then Ozbargain is a site worth polling, every day there s interesting things at low prices. The seller of the switch is KeeplinkStore [2] who distinguished themselves by phoning me from China to inform me that I had ordered a switch with a UK plug for delivery to Australia and suggesting that I cancel the order and make a new order with an Australian plug. It wouldn t have been a big deal if I had received a UK plug as I ve got a collection of adaptors but it was still nice of them to make it convenient for me. The switch basically does what it s expected to do and has no fan so it s quiet. I got a single port 2.5Gbit PCIe card for $18.77 and a dual port card for $34.07. Those cards are a little expensive when compared to 1Gbit cards but very cheap when compared to the computers they are installed in. These cards use the Realtek RTL8125 chipset and work well. I got a USB-3 2.5Gbit device for $17.43. I deliberately didn t get USB-C because I still use laptops without USB-C and most of the laptops with USB-C only have a single USB-C port which is used for power. I don t plan to stop using my 100Mbit USB ethernet device because most of the time I don t need a lot of speed. But sometimes I do things like testing auto-install on laptops and then having something faster than Gigabit is good. This card worked at 1Gbit speed on a 1Gbit network when used with a system running Debian/Bookworm with kernel 6.1 and worked at 2.5Gbit speed when connected to my LicheePi RISC-V system running Linux 5.10, but it would only do 100Mbit on my laptop running Debian/Unstable with kernel 6.6 (Debian Bug #1061095) [3]. It s a little disappointing but not many people have such hardware so it probably doesn t get a lot of testing. For the moment I plan to just use a 1Gbit USB Ethernet device most of the time and if I really need the speed I ll just use an older kernel. I did some tests with wget and curl to see if I could get decent speeds. When using wget 1.21.3 on Debian/Bookworm I got transfer speeds of 103MB/s and 18.8s of system CPU time out of 23.6s of elapsed time. Curl on Debian/Bookworm did 203MB/s and took 10.7s of system CPU time out of 11.8s elapsed time. The difference is that curl was using 100KB read buffers and a mix of 12K and 4K write buffers while wget was using 8KB read buffers and 4KB write buffers. On Debian/Unstable wget 1.21.4 uses 64K read buffers and a mix of 4K and 60K write buffers and gets a speed of 208MB/s. As an experiment I changed the read buffer size for wget to 256K and that got the speed up to around 220MB/s but it was difficult to measure as the occasional packet loss slowed things down. The pattern of writing 4K and then writing the rest continued, it seemed related to fwrite() buffering. For anyone else who wants to experiment with the code, the wget code is simpler (due to less features) and the package builds a lot faster (due to fewer tests) so that s the one to work on. The client machine for these tests has a E5-2696 v3 CPU, this doesn t compare well to some of the recent AMD CPUs on single-core performance but is still a decently powerful system. Getting good performance at Gigabit speeds on an ARM or RISC-V system is probably going to be a lot harder than getting good performance at 2.5Gbit speeds on this system. In conclusion 2.5Gbit basically works apart from a problem with new kernels and a problem with the old version of wget. I expect that when Debian/Trixie is released (probably mid 2025) things will work well. For good transfer rates use wget version 1.21.4 or newer or use curl. As an aside I use a 1500byte MTU because I have some 100baseT systems on my LAN and the settings regarding TCP acceleration etc are all the defaults.

16 January 2024

Jonathan Dowland: Reading hack

My to-read shelf My to-read shelf
This year, with respect to my ever-growing reading backlog, I'm going to try something new: when I acquire a new book, I'm going to try to read at least a few pages of it immediately. My theory is this will help me to have a better idea of what to expect when I come to pick the next book to start, later on. A few pages may not be very representative of a full book (In "How to read a Novel: A User's Guide John Sullivan suggests reading 69 pages before giving up on a book), but it may be better than nothing. I'll report back if it seems to work.

Jonathan Dowland: Two reissued Coil LPs

Happy 2024! DAIS have continued their programme of posthumous Coil remasters and re-issues. Constant Shallowness Leads To Evil was remastered by Josh Bonati in 2021 and re-released in 2022 in a dizzying array of different packaging variants. The original releases in 2000 had barely any artwork, and given that void I think Nathaniel Young has done a great job of creating something compelling.
Constant Shallowness leads to Evil and Queens of te Circulating Library
A limited number of the original re-issue have special lenticular covers, although these were not sold by any distributors outside the US. I tried to find a copy on my trip to Portland in 2022, to no avail. Last year DAIS followed Constant with Queens Of The Circulating Library, same deal: limited lenticular covers, US only. Both are also available digital-only, e.g. on Bandcamp: Constant , Queens . The original, pre-remastered releases have been freely available on archive.org for a long time: Constant , Queens Both of these releases feel to me that they were made available by the group somewhat as an afterthought, having been produced primarily as part of their live efforts. (I'm speculating freely here, it might not be true). Live takes of some of this material exist in the form of Coil Presents Time Machines, which has not (yet) been reissued. In my opinion this is a really compelling recording. I vividly remember listening to this whilst trying to get an hour's rest in a hotel somewhere on a work trip. It took me to some strange places! I'll leave you from one of my favourite moments from "Colour Sound Oblivion", Coil's video collection of live backdrops. When this was performed live it was also called "Constant Shallowness Leads To Evil", although it's distinct from the material on the LP: also available on archive.org. A version of this Constant made it onto a Russian live bootleg, which is available on Spotify and Bandcamp complete with some John Balance banter: we only do this on religious holidays Constant Shallowness Leads to Evil by Coil

12 January 2024

Dirk Eddelbuettel: RcppSpdlog 0.0.16 on CRAN: New Upstream

Version 0.0.16 of RcppSpdlog is now on CRAN and will be uploaded to Debian. RcppSpdlog bundles spdlog, a wonderful header-only C++ logging library with all the bells and whistles you would want that was written by Gabi Melman, and also includes fmt by Victor Zverovich. You can learn more at the nice package documention site. This releases updates the code to the version 1.13 of spdlog which was release this morning. The NEWS entry for this release follows.

Changes in RcppSpdlog version 0.0.16 (2024-01-12)
  • Upgraded to upstream releases spdlog 1.13.0

Courtesy of my CRANberries, there is also a diffstat report. More detailed information is on the RcppSpdlog page, or the package documention site. If you like this or other open-source work I do, you can sponsor me at GitHub.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

11 January 2024

Reproducible Builds: Reproducible Builds in December 2023

Welcome to the December 2023 report from the Reproducible Builds project! In these reports we outline the most important things that we have been up to over the past month. As a rather rapid recap, whilst anyone may inspect the source code of free software for malicious flaws, almost all software is distributed to end users as pre-compiled binaries (more).

Reproducible Builds: Increasing the Integrity of Software Supply Chains awarded IEEE Software Best Paper award In February 2022, we announced in these reports that a paper written by Chris Lamb and Stefano Zacchiroli was now available in the March/April 2022 issue of IEEE Software. Titled Reproducible Builds: Increasing the Integrity of Software Supply Chains (PDF). This month, however, IEEE Software announced that this paper has won their Best Paper award for 2022.

Reproducibility to affect package migration policy in Debian In a post summarising the activities of the Debian Release Team at a recent in-person Debian event in Cambridge, UK, Paul Gevers announced a change to the way packages are migrated into the staging area for the next stable Debian release based on its reproducibility status:
The folks from the Reproducibility Project have come a long way since they started working on it 10 years ago, and we believe it s time for the next step in Debian. Several weeks ago, we enabled a migration policy in our migration software that checks for regression in reproducibility. At this moment, that is presented as just for info, but we intend to change that to delays in the not so distant future. We eventually want all packages to be reproducible. To stimulate maintainers to make their packages reproducible now, we ll soon start to apply a bounty [speedup] for reproducible builds, like we ve done with passing autopkgtests for years. We ll reduce the bounty for successful autopkgtests at that moment in time.

Speranza: Usable, privacy-friendly software signing Kelsey Merrill, Karen Sollins, Santiago Torres-Arias and Zachary Newman have developed a new system called Speranza, which is aimed at reassuring software consumers that the product they are getting has not been tampered with and is coming directly from a source they trust. A write-up on TechXplore.com goes into some more details:
What we have done, explains Sollins, is to develop, prove correct, and demonstrate the viability of an approach that allows the [software] maintainers to remain anonymous. Preserving anonymity is obviously important, given that almost everyone software developers included value their confidentiality. This new approach, Sollins adds, simultaneously allows [software] users to have confidence that the maintainers are, in fact, legitimate maintainers and, furthermore, that the code being downloaded is, in fact, the correct code of that maintainer. [ ]
The corresponding paper is published on the arXiv preprint server in various formats, and the announcement has also been covered in MIT News.

Nondeterministic Git bundles Paul Baecher published an interesting blog post on Reproducible git bundles. For those who are not familiar with them, Git bundles are used for the offline transfer of Git objects without an active server sitting on the other side of a network connection. Anyway, Paul wrote about writing a backup system for his entire system, but:
I noticed that a small but fixed subset of [Git] repositories are getting backed up despite having no changes made. That is odd because I would think that repeated bundling of the same repository state should create the exact same bundle. However [it] turns out that for some, repositories bundling is nondeterministic.
Paul goes on to to describe his solution, which involves forcing git to be single threaded makes the output deterministic . The article was also discussed on Hacker News.

Output from libxlst now deterministic libxslt is the XSLT C library developed for the GNOME project, where XSLT itself is an XML language to define transformations for XML files. This month, it was revealed that the result of the generate-id() XSLT function is now deterministic across multiple transformations, fixing many issues with reproducible builds. As the Git commit by Nick Wellnhofer describes:
Rework the generate-id() function to return deterministic values. We use
a simple incrementing counter and store ids in the 'psvi' member of
nodes which was freed up by previous commits. The presence of an id is
indicated by a new "source node" flag.
This fixes long-standing problems with reproducible builds, see
https://bugzilla.gnome.org/show_bug.cgi?id=751621
This also hardens security, as the old implementation leaked the
difference between a heap and a global pointer, see
https://bugs.chromium.org/p/chromium/issues/detail?id=1356211
The old implementation could also generate the same id for dynamically
created nodes which happened to reuse the same memory. Ids for namespace
nodes were completely broken. They now use the id of the parent element
together with the hex-encoded namespace prefix.

Community updates There were made a number of improvements to our website, including Chris Lamb fixing the generate-draft script to not blow up if the input files have been corrupted today or even in the past [ ], Holger Levsen updated the Hamburg 2023 summit to add a link to farewell post [ ] & to add a picture of a Post-It note. [ ], and Pol Dellaiera updated the paragraph about tar and the --clamp-mtime flag [ ]. On our mailing list this month, Bernhard M. Wiedemann posted an interesting summary on some of the reasons why packages are still not reproducible in 2023. diffoscope is our in-depth and content-aware diff utility that can locate and diagnose reproducibility issues. This month, Chris Lamb made a number of changes, including processing objdump symbol comment filter inputs as Python byte (and not str) instances [ ] and Vagrant Cascadian extended diffoscope support for GNU Guix [ ] and updated the version in that distribution to version 253 [ ].

Challenges of Producing Software Bill Of Materials for Java Musard Balliu, Benoit Baudry, Sofia Bobadilla, Mathias Ekstedt, Martin Monperrus, Javier Ron, Aman Sharma, Gabriel Skoglund, C sar Soto-Valero and Martin Wittlinger (!) of the KTH Royal Institute of Technology in Sweden, have published an article in which they:
deep-dive into 6 tools and the accuracy of the SBOMs they produce for complex open-source Java projects. Our novel insights reveal some hard challenges regarding the accurate production and usage of software bills of materials.
The paper is available on arXiv.

Debian Non-Maintainer campaign As mentioned in previous reports, the Reproducible Builds team within Debian has been organising a series of online and offline sprints in order to clear the huge backlog of reproducible builds patches submitted by performing so-called NMUs (Non-Maintainer Uploads). During December, Vagrant Cascadian performed a number of such uploads, including: In addition, Holger Levsen performed three no-source-change NMUs in order to address the last packages without .buildinfo files in Debian trixie, specifically lorene (0.0.0~cvs20161116+dfsg-1.1), maria (1.3.5-4.2) and ruby-rinku (1.7.3-2.1).

Reproducibility testing framework The Reproducible Builds project operates a comprehensive testing framework (available at tests.reproducible-builds.org) in order to check packages and other artifacts for reproducibility. In December, a number of changes were made by Holger Levsen:
  • Debian-related changes:
    • Fix matching packages for the [R programming language](https://en.wikipedia.org/wiki/R_(programming_language). [ ][ ][ ]
    • Add a Certbot configuration for the Nginx web server. [ ]
    • Enable debugging for the create-meta-pkgs tool. [ ][ ]
  • Arch Linux-related changes
    • The asp has been deprecated by pkgctl; thanks to dvzrv for the pointer. [ ]
    • Disable the Arch Linux builders for now. [ ]
    • Stop referring to the /trunk branch / subdirectory. [ ]
    • Use --protocol https when cloning repositories using the pkgctl tool. [ ]
  • Misc changes:
    • Install the python3-setuptools and swig packages, which are now needed to build OpenWrt. [ ]
    • Install pkg-config needed to build Coreboot artifacts. [ ]
    • Detect failures due to an issue where the fakeroot tool is implicitly required but not automatically installed. [ ]
    • Detect failures due to rename of the vmlinuz file. [ ]
    • Improve the grammar of an error message. [ ]
    • Document that freebsd-jenkins.debian.net has been updated to FreeBSD 14.0. [ ]
In addition, node maintenance was performed by Holger Levsen [ ] and Vagrant Cascadian [ ].

Upstream patches The Reproducible Builds project detects, dissects and attempts to fix as many currently-unreproducible packages as possible. We endeavour to send all of our patches upstream where appropriate. This month, we wrote a large number of such patches, including:

If you are interested in contributing to the Reproducible Builds project, please visit our Contribute page on our website. However, you can get in touch with us via:

9 January 2024

Louis-Philippe V ronneau: 2023 A Musical Retrospective

I ended 2022 with a musical retrospective and very much enjoyed writing that blog post. As such, I have decided to do the same for 2023! From now on, this will probably be an annual thing :) Albums In 2023, I added 73 new albums to my collection nearly 2 albums every three weeks! I listed them below in the order in which I acquired them. I purchased most of these albums when I could and borrowed the rest at libraries. If you want to browse though, I added links to the album covers pointing either to websites where you can buy them or to Discogs when digital copies weren't available. Once again this year, it seems that Punk (mostly O !) and Metal dominate my list, mostly fueled by Angry Metal Guy and the amazing Montr al Skinhead/Punk concert scene. Concerts A trend I started in 2022 was to go to as many concerts of artists I like as possible. I'm happy to report I went to around 80% more concerts in 2023 than in 2022! Looking back at my list, April was quite a busy month... Here are the concerts I went to in 2023: Although metalfinder continues to work as intended, I'm very glad to have discovered the Montr al underground scene has departed from Facebook/Instagram and adopted en masse Gancio, a FOSS community agenda that supports ActivityPub. Our local instance, askapunk.net is pretty much all I could ask for :) That's it for 2023!

31 December 2023

Chris Lamb: Favourites of 2023

This post should have marked the beginning of my yearly roundups of the favourite books and movies I read and watched in 2023. However, due to coming down with a nasty bout of flu recently and other sundry commitments, I wasn't able to undertake writing the necessary four or five blog posts In lieu of this, however, I will simply present my (unordered and unadorned) highlights for now. Do get in touch if this (or any of my previous posts) have spurred you into picking something up yourself

Books

Peter Watts: Blindsight (2006) Reymer Banham: Los Angeles: The Architecture of Four Ecologies (2006) Joanne McNeil: Lurking: How a Person Became a User (2020) J. L. Carr: A Month in the Country (1980) Hilary Mantel: A Memoir of My Former Self: A Life in Writing (2023) Adam Higginbotham: Midnight in Chernobyl (2019) Tony Judt: Postwar: A History of Europe Since 1945 (2005) Tony Judt: Reappraisals: Reflections on the Forgotten Twentieth Century (2008) Peter Apps: Show Me the Bodies: How We Let Grenfell Happen (2021) Joan Didion: Slouching Towards Bethlehem (1968)Erik Larson: The Devil in the White City (2003)

Films Recent releases

Unenjoyable experiences included Alejandro G mez Monteverde's Sound of Freedom (2023), Alex Garland's Men (2022) and Steven Spielberg's The Fabelmans (2022).
Older releases (Films released before 2022, and not including rewatches from previous years.) Distinctly unenjoyable watches included Ocean's Eleven (1960), El Topo (1970), L olo (1992), Hotel Mumbai (2018), Bulworth (1998) and and The Big Red One (1980).

19 December 2023

Jonathan Dowland: William Basinski, Gateshead, 2022

I was looking over the list of live music I'd seen this year and realised that avante-garde composer William Basinski was actually last year and I had forgotten to write about it! In November 2022, Basinski headlined a night of performances which otherwise featured folk from the venue's "Arists in Residence" programme, with some affiliation to Newcastle's DIY music scene. Unfortunately we arrived too late to catch any of the other acts: partly because of the venue's sometimes doggiest insistence that people can only enter or leave the halls during intervals, and partly because the building works surrounding it had made the southern entrance effectively closed, so we had to walk to the north side of the building to get in1. Basinski was performing work from Lamentations. Basinski himself presented very unexpectedly to how I imagined him: he's got the Texas drawl, mediated through a fair amount of time spent in New York; very camp, in a glittery top; he kicked off the gig complaining about how tired he was, before a mini rant about the state of the world, riffing on a title from the album: Please, This Shit Has Got To Stop. We were in Hall 1, the larger of the two, and it was sparsely attended; a few people walked out mid performance. My gig-buddy Rob (a useful barometer for me on how things have gone) remarked that it was one of the most unique and unusual gigs he'd been to. I recognised snatches of the tracks from the album, but I'm hard-placed to name or sequence them, and they flowed into each other. I don't know how much of what we were hearing was "live" or what, if anything, was being decided during the performance, but Basinski's set-up included what looked like archaic tape equipment, with exposed loops of tape running between spools that could be interfered with by other tools. The encore was a unique, unreleased mix of Melancholia (II), which (making no apologies) Basinski hit play on before retiring backstage. I didn't take any photos. From memory, I think the venue had specifically stated filming or photos were not allowed for this performance. People at prior shows in New York and London filmed some of their shows; which were substantially similar: I've included embeds of them above. Lots of Basinski's work is on Bandcamp; the three pieces I particularly enjoy are Lamentations, Lamentations by William Basinski On Time Out of Time, On Time Out of Time by William Basinski and his best-known work, The Disintegration Loops. The Disintegration Loops by William Basinski

  1. I don't want to speak ill of the venue, though: The Sage, as it was, and the Glasshouse, as it is now known, has ended up being the venue I've attended most this year (2023), and it's such a civilised place: plenty of bars, great drinks selection (both alcoholic and not, hot and cold), loads of clean toilets, a free cloakroom, fantastic accoustics, polite staff; the list goes on.

Antoine Beaupr : (Re)introducing screentest

I have accidentally rewritten screentest, an old X11/GTK2 program that I was previously using to, well, test screens.

Screentest is dead It was removed from Debian in May 2023 but had already missed two releases (Debian 11 "bullseye" and 12 "bookworm") due to release critical bugs. The stated reason for removal was:
The package is orphaned and its upstream is no longer developed. It depends on gtk2, has a low popcon and no reverse dependencies.
So I had little hope to see this program back in Debian. The git repository shows little activity, the last being two years ago. Interestingly, I do not quite remember what it was testing, but I do remember it to find dead pixels, confirm native resolution, and various pixel-peeping. Here's a screenshot of one of the screentest screens: screentest screenshot showing a white-on-black checkered background, with some circles in the corners, shades of gray and colors in the middle Now, I think it's safe to assume this program is dead and buried, and anyways I'm running wayland now, surely there's something better? Well, no. Of course not. Someone would know about it and tell me before I go on a random coding spree in a fit of procrastination... riiight? At least, the Debconf video team didn't seem to know of any replacement. They actually suggested I just "invoke gstreamer directly" and "embrace the joy of shell scripting".

Screentest reborn So, I naively did exactly that and wrote a horrible shell script. Then I realized the next step was to write an command line parser and monitor geometry guessing, and thought "NOPE, THIS IS WHERE THE SHELL STOPS", and rewrote the whole thing in Python. Now, screentest lives as a ~400-line Python script, half of which is unit test data and command-line parsing.

Why screentest Some smarty pants is going to complain and ask why the heck one would need something like that (and, well, someone already did), so maybe I can lay down a list of use case:
  • testing color output, in broad terms (answering the question of "is it just me or this project really yellow?")
  • testing focus and keystone ("this looks blurry, can you find a nice sharp frame in that movie to adjust focus?")
  • test for native resolution and sharpness ("does this projector really support 4k for 30$? that sounds like bullcrap")
  • looking for dead pixels ("i have a new monitor, i hope it's intact")

What does screentest do? Screentest displays a series of "patterns" on screen. The list of patterns is actually hardcoded in the script, copy-pasted from this list from the videotestsrc gstreamer plugin, but you can pass any pattern supported by your gstreamer installation with --patterns. A list of patterns relevant to your installation is available with the gst-inspect-1.0 videotestsrc command. By default, screentest goes through all patterns. Each pattern runs indefinitely until the you close the window, then the next pattern starts. You can restrict to a subset of patterns, for example this would be a good test for dead pixels:
screentest --patterns black,white,red,green,blue
This would be a good sharpness test:
screentest --patterns pinwheel,spokes,checkers-1,checkers-2,checkers-4,checkers-8
A good generic test is the classic SMPTE color bars and is the first in the list, but you can run only that test with:
screentest --patterns smpte
(I will mention, by the way, that as a system administrator with decades of experience, it is nearly impossible to type SMPTE without first typing SMTP and re-typing it again a few times before I get it right. I fully expect this post to have numerous typos.)
Here's an example of the SMPTE pattern from Wikipedia: SMPTE color bars For multi-monitor setups, screentest also supports specifying which output to use as a native resolution, with --output. Failing that, it will try to look at the outputs and use the first it will find. If it fails to find anything, you can specify a resolution with --resolution WIDTHxHEIGHT. I have tried to make it go full screen by default, but stumbled a bug in Sway that crashes gst-launch. If your Wayland compositor supports it, you can possibly enable full screen with --sink waylandsink fullscreen=true. Otherwise it will create a new window that you will have to make fullscreen yourself. For completeness, there's also an --audio flag that will emit the classic "drone", a sine wave at 440Hz at 40% volume (the audiotestsrc gstreamer plugin. And there's a --overlay-name option to show the pattern name, in case you get lost and want to start with one of them again.

How this works Most of the work is done by gstreamer. The script merely generates a pipeline and calls gst-launch to show the output. That both limits what it can do but also makes it much easier to use than figuring out gst-launch. There might be some additional patterns that could be useful, but I think those are better left to gstreamer. I, for example, am somewhat nostalgic of the Philips circle pattern that used to play for TV stations that were off-air in my area. But that, in my opinion, would be better added to the gstreamer plugin than into a separate thing. The script shows which command is being ran, so it's a good introduction to gstreamer pipelines. Advanced users (and the video team) will possibly not need screentest and will design their own pipelines with their own tools. I've previously worked with ffmpeg pipelines (in another such procrastinated coding spree, video-proxy-magic), and I found gstreamer more intuitive, even though it might be slightly less powerful. In retrospect, I should probably have picked a new name, to avoid crashing the namespace already used by the project, which is now on GitHub. Who knows, it might come back to life after this blog post; it would not be the first time. For now, the project lives along side the rest of my scripts collection but if there's sufficient interest, I might move it to its own git repositories. Comments, feedback, contributions are as usual welcome. And naturally, if you know something better for this kind of stuff, I'm happy to learn more about your favorite tool! So now I have finally found something to test my projector, which will likely confirm what I've already known all along: that it's kind of a piece of crap and I need to get a proper one.

13 December 2023

Jonathan Dowland: equivalence problems with StreamGraph

I've been tackling an equivalence problem with rewritten programs in StrIoT, our proof-of-concept stream-processing system. The StrIoT Logical Optimiser applies a set of rewrite rules to a stream-processing program, generating a set of variants that can be reasoned about, ranked, and deployed. The problem I've been tackling is that a variant may appear to be semantically equivalent to another, but compare (with ==) as distinct. The issue relates to the design of our data-type representing programs, in particular, a consequence of our choice to outsource the structural aspect to a 3rd-party library (Algebra.Graph). The Graph library deems nodes that compare as equivalent (again with ==) to be the same. Since a stream-processing program may contain many operators which are equivalent, but distinct, we needed to add a field to our payload type to differentiate them: so we opted for an Integer field, vertexId (something I've described as a "wart" elsewhere) Here's a simplified example of our existing payload type, StreamVertex:
data StreamVertex = StreamVertex
      vertexId   :: Int
    , operator   :: StreamOperator
    , parameters :: [ExpQ]
    , intype     :: String
    , outtype    :: String
     
A rewrite rule might introduce or eliminate operators from a stream-processing program. For example, consider the rule which "hoists" a filter upstream from a merge operator. In pseudo-Haskell,
streamFilter p . streamMerge [a , b, ...]
=>
streamMerge [ streamFilter p a
            , streamFilter p b
            , ...]
The original streamFilter is removed, and new streamFilters are introduced, one per stream arriving at streamMerge. In general, rules may need to synthesise new operators, and thus new vertexIds. Another rewrite rule might perform the reverse operation. But the individual rules operate in isolation: and so, the program variant that results after applying a rule and then applying an inverse rule may not have the same vertexIds, or the same order of vertexIds, as the original program. I thought of the outline of two possible solutions to this. "well-numbered" StreamGraphs The first was to encode (and enforce) some rules about how vertexIds are used. If they always began from (say) 1, and were strictly-ascending from the source operator(s), and rewrite rules guaranteed that a "well numbered" input would be "well numbered" after rewriting, this would be sufficient to rule out a rewritten-but-semantically-equivalent program being considered distinct. The trouble with this approach is using properties of a numerical system built around vertexId as a stand-in for the real structural problem. I was not sure I could prove both that the stand-in system was sound and that it was a proper analogue for the underlying structural issue. It feels to me more that the choice to use an external library to encode the structure of a stream-processing program was the issue: the structure itself is a fundamental part of the semantics of the program. What if we had encoded the structure of programs within the same data-type? alternative data-type StrIoT programs are trees. The root is the sink node: there is always exactly one. There can be multiple source (leaf nodes), but they always converge. Operators can have multiple inputs (including zero). The root node has no output, but all other operators have exactly one. I explored transforming StreamVertex into a tree by adding a field representing incoming streams, and dispensing with Graph and vertexId. Something like this
data StreamProg = StreamProg StreamOperator [Exp] String String [StreamProg]
A uni-directional transformation from Graph StreamVertex to StreamProg is all that's needed to implement something like ==, so we don't need to keep track of vertexId mappings. Unfortunately, we can't fix the actual Eq (Graph StreamVertex) implementation this way: it delegates to Eq StreamVertex, and we just don't have enough information to fix the problem at that level. But, we can write a separate graphEq and use that instead where we need to. could I go further? Spoiler: I haven't. But I've been sorely tempted. We still have a separate StreamOperator type, which it would be nice to fold in; and we still have to use a list around the incoming nodes, since different operators accept different numbers of incoming streams. It would be better to encode the correct valences in the type. In 2020 I explored iteratively reducing the StreamVertex data-type to try and get it as close as possible to the ideal end-user API: simple functions. I wrote about one step along that path in Template Haskell and Stream-processing programs, but concluded that, since this was not my main PhD focus, I wouldn't go further. But it was nagging at my subconcious ever since. I allowed myself a couple of days exploring some advanced concepts including typed Template Haskell (that has had some developments since 2020), generalised abstract data types (GADTs) and more generic programming to see what could be achieved. I'll summarise all that in the next blog post.

11 December 2023

Jonathan Dowland: Talks: why?

I'd planned to write some private mail on the subject of preparing and delivering conference talks. However, each time I try to write that mail, I've managed to somehow contrive to lose it. So I thought I'd try as a blog post instead, to break the curse. The first aspect I wanted to write about is the pre-planning phase, or, the bit where you decide to give a talk in the first place. But first a bit about me. I don't talk all that regularly. I think I'm averaging one talk a year. I don't consider myself to be a natural talk-giver: I don't particularly enjoy it and I still get quite nervous. So the first question is: why do it? One motivation is that you want to attend a particular conference, and presenting at it makes it much easier to get institutional support for doing so (i.e., travel and accommodation covered). At the moment, I've written some talk proposals for FOSDEM because I want to attend, and it increases my chances if I'm delivering a talk. Another reason, pertinent to academia, is you wish to have a paper published. Last year I attended a conference in Portland that I had a paper accepted to. A condition of the paper being accepted is you attend and do a presentation about it. Obviously, the presentation itself is a useful form of dissemination for your work, but the paper has the potential to reach more people. You may wish to promote what you're talking about: academic work, but perhaps a piece of open source software that would benefit from wider awareness, more adoption, more bug reports, testing, and patches. You may wish to support the venue. There are a some of small-scale conferences that I enjoy participating in which don't receive a lot of submissions and so I tend to send one or more in order to help make sure there are enough possible talks to keep the whole thing viable. Finally, you may wish to promote yourself: certainly, some Software Engineers I've met seem to spend as much time on talks and travelling as writing software. It's a good way to see a lot of the world, and might be a good way to get your name known and increase your employment prospects. I feel lucky I haven't had to rely on this.

Jonathan Dowland: Tex Shura

So yeah, I bought the Shura.
Tex Shura keyboard, ISO-UK layout
It's been about a year since I got the Tex Shinobi keyboard. I ended up taking to the office and using it there. The MX Silent Red switches are a good fit for a shared space, and I have a bit more desk space so the extra large footprint is not a problem. Back at home, I have a reasonably large desk, but I've got a Synth jammed at the back-centre, leaving a slightly tight budget for keyboard depth. The Shura is nice and compact and fits in perfectly. So what should I say about it? Build quality is excellent. I went with MX Reds (non-silent this time) which feel a lot better to me than the silent variant. I do worry about waking the kids up if I type after they've gone to bed, but it hasn't actually been a problem (and the switches activate quite early in travel so you can "tip-toe" type silently, and slowly). I like these keyboards (and I've otherwise avoided the Mech keyboard money pit) because they have the integrated trackpoint, which I rely on. Just as with the Shinobi, the Trackpoint is of an excellent quality, pretty much indistinguishable from that on the official Lenovo trackpoint keyboards. Since the Shura is a a "60%" or "65%" or "70%" or something, thus forgoing the Function keys and such, I rely on "layers": switching the function of all the regular keys whilst "Fn" is pressed. You can reprogram the Tex keyboards using a profile output by their web-based configurator which I've used to mildly customize the layout: swapped left-hand "Win" with "Fn" (FN1), mapped FN1 to the right-hand "Win". That's it so far, the defaults are otherwise sufficient for me. I've also used the DIP switches to enable mouse wheel emulation with the trackpoint (in common with the Lenovos). In September, Justin from TeX left an intriguing comment on my last blog post:
Thanks for your promotion !! We will try to design a new keyboard ( a little ergo keyboard ) should be release end of this year !!

9 December 2023

Thorsten Alteholz: My Debian Activities in November 2023

FTP master This month I accepted 276 and rejected 25 packages. The overall number of packages that got accepted was 276. I also handled several RM bugs, so the archive did not grow that much :-). Debian LTS This was my hundred-thirteenth month that I did some work for the Debian LTS initiative, started by Raphael Hertzog at Freexian. During my allocated time I uploaded: The update of libde265 was a bit unusual this time. The security tracker had three CVEs listed for it and the maintainer was looking for a sponsor to fix them in Unstable. So far, so good! I sponsored the upload and suddenly a fourth CVE appeared in the security tracker. As the debian/changelog mentioned a different CVE, it was automatically added. Indeed upstreams changelog contained a patch for a CVE that was reserved but not yet published (hence the security tracker could not connect it to libde265). I informed upstream and as things turned out marking the CVE as public was just forgotten. Luckily there was some time left for the upcoming point release and all four patches finally arrived in Bookworm. Debian ELTS This month was the sixty-fourth ELTS month. During my allocated time I uploaded: In order to check whether the patch for the standalone version of minizip was ok, I used a test from the embedded minizip version in chromium and it worked. Debian Printing This month I uploaded a new upstream version of: Within the context of preserving old printing packages, I adopted: If you know of any other package that is also needed and still maintained by the QA team, please tell me. This work is generously funded by Freexian! Debian Astro This month I uploaded a new upstream version of: Debian IoT This month I uploaded a new upstream version of: Debian Mobcom This month I uploaded a package to fix one or the other issue: Other stuff This month I uploaded new upstream version of packages, did a source upload for the transition or uploaded it to fix one or the other issue:

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