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#self#data#binary#upgrade#service#file#segments#schema#old#migration

Discussion (5 Comments)Read Original on HackerNews

jdub•about 1 hour ago
Instead of post-processing the binary to add the application (non-SELF) schema, you could run database migrations before servicing requests. Thus, every time you start the process, the app creates and/or upgrades its own schema.

The SELF upgrade (heh, self upgrade) and rollback processes could benefit from some... fancier... footwork.

Your example has a new binary copying old data into it, but then you have to move the new binary to the deployed location. Which means an outage through stop service, data migration, replace file, start service.

What if the upgrade process was more like... write the new SELF data into the old binary, send SIGHUP, and then the service fork+execs itself, while doing haproxy-like zero downtime FD handover?

Replacing the SELF data in the existing file is safe right now, because you can't mmap segments into memory. But if you do end up figuring out some clever BLOB alignment mmap stuff, you could do the SELF upgrade like a data migration! INSERT segments/symbols, fork+exec, and the data migration cleans out the old code. :-D

Updating the SELF schema to allow multiple sets of segments and symbols would allow for this upgrade trick, but could do other fancy things... thin multi-arch binaries where only the code segments differ.

BLOB alignment should also mean more efficient static asset serving and a bunch of other niceties... definitely worthy of investigation.

However -- very strong however -- as fun as this is, I would never, ever, ever allow an internet-facing service binary to be self-writable. :-)

robviren•about 2 hours ago
Between this and actually portable executable I'm not convinced someone hasn't made a PNG thats a spreadsheet, or an audio file the somehow renders DOOM across the room. HN amazes me with the absolutely cursed ideas of implementing a minecraft in pure css (or showing whatever other nightmares one can do with CSS). It shows the most incredible creativity in what one can do with the freedom of arranging bits however one wants. I'm in love with all these cursed projects and hope they never stop.
mirashii•about 1 hour ago
PoC || GTFO has an issue that is a PDF that is also a valid NES rom which will render the md5sum of the PDF itself, and other crazy tricks of that type over the years.

https://dl.packetstormsecurity.net/mag/pocgtfo/pocorgtfo14.p...

drdexebtjl•about 3 hours ago
I wonder if the interpreter could create a mount namespace and mount virtual filesystems backed by the SQLite database itself, so you wouldn’t need source changes to self-contain (ha!) file accesses.
stephenlf•about 3 hours ago
Fantastic ideas. The SQL Injection to ACE pipeline is incredible.