Making Minimalist Web Server in Assembly on Linux (x64) 

@@yestechguy-fj9tm Right, but the point of frameworks and standard libraries is to abstract the implementation of the ABI away from the programmer so we get a unique interface that works the same regardless of the underlying architechture. So the actual syscall number and how the arguments are passed is handled by the library. Though when you know your target, of course you can directly issue the syscall. I haven't done any low level programming on modern systems. I've done a lot during the Win95/98/XP times :)

@yestechguy-fj9tm It's even more fun when you design your own ISA & ABI...

Thanks!

Thanks! I appreciate the compliment :)

Thanks :)

Flip the registers and insert the appropriate tokens. Conversion to and from GAS is pretty simple.

also mormat elf is unnecessary i think@@NOPerative

@@ItsCOMMANDer_ Yes. Format ELF is FAsm exclusive. The format directive is unnecessary with GAS and NAsm.

Thanks! added :)

Another option instead of doing the trick I did with the GCC preprocessor and header files is to manually copy over the values from the header files to the Assembly, but notice that syscall numbers change between different processor architectures so make sure you are copying the correct numbers for your architecture. Another way is to locate these values from the Linux kernel source, for example here is sockaddr_in in the kernel source elixir.bootlin.com/linux/latest/source/include/uapi/linux/in.h#L256

Yah I used to have a dual monitor setup as well but decided a couple of years ago to move back to single monitor due to neck strain

I find that even with an UWQHD monitor, it's hard to find a good way to partition the screen so that it is better than dual screens. I really need a SUWQHD I think... or just keep using dual screens. At least the footprint of a single UWQHD is an improvement.

תודה!

I am also used to NASM but recently I started using FASM and I like it a lot more :)

Thanks! Yah I skipped doing cleanup/error checking to keep the video short (also have a disclaimer about this on the vid), but I added close in the code on Github. You can indeed get the syscall values directly from the header files as well (on my machine it has a different path), the idea of the preprocessor trick I did in the video is to automate this

Thanks! I have a playlist "Vim Tips" with videos about how I work with Vim, when I do Windows dev I work with Vim for Windows and when doing Linux dev I mostly work with Vim running on WSL. Yes, the request was automatically forwarded to WSL, I didn't configure anything special

@@nirlichtmanThanks for full response. Will check you "Vim Tips"

Thanks! I have a playlist "Vim Tips" with information about that :)

Thanks! You mean which scenarios are appropriate to use Assembly in general? There are all kinds, for example early boot code for bootloaders, using in conjunction with C/C++ code since there are cases where using Assembly for certain parts is required to call certain specific instructions, or optimize a specific part, and of course in extreme cases you can even write full programs with Assembly - like Roller Coaster Tycoon :)

@@nirlichtman Yea the famous game Roller Coaster Tycoon! I'm starting to re-learn C and NASM. Do you also have experience with microcontrollers?

@@biohazardouszxellium Not a lot just playing a little with Arduino, but I definitely plan on learning some Arduino AVR assembly when I have more time, interesting subject!

You mean a video explaining how to call assembly code from C ?

no like using thread and epoll using fasm @@nirlichtman

🤯

Yah, the segfault occurs since I did not exit properly by invoking the exit system call so the execution slided after finishing. I added that jump to the accept instruction in the Github code, that would make it wait for more connections

Okay, thank you!

6502

assembly is literally a fancy machine code in english

nope, nginx utilizes multiprocessing, this one does not

Just use another app to route the incoming requests to different ports and have each core run a process of this server listening on each of those ports. Even that can be done via round robin in a fresh assembly project. As the code is so simple and has no security checks (which is ok when you don't serve client data), it should be blazing fast. You can even add a counter to save visits by IP in case you are DDoSed, you will still get most basic attacks off your back with a few more lines.

@@TheUnkow so a reverse proxy? 😃

@@interrrp_with_three_rs this is almost certainly faster than nginx for what it does - return a single file. Just the code in nginx to handle processing the request content, parse the url, map to a local file and related security checks/etc would be orders of magnitude more instructions than this entire program.

If you man -k socket You see that it's in manual 7. So man 7 socket

Thanks for the feedback, will take that into consideration 👍

you can change the speed of the vid at will

Skipped cleanup/error handling in the video to keep it short (also added a disclaimer in the video around the middle). In the Github repo, I added calls to close

That would really be interesting to see the differences in this low level!

Winsock is also planned :)

lmao

I had this same thought, but the bottom line is, it's for fun. If he wasn't using the syscalls or c libs, he'd have to write his own OS to do it.

syscalls are 'plugs' in the kernel. The simplest way to discover the syscall 'names' is to backtrace c 'wrappers' and voila

He's not really using c libraries. The c code is a trick to get constants out of the header files.

He's accessing to a Linux system through Windows

he is using wsl 2

"Code never lies, comments sometimes do"

Comments are fairly pointless unless they help *you* remember something for yourself. If you can’t read the code then umm…yeah. 😬

@@Crux161Comments are not only there for you, they are there for the poor shmuck that has to deep dive into your code maybe even years later. I have built my entire career around having to fix or maintain code written decades ago that has been hacked on repeatedly making the entire thing an unmaintainable cluster bleep (think of "a patchy web server" becoming the "apache web server" for example). Comments explain what you are thinking while you code, the logic behind the inner workings. I have also always said that if you have thought about your code long enough to explain it to someone else then you have thought about it long enough to code it otherwise you have not. NO code is self documenting, specially when you have if/and/but loops nested to the umpteenth level. Every block is an inlined, anonymous function. If people broke blocks out into sub functions it would move towards self documening but it NEVER truly gets there.