How can I see all the system calls IDs of my system?

So today our teacher briefly explained us how system calls for native functions work. He showed us an example for an arch x86 with Linux kernel 2.6 in where the file that contains the system call numbers (IDs) is in include/asm-i386/unistd.h

Then, the process of calling the specific native function will start with int 0x80 and __init trap_init() which is in (in his example) arch/x86/kernel/traps.c in whose code is the method for entering kernel mode via the function set_system_gate(SYSCALL_VECTOR,&system_call). Then “calling” the function system_call() which is in arch/x86/kernel/entry_32.S

Now, he asked us to find out what I’m asking in the title: where to find (e.g. a file or a command in shell) all the system calls IDs for the last Ubuntu version despite the arch (for the latest linux kernel version). AND to also find out which is the path (again, for the latest kernel version and in Ubuntu) for the traps.c file.

I’m sorry for not using some of the terms properly but I’m a new student. All help and simplified explanations will be much apreciated.

How are calls or SMS used to exploit a smartphone?

How could a phone number be used as a means to gain access to a smartphone? I am reading claims that you could receive a call or SMS on your phone and an attacker can install their malware that way. Are methods like that possible? That seems a bit over the top to believe. What exactly are the methods used to install malware on a smartphone. I have a pretty elementary understanding of information security, any books or sites to read are appreciated.

[ Global Warming ] Open Question : Presidential Democratic candidate Marianne Willamson calls for conscription to combat “climate change.” Will her idea catch on?

Marianne Williamson wants a national mandatory service for people ages 18-26 to combat climate change —– Jeanine Santucci, USA TODAY Published 3:22 p.m. ET Sept. 19, 2019 Passage from article….. “At a presidential climate change forum on Thursday, author and Democratic presidential hopeful Marianne Williamson floated the idea of a national mandatory year of service for young adults to tackle climate change. “I would like to ask your opinion, I think during the ‘season of repair,’ we should have a mandatory national service, one year, for people between 18 and 26 because we need you,” Williamson said. “We need to fix this climate. We need to fix this country.”

What is it called when spouse calls, But always denying everything

what is it when your spouse is being very secretive, multiple phone lines, calling different phone numbers, on phone maybe 12 – 30 sec. But always denying everything. Some numbers are local. When I call them it has a fake business like Verizon help desk, I don’t know if they are doing VM or what..been married 34 wyears and now separated. Swears they are not cheating . Gets on this site from Russia called 1c connect. Anyone?

My campaign calls for characters of a certain level for the final boss fight. How do I best get them there?

In a custom 5e campaign I’ve designed, the big boss is a very powerful entity. It is not stylistically reasonable for the players to fight it below level 17. They are currently level 6. My planned campaign content should take roughly twelve (12) 4-hour sessions to complete. This means, in order to reach the desired character level, the PCs must gain one level per session.

As for why the final boss fight should be a very high-level encounter,

Leveling up once per session seems unreasonably fast. I worry the players won’t have time to adjust to new abilities and spells, but also that it will be difficult to convey that reaching such a high level was an achievement. In addition, the experience required to do this is very high; employing the milestone method seems to cheapen the difficulty of reaching such a pinnacle of power, but actually earning the required experience will require every encounter be of Deadly level or higher.

Possible solutions I’ve come up with:

  • Add more content. I can certainly develop more content, adding more sessions to the campaign. This would seem an obvious solution, except we typically play 1-2 times a month. 12 sessions will take at least 6 months, more likely 9 months. I am loath to extend this by 8 sessions (to a total of 20), which would be the rough minimum to make it not feel like a level every session.
  • Change the big boss. I can make the boss different, scaling difficulty down and enabling the final encounter to be less than a level 17 fight. This would be fairly simple mechanically, but require massive changes to the plot- some of which would be difficult to pull off, since we are already three sessions into the campaign.
  • Increase the leveling speed to match, as discussed above.
  • Find a story reason to give more experience than granted in sessions. “You spend a week fighting bandits and get 12000 experience” would be a (terrible) example of this principle. If done well, with random event tables the players roll against and fun “scripted” events, this could allow the fast leveling required without constant near-death fighting in every single session, but still suffers from possible problems resulting from such rapid advancement.
  • Something else, perhaps?

How do I best get the PCs from level 6 to 17+?

Following advice from SevenSidedDie, I’m posting the real question. We’ll see if it works or if it needs to be adjusted/edited/asked differently.

Web service calls return HTTP 500 Internal Server Error on my SharePoint 2013 site

I have a SharePoint site that was running without any problem. Few days ago the search stopped working with an error in the crawl log

The crawler could not communicate with the server. Check that the server is available and that the firewall access is configured correctly

From the ULS log I was able to see that the crawler is trying to call a web service _vti_bin/sitedata.asmx, but it is failing with error HTTP 500 Internal Server Error. I believe because of this failure the crawl is not working in the farm. When I tried to call other built-in webservices in SP2013 (such as lists.asmx?WSDL), I noticed that all the ASMX services have the same problem.

Can anybody please help me to figure out what is going wrong in SharePoint? I tried to see the ULS and event viewer; nothing logged there.

Is there any way I can “reinstall” the ASMX web services in SharePoint?


The web services are not working on the site collection root site. For any subsite the web services works properly. I am still confused.

Thank you

HTTP 404 for REST calls from client side (browsers)

I’m having troubles with the issue of distinguishing between “real” 404s and 404s where the path is correct but the id, for example, doesn’t exist when it comes to client side apps.

Most REST articles and answers here talk about returning a 404 if a resource isn’t found. I do understand that a REST URI points to a specific resource and therefore, whether the requested resource isn’t there (no such id) or the whole path is wrong, 404 is still the response.

The problem is that browsers tend to treat 404s as actual errors before the request even reaches the app code, which pollutes the console and hides real 404s (image isn’t present on the CDN). The second issue is that 400 HTTP codes are described everywhere as client errors. But if the path is correct by an ID is not present, this isn’t technically an error. It’s proper and expected functionality. It looks akin relying on exceptions for logical flow in the code.

Is there a proper way to handle such scenarios, without spamming the browser console?

How would one change this architecture to avoid synchronous REST calls?

right now I have an architecture where several “microservices” are daisy-chained together in a row via synchronous REST called. Obviously this is far from ideal since synchronous communication between microservices is strongly discouraged and, as mentioned on slide 37 here, the overall availability of your application drops exponentially with how many services you have chained together behind it.

Picture a flow somewhat like this:

From the front-end, the user submits an application form. This starts a process for either accepting or denying the application.

first service1 is called, which inserts the form data into a database

once the insertion is complete service1 calls service2 which does some preliminary sanity checks

if those checks pass then service2 will proceed to call service3 to perform some more advanced checks.

service3 will in turn call serviceA, serviceB, and serviceC in parallel, and aggregate their responses into a final decision.

Some challenges are:

  • service3 has to come after we know the results of service2‘s checks. This is because service3‘s checks are more expensive to do so if the sanity checks already fail, we don’t want to bother calling service3 at all.
  • The calls to serviceA, serviceB, and serviceC, should technically be considered “query” calls(under CQS/CQRS) since we are expecting a return value and there is no change in state. However, some or all of these services are in fact complex machine learning models. This differentiates them from regular query calls in 2 ways: 1. they can be slower than what you would usually expect from a “query” call, and 2. we don’t have the option of retaining a local copy of the data using service3‘s DB since said data is generated on the fly.
  • It is a requirement that we have an answer(to accept or deny the application) in real time: a few seconds after the customer clicks submit they should know whether we accepted them or not. At the same time, the financial impact of making the wrong decision, even for a short time is too high to risk so giving some answer and then correcting it later(eventual consistency) is not an option here.

Any ideas on how I could reorganize an architecture like this? Or do the requirements in this case mean we have to live with the issues of coupling?


External API and database calls in Frontend or Backend?

I am working on a startup. During a meeting an investor asked me why am I calling the external APIs and database queries in the frontend with Ajax-Javascript and not in the backend? I couldn’t answer the question. I have not much experience in backend development. Is there anything which I should consider in my frontend development? Performance? Scaling? Any advantages or disadvantages with frontend or backend?

Thank so much.

How to let a matlab mex function file create threads which keep on living in between function calls?

I have found out that statically allocated memory in mex files seems to survive between different calls from Matlab (unless the user types “clear mex” or “clear all”). Even if they didn’t, there do exist functions which let you mark stuff as persistent in memory.

Now to the question of mine: I am aware that some OS:es cough can take considerable time to start and stop threads. Would there be some way to let threads live on after a mex function call and be taken right back up at the next call.

The obvious goal would be to gain speed so any answer which gives some other kind of hint how to do this would be acceptable to me too.