Questions tagged [system-programming]
All questions regarding programming, tweaking and configuring of Unix & Linux core system as a whole or a sub-set of it.
1
vote
1answer
30 views
CPU statistics calculation algorithm
I too many search on internet to found algorithm calculated %Us , %Sy , %Id , ... on result of top command . but can not found any documentation .
some documents like this or this calculate cpu ...
0
votes
0answers
6 views
Using pa_simple api efficiently [migrated]
I'm playing around with pa_simple api to get a better understanding of digital audio. I've written some code to feed custom generated audio data to the pulseaudio server:
char buff[2];
while (playing)...
0
votes
0answers
15 views
If it's possible to programmatically reset Mac to factory defaults
Wondering if there is a way to programmatically do something close to this process.
The main steps are:
Backup computer. This can be done with standard stuff I imagine.
Deauthorize accounts. This ...
1
vote
2answers
1k views
How can I make my Linux server sleep and wake on LAN when not in use?
I have recently purchased myself an HP rack server for use as a personal fileserver. This server currently lives under my bed as I have nowhere else to put it. For those not aware (as I was not ...
3
votes
3answers
309 views
Process creation time, shell script and system call overhead
I have a machine dual booted with Arch Linux and Ubuntu (16.04).
I have recently started using the Kakoune text editor, and noticed that its startup time is drastically different depending on which ...
1
vote
1answer
32 views
What does the STICKY_TIMEOUTS flag for personality(2) do?
Is there a good description of exactly what each of the flags you can pass to personality(2) does? I'm particularly interested in STICKY_TIMEOUTS, but a general detailed description of all of them ...
2
votes
0answers
48 views
How does vlan driver pass vlan info to the h/w ethernet driver
I'm trying to implement vlans on a target programmatically.
But first I wanted to set up vlans manually to help get a better understanding of vlan setup. So I setup a vlan manually on my development ...
1
vote
0answers
691 views
Running a command on a new terminal window through Python [closed]
I would like to open a new terminal using any method (subprocess, etc.) through my original Python script with a following command -- ls -- and keep it minimized so it won't appear on my screen, but ...
-2
votes
1answer
334 views
Use supercomputer to run a program [closed]
I wrote a c++ program using some libraries called linbox, givaro, gmp.
Now because my computer is to slow I want to run my program on a supercomputer.
I am not very familiar with networks and my ...
0
votes
1answer
49 views
Move files shell program
Hello i have got problem, on shell program(.sh), with this code I should copy the file JPG from the directory sorgente to destinazione
but the code does not work, can you help me!!
#!/bin/bash
...
1
vote
1answer
63 views
How to programmatically query the Freedesktop application database?
I know about xdg-mime which can query the mapping from MIME filetype to associated desktop application. But this can return mappings to non-existent applications, e.g.
$ xdg-mime default non-...
0
votes
0answers
31 views
How to find the default application to open a file in shell script? [duplicate]
I need to find the default application for a particular file type using shell script in GNOME desktop environment. Like in my system all .c files are opened by gedit and mp4 by vlc. How to find the ...
1
vote
0answers
32 views
USB devices not showing
I'm trying to write a C program that goes through all USB devices and extracts some information from them. When I run ls /sys/bus/usb/devices from the terminal, I get this output:
1-0:1.0 1-1.1 ...
1
vote
1answer
1k views
How to specify a namespace when creating a tun/tap device?
On linux I can create a new tun/tap device in C using something like:
int fd = open("/dev/net/tun", O_RDWR);
ioctl(fd, TUNSETIFF, (void *)&ifr);
This will create a new network interface in the ...
6
votes
1answer
306 views
Is there filesystem that allows me to insert some block in the middle of file in O(1)?
Assuming
we have huge file F.
we like to put "around" seek s a new empty (filled with zeros) block in O(1) time (i.e. without rewriting all remining part)
"around" means we can round s to nearest ...
-1
votes
2answers
36 views
How can I save output of my script to different directory in txt or pdf format [duplicate]
`clear
echo "testing calc"
date
echo -e "======================================"
yc1=0
yc2=0
yc3=0
lol=0
tnd=0
lno=0
c1=0
c1b=0
c2=0
c2b=0
c3=0
c3b=0
bb=12
wt=100
con=768
rip=0
sw=0
echo ""
echo ""
...
2
votes
3answers
1k views
Trouble with creating an empty file using C programming language in UNIX environment
I have recently started programming in UNIX environment. I need to write a program which creates an empty file with name and size given in the terminal using this commands
gcc foo.c -o foo.o
./foo.o ...
0
votes
1answer
79 views
Permission check on profile file in home directory: should it be done?
Say I'm implementing a programming language which has an interactive mode, and that interactive mode reads some ~/.foo_rc file in the user's home directory. The file contains code in that language ...
1
vote
0answers
720 views
How to get minor and major page fault for individual or group of processes?
I am trying to write a program in C to run under Linux. Basically I am trying to draw a statistic that should show like: pid, number of process, page fault(major/minor) and total number of page ...
1
vote
0answers
149 views
How to catch my bluetooth service events
I have usb bluetooth device which is using btusb 0.6 module (driver). The thing is I am interested to know is: how is the systemctl start bluetooth.service event invoked?
I was looking info about ...
-1
votes
2answers
78 views
How to find documentation about macros in the manpages?
I've been working on a Routing Protocol and looking at legacy code for different routing protocols. I constantly find different macros where I it is very hard to find it in the header files because ...
0
votes
2answers
4k views
Loading and execution of programs in memory [closed]
While comparing between linking loader and linkage editor I came across a point that in case of linking loader linking and relocation takes place for each execution of the program( and happens at time ...
2
votes
0answers
48 views
calling library functions from different language
As we know libraries are precompiled codes, so we do not need to compile them. Can we call library functions of one language from a different language?
3
votes
2answers
1k views
Low level system call [closed]
C provides library functions such as write(),read().. for system calls.How to make a system call without using any library in linux in C ?
3
votes
3answers
9k views
System calls source code
C library provides functions such as write(),read(),open()...that we can use in our C program to make system calls. where can I find source code for these functions?
2
votes
1answer
154 views
System calls in linux
Generally, systems provide a library or API that sits between normal programs and the operating system. On Unix-like systems, that API is usually part of an implementation of the C library (libc), ...
4
votes
1answer
249 views
FILE size limitation according to Robert Love's textbook
From Robert Love's Linux System Programming (2007, O'Reilly), this is what is given in the first paragraph (Chapter 1, Page 10):
The file position’s maximum value is bounded only by the size of the ...
3
votes
5answers
2k views
How to set proper monitoring of my services in a automated way? So that if one crash it auto on the fly restarts?
How can i setup monitoring to my system services?
Either using automated script which scan every moment, if httpd, mysqld, and my custom daemon is running or not, if not running it will automatically ...
7
votes
2answers
26k views
Online course that covers Unix/Linux Systems programming [closed]
I am looking for an online course, something similar to the Berkely and Stanford Courses that covers Linux systems programming. A course which could use Stevens ( with some supplemental material ...
-1
votes
3answers
3k views
telnet implementation using C [closed]
The program in general is I want to implement telnet program.
On the client side user send its logging name and password, and if it is correct he starts to send commands to the server
On the Server ...
4
votes
1answer
4k views
Concept of memory mapping in Unix like systems
Can some one explain in an easy to understand way the concept of memory mappings (achieved by mmap() system call) in Unix like systems ? When do we require this functionality ?
0
votes
2answers
557 views
Can linux be configured as a server or workstation in DCS and how? [closed]
I am a student of Instrumentation and Control. Considering the versatility and stability of Linux, I was wondering if Linux can be configured to act as a Distributed Control System?
Also if yes, ...
3
votes
0answers
1k views
modetest.c from libdrm tests lists no framebuffers
I wanted to play with KMS since it seems to be the preferred low-level graphics library on Linux. However, after compiling the appropriate modetest.c version (2.4.32, since that's the version of ...
2
votes
1answer
809 views
Preventing ChromeOS from blanking the screen when working on a different tty
I am running Archlinux in a chroot alongside Chrome OS on a chromebook. The original project is there, my fork of it is here (mostly similar).
The issue is that the display power management of Chrome ...
0
votes
2answers
1k views
Automated SSH Login [duplicate]
Possible Duplicate:
Shell Script for logging into a ssh server
Autentification on SSH connection in OneLine
How could I make a SSH Login programmatically on a unix server, I don't have rights ...
6
votes
2answers
12k views
How to find the header file where a c function is defined?
Is there an easy way to find out which header file a C function declaration is in? cding into /usr/include and running (grep -E 'system.*\(' *.h -R) works with some trial and error, but isn't there an ...
11
votes
2answers
12k views
Difference between slow system calls and fast system calls
What's the difference between slow system calls and fast system calls? I have learned that slow system call can block if the process catches some signals, because the caught signals may wake up the ...
4
votes
3answers
2k views
Cursor movement in terminals
I'm trying to wrap my head how shells move the screen cursor around (Moving around input the arrow keys and such).
I've been doing a lot of testing, and I haven't found any system call that allows ...
2
votes
3answers
853 views
Are all system call error numbers unique?
I'm writing a program for Systems Programming in Unix, and one of the requirements is to process all possible error returns from system calls.
So, rather than having a function tailored to each ...
6
votes
2answers
6k views
Learn Linux System Programming by doing projects [closed]
I have only a very basic idea about linux system programming. I have not done any real projects using linux system programming. In my current company I do system admin type work, but I am more ...
4
votes
2answers
3k views
Implementing a Unix shell in C: Logging [closed]
I am currently working on implementing my own UNIX shell in C. The basis of the shell is working, you could find the source code here.
Right now my next task is to implement a logging feature for the ...
3
votes
4answers
158 views
SDK for Developer
Is there any SDK for developers under Linux? I mean more than man pages, it would be more like MSDN Library or Windows SDK under windows, where all documentation about programming and developer guide ...
25
votes
9answers
46k views
What is the best book to learn Linux system programming? [closed]
I am trying to learn Linux system programming, which is the best book to learn this?
