Questions concerning the details of how a program uses system calls to interact with the kernel API, what calls are available, how they work etc.

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21
votes
2answers
3k views

Where is the fork() on the fork bomb :(){ :|: & };:?

Warning: Running this command in most shells will result in a broken system that will need a forced shutdown to fix I understand the recursive function :(){ :|: & };: and what it does. But I ...
5
votes
2answers
115 views

Making a process read a different file for the same filename

I have an application that reads a file. Let's call it processname and the file ~/.configuration. When processname runs it always reads ~/.configuration and can't be configured differently. There are ...
10
votes
1answer
5k views

What's the difference between fork() and vfork()?

I would like to understand in detail the difference between fork() and vfork(). I was not able to digest the man page completely. I would also like to clarify one of my colleagues comment "In ...
16
votes
4answers
4k views

How to understand pipes

When I just used pipe in bash, I didn't think more about this. But when I read some C code example using system call pipe() together with fork(), I wonder how to understand pipes, including both ...
6
votes
5answers
4k views

What is the difference between a Library call and a System call in Linux?

I would like to know what is the difference between a Library call and a System call in Linux. Any pointers for a good understanding of the concepts behind both will be greatly appreciated.
5
votes
3answers
513 views

System calls supported in running Kernel

Is there a way to get the number of or list of system calls supported by currently running Linux Kernel? So I want to find a way to 'read' the syscall table of a running kernel.
3
votes
3answers
219 views

API with no system calls

The book 'Understanding Linux Kernel' says that 'for something abstract such as math functions, there may be no reason to make system calls'. Can any one please explain how is a system call not ...
2
votes
1answer
210 views

Strace Hello World program

So I am trying to understand systemcalls with the following "Hello World!" program: #include <stdio.h> int main(){ printf("Hello World!\n"); return 0; } and then I run strace on the ...
1
vote
2answers
193 views

How to notice log file changes with Linux standard tools? [duplicate]

I need something that does not need to be installed. It's on an embedded system with very little space on the HD. I can't instal anything. I need to do it with something that is already included. I ...
1
vote
1answer
301 views

what is a Kernel? [closed]

I'm learning Unix from the Unix Architecture book by Maurice J Bach. So if my question seems too stupid, please do bear with it. I read a few related questions but I would like a more simple ...
5
votes
3answers
475 views

How can you change the process name of Wing IDE from python to something more descriptive

In my process list under Ubuntu (using top/System Monitor) one of the largest memory hogs (200+Mb) was python. I searched a bit for one of my programs to be the cause until I realised this was my ...
4
votes
4answers
3k views

Understand error codes in Linux

I am working on Linux (Kernel Version 2.6.32.28) laptop. After I inserted/did file io/removed a SD combo card, I got following errors: mmcblk0: error -123 sending status command mmcblk0: error ...
3
votes
3answers
2k views

Command to trace rsh server to check behaviour of particular system call

I am working with rsh. I want to check the whole process from beginning to end. For that I used strace. Os name is CentOS. I am working on single machine, server and client are on same machine. My ...
2
votes
2answers
402 views

Are system calls the only way to interact with the Linux kernel from user land?

Are there any other interfaces, e.g. the /proc filesystem?