Replace C instructions for system calls Post: 302944405

Sponsored Content

Homework and Emergencies Homework & Coursework Questions Replace C instructions for system calls Post 302944405 by alwayslearn on Tuesday 19th of May 2015 07:06:07 AM

05-19-2015

Registered User

Replace C instructions for system calls

Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!

1. The problem statement, all variables and given/known data:

Modify the program exec_in.c to obtain the same result but replacing the functions sleep and system for system calls. You can use exit, exec*, pause, alarm, etc. The new program will be called exec_in2.c and keep the original program syntax

2. Relevant commands, code, scripts, algorithms:

Code:

#include <stdlib.h>  
#include <stdio.h>  
#include <string.h>  
#include <errno.h>  
#include <unistd.h>   
#include "rutines.h"  

 int main(int argc, char *argv[])  
{      
      char cmd[256];
      int a;

      if (argc<2)
          Error("Insufficient arguments: exec_in <sec> <cmd> [args...]");

     sleep(atoi(argv[1]));
     cmd[0]='\0';

     for(a=2;a<argc;a++)
     {
          strcat(cmd,argv[a]);
          strcat(cmd," ");
      }

     system(cmd);
     exit(0);
}

3. The attempts at a solution (include all code and scripts):

I'm not sure what system call I need to solve the problem, I think that I need to use alarm but I don't know how to use correctly that, I never used system calls in C before, also I have only been using linux one week and I'm really lost.

4. Complete Name of School (University), City (State), Country, Name of Professor, and Course Number (Link to Course): Centre d'estudis Roca, Barcelona, Spain, Mariano Torres

Note: Without school/professor/course information, you will be banned if you post here! You must complete the entire template (not just parts of it).

I use ubuntu 12.04 64 bits

Last edited by alwayslearn; 05-19-2015 at 08:11 AM..

alwayslearn

View Public Profile for alwayslearn

Find all posts by alwayslearn

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

System Calls

What does the system call "dup" do? What is the difference between dup and dup2 I have a fair idea of what it does but I am confused when its coming down to the exact details... Please help me!:confused:

2. UNIX for Dummies Questions & Answers

System calls for cp and mv

Which system calls are made for operations cp and mv

3. UNIX for Dummies Questions & Answers

System calls?

open, creat, read, write, lseek and close Are they all primitive? :confused: *Another Question: is there a different between a system call, and an i/o system call?

4. Solaris

System calls ?

where can i find the differences in System calls between solaris and aix? also is it possible to find a comprehensive list of them?

5. UNIX Desktop Questions & Answers

Using system calls

Hi, I'm new to UNIX system calls. Can someone share your knowledge as to how exactly system calls should be executed? Can they be typed like commands such as mkdir on the terminal itself? Also, are there any websites which will show me an example of the output to expect when a system call like...

6. Programming

System calls

why user is not able to switch from user to kernel mode by writing the function whose code is identical to system call.

7. BSD

system calls

what is the functions and relationship between fork,exec,wait system calls as i am a beginer just want the fundamentals.

8. UNIX for Dummies Questions & Answers

About system calls.

Hi all, I am new here . I want to know about system call in detail. As system calls are also function .How system identifies it.:)

9. UNIX for Dummies Questions & Answers

system calls in C

Hello, how would i be able to call ps in C programming? thanks, ---------- Post updated at 01:39 AM ---------- Previous update was at 01:31 AM ---------- here's the complete system call, ps -o pid -p %d, getpit()

10. Shell Programming and Scripting