Exercise 1-1. sleep

Implement a user-level sleep program for xv6, along the lines of the UNIX sleep command.
Your sleep should pause for a user-specified number of ticks. 
A tick is a notion of time defined by the xv6 kernel, namely the time between two interrupts 
from the timer chip. Your solution should be in the file user/sleep.c.

 

// user/sleep.c

#include "kernel/types.h"
#include "kernel/stat.h"
#include "user/user.h"

int main(int argc, char* argv[]){
    if(argv[1] == 0){
        fprintf(2, "Usage: sleep [Seconds]\n");
        exit(1);
    }

    for(uint i = 0; argv[1][i] != 0; i++){
        if(!(argv[1][i] >= '0' && argv[1][i] <= '9')){
            fprintf(2, "Usage: sleep [Seconds_in_Integer]\n");
            exit(1);
        }
    }
    uint Seconds = atoi(argv[1]);

    sleep(Seconds);

    exit(0);
}