Assignment 4 - Problem 2

problem2.c

#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <time.h>
#include <sys/time.h>

int main(int argc, char **argv) {
    char *file;
    char buffer[4096];
    int ffd, rc, i, j;
    char answer = 'n';
    
    if(argc < 2) {
        printf("%s file\n\tPrints file if you have access to it\n", argv[0]);
        exit(1);
    }
    
    file = argv[1];
    
    if(access(argv[1], R_OK) == 0) {
        printf("Do you really want to open [%s]? ", argv[1]);
        scanf(" %c", &answer);
        if(answer != 'y') {
            exit(1);
        }
        
        ffd = open(file, O_RDONLY);
        if(ffd == -1) {
            printf("Unable to open file\n");
            exit(EXIT_FAILURE);
        }
        
        rc = read(ffd, buffer, sizeof(buffer));
        if(rc == -1) {
            printf("Unable to read from file: %s\n", strerror(errno));
            exit(EXIT_FAILURE);
        }
        
        printf("%s\n", buffer);
    } else {
        printf("You don't have access to %s\n", file);
    }
}

This code snippet is based on Sam Bowne's lab on Race Conditions.