deadly_bug1.c

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>

#define BUFFER_SIZE 400

#define     true    1
#define     false   0

char isFileExist(char *filename){
    if(access(filename, F_OK) != -1){
        return true;
    }
    else{
        return false;
    }
}

int main(int argc, char *argv[]){
    // first part of file command
    char *sys_cmd1 = "cat ";
    // second part of file command
    char *sys_cmd2 = " | ./kernel/kernel 1";

    int sys_cmd1_len = strlen(sys_cmd1);
    int sys_cmd2_len = strlen(sys_cmd2);
    

    if (argc == 2)
    {   
        int arg_len = strlen(argv[1]);
        int buffer_length = sys_cmd1_len + sys_cmd2_len + arg_len + 1;

        char buffer[buffer_length];

       
        if(isFileExist(argv[1]) != true){
            printf("No such file\n");
            return EXIT_FAILURE;
        }

        strcpy(buffer, sys_cmd1);
        strcat(buffer, argv[1]);
        strcat(buffer, sys_cmd2);

        system(buffer);
    }
    else{
      return EXIT_FAILURE;
    }

    return EXIT_SUCCESS;
}