#include <errno.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>


static const char* kRandomDevice = "/dev/urandom";


int
main()
{
        int fd = open(kRandomDevice, O_RDONLY);
        if (fd < 0) {
                fprintf(stderr, "Error: Failed to open \"%s\": %s", kRandomDevice,
                        strerror(errno));
                exit(1);
        }

        uint8_t buffer[16];
        ssize_t bytesRead = read(fd, buffer, sizeof(buffer));
        if (bytesRead < 0) {
                fprintf(stderr, "Error: Failed to read from random device: %s",
                        strerror(errno));
                exit(1);
        }

        printf("Read %d bytes from random device: ", (int)bytesRead);
        for (int i = 0; i < bytesRead; i++)
                printf("%02x", buffer[i]);
        printf("\n");

        return 0;
}