A test for map

#include <sys/stat.h>
#include <fcntl.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>

int copy_file (const char *in, const char *out)
{
    int copy_ok = 1;
    int fin = open (in, O_RDONLY);
    if (fin == -1) goto ret;
    int fout = open (out, O_WRONLY|O_CREAT|O_TRUNC, DEFFILEMODE);
    if (fout == -1) goto close_in;

#define BLOCK_SIZE 10
    uint8_t buf[BLOCK_SIZE];
    ssize_t bytes_read, bytes_written;
    do
    {
        bytes_read = read (fin, buf, sizeof(buf));
        if (bytes_read < 0) {copy_ok = 0; goto close_out;}
        bytes_written = write (fout, buf, bytes_read);
        if (bytes_written != bytes_read) {copy_ok = 0; goto close_out;}
    }
    while (bytes_read != 0);

close_out:
    close (fout);
close_in: ;
    close (fin);
ret:
    return ((fin != -1) && (fout != -1) && copy_ok) ? 0 : -1;
}

int main ()
{
    int err;
    err = copy_file ("/proc/curproc/map", "map");
    printf ("%i\n", err);
    return 0;
}