/* These replace the system command cp and mv without doing a system command */
/* If the file is on a different filesystem, it will do a copy, then unlink */
/* Returns 0 on success and -1 on failure */

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

#define BUFSIZE 8192

int FileCopy (const char *source, const char *dest)
{
    char buf[BUFSIZE];
    int f, t, k, mode, perm;
    struct stat statbuf;

    if ((f = open(source, O_RDONLY, 0)) < 0)
        return(-1);
    fstat (f, &statbuf);
    perm = statbuf.st_mode;
    mode = O_CREAT | O_WRONLY | O_TRUNC;
    if ((t = open(dest, mode, perm)) < 0) {
        close(f);
        return(-1);
    }
    while ((k = read(f, buf, BUFSIZE)) > 0 && write(t, buf, k) == k);
    close(f);
    close(t);
    if (k != 0) {
        return(-1);
    }
    return(0);
}

int FileMove (const char *source, const char *dest)
{
    int status;

    status = rename (source, dest);
    if ((status == -1) && (errno = EXDEV)) {
        if ((status = FileCopy (source, dest)) == 0) unlink (source);
            else return (-1);
    }
    return (status);
}