static struct inode *namex(char *path, int nameiparent, char *name)
{
    struct inode *ip, *next;
    if (*path == '/')
        ip = iget(ROOTDEV, ROOTINO);
    else
        ip = idup(myproc()->cwd);

    while ((path = skipelem(path, name)) != 0)
    {
        ilock(ip);
        if (ip->type != T_DIR)
        {
            iunlockput(ip);
            return 0;
        }

        if (nameiparent == 1 && *path == '\0')
        {
            // Stop one level early.
            iunlock(ip);
            return ip;
        }
        if ((next = dirlookup(ip, name, 0)) == 0)
        {
            iunlockput(ip);
            return 0;
        }
        if(nameiparent == 2 && *path == '\0'){
            iunlockput(ip);
            return next;
        }
        if(ip->mode != M_READ && ip->mode != M_ALL){
            iunlockput(ip);
            return 0;
        }
        iunlockput(ip);
        ilock(next);
        char buf[MAXPATH];
        while(next->type == T_SYMLINK){
            int len = 0;
            readi(next, 0, (uint64)&len, 0, sizeof(int));
            readi(next, 0, (uint64)buf, sizeof(int), len + 1);
            iunlockput(next);
            if((next = namei(buf, 0)) == 0){
                end_op();
                return 0;
            }
            ilock(next);
        }
        iunlock(next);
        ip = next;
    }
    if (nameiparent)
    {
        iput(ip);
        return 0;
    }
    return ip;
}

struct inode *namei(char *path, int trace)
{
    char name[DIRSIZ];
    return namex(path, trace, name);
}

struct inode *nameiparent(char *path, char *name)
{
    return namex(path, 1, name);
}