[uml-devel] Hostfs doesn't work - digging the kernel

[<alnsn@yandex.ru>]

[-- Attachment #1: Type: text/plain, Size: 1052 bytes --]

Hi,
I'm trying to mount hostfs from inside my tiny uml. Host linux is RH9
with linux-2.6.6 and linux-2.4.26 vanilla kernels. UML patch is
2.4.26-1.
Mounting with no -o option results in UML kernel panic because
mount_arg argument is NULL in this case:

char *host_root_filename(char *mount_arg)
{   
    char *root = DEFAULT_ROOT;

    if((mount_arg != NULL) && (*mount_arg != '\0'))
        root = mount_arg;

    return(uml_strdup(mount_arg));
}

Returning uml_strdup(NULL) causes this panic to happen.
Correct behavior, I think, is return uml_strdup(root).

Even with -o option I can't mount. Function hostfs_init_file composes a
path beginning with jail_dir (/ in my case), then go mount and file.
    const char *path[] = { jail_dir, mount, file, NULL };
In my case path is either // or //tmp. The open64 function can't open both.
If I do these transformations:
"//" -> ""
"//tmp" -> "/tmp"
they are mounted but I can't read files.
I suggest always transform path like this. What do you think?
-- 
Alexander Nasonov

[-- Attachment #2: Type: application/pgp-signature, Size: 189 bytes --]