Re: [PATCH] Devnode: Fix the pseudo-master device port opening flags.

[Da Zheng]

Sergiu Ivanov wrote:
> * devnode/devnode.c (parse_opt): Open the pseudo-master
> devide port with O_READ | O_WRITE flags to allow subsequent
> device creation.
> ---
> 
> Hello,
> 
> Originally, devnode would open the pseudo-master device port with 0
> flags.  These flags are stored by eth-multiplexer in the peropen
> structure and the subsequent attempt to create a virtual device should
> provide flags forming a subset of the flags stored in the peropen.
> Obviously, if the pseudo-master device port is opened with 0 flags, no
> further meaningful virtual device creation is possible.  This patch
> fixes this problem.
> 
> Regards,
> Sergiu
> 
> ---
>  devnode/devnode.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/devnode/devnode.c b/devnode/devnode.c
> index 55fd8d9..8819252 100644
> --- a/devnode/devnode.c
> +++ b/devnode/devnode.c
> @@ -275,7 +275,7 @@ parse_opt (int opt, char *arg, struct argp_state *state)
>    switch (opt)
>      {
>      case 'M':
> -      master_device = file_name_lookup (arg, 0, 0);
> +      master_device = file_name_lookup (arg, O_READ | O_WRITE, 0);
>        if (master_device == MACH_PORT_NULL)
>       error (1, errno, "file_name_lookup");
>        break;

What happens if .MASTER file is read-only?
Certainly, file_name_lookup in devnode fails. But the questions is: can .MASTER 
node be read-only?

Zheng Da