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Re: [Qemu-devel] [RFC 2/5] block: add new command line parameter that an
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] [RFC 2/5] block: add new command line parameter that and protocol description |
Date: |
Wed, 2 May 2012 10:03:56 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Tue, May 01, 2012 at 04:31:44PM +0100, Stefan Hajnoczi wrote:
> From: Anthony Liguori <address@hidden>
>
> Signed-off-by: Anthony Liguori <address@hidden>
> Signed-off-by: Stefan Hajnoczi <address@hidden>
> ---
> qemu-options.hx | 42 ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 42 insertions(+)
>
> diff --git a/qemu-options.hx b/qemu-options.hx
> index a169792..ccf4d1d 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -2724,6 +2724,48 @@ DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log,
> "-qtest-log LOG specify tracing options\n",
> QEMU_ARCH_ALL)
>
> +DEF("open-hook-fd", HAS_ARG, QEMU_OPTION_open_hook_fd,
> + "-open-hook-fd <fd>\n"
> + " delegate opens to external process using <fd>\n",
> QEMU_ARCH_ALL)
> +STEXI
> address@hidden -open-hook-fd @var{fd}
> address@hidden -open-hook-fd
> +Delegates open()s to an external process using @var<fd> to communicate
> commands.
> address@hidden<fd> should be an open Unix Domain socket pipe that file
> descriptors can be
> +received from. The protocol the socket uses is a simple request/response
> initiated
> +by the client. All integers are in host byte order. It is assumed that
> this protocol
> +is only ever used on the same physical machine. It is currently defined as:
> +
> +u32 message_size
> +u32 command
> +u8 payload[message_size - 8]
> +
> +The contents of payload depend on command. Currently the following commands
> are
> +defined:
> +
> +1. QEMU_OPEN (1)
> +
> +The full message will be:
> +
> +u32 message_size
> +u32 command = 1
> +u32 flags (O_ flags defined by libc)
> +u32 mode (mode_t flags as defined by libc)
> +u16 filename_len;
> +u8 filename[filename_len]
I think this should include the ID of the backend of the drive wanting
this file opened, so you can reliably match up to the -drive that mgmt
configured at startup. ie not have to search through every single
device in the guest & all their backing files to find if there is a
match.
Regards,
Daniel
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- [Qemu-devel] [RFC 0/5] block: File descriptor passing using -open-hook-fd, Stefan Hajnoczi, 2012/05/01
- [Qemu-devel] [RFC 2/5] block: add new command line parameter that and protocol description, Stefan Hajnoczi, 2012/05/01
- [Qemu-devel] [RFC 3/5] block: plumb up open-hook-fd option, Stefan Hajnoczi, 2012/05/01
- [Qemu-devel] [RFC 4/5] osdep: add qemu_recvmsg() wrapper, Stefan Hajnoczi, 2012/05/01
- [Qemu-devel] [RFC 1/5] block: add open() wrapper that can be hooked by libvirt, Stefan Hajnoczi, 2012/05/01
- [Qemu-devel] [RFC 5/5] Example -open-hook-fd server, Stefan Hajnoczi, 2012/05/01
- Re: [Qemu-devel] [RFC 0/5] block: File descriptor passing using -open-hook-fd, Anthony Liguori, 2012/05/01