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Re: [Qemu-devel] [PATCH 06/17] migration-local: add send_pipefd()
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] [PATCH 06/17] migration-local: add send_pipefd() |
Date: |
Fri, 29 Nov 2013 11:14:27 +0000 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Fri, Nov 29, 2013 at 06:06:13PM +0800, Lei Li wrote:
> This patch adds send_pipefd() to pass the pipe file descriptor
> to destination process.
>
> Signed-off-by: Lei Li <address@hidden>
> ---
> migration-local.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 46 insertions(+), 0 deletions(-)
>
> diff --git a/migration-local.c b/migration-local.c
> index 929ed60..f479530 100644
> --- a/migration-local.c
> +++ b/migration-local.c
> @@ -167,3 +167,49 @@ fail:
> g_free(s);
> return NULL;
> }
> +
> +
> +/*
> + * Pass a pipe file descriptor to another process.
> + *
> + * Return negative value If pipefd < 0. Return 0 on
> + * success.
> + *
> + */
> +static int send_pipefd(int sockfd, int pipefd)
> +{
> + struct msghdr msg;
> + struct iovec iov[1];
> + ssize_t ret;
> + char req[1] = { 0x01 };
> +
> + union {
> + struct cmsghdr cm;
> + char control[CMSG_SPACE(sizeof(int))];
> + } control_un;
> + struct cmsghdr *cmptr;
> +
> + msg.msg_control = control_un.control;
> + msg.msg_controllen = sizeof(control_un.control);
> +
> + cmptr = CMSG_FIRSTHDR(&msg);
> + cmptr->cmsg_len = CMSG_LEN(sizeof(int));
> + cmptr->cmsg_level = SOL_SOCKET;
> + cmptr->cmsg_type = SCM_RIGHTS;
> + *((int *) CMSG_DATA(cmptr)) = pipefd;
> +
> + msg.msg_name = NULL;
> + msg.msg_namelen = 0;
> +
> + iov[0].iov_base = req;
> + iov[0].iov_len = sizeof(req);
> + msg.msg_iov = iov;
> + msg.msg_iovlen = 1;
> +
> + ret = sendmsg(sockfd, &msg, 0);
> + if (ret <= 0) {
> + DPRINTF("sendmsg error: %s\n", strerror(errno));
> + }
> +
> + return ret;
> +}
There are already two copies of this function in QEMU, not to mention
several copies of code for receving FDs.
Rather than adding yet more copies of this functionality it would be
much better to add 2 methods to util/qemu-sockets.{c,h} for sending
and receiving file descriptors and update all existing code to use
them.
Daniel
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- [Qemu-devel] [PATCH 0/17 v4] Localhost migration with side channel for ram, Lei Li, 2013/11/29
- [Qemu-devel] [PATCH 01/17] QAPI: introduce migration capability unix_page_flipping, Lei Li, 2013/11/29
- [Qemu-devel] [PATCH 03/17] qmp-command.hx: add missing docs for migration capabilites, Lei Li, 2013/11/29
- [Qemu-devel] [PATCH 02/17] migration: add migrate_unix_page_flipping(), Lei Li, 2013/11/29
- [Qemu-devel] [PATCH 04/17] migration-local: add QEMUFileLocal with socket based QEMUFile, Lei Li, 2013/11/29
- [Qemu-devel] [PATCH 05/17] migration-local: introduce qemu_fopen_socket_local(), Lei Li, 2013/11/29
- [Qemu-devel] [PATCH 06/17] migration-local: add send_pipefd(), Lei Li, 2013/11/29
- Re: [Qemu-devel] [PATCH 06/17] migration-local: add send_pipefd(),
Daniel P. Berrange <=
- [Qemu-devel] [PATCH 07/17] save_page: replace block_offset with a MemoryRegion, Lei Li, 2013/11/29
- [Qemu-devel] [PATCH 08/17] migration-local: override save_page for page transmit, Lei Li, 2013/11/29
- [Qemu-devel] [PATCH 09/17] savevm: adjust ram_control_save_page for page flipping, Lei Li, 2013/11/29
- [Qemu-devel] [PATCH 10/17] add unix_msgfd_lookup() to callback get_buffer, Lei Li, 2013/11/29
- [Qemu-devel] [PATCH 11/17] add argument ram_addr_t to hook_ram_load, Lei Li, 2013/11/29
- [Qemu-devel] [PATCH 12/17] migration-local: override hook_ram_load, Lei Li, 2013/11/29
- [Qemu-devel] [PATCH 13/17] migration-unix: replace qemu_fopen_socket with qemu_fopen_socket_local, Lei Li, 2013/11/29
- [Qemu-devel] [PATCH 14/17] add new RanState RAN_STATE_MEMORY_STALE, Lei Li, 2013/11/29
- [Qemu-devel] [PATCH 15/17] migration-unix: page flipping support on unix outgoing, Lei Li, 2013/11/29
- [Qemu-devel] [PATCH 16/17] migration: adjust migration_thread() process for page flipping, Lei Li, 2013/11/29