[CRIU] [PATCH 1/2] vzctl: synchronize CRIU with vzctl
Kir Kolyshkin
kir at parallels.com
Fri May 31 14:15:00 EDT 2013
On 05/31/2013 02:56 AM, Andrey Vagin wrote:
> vzctl provides two descriptors signalfd and waitfd, it's used for apply
> host-side configuration after creating environment.
> A signal is send to signalfd after creating environment and an answer is
> recieved from waitfd.
Looks awesome overall. See some notes below.
> Signed-off-by: Andrey Vagin <avagin at openvz.org>
> ---
> scripts/Makefile.am | 3 ++-
> scripts/vps-rst-env.in | 44 ++++++++++++++++++++++++++++++++++++++++++++
> scripts/vps-rst.in | 4 ++++
> src/lib/hooks_ct.c | 33 +++++++++++++++++++++------------
> 4 files changed, 71 insertions(+), 13 deletions(-)
> create mode 100755 scripts/vps-rst-env.in
>
> diff --git a/scripts/Makefile.am b/scripts/Makefile.am
> index 05381f8..e77f19d 100644
> --- a/scripts/Makefile.am
> +++ b/scripts/Makefile.am
> @@ -29,7 +29,8 @@ script_SCRIPTS = \
> vzevent-reboot \
> vps-pci \
> vps-cpt \
> - vps-rst
> + vps-rst \
> + vps-rst-env
>
> EXTRA_DIST = \
> $(script_SCRIPTS:%=%.in)
> diff --git a/scripts/vps-rst-env.in b/scripts/vps-rst-env.in
> new file mode 100755
> index 0000000..a0ec898
> --- /dev/null
> +++ b/scripts/vps-rst-env.in
> @@ -0,0 +1,44 @@
> +#!/bin/sh
> +# Copyright (C) 2013, Parallels, Inc. All rights reserved.
> +#
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 2 of the License, or
> +# (at your option) any later version.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program; if not, write to the Free Software
> +# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
> +#
> +# This script is called by CRIU (http://criu.org) after creating namespaces.
> +#
> +# Parameters are passed in environment variables.
> +# Required parameters:
> +# VZCTL_PID - pid of vzctl
whitespace at EOL
> +# STATUSFD - file descriptor for sending signal to vzctl
> +# WAITFD - file descriptor for receiving signal from vzctl
> +# VE_STATE_FILE - file with PID of container init process
> +# VE_NETNS_FILE - file, which used by ip netns
There's also CRTOOLS_SCRIPT_ACTION which is set by criu.
> +
> +[[ "setup-namespaces" == "$CRTOOLS_SCRIPT_ACTION" ]] || exit 0
bashism
it should be something like
[ "x$CRTOOLS_SCRIPT_ACTION" = "xsetup-namespaces" ] || exit 0
> +
> +exec 1>&2
why?
> +. @SCRIPTDIR@/vps-functions
> +
> +vzcheckvar VZCTL_PID
> +vzcheckvar STATUSFD
> +vzcheckvar WAITFD
> +vzcheckvar VE_NETNS_FILE
> +vzcheckvar VE_STATE_FILE
> +
maybe you should do 'set -e' here, since you are running some commands
below that may fail, and you don't check their exit codes.
> +pid=$(cat $VE_STATE_FILE)
> +ln -sf /proc/$pid/ns/net $VE_NETNS_FILE
> +
> +echo -ne '\0\0\0\0' > /proc/$VZCTL_PID/fd/$STATUSFD
> +ret=$(cat /proc/$VZCTL_PID/fd/$WAITFD | xxd -p -l 4)
Oh well, xxd comes from vim. I doubt we want to have vim as a dependency.
Maybe hexdump -e '"%d"'?
> +[ "$ret" = "00000000" ] && exit 0 || exit 1
You don't have to do that, just
[ "$ret" = "00000000" ]
exit
and "exit" is optional if it's last line of the file.
> diff --git a/scripts/vps-rst.in b/scripts/vps-rst.in
> index 91080b3..7cfe658 100755
> --- a/scripts/vps-rst.in
> +++ b/scripts/vps-rst.in
> @@ -26,6 +26,8 @@
> # VE_DUMP_DIR - directory for saving dump files
> # VE_STATE_FILE - file to write CT init PID to
> # VE_VETH_DEVS - pair of veth names (CT=HW\n)
> +# VE_NS_SCRIPT - script, which will be executed after creating namespaces
1 "script to execute after creating namespaces"
2 Can we just hardcode it to vps-rst-env?
> +#
>
> exec 1>&2
> . @SCRIPTDIR@/vps-functions
> @@ -34,6 +36,7 @@ vzcheckvar VE_ROOT
> vzcheckvar VE_STATE_FILE
> vzcheckvar VE_DUMP_DIR
> vzcheckvar VE_VETH_DEVS
> +vzcheckvar VE_NS_SCRIPT
>
> veth_args=""
> for dev in $VE_VETH_DEVS; do
> @@ -46,6 +49,7 @@ criu restore --file-locks \
> --link-remap \
> --root $VE_ROOT \
> --restore-detached \
> + --action-script $VE_NS_SCRIPT \
> -D $VE_DUMP_DIR \
> -o restore.log \
> -vvvv \
> diff --git a/src/lib/hooks_ct.c b/src/lib/hooks_ct.c
> index 18650e0..bf20779 100644
> --- a/src/lib/hooks_ct.c
> +++ b/src/lib/hooks_ct.c
> @@ -391,6 +391,7 @@ static int ct_env_create_real(struct arg_start *arg)
> int userns_p[2];
> int ret, fd;
> char pidpath[STR_SIZE];
> + char ctpath[STR_SIZE];
>
> stack_size = get_pagesize();
> if (stack_size < 0)
> @@ -478,13 +479,20 @@ static int ct_env_create_real(struct arg_start *arg)
> close(userns_p[1]);
> }
>
> + snprintf(ctpath, STR_SIZE, "%s/%d", NETNS_RUN_DIR, arg->veid);
> + snprintf(pidpath, STR_SIZE, "/proc/%d/ns/net", ret);
> + if (symlink(pidpath, ctpath)) {
> + logger(-1, errno, "Can't symlink into netns file %s", ctpath);
> + destroy_container(arg->veid);
> + return -VZ_RESOURCE_ERROR;
> + }
> +
> return ret;
> }
>
> int ct_env_create(struct arg_start *arg)
> {
> int ret;
> - char procpath[STR_SIZE];
> char ctpath[STR_SIZE];
>
> /* non-fatal */
> @@ -519,14 +527,6 @@ int ct_env_create(struct arg_start *arg)
> if (ret < 0)
> return -ret;
>
> - snprintf(procpath, STR_SIZE, "/proc/%d/ns/net", ret);
> - ret = symlink(procpath, ctpath);
> - if (ret) {
> - logger(-1, errno, "Can't symlink into netns file %s", ctpath);
> - destroy_container(arg->veid);
> - return VZ_RESOURCE_ERROR;
> - }
> -
> return 0;
> }
>
> @@ -924,7 +924,7 @@ static int ct_chkpnt(vps_handler *h, envid_t veid,
> static int ct_restore_fn(vps_handler *h, envid_t veid, const vps_res *res,
> int wait_p, int old_wait_p, int err_p, void *data)
> {
> - char *argv[2], *env[5];
> + char *argv[2], *env[10];
> const char *dumpfile = NULL;
> const char *statefile = NULL;
> cpt_param *param = data;
> @@ -957,8 +957,17 @@ static int ct_restore_fn(vps_handler *h, envid_t veid, const vps_res *res,
> "%s=%s\n", veth->dev_name_ve, veth->dev_name);
> }
> env[3] = strdup(buf);
> -
> - env[4] = NULL;
> + snprintf(buf, sizeof(buf), "VE_NS_SCRIPT=%s", SCRIPTDIR "/vps-rst-env");
> + env[4] = strdup(buf);
> + snprintf(buf, sizeof(buf), "VZCTL_PID=%d", getpid());
> + env[5] = strdup(buf);
> + snprintf(buf, sizeof(buf), "STATUSFD=%d", STDIN_FILENO);
> + env[6] = strdup(buf);
> + snprintf(buf, sizeof(buf), "WAITFD=%d", wait_p);
> + env[7] = strdup(buf);
> + snprintf(buf, sizeof(buf), "VE_NETNS_FILE=%s/%d", NETNS_RUN_DIR, veid);
> + env[8] = strdup(buf);
> + env[9] = NULL;
>
> ret = run_script(argv[0], argv, env, 0);
> free_arg(env);
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