[lxc-devel] [PATCH 2/2] add lxc.haltsignal for soft shutdown

Dwight Engen dwight.engen at oracle.com
Mon Jan 6 16:25:48 UTC 2014


On Mon, 6 Jan 2014 10:05:28 +0000
"bogdan.purcareata at freescale.com" <bogdan.purcareata at freescale.com> wrote:

> > -----Original Message-----
> > From: lxc-devel-bounces at lists.linuxcontainers.org [mailto:lxc-devel-
> > bounces at lists.linuxcontainers.org] On Behalf Of Dwight Engen
> > Sent: Friday, January 03, 2014 9:37 PM
> > To: lxc-devel at lists.linuxcontainers.org
> > Subject: [lxc-devel] [PATCH 2/2] add lxc.haltsignal for soft
> > shutdown
> > 
> > - use this in the busybox template since busybox's init expects
> >   to receive SIGUSR1 to halt
> 
> Just as a FYI, patch [1] makes busybox init respond to SIGPWR as well.

Hi Bogdan, seeing your patch is what reminded me that busybox not
shutting down nicely has been bothering me for a while. Its great that your
change will fix busybox in the future, but I also wanted older busybox
versions to shut down clean now, so that is why I submitted this.

> Best regards,
> Bogdan P.
> 
> [1]
> http://git.busybox.net/busybox/commit/?id=760fc6debcba8cb5ca8d8e2252fac3757c453e11
> 
> > 
> > - fix lxc.stopsignal to be output by write_config so lxcapi_clone()
> >   and lxcapi_save_config() will output it
> > 
> > Signed-off-by: Dwight Engen <dwight.engen at oracle.com>
> > ---
> >  doc/lxc-stop.sgml.in     | 13 ++++++-------
> >  src/lxc/conf.h           |  3 ++-
> >  src/lxc/confile.c        | 28 ++++++++++++++++++++++++++++
> >  src/lxc/lxccontainer.c   |  5 ++++-
> >  templates/lxc-busybox.in |  1 +
> >  5 files changed, 41 insertions(+), 9 deletions(-)
> > 
> > diff --git a/doc/lxc-stop.sgml.in b/doc/lxc-stop.sgml.in
> > index bdb0ef5..dc002c5 100644
> > --- a/doc/lxc-stop.sgml.in
> > +++ b/doc/lxc-stop.sgml.in
> > @@ -65,13 +65,12 @@ Foundation, Inc., 51 Franklin Street, Fifth
> > Floor, Boston, MA 02110-1301 USA
> >      <para>
> >        <command>lxc-stop</command> reboots, cleanly shuts down, or
> > kills all the processes inside the container.  By default, it will
> > -      request a clean shutdown of the container (by sending SIGPWR
> > to
> > -      the container), wait 60 seconds for the container to exit,
> > and
> > -      returns.  If the container fails to cleanly exit, then after
> > 60
> > -      seconds the container will be sent the
> > -      <command>lxc.stopsignal</command> to force it to shut down.
> > If
> > -      <command>lxc.stopsignal</command> is not specified, the
> > signal sent is
> > -      SIGKILL.
> > +      request a clean shutdown of the container by sending
> > +      <command>lxc.haltsignal</command> (defaults to SIGPWR) to
> > +      the container's init process, waiting up to 60 seconds for
> > the container
> > +      to exit, and then returning. If the container fails to
> > cleanly exit in
> > +      60 seconds, it will be sent the
> > <command>lxc.stopsignal</command>
> > +      (defaults to SIGKILL) to force it to shut down.
> >      </para>
> >  	<para>
> >  	The <optional>-W</optional>, <optional>-r</optional>,
> > diff --git a/src/lxc/conf.h b/src/lxc/conf.h
> > index e881635..8efd0f3 100644
> > --- a/src/lxc/conf.h
> > +++ b/src/lxc/conf.h
> > @@ -307,7 +307,8 @@ struct lxc_conf {
> >  #endif
> >  	int maincmd_fd;
> >  	int autodev;  // if 1, mount and fill a /dev at start
> > -	int stopsignal; // signal used to stop container
> > +	int haltsignal; // signal used to halt container
> > +	int stopsignal; // signal used to hard stop container
> >  	int kmsg;  // if 1, create /dev/kmsg symlink
> >  	char *rcfile;	// Copy of the top level rcfile we
> > read
> > 
> > diff --git a/src/lxc/confile.c b/src/lxc/confile.c
> > index 0982b3e..d21fbec 100644
> > --- a/src/lxc/confile.c
> > +++ b/src/lxc/confile.c
> > @@ -90,6 +90,7 @@ static int config_seccomp(const char *, const
> > char *, struct lxc_conf *);
> >  static int config_includefile(const char *, const char *, struct
> > lxc_conf *); static int config_network_nic(const char *, const char
> > *, struct lxc_conf *); static int config_autodev(const char *,
> > const char *, struct lxc_conf *); +static int
> > config_haltsignal(const char *, const char *, struct lxc_conf *);
> > static int config_stopsignal(const char *, const char *, struct
> > lxc_conf *); static int config_start(const char *, const char *,
> > struct lxc_conf *); static int config_group(const char *, const
> > char *, struct lxc_conf *); @@ -142,6 +143,7 @@ static struct
> > lxc_config_t config[] = { { "lxc.seccomp",
> > config_seccomp              }, { "lxc.include",
> > config_includefile          }, { "lxc.autodev",
> > config_autodev              },
> > +	{ "lxc.haltsignal",
> > config_haltsignal           }, { "lxc.stopsignal",
> > config_stopsignal           }, { "lxc.start.auto",
> > config_start                }, { "lxc.start.delay",
> > config_start                }, @@ -1108,6 +1110,16 @@ static int
> > rt_sig_num(const char *signame) return sig_n;
> >  }
> > 
> > +static const char *sig_name(int signum) {
> > +	int n;
> > +
> > +	for (n = 0; n < sizeof(signames) / sizeof((signames)[0]);
> > n++) {
> > +		if (n == signames[n].num)
> > +			return signames[n].name;
> > +	}
> > +	return "";
> > +}
> > +
> >  static int sig_parse(const char *signame) {
> >  	int n;
> > 
> > @@ -1125,6 +1137,18 @@ static int sig_parse(const char *signame) {
> >  	return -1;
> >  }
> > 
> > +static int config_haltsignal(const char *key, const char *value,
> > +			     struct lxc_conf *lxc_conf)
> > +{
> > +	int sig_n = sig_parse(value);
> > +
> > +	if (sig_n < 0)
> > +		return -1;
> > +	lxc_conf->haltsignal = sig_n;
> > +
> > +	return 0;
> > +}
> > +
> >  static int config_stopsignal(const char *key, const char *value,
> >  			  struct lxc_conf *lxc_conf)
> >  {
> > @@ -2119,6 +2143,10 @@ void write_config(FILE *fout, struct
> > lxc_conf *c) fprintf(fout, "lxc.pts = %d\n", c->pts);
> >  	if (c->ttydir)
> >  		fprintf(fout, "lxc.devttydir = %s\n", c->ttydir);
> > +	if (c->haltsignal)
> > +		fprintf(fout, "lxc.haltsignal = SIG%s\n",
> > sig_name(c-
> > >haltsignal));
> > +	if (c->stopsignal)
> > +		fprintf(fout, "lxc.stopsignal = SIG%s\n",
> > sig_name(c-
> > >stopsignal));
> >  	#if HAVE_SYS_PERSONALITY_H
> >  	switch(c->personality) {
> >  	case PER_LINUX32: fprintf(fout, "lxc.arch = x86\n"); break;
> > diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
> > index 75f6ce3..e066b16 100644
> > --- a/src/lxc/lxccontainer.c
> > +++ b/src/lxc/lxccontainer.c
> > @@ -1310,6 +1310,7 @@ static bool lxcapi_shutdown(struct
> > lxc_container *c, int timeout)
> >  {
> >  	bool retv;
> >  	pid_t pid;
> > +	int haltsignal = SIGPWR;
> > 
> >  	if (!c)
> >  		return false;
> > @@ -1321,7 +1322,9 @@ static bool lxcapi_shutdown(struct
> > lxc_container *c, int timeout)
> >  	pid = c->init_pid(c);
> >  	if (pid <= 0)
> >  		return true;
> > -	kill(pid, SIGPWR);
> > +	if (c->lxc_conf->haltsignal)
> > +		haltsignal = c->lxc_conf->haltsignal;
> > +	kill(pid, haltsignal);
> >  	retv = c->wait(c, "STOPPED", timeout);
> >  	if (!retv && timeout > 0) {
> >  		c->stop(c);
> > diff --git a/templates/lxc-busybox.in b/templates/lxc-busybox.in
> > index 8232334..974377d 100644
> > --- a/templates/lxc-busybox.in
> > +++ b/templates/lxc-busybox.in
> > @@ -272,6 +272,7 @@ copy_configuration()
> > 
> >  grep -q "^lxc.rootfs" $path/config 2>/dev/null || echo "lxc.rootfs
> > = $rootfs"
> > >> $path/config
> >  cat <<EOF >> $path/config
> > +lxc.haltsignal = SIGUSR1
> >  lxc.utsname = $name
> >  lxc.tty = 1
> >  lxc.pts = 1
> > --
> > 1.8.3.1
> > 
> > _______________________________________________
> > lxc-devel mailing list
> > lxc-devel at lists.linuxcontainers.org
> > http://lists.linuxcontainers.org/listinfo/lxc-devel
> > 
> 
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