[lxc-devel] [PATCH/RFC] Add lxc.stopsignal config option
Serge Hallyn
serge.hallyn at ubuntu.com
Tue Mar 12 13:37:55 UTC 2013
Quoting Alexander Vladimirov (alexander.idkfa.vladimirov at gmail.com):
> I remember discussion about implementing proper way to shutdown
> guests using different signals, so here's a patch proposal.
> It allows to use specific signal numbers to shutdown guests
> gracefully, for example SIGRTMIN+4 starts poweroff.target in
> systemd.
> Signed-off-by: Alexander Vladimirov <alexander.idkfa.vladimirov at gmail.com>
Looks good to me.
Acked-by: Serge E. Hallyn <serge.hallyn at ubuntu.com>
> ---
> doc/lxc.conf.sgml.in | 23 ++++++++++++++
> src/lxc/conf.h | 1 +
> src/lxc/confile.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> src/lxc/stop.c | 6 +++-
> 4 files changed, 119 insertions(+), 1 deletion(-)
>
> diff --git a/doc/lxc.conf.sgml.in b/doc/lxc.conf.sgml.in
> index ae91221..8ff1f20 100644
> --- a/doc/lxc.conf.sgml.in
> +++ b/doc/lxc.conf.sgml.in
> @@ -130,6 +130,29 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
> </refsect2>
>
> <refsect2>
> + <title>Stop signal</title>
> + <para>
> + Allows to specify signal name or number, sent by lxc-stop to
> + shutdown the container. Different init systems could use
> + different signals to perform clean shutdown sequence. Option
> + allows signal to be specified in kill(1) fashion, e.g.
> + SIGKILL, SIGRTMIN+14, SIGRTMAX-10 or plain number.
> + </para>
> + <variablelist>
> + <varlistentry>
> + <term>
> + <option>lxc.stopsignal</option>
> + </term>
> + <listitem>
> + <para>
> + specify the signal used to stop the container
> + </para>
> + </listitem>
> + </varlistentry>
> + </variablelist>
> + </refsect2>
> +
> + <refsect2>
> <title>Network</title>
> <para>
> The network section defines how the network is virtualized in
> diff --git a/src/lxc/conf.h b/src/lxc/conf.h
> index f20fb2f..61456ae 100644
> --- a/src/lxc/conf.h
> +++ b/src/lxc/conf.h
> @@ -277,6 +277,7 @@ 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
> char *rcfile; // Copy of the top level rcfile we read
> };
>
> diff --git a/src/lxc/confile.c b/src/lxc/confile.c
> index d350f01..8dbe83d 100644
> --- a/src/lxc/confile.c
> +++ b/src/lxc/confile.c
> @@ -27,6 +27,8 @@
> #include <unistd.h>
> #include <errno.h>
> #include <fcntl.h>
> +#include <ctype.h>
> +#include <signal.h>
> #include <sys/stat.h>
> #include <sys/types.h>
> #include <sys/param.h>
> @@ -87,6 +89,7 @@ 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_stopsignal(const char *, const char *, struct lxc_conf *);
>
> static struct lxc_config_t config[] = {
>
> @@ -134,6 +137,34 @@ static struct lxc_config_t config[] = {
> { "lxc.seccomp", config_seccomp },
> { "lxc.include", config_includefile },
> { "lxc.autodev", config_autodev },
> + { "lxc.stopsignal", config_stopsignal },
> +};
> +
> +struct signame {
> + int num;
> + char *name;
> +};
> +
> +struct signame signames[] = {
> + { SIGHUP, "HUP" },
> + { SIGINT, "INT" },
> + { SIGQUIT, "QUIT" },
> + { SIGILL, "ILL" },
> + { SIGABRT, "ABRT" },
> + { SIGFPE, "FPE" },
> + { SIGKILL, "KILL" },
> + { SIGSEGV, "SEGV" },
> + { SIGPIPE, "PIPE" },
> + { SIGALRM, "ALRM" },
> + { SIGTERM, "TERM" },
> + { SIGUSR1, "USR1" },
> + { SIGUSR2, "USR2" },
> + { SIGCHLD, "CHLD" },
> + { SIGCONT, "CONT" },
> + { SIGSTOP, "STOP" },
> + { SIGTSTP, "TSTP" },
> + { SIGTTIN, "TTIN" },
> + { SIGTTOU, "TTOU" },
> };
>
> static const size_t config_size = sizeof(config)/sizeof(struct lxc_config_t);
> @@ -959,6 +990,65 @@ static int config_autodev(const char *key, const char *value,
> return 0;
> }
>
> +static int sig_num(const char *sig)
> +{
> + int n;
> + char *endp = NULL;
> +
> + errno = 0;
> + n = strtol(sig, &endp, 10);
> + if (sig == endp || n < 0 || errno != 0)
> + return -1;
> + return n;
> +}
> +
> +static int rt_sig_num(const char *signame)
> +{
> + int sig_n = 0;
> + int rtmax = 0;
> +
> + if (strncasecmp(signame, "max-", 4) == 0) {
> + rtmax = 1;
> + }
> + signame += 4;
> + if (!isdigit(*signame))
> + return -1;
> + sig_n = sig_num(signame);
> + sig_n = rtmax ? SIGRTMAX - sig_n : SIGRTMIN + sig_n;
> + if (sig_n > SIGRTMAX || sig_n < SIGRTMIN)
> + return -1;
> + return sig_n;
> +}
> +
> +static int sig_parse(const char *signame) {
> + int n;
> +
> + if (isdigit(*signame)) {
> + return sig_num(signame);
> + } else if (strncasecmp(signame, "sig", 3) == 0) {
> + signame += 3;
> + if (strncasecmp(signame, "rt", 2) == 0)
> + return rt_sig_num(signame + 2);
> + for (n = 0; n < sizeof(signames) / sizeof((signames)[0]); n++) {
> + if (strcasecmp (signames[n].name, signame) == 0)
> + return signames[n].num;
> + }
> + }
> + return -1;
> +}
> +
> +static int config_stopsignal(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->stopsignal = sig_n;
> +
> + return 0;
> +}
> +
> static int config_cgroup(const char *key, const char *value,
> struct lxc_conf *lxc_conf)
> {
> diff --git a/src/lxc/stop.c b/src/lxc/stop.c
> index 851a4bf..7fea6b6 100644
> --- a/src/lxc/stop.c
> +++ b/src/lxc/stop.c
> @@ -34,6 +34,7 @@
>
> #include <lxc/log.h>
> #include <lxc/start.h>
> +#include <lxc/conf.h>
>
> #include "lxc.h"
> #include "commands.h"
> @@ -82,9 +83,12 @@ extern int lxc_stop_callback(int fd, struct lxc_request *request,
> {
> struct lxc_answer answer;
> int ret;
> + int stopsignal = SIGKILL;
>
> + if (handler->conf->stopsignal)
> + stopsignal = handler->conf->stopsignal;
> memset(&answer, 0, sizeof(answer));
> - answer.ret = kill(handler->pid, SIGKILL);
> + answer.ret = kill(handler->pid, stopsignal);
> if (!answer.ret) {
> ret = lxc_unfreeze_bypath(handler->cgroup);
> if (!ret)
> --
> 1.8.1.5
>
>
> ------------------------------------------------------------------------------
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