lxc: introduce lxc-kill command (v4)

configure.ac

@@ -95,6 +95,7 @@ AC_CONFIG_FILES([
 	doc/lxc-ls.sgml
 	doc/lxc-ps.sgml
 	doc/lxc-cgroup.sgml
+	doc/lxc-kill.sgml
 	doc/lxc.conf.sgml
 	doc/lxc.sgml
 	doc/common_options.sgml

doc/Makefile.am

@@ -20,6 +20,7 @@ man_MANS = \
 	lxc-ls.1 \
 	lxc-ps.1 \
 	lxc-cgroup.1 \
+	lxc-kill.1 \
 	\
 	lxc.conf.5 \
 	\

doc/lxc-execute.sgml.in

@@ -86,6 +86,12 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
       container, <command>lxc-init</command> has the pid 1 and the
       first process of the application has the pid 2.
      </para>
+     <para>
+      The above <command>lxc-init</command> is designed to forward received
+      signals to the started command.
+      So <command>lxc-kill</command> (1) sent signal is received
+      by the user specified command (pid 2 in the container).
+     </para>
   </refsect1>
 
   <refsect1>

doc/lxc-kill.sgml.in

+<!DOCTYPE refentry PUBLIC "-//Davenport//DTD DocBook V3.0//EN" [
+
+<!ENTITY copyrights SYSTEM "@builddir@/copyrights.sgml">
+<!ENTITY commonoptions SYSTEM "@builddir@/common_options.sgml">
+<!ENTITY seealso SYSTEM "@builddir@/see_also.sgml">
+
+<!ENTITY mcr "<citerefentry>
+<refentrytitle><command>mcr</command></refentrytitle>
+<manvolnum/1/</citerefentry>">
+
+]>
+
+<refentry>
+
+  <docinfo><date>@LXC_GENERATE_DATE@</date></docinfo>
+
+  <refmeta>
+    <refentrytitle>lxc-kill</refentrytitle>
+    <manvolnum>1</manvolnum>
+    <refmiscinfo>IBM</refmiscinfo>
+  </refmeta>
+
+  <refnamediv>
+    <refname>lxc-kill</refname>
+
+    <refpurpose>
+      Send a signal to the process 1 of the container.
+    </refpurpose>
+  </refnamediv>
+
+  <refsynopsisdiv>
+    <cmdsynopsis>
+      <command>lxc-kill --name=<replaceable>NAME</replaceable> <replaceable>SIGNUM</replaceable></command>
+    </cmdsynopsis>
+  </refsynopsisdiv>
+
+  <refsect1>
+    <title>Description</title>
+
+    <para>
+      <command>lxc-kill</command> send
+      the <replaceable>SIGNUM</replaceable> signal to the first process of the container.
+    </para>
+
+    <para>
+	If this command is used on an application container ran by
+	lxc-execute, the lxc-init will receive the signal and will forward it to
+	the process 2 which is the command specified in the command line. See
+	lxc-execute (1).
+    </para>
+  </refsect1>
+
+  &commonoptions;
+
+  <refsect1>
+    <title>Examples</title>
+
+    <para>
+      To send the signal 26 to the process pi1 running in container
+      <literal>123</literal> :
+    </para>
+
+    <programlisting>
+      lxc-execute -n 123 -- pi1 -d 500000
+      lxc-kill --name=123 26
+    </programlisting>
+
+  </refsect1>
+
+  &copyrights;
+
+  &seealso;
+
+</refentry>
+
+<!-- Keep this comment at the end of the file
+Local variables:
+mode: sgml
+sgml-omittag:t
+sgml-shorttag:t
+sgml-minimize-attributes:nil
+sgml-always-quote-attributes:t
+sgml-indent-step:2
+sgml-indent-data:t
+sgml-parent-document:nil
+sgml-default-dtd-file:nil
+sgml-exposed-tags:nil
+sgml-local-catalogs:nil
+sgml-local-ecat-files:nil
+End:
+-->

doc/see_also.sgml.in

@@ -58,6 +58,11 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
       </citerefentry>,
 
       <citerefentry>
+	<refentrytitle><command>lxc-kill</command></refentrytitle>
+	<manvolnum>1</manvolnum>
+      </citerefentry>,
+
+      <citerefentry>
 	<refentrytitle><command>lxc-console</command></refentrytitle>
 	<manvolnum>1</manvolnum>
       </citerefentry>,

src/lxc/Makefile.am

@@ -82,7 +82,8 @@ bin_PROGRAMS = \
 	lxc-cgroup \
 	lxc-unfreeze \
 	lxc-checkpoint \
-	lxc-restart
+	lxc-restart \
+	lxc-kill
 
 libexec_PROGRAMS = \
 	lxc-init
@@ -105,6 +106,7 @@ lxc_stop_SOURCES = lxc_stop.c
 lxc_unfreeze_SOURCES = lxc_unfreeze.c
 lxc_unshare_SOURCES = lxc_unshare.c
 lxc_wait_SOURCES = lxc_wait.c
+lxc_kill_SOURCES = lxc_kill.c
 
 install-exec-local: install-soPROGRAMS
 	mv $(DESTDIR)$(libdir)/liblxc.so $(DESTDIR)$(libdir)/liblxc.so.$(VERSION)

src/lxc/lxc_init.c

@@ -46,12 +46,23 @@ static struct option options[] = {
 	{ 0, 0, 0, 0 },
 };
 
+static	int was_interrupted = 0;
+
 int main(int argc, char *argv[])
 {
+
+	void interrupt_handler(int sig)
+	{
+		if (!was_interrupted)
+			was_interrupted = sig;
+	}
+
 	pid_t pid;
 	int nbargs = 0;
 	int err = -1;
 	char **aargv;
+	sigset_t mask, omask;
+	int i;
 
 	while (1) {
 		int ret = getopt_long_only(argc, argv, "", options, NULL);
@@ -75,6 +86,18 @@ int main(int argc, char *argv[])
 	aargv = &argv[optind];
 	argc -= nbargs;
 
+	sigfillset(&mask);
+	sigprocmask(SIG_SETMASK, &mask, &omask);
+
+	for (i = 1; i < NSIG; i++) {
+		struct sigaction act;
+
+		sigfillset(&act.sa_mask);
+		act.sa_flags = 0;
+		act.sa_handler = interrupt_handler;
+		sigaction(i, &act, NULL);
+	}
+
 	pid = fork();
 	
 	if (pid < 0)
@@ -82,6 +105,10 @@ int main(int argc, char *argv[])
 
 	if (!pid) {
 		
+		for (i = 1; i < NSIG; i++)
+			signal(i, SIG_DFL);
+		sigprocmask(SIG_SETMASK, &omask, NULL);
+
 		if (lxc_setup_fs())
 			exit(err);
 
@@ -92,6 +119,8 @@ int main(int argc, char *argv[])
 		exit(err);
 	}
 
+	sigprocmask(SIG_SETMASK, &omask, NULL);
+
 	/* no need of other inherited fds but stderr */
 	close(fileno(stdin));
 	close(fileno(stdout));
@@ -102,6 +131,11 @@ int main(int argc, char *argv[])
 		int orphan = 0;
 		pid_t waited_pid;
 
+		if (was_interrupted) {
+			kill(pid, was_interrupted);
+			was_interrupted = 0;
+		}
+
 		waited_pid = wait(&status);
 		if (waited_pid < 0) {
 			if (errno == ECHILD)

src/lxc/lxc_kill.c

+/*
+ * lxc: linux Container library
+ *
+ * (C) Copyright IBM Corp. 2007, 2010
+ *
+ * Authors:
+ * Daniel Lezcano <dlezcano at fr.ibm.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <unistd.h>
+#include <errno.h>
+#include <sys/param.h>
+#include <stdlib.h>
+#include <signal.h>
+#include "commands.h"
+#include "arguments.h"
+#include "namespace.h"
+#include "log.h"
+
+lxc_log_define(lxc_kill_ui, lxc);
+
+static const struct option my_longopts[] = {
+	LXC_COMMON_OPTIONS
+};
+
+static struct lxc_arguments my_args = {
+	.progname = "lxc-kill",
+	.help     = "\
+--name=NAME SIGNUM\n\
+\n\
+Sends signal number SIGNUM to the first user process in container NAME\n\
+\n\
+Options :\n\
+  -n, --name=NAME     NAME for name of the container\n",
+	.options  = my_longopts,
+	.parser   = NULL,
+	.checker  = NULL,
+};
+
+int main(int argc, char *argv[], char *envp[])
+{
+	int ret;
+	pid_t pid;
+	int sig;
+
+	ret = lxc_arguments_parse(&my_args, argc, argv);
+	if (ret)
+		return ret;
+
+	ret = lxc_log_init(my_args.log_file, my_args.log_priority,
+			   my_args.progname, my_args.quiet);
+	if (ret)
+		return ret;
+
+	if (my_args.argc) {
+		sig = atoi(my_args.argv[0]);
+		if (!sig || sig >= NSIG) {
+			ERROR("'%s' isn't a valid signal number",
+			      my_args.argv[0]);
+			return -1;
+		}
+	} else
+		sig=SIGKILL;
+
+	pid = get_init_pid(my_args.name);
+	if (pid < 0) {
+		ERROR("failed to get the init pid");
+		return -1;
+	}
+
+	ret = kill(pid, sig);
+	if (ret < 0) {
+		ERROR("failed to kill the init pid");
+		return -1;
+	}
+
+	return 0;
+}