<div dir="ltr">Hey Dwight,<div><br></div><div>This sounds great, I'll give it a try ASAP. In the meantime ,if you want to test it yourself, you can grab go bindings from github via "go get <a href="http://github.com/caglar10ur/lxc">github.com/caglar10ur/lxc</a>" but please keep in your mind that you need my other two patches to start/stop work reliably [1]/[2]. <a href="https://github.com/caglar10ur/lxc/tree/master/examples">https://github.com/caglar10ur/lxc/tree/master/examples</a> directory contains concurrent versions of create/start/stop/shutdown to test.</div>
<div><br></div><div>[1] <a href="https://github.com/caglar10ur/lxc-upstream/commit/db60b9c38083e8ed553f3cbdd96ad410bd5eb7ed.patch">https://github.com/caglar10ur/lxc-upstream/commit/db60b9c38083e8ed553f3cbdd96ad410bd5eb7ed.patch</a></div>
<div>[2] <a href="https://github.com/caglar10ur/lxc-upstream/commit/97d4daf4cc5016bcb01c72e5cf9fe3189e9df4f5.patch">https://github.com/caglar10ur/lxc-upstream/commit/97d4daf4cc5016bcb01c72e5cf9fe3189e9df4f5.patch</a></div>
<div><br></div><div style>Cheers,</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Apr 18, 2013 at 2:09 PM, Dwight Engen <span dir="ltr"><<a href="mailto:dwight.engen@oracle.com" target="_blank">dwight.engen@oracle.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">After the recent discussions on the lxc monitor, I took a closer look at<br>
it. It seems like Serge was resigned to having some sort of daemon as<br>
having multicast unix domain supported by the kernel is not going to<br>
happen any time soon, and doing it over loopback has some<br>
complications too.<br>
<br>
Initially I thought it would be nice to just have lxc-start "be the<br>
daemon" as Stéphane had suggested. I tried this out, putting the fds<br>
for the consumer clients (lxc-monitors) in lxc_mainloop , but this is<br>
problematic for the scenario where lxc-monitor runs first and we miss<br>
some startup states.<br>
<br>
So here is what I'm proposing: when lxc-monitor starts, it attempts to<br>
start lxc-monitord. lxc-monitord creates a fifo and a socket on lxcpath.<br>
<br>
Producers (containers) wishing to send messages open the fifo and<br>
write their lxc_msg's on it. The reason I used a fifo is so that we get<br>
permission checks on the opening of it. Right now it is created 0600.<br>
This fixes the problem we have today where anyone can open the unix<br>
socket and send state changes in.<br>
<br>
Consumers (lxc-monitor) connect to the unix socket and each gets a copy<br>
of the messages. lxc-monitord can do a PEERCRED to ensure the client<br>
should be able to get these messages, this is one benefit to using unix<br>
domain. I don't think it would be difficult to write a lxc-monitor<br>
like client that would bridge the messages onto d-bus.<br>
<br>
When lxc-monitord hasn't had a client for 30 seconds it will exit.<br>
<br>
Attached is a proof of concept patch for your comments. It works for<br>
the common cases that I've tried but I know it needs some cleanup and<br>
testing if we like the approach. The monitor.c part is hard to read<br>
because that file is mostly rewritten.<br>
<br>
I need to test S.Çağlar Onur's scenario of parallel startup with his<br>
test script. We need to decide if we want to monitor per lxcpath or per<br>
container, today it is per path and I think that being able to do<br>
lxc-monitor * would be very useful.<br>
<br>
--<br>
<br>
Signed-off-by: Dwight Engen <<a href="mailto:dwight.engen@oracle.com">dwight.engen@oracle.com</a>><br>
---<br>
src/lxc/Makefile.am | 2 +<br>
src/lxc/af_unix.c | 5 +-<br>
src/lxc/lxc_monitor.c | 2 +<br>
src/lxc/lxc_monitord.c | 334 +++++++++++++++++++++++++++++++++++++++++++++++++<br>
src/lxc/mainloop.c | 11 +-<br>
src/lxc/mainloop.h | 7 ++<br>
src/lxc/monitor.c | 180 ++++++++++++++++----------<br>
src/lxc/monitor.h | 11 +-<br>
src/lxc/start.c | 7 +-<br>
9 files changed, 484 insertions(+), 75 deletions(-)<br>
create mode 100644 src/lxc/lxc_monitord.c<br>
<br>
diff --git a/src/lxc/Makefile.am b/src/lxc/Makefile.am<br>
index ebeca466..1fa0fa8 100644<br>
--- a/src/lxc/Makefile.am<br>
+++ b/src/lxc/Makefile.am<br>
@@ -150,6 +150,7 @@ bin_PROGRAMS = \<br>
lxc-start \<br>
lxc-execute \<br>
lxc-monitor \<br>
+ lxc-monitord \<br>
lxc-wait \<br>
lxc-console \<br>
lxc-freeze \<br>
@@ -181,6 +182,7 @@ lxc_freeze_SOURCES = lxc_freeze.c<br>
lxc_info_SOURCES = lxc_info.c<br>
lxc_init_SOURCES = lxc_init.c<br>
lxc_monitor_SOURCES = lxc_monitor.c<br>
+lxc_monitord_SOURCES = lxc_monitord.c<br>
lxc_restart_SOURCES = lxc_restart.c<br>
lxc_start_SOURCES = lxc_start.c<br>
lxc_stop_SOURCES = lxc_stop.c<br>
diff --git a/src/lxc/af_unix.c b/src/lxc/af_unix.c<br>
index eff13d4..ceef340 100644<br>
--- a/src/lxc/af_unix.c<br>
+++ b/src/lxc/af_unix.c<br>
@@ -52,6 +52,7 @@ int lxc_af_unix_open(const char *path, int type, int flags)<br>
<br>
addr.sun_family = AF_UNIX;<br>
/* copy entire buffer in case of abstract socket */<br>
+ /* FIXME: this is unsafe if path is too long... */<br>
memcpy(addr.sun_path, path,<br>
path[0]?strlen(path):sizeof(addr.sun_path));<br>
<br>
@@ -61,7 +62,7 @@ int lxc_af_unix_open(const char *path, int type, int flags)<br>
errno = tmp;<br>
return -1;<br>
}<br>
-<br>
+<br>
if (type == SOCK_STREAM && listen(fd, 100)) {<br>
int tmp = errno;<br>
close(fd);<br>
@@ -76,7 +77,7 @@ int lxc_af_unix_close(int fd)<br>
{<br>
struct sockaddr_un addr;<br>
socklen_t addrlen = sizeof(addr);<br>
-<br>
+<br>
if (!getsockname(fd, (struct sockaddr *)&addr, &addrlen) &&<br>
addr.sun_path[0])<br>
unlink(addr.sun_path);<br>
diff --git a/src/lxc/lxc_monitor.c b/src/lxc/lxc_monitor.c<br>
index 8c15869..0ca829f 100644<br>
--- a/src/lxc/lxc_monitor.c<br>
+++ b/src/lxc/lxc_monitor.c<br>
@@ -87,6 +87,8 @@ int main(int argc, char *argv[])<br>
return -1;<br>
}<br>
<br>
+ lxc_monitord_spawn(my_args.lxcpath);<br>
+<br>
fd = lxc_monitor_open(my_args.lxcpath);<br>
if (fd < 0)<br>
return -1;<br>
diff --git a/src/lxc/lxc_monitord.c b/src/lxc/lxc_monitord.c<br>
new file mode 100644<br>
index 0000000..3e9c708<br>
--- /dev/null<br>
+++ b/src/lxc/lxc_monitord.c<br>
@@ -0,0 +1,334 @@<br>
+/*<br>
+ * lxc: linux Container library<br>
+ *<br>
+ * Copyright © 2012 Oracle.<br>
+ *<br>
+ * Authors:<br>
+ * Dwight Engen <<a href="mailto:dwight.engen@oracle.com">dwight.engen@oracle.com</a>><br>
+ *<br>
+ * This library is free software; you can redistribute it and/or<br>
+ * modify it under the terms of the GNU Lesser General Public<br>
+ * License as published by the Free Software Foundation; either<br>
+ * version 2.1 of the License, or (at your option) any later version.<br>
+ *<br>
+ * This library is distributed in the hope that it will be useful,<br>
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of<br>
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU<br>
+ * Lesser General Public License for more details.<br>
+ *<br>
+ * You should have received a copy of the GNU Lesser General Public<br>
+ * License along with this library; if not, write to the Free Software<br>
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA<br>
+ */<br>
+<br>
+#define _GNU_SOURCE<br>
+#include <stdio.h><br>
+#include <signal.h><br>
+#include <errno.h><br>
+#include <unistd.h><br>
+#include <string.h><br>
+#include <stdlib.h><br>
+#include <fcntl.h><br>
+#include <sys/types.h><br>
+#include <sys/stat.h><br>
+#include <sys/param.h><br>
+#include <sys/socket.h><br>
+#include <sys/un.h><br>
+#include <netinet/in.h><br>
+#include <net/if.h><br>
+<br>
+#include <lxc/af_unix.h><br>
+#include <lxc/log.h><br>
+#include <lxc/mainloop.h><br>
+#include <lxc/monitor.h><br>
+#include <lxc/utils.h><br>
+<br>
+lxc_log_define(lxc_monitord, lxc);<br>
+<br>
+/*<br>
+ * Defines the structure to store the monitor information<br>
+ * @fifofd : the file descriptor for publishers (containers) to write state<br>
+ * @listenfd : the file descriptor for subscribers (lxc-monitors) to connect<br>
+ * @clientfds : accepted client file descriptors<br>
+ * @clientfds_cnt: the count of valid fds in clientfds<br>
+ */<br>
+struct lxc_monitor {<br>
+ int fifofd;<br>
+ int listenfd;<br>
+ int clientfds[1024];<br>
+ int clientfds_cnt;<br>
+ struct lxc_epoll_descr descr;<br>
+};<br>
+<br>
+static int lxc_monitord_fifo_create(struct lxc_monitor *mon, const char *lxcpath)<br>
+{<br>
+ char fifo_path[PATH_MAX];<br>
+ int ret;<br>
+<br>
+ ret = snprintf(fifo_path, sizeof(fifo_path), "%s/monitor", lxcpath);<br>
+ if (ret < 0 || ret >= sizeof(fifo_path)) {<br>
+ ERROR("lxcpath too long to monitor fifo");<br>
+ return -1;<br>
+ }<br>
+<br>
+ ret = mknod(fifo_path, S_IFIFO|S_IRUSR|S_IWUSR, 0);<br>
+ if (ret < 0) {<br>
+ INFO("existing monitor fifo at %s, monitor already running?", fifo_path);<br>
+ return -1;<br>
+ }<br>
+ mon->fifofd = open(fifo_path, O_RDWR);<br>
+ if (mon->fifofd < 0) {<br>
+ ERROR("failed to open monitor fifo");<br>
+ return -1;<br>
+ }<br>
+ return 0;<br>
+}<br>
+<br>
+static int lxc_monitord_fifo_delete(const char *lxcpath)<br>
+{<br>
+ char fifo_path[PATH_MAX];<br>
+ int ret;<br>
+<br>
+ ret = snprintf(fifo_path, sizeof(fifo_path), "%s/monitor", lxcpath);<br>
+ if (ret < 0 || ret >= sizeof(fifo_path)) {<br>
+ ERROR("lxcpath too long to monitor fifo");<br>
+ return -1;<br>
+ }<br>
+ unlink(fifo_path);<br>
+ return 0;<br>
+}<br>
+<br>
+static void lxc_monitord_sockfd_remove(struct lxc_monitor *mon, int fd) {<br>
+ int i;<br>
+<br>
+ lxc_mainloop_del_handler(&mon->descr, fd);<br>
+ close(fd);<br>
+<br>
+ for (i = 0; i < mon->clientfds_cnt; i++) {<br>
+ if (mon->clientfds[i] == fd)<br>
+ break;<br>
+ }<br>
+ if (i >= mon->clientfds_cnt) {<br>
+ CRIT("fd not found");<br>
+ exit(EXIT_FAILURE);<br>
+ }<br>
+ DEBUG("MON: removing client fd:%d memmoving %p %p %lu bytes", fd,<br>
+ &mon->clientfds[mon->clientfds_cnt],<br>
+ &mon->clientfds[i],<br>
+ (&mon->clientfds[mon->clientfds_cnt-1] - &mon->clientfds[i]) * sizeof(int));<br>
+ memmove(&mon->clientfds[i], &mon->clientfds[i+1],<br>
+ (&mon->clientfds[mon->clientfds_cnt-1] - &mon->clientfds[i]) * sizeof(int));<br>
+ mon->clientfds_cnt--;<br>
+}<br>
+<br>
+static int lxc_monitord_sock_handler(int fd, void *data,<br>
+ struct lxc_epoll_descr *descr)<br>
+{<br>
+ struct lxc_monitor *mon = data;<br>
+ lxc_monitord_sockfd_remove(mon, fd);<br>
+ return 0;<br>
+}<br>
+<br>
+static int lxc_monitord_sock_accept(int fd, void *data,<br>
+ struct lxc_epoll_descr *descr)<br>
+{<br>
+ int ret,clientfd;<br>
+ struct lxc_monitor *mon = data;<br>
+<br>
+ ret = -1;<br>
+ clientfd = accept(fd, NULL, 0);<br>
+ if (clientfd < 0) {<br>
+ SYSERROR("failed to accept connection");<br>
+ goto out;<br>
+ }<br>
+<br>
+ if (fcntl(clientfd, F_SETFD, FD_CLOEXEC)) {<br>
+ SYSERROR("failed to set close-on-exec on incoming connection");<br>
+ goto err1;<br>
+ }<br>
+<br>
+ /* FIXME: check the connected clients credentials here, drop if we don't<br>
+ * like them.<br>
+ int on = 1;<br>
+ if (setsockopt(clientfd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on))) {<br>
+ ERROR("failed to enable credential on socket");<br>
+ goto err1;<br>
+ }<br>
+ */<br>
+<br>
+ ret = lxc_mainloop_add_handler(&mon->descr, clientfd,<br>
+ lxc_monitord_sock_handler, mon);<br>
+ if (ret) {<br>
+ ERROR("failed to add socket handler");<br>
+ goto err1;<br>
+ }<br>
+ mon->clientfds[mon->clientfds_cnt++] = clientfd;<br>
+ INFO("accepted new client fd:%d clientfds_cnt:%d", clientfd, mon->clientfds_cnt);<br>
+ goto out;<br>
+<br>
+err1:<br>
+ close(clientfd);<br>
+out:<br>
+ return ret;<br>
+}<br>
+<br>
+static int lxc_monitord_sock_create(struct lxc_monitor *mon, const char *lxcpath)<br>
+{<br>
+ struct sockaddr_un addr;<br>
+ int fd;<br>
+<br>
+ if (lxc_monitor_sock_name(lxcpath, &addr) < 0)<br>
+ return -1;<br>
+<br>
+ fd = lxc_af_unix_open(addr.sun_path, SOCK_STREAM, O_TRUNC);<br>
+ if (fd < 0) {<br>
+ ERROR("failed to open unix socket : %s", strerror(errno));<br>
+ return -1;<br>
+ }<br>
+<br>
+ mon->listenfd = fd;<br>
+ return 0;<br>
+}<br>
+<br>
+static int lxc_monitord_sock_delete(const char *lxcpath)<br>
+{<br>
+ struct sockaddr_un addr;<br>
+<br>
+ if (lxc_monitor_sock_name(lxcpath, &addr) < 0)<br>
+ return -1;<br>
+ if (addr.sun_path[0])<br>
+ unlink(addr.sun_path);<br>
+ return 0;<br>
+}<br>
+<br>
+static int lxc_monitord_create(struct lxc_monitor *mon, const char *lxcpath)<br>
+{<br>
+ int ret;<br>
+<br>
+ ret = lxc_monitord_fifo_create(mon, lxcpath);<br>
+ if (ret < 0)<br>
+ return ret;<br>
+<br>
+ ret = lxc_monitord_sock_create(mon, lxcpath);<br>
+ return ret;<br>
+}<br>
+<br>
+static void lxc_monitord_delete(struct lxc_monitor *mon, const char *lxcpath)<br>
+{<br>
+ int i;<br>
+<br>
+ lxc_mainloop_del_handler(&mon->descr, mon->listenfd);<br>
+ close(mon->listenfd);<br>
+ lxc_monitord_sock_delete(lxcpath);<br>
+<br>
+ lxc_mainloop_del_handler(&mon->descr, mon->fifofd);<br>
+ close(mon->fifofd);<br>
+ lxc_monitord_fifo_delete(lxcpath);<br>
+<br>
+ for (i = 0; i < mon->clientfds_cnt; i++) {<br>
+ lxc_mainloop_del_handler(&mon->descr, mon->clientfds[i]);<br>
+ close(mon->clientfds[i]);<br>
+ }<br>
+ mon->clientfds_cnt = 0;<br>
+}<br>
+<br>
+static int lxc_monitord_fifo_handler(int fd, void *data,<br>
+ struct lxc_epoll_descr *descr)<br>
+{<br>
+ int ret,i;<br>
+ struct lxc_msg msglxc;<br>
+ struct lxc_monitor *mon = data;<br>
+<br>
+ ret = read(fd, &msglxc, sizeof(msglxc));<br>
+ if (ret != sizeof(msglxc)) {<br>
+ SYSERROR("read fifo failed : %s", strerror(errno));<br>
+ return 1;<br>
+ }<br>
+<br>
+ for (i = 0; i < mon->clientfds_cnt; i++) {<br>
+ ret = write(mon->clientfds[i], &msglxc, sizeof(msglxc));<br>
+ if (ret < 0) {<br>
+ ERROR("write failed to client sock, removing");<br>
+ lxc_monitord_sockfd_remove(mon, i);<br>
+ }<br>
+ }<br>
+<br>
+ return 0;<br>
+}<br>
+<br>
+static int lxc_monitord_mainloop_add(struct lxc_monitor *mon)<br>
+{<br>
+ int ret;<br>
+<br>
+ ret = lxc_mainloop_add_handler(&mon->descr, mon->fifofd,<br>
+ lxc_monitord_fifo_handler, mon);<br>
+ if (ret < 0) {<br>
+ ERROR("failed to add to mainloop monitor handler for fifo");<br>
+ return -1;<br>
+ }<br>
+<br>
+ ret = lxc_mainloop_add_handler(&mon->descr, mon->listenfd,<br>
+ lxc_monitord_sock_accept, mon);<br>
+ if (ret < 0) {<br>
+ ERROR("failed to add to mainloop monitor handler for listen socket");<br>
+ return -1;<br>
+ }<br>
+<br>
+ return 0;<br>
+}<br>
+<br>
+static void lxc_monitord_sig_handler(int sig)<br>
+{<br>
+ INFO("caught signal %d", sig);<br>
+}<br>
+<br>
+int main(int argc, char *argv[])<br>
+{<br>
+ struct lxc_monitor mon;<br>
+ int ret,pipefd;<br>
+ char *lxcpath = argv[1];<br>
+ char logpath[PATH_MAX];<br>
+<br>
+ signal(SIGTERM, lxc_monitord_sig_handler);<br>
+ snprintf(logpath, sizeof(logpath), "%s/lxc-monitord.log", lxcpath);<br>
+ ret = lxc_log_init(NULL, logpath, "INFO", "lxc-monitord", 0);<br>
+ if (ret)<br>
+ return ret;<br>
+<br>
+ pipefd = atoi(argv[2]);<br>
+<br>
+ ret = EXIT_FAILURE;<br>
+ memset(&mon, 0, sizeof(mon));<br>
+ if (lxc_mainloop_open(&mon.descr)) {<br>
+ ERROR("failed to create mainloop");<br>
+ goto out;<br>
+ }<br>
+<br>
+ if (lxc_monitord_create(&mon, lxcpath)) {<br>
+ goto out;<br>
+ }<br>
+<br>
+ /* sync with parent */<br>
+ write(pipefd, "S", 1);<br>
+ close(pipefd);<br>
+<br>
+ if (lxc_monitord_mainloop_add(&mon)) {<br>
+ ERROR("failed to add mainloop handlers");<br>
+ goto out;<br>
+ }<br>
+<br>
+ NOTICE("monitoring lxcpath %s", lxcpath);<br>
+ for(;;) {<br>
+ ret = lxc_mainloop_timeout(&mon.descr, 1000 * 30);<br>
+ if (mon.clientfds_cnt <= 0)<br>
+ {<br>
+ NOTICE("no clients for 30 seconds, exiting");<br>
+ break;<br>
+ }<br>
+ }<br>
+<br>
+ lxc_monitord_delete(&mon, lxcpath);<br>
+ lxc_mainloop_close(&mon.descr);<br>
+out:<br>
+ return ret;<br>
+}<br>
diff --git a/src/lxc/mainloop.c b/src/lxc/mainloop.c<br>
index 975215d..4805dcd 100644<br>
--- a/src/lxc/mainloop.c<br>
+++ b/src/lxc/mainloop.c<br>
@@ -38,7 +38,7 @@ struct mainloop_handler {<br>
<br>
#define MAX_EVENTS 10<br>
<br>
-int lxc_mainloop(struct lxc_epoll_descr *descr)<br>
+int lxc_mainloop_timeout(struct lxc_epoll_descr *descr, int timeout_ms)<br>
{<br>
int i, nfds;<br>
struct mainloop_handler *handler;<br>
@@ -46,7 +46,7 @@ int lxc_mainloop(struct lxc_epoll_descr *descr)<br>
<br>
for (;;) {<br>
<br>
- nfds = epoll_wait(descr->epfd, events, MAX_EVENTS, -1);<br>
+ nfds = epoll_wait(descr->epfd, events, MAX_EVENTS, timeout_ms);<br>
if (nfds < 0) {<br>
if (errno == EINTR)<br>
continue;<br>
@@ -64,11 +64,18 @@ int lxc_mainloop(struct lxc_epoll_descr *descr)<br>
return 0;<br>
}<br>
<br>
+ if (nfds == 0 && timeout_ms != 0)<br>
+ return 0;<br>
+<br>
if (lxc_list_empty(&descr->handlers))<br>
return 0;<br>
}<br>
}<br>
<br>
+int lxc_mainloop(struct lxc_epoll_descr *descr) {<br>
+ return lxc_mainloop_timeout(descr, -1);<br>
+}<br>
+<br>
int lxc_mainloop_add_handler(struct lxc_epoll_descr *descr, int fd,<br>
lxc_mainloop_callback_t callback, void *data)<br>
{<br>
diff --git a/src/lxc/mainloop.h b/src/lxc/mainloop.h<br>
index 6b16242..c79c4fd 100644<br>
--- a/src/lxc/mainloop.h<br>
+++ b/src/lxc/mainloop.h<br>
@@ -21,6 +21,9 @@<br>
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA<br>
*/<br>
<br>
+#ifndef _mainloop_h<br>
+#define _mainloop_h<br>
+<br>
#include "list.h"<br>
<br>
struct lxc_epoll_descr {<br>
@@ -33,6 +36,8 @@ typedef int (*lxc_mainloop_callback_t)(int fd, void *data,<br>
<br>
extern int lxc_mainloop(struct lxc_epoll_descr *descr);<br>
<br>
+extern int lxc_mainloop_timeout(struct lxc_epoll_descr *descr, int timeout_ms);<br>
+<br>
extern int lxc_mainloop_add_handler(struct lxc_epoll_descr *descr, int fd,<br>
lxc_mainloop_callback_t callback,<br>
void *data);<br>
@@ -42,3 +47,5 @@ extern int lxc_mainloop_del_handler(struct lxc_epoll_descr *descr, int fd);<br>
extern int lxc_mainloop_open(struct lxc_epoll_descr *descr);<br>
<br>
extern int lxc_mainloop_close(struct lxc_epoll_descr *descr);<br>
+<br>
+#endif<br>
diff --git a/src/lxc/monitor.c b/src/lxc/monitor.c<br>
index afdaf67..0438fbc 100644<br>
--- a/src/lxc/monitor.c<br>
+++ b/src/lxc/monitor.c<br>
@@ -20,6 +20,7 @@<br>
* License along with this library; if not, write to the Free Software<br>
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA<br>
*/<br>
+<br>
#include <stdio.h><br>
#include <errno.h><br>
#include <unistd.h><br>
@@ -30,7 +31,7 @@<br>
#include <sys/stat.h><br>
#include <sys/param.h><br>
#include <sys/socket.h><br>
-#include <sys/un.h><br>
+#include <sys/wait.h><br>
#include <netinet/in.h><br>
#include <net/if.h><br>
<br>
@@ -43,35 +44,24 @@<br>
<br>
lxc_log_define(lxc_monitor, lxc);<br>
<br>
-#ifndef UNIX_PATH_MAX<br>
-#define UNIX_PATH_MAX 108<br>
-#endif<br>
-<br>
-static void lxc_monitor_send(struct lxc_msg *msg, const char *lxcpath)<br>
+/* routines used by monitor publishers (containers) */<br>
+static void lxc_monitor_fifo_send(struct lxc_msg *msg, const char *lxcpath)<br>
{<br>
- int fd;<br>
- struct sockaddr_un addr = { .sun_family = AF_UNIX };<br>
- char *offset = &addr.sun_path[1];<br>
- size_t ret, len;<br>
+ int fd,ret;<br>
+ char fifo_path[PATH_MAX];<br>
<br>
- /*<br>
- * addr.sun_path is only 108 bytes.<br>
- * should we take a hash of lxcpath? a subset of it?<br>
- */<br>
- len = sizeof(addr.sun_path) - 1;<br>
- ret = snprintf(offset, len, "%s/lxc-monitor", lxcpath);<br>
- if (ret < 0 || ret >= len) {<br>
- ERROR("lxcpath too long to open monitor");<br>
+ //FIXME: BuildAssert(sizeof(*msg) < PIPE_BUF), "write not guaranteed atomic");<br>
+ ret = snprintf(fifo_path, sizeof(fifo_path), "%s/monitor", lxcpath);<br>
+ if (ret < 0 || ret >= sizeof(fifo_path)) {<br>
+ ERROR("lxcpath too long to open monitor fifo");<br>
return;<br>
}<br>
-<br>
- fd = socket(PF_UNIX, SOCK_DGRAM, 0);<br>
- if (fd < 0)<br>
+ fd = open(fifo_path, O_WRONLY);<br>
+ if (fd < 0) {<br>
+ ERROR("failed to open monitor fifo %s", fifo_path);<br>
return;<br>
-<br>
- sendto(fd, msg, sizeof(*msg), 0,<br>
- (const struct sockaddr *)&addr, sizeof(addr));<br>
-<br>
+ }<br>
+ ret = write(fd, msg, sizeof(*msg));<br>
close(fd);<br>
}<br>
<br>
@@ -82,72 +72,74 @@ void lxc_monitor_send_state(const char *name, lxc_state_t state, const char *lxc<br>
strncpy(<a href="http://msg.name" target="_blank">msg.name</a>, name, sizeof(<a href="http://msg.name" target="_blank">msg.name</a>));<br>
<a href="http://msg.name" target="_blank">msg.name</a>[sizeof(<a href="http://msg.name" target="_blank">msg.name</a>) - 1] = 0;<br>
<br>
- lxc_monitor_send(&msg, lxcpath);<br>
+ lxc_monitor_fifo_send(&msg, lxcpath);<br>
}<br>
<br>
-int lxc_monitor_open(const char *lxcpath)<br>
+<br>
+/* routines used by monitor subscribers (lxc-monitor) */<br>
+int lxc_monitor_close(int fd)<br>
{<br>
- struct sockaddr_un addr = { .sun_family = AF_UNIX };<br>
- char *offset = &addr.sun_path[1];<br>
- int fd;<br>
- size_t ret, len;<br>
+ return close(fd);<br>
+}<br>
<br>
- /*<br>
- * addr.sun_path is only 108 bytes.<br>
- * should we take a hash of lxcpath? a subset of it?<br>
+int lxc_monitor_sock_name(const char *lxcpath, struct sockaddr_un *addr) {<br>
+ size_t len,ret;<br>
+ char *sockname = &addr->sun_path[0]; // 1 for abstract<br>
+<br>
+ /* addr.sun_path is only 108 bytes.<br>
+ * should we take a hash of lxcpath? a subset of it? ftok()? none<br>
+ * are guaranteed.<br>
*/<br>
- len = sizeof(addr.sun_path) - 1;<br>
- ret = snprintf(offset, len, "%s/lxc-monitor", lxcpath);<br>
+ memset(addr, 0, sizeof(*addr));<br>
+ addr->sun_family = AF_UNIX;<br>
+ len = sizeof(addr->sun_path) - 1;<br>
+ ret = snprintf(sockname, len, "%s/monitor-sock", lxcpath);<br>
if (ret < 0 || ret >= len) {<br>
- ERROR("lxcpath too long to open monitor");<br>
+ ERROR("lxcpath too long for unix socket");<br>
return -1;<br>
}<br>
+ return 0;<br>
+}<br>
+<br>
+int lxc_monitor_open(const char *lxcpath)<br>
+{<br>
+ struct sockaddr_un addr;<br>
+ size_t ret;<br>
+ int fd;<br>
<br>
- fd = socket(PF_UNIX, SOCK_DGRAM, 0);<br>
+ if (lxc_monitor_sock_name(lxcpath, &addr) < 0)<br>
+ return -1;<br>
+<br>
+ fd = socket(PF_UNIX, SOCK_STREAM, 0);<br>
if (fd < 0) {<br>
ERROR("socket : %s", strerror(errno));<br>
return -1;<br>
}<br>
<br>
- if (bind(fd, (struct sockaddr *)&addr, sizeof(addr))) {<br>
- ERROR("bind : %s", strerror(errno));<br>
- close(fd);<br>
- return -1;<br>
+ ret = connect(fd, (struct sockaddr *)&addr, sizeof(addr));<br>
+ if (ret < 0) {<br>
+ /* try to spawn a lxc-monitord here instead ? */<br>
+ ERROR("connect : %s", strerror(errno));<br>
+ goto err1;<br>
}<br>
-<br>
return fd;<br>
+err1:<br>
+ close(fd);<br>
+ return ret;<br>
}<br>
<br>
-/* timeout of 0 means return immediately; -1 means wait forever */<br>
-int lxc_monitor_read_timeout(int fd, struct lxc_msg *msg, int timeout)<br>
+int lxc_monitor_read_timeout(int fd, struct lxc_msg *msglxc, int timeout)<br>
{<br>
struct sockaddr_un from;<br>
socklen_t len = sizeof(from);<br>
int ret;<br>
- fd_set rfds;<br>
- struct timeval tv;<br>
<br>
- if (timeout != -1) {<br>
- FD_ZERO(&rfds);<br>
- FD_SET(fd, &rfds);<br>
-<br>
- tv.tv_sec = timeout;<br>
- tv.tv_usec = 0;<br>
-<br>
- ret = select(fd+1, &rfds, NULL, NULL, &tv);<br>
- if (ret == -1)<br>
- return -1;<br>
- else if (!ret)<br>
- return -2; // timed out<br>
- }<br>
-<br>
- ret = recvfrom(fd, msg, sizeof(*msg), 0,<br>
+ ret = recvfrom(fd, msglxc, sizeof(*msglxc), 0,<br>
(struct sockaddr *)&from, &len);<br>
- if (ret < 0) {<br>
- SYSERROR("failed to receive state");<br>
+ if (ret <= 0) {<br>
+ SYSERROR("client failed to receive lxc_msg (monitord died?)");<br>
return -1;<br>
}<br>
-<br>
return ret;<br>
}<br>
<br>
@@ -156,7 +148,61 @@ int lxc_monitor_read(int fd, struct lxc_msg *msg)<br>
return lxc_monitor_read_timeout(fd, msg, -1);<br>
}<br>
<br>
-int lxc_monitor_close(int fd)<br>
+<br>
+<br>
+/* used to spawn a monitord either on startup of a container, or when<br>
+ * lxc-monitor starts<br>
+ */<br>
+int lxc_monitord_spawn(const char *lxcpath)<br>
{<br>
- return close(fd);<br>
+ pid_t pid1,pid2;<br>
+ int pipefd[2];<br>
+ char pipefd_str[10];<br>
+<br>
+ char * const args[] = {<br>
+ "/usr/bin/lxc-monitord",<br>
+ (char *)lxcpath,<br>
+ pipefd_str,<br>
+ NULL,<br>
+ };<br>
+<br>
+ /* double fork to avoid zombies when monitord exits */<br>
+ pid1 = fork();<br>
+ if (pid1 < 0) {<br>
+ SYSERROR("failed to fork");<br>
+ return -1;<br>
+ }<br>
+<br>
+ if (pid1) {<br>
+ waitpid(pid1, NULL, 0);<br>
+ return 0;<br>
+ }<br>
+<br>
+ if (pipe(pipefd) < 0) {<br>
+ SYSERROR("failed to create pipe");<br>
+ exit(EXIT_FAILURE);<br>
+ }<br>
+<br>
+ pid2 = fork();<br>
+ if (pid2) {<br>
+ char c;<br>
+ /* wait for daemon to create socket */<br>
+ close(pipefd[1]);<br>
+ read(pipefd[0], &c, 1);<br>
+ close(pipefd[0]);<br>
+ exit(EXIT_SUCCESS);<br>
+ }<br>
+<br>
+ umask(0);<br>
+ if (setsid() < 0) {<br>
+ SYSERROR("failed to setsid");<br>
+ exit(EXIT_FAILURE);<br>
+ }<br>
+ freopen("/dev/null", "r", stdin);<br>
+ freopen("/dev/null", "w", stdout);<br>
+ freopen("/dev/null", "w", stderr);<br>
+ close(pipefd[0]);<br>
+ sprintf(pipefd_str, "%d", pipefd[1]);<br>
+ execvp(args[0], args);<br>
+ exit(EXIT_FAILURE);<br>
}<br>
diff --git a/src/lxc/monitor.h b/src/lxc/monitor.h<br>
index 8bef4c7..faa606c 100644<br>
--- a/src/lxc/monitor.h<br>
+++ b/src/lxc/monitor.h<br>
@@ -24,6 +24,10 @@<br>
#define __monitor_h<br>
<br>
#include <sys/param.h><br>
+#include <sys/un.h><br>
+<br>
+#include <lxc/conf.h><br>
+#include <lxc/mainloop.h><br>
<br>
typedef enum {<br>
lxc_msg_state,<br>
@@ -32,11 +36,14 @@ typedef enum {<br>
<br>
struct lxc_msg {<br>
lxc_msg_type_t type;<br>
- char name[MAXPATHLEN];<br>
+ char name[NAME_MAX+1];<br>
int value;<br>
};<br>
<br>
-void lxc_monitor_send_state(const char *name, lxc_state_t state,<br>
+extern int lxc_monitor_open(const char *lxcpath);<br>
+extern int lxc_monitor_sock_name(const char *lxcpath, struct sockaddr_un *addr);<br>
+extern void lxc_monitor_send_state(const char *name, lxc_state_t state,<br>
const char *lxcpath);<br>
+extern int lxc_monitord_spawn(const char *lxcpath);<br>
<br>
#endif<br>
diff --git a/src/lxc/start.c b/src/lxc/start.c<br>
index aefccd6..9451fb7 100644<br>
--- a/src/lxc/start.c<br>
+++ b/src/lxc/start.c<br>
@@ -429,6 +429,9 @@ struct lxc_handler *lxc_init(const char *name, struct lxc_conf *conf, const char<br>
if (lxc_command_init(name, handler, lxcpath))<br>
goto out_free_name;<br>
<br>
+ if (lxc_monitord_spawn(lxcpath))<br>
+ goto out_close_maincmd_fd;<br>
+<br>
if (lxc_read_seccomp_config(conf) != 0) {<br>
ERROR("failed loading seccomp policy");<br>
goto out_close_maincmd_fd;<br>
@@ -437,7 +440,7 @@ struct lxc_handler *lxc_init(const char *name, struct lxc_conf *conf, const char<br>
/* Begin the set the state to STARTING*/<br>
if (lxc_set_state(name, handler, STARTING)) {<br>
ERROR("failed to set state '%s'", lxc_state2str(STARTING));<br>
- goto out_free_name;<br>
+ goto out_close_maincmd_fd;<br>
}<br>
<br>
/* Start of environment variable setup for hooks */<br>
@@ -808,7 +811,7 @@ int lxc_spawn(struct lxc_handler *handler)<br>
/* TODO - pass lxc.cgroup.dir (or user's pam cgroup) in for first argument */<br>
if ((handler->cgroup = lxc_cgroup_path_create(NULL, name)) == NULL)<br>
goto out_delete_net;<br>
-<br>
+<br>
if (lxc_cgroup_enter(handler->cgroup, handler->pid) < 0)<br>
goto out_delete_net;<br>
<br>
--<br>
1.8.1.4<br>
<br>
<br>
<br>
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</blockquote></div><br><br clear="all"><div><br></div>-- <br>S.Çağlar Onur <<a href="mailto:caglar@10ur.org">caglar@10ur.org</a>>
</div>