lxc_monitor_open: prepend lxcpath

This is needed for lxc_wait and lxc_monitor to handle lxcpath.  However,
the full path name is limited to 108 bytes.  Should we use a md5sum of
the lxcpath instead of the path itself?

In any case, with this patch, lxc-wait and lxc-monitor work right with
respect to multiple lxcpaths.

The lxcpath is added to the lxc_handler to make it available most of the
places we need it.

I also remove function prototypes in monitor.h for two functions which
are not defined or used anywhere.

TODO: make cgroups tolerate multiple same-named containers.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

src/lxc/freezer.c

@@ -40,7 +40,7 @@
 
 lxc_log_define(lxc_freezer, lxc);
 
-static int freeze_unfreeze(const char *name, int freeze)
+static int freeze_unfreeze(const char *name, int freeze, const char *lxcpath)
 {
 	char *nsgroup;
 	char freezer[MAXPATHLEN], *f;
@@ -98,7 +98,7 @@ static int freeze_unfreeze(const char *name, int freeze)
 		ret = strncmp(f, tmpf, strlen(f));
 		if (!ret)
 		{
-			lxc_monitor_send_state(name, freeze ? FROZEN : THAWED);
+			lxc_monitor_send_state(name, freeze ? FROZEN : THAWED, lxcpath);
 			break;		/* Success */
 		}
 
@@ -122,14 +122,14 @@ static int freeze_unfreeze(const char *name, int freeze)
 	return ret;
 }
 
-int lxc_freeze(const char *name)
+int lxc_freeze(const char *name, const char *lxcpath)
 {
-	lxc_monitor_send_state(name, FREEZING);
-	return freeze_unfreeze(name, 1);
+	lxc_monitor_send_state(name, FREEZING, lxcpath);
+	return freeze_unfreeze(name, 1, lxcpath);
 }
 
-int lxc_unfreeze(const char *name)
+int lxc_unfreeze(const char *name, const char *lxcpath)
 {
-	return freeze_unfreeze(name, 0);
+	return freeze_unfreeze(name, 0, lxcpath);
 }
 

src/lxc/lxc.h

@@ -74,7 +74,7 @@ extern int lxc_execute(const char *name, char *const argv[], int quiet,
  * The function will return an fd corresponding to the events
  * Returns a file descriptor on success, < 0 otherwise
  */
-extern int lxc_monitor_open(void);
+extern int lxc_monitor_open(const char *lxcpath);
 
 /*
  * Read the state of the container if this one has changed
@@ -108,14 +108,14 @@ extern int lxc_console(const char *name, int ttynum, int *fd, const char *lxcpat
  * @name : the container name
  * Returns 0 on success, < 0 otherwise
  */
-extern int lxc_freeze(const char *name);
+extern int lxc_freeze(const char *name, const char *lxcpath);
 
 /*
  * Unfreeze all previously frozen tasks.
  * @name : the name of the container
  * Return 0 on sucess, < 0 otherwise
  */
-extern int lxc_unfreeze(const char *name);
+extern int lxc_unfreeze(const char *name, const char *lxcpath);
 
 /*
  * Retrieve the container state

src/lxc/lxc_freeze.c

@@ -58,6 +58,6 @@ int main(int argc, char *argv[])
 			 my_args.progname, my_args.quiet))
 		return -1;
 
-	return lxc_freeze(my_args.name);
+	return lxc_freeze(my_args.name, my_args.lxcpath);
 }
 

src/lxc/lxc_monitor.c

@@ -87,7 +87,7 @@ int main(int argc, char *argv[])
 		return -1;
 	}
 
-	fd = lxc_monitor_open();
+	fd = lxc_monitor_open(my_args.lxcpath);
 	if (fd < 0)
 		return -1;
 

src/lxc/lxc_unfreeze.c

@@ -57,6 +57,6 @@ int main(int argc, char *argv[])
 			 my_args.progname, my_args.quiet))
 		return -1;
 
-	return lxc_unfreeze(my_args.name);
+	return lxc_unfreeze(my_args.name, my_args.lxcpath);
 }
 

src/lxc/lxccontainer.c

@@ -195,7 +195,7 @@ static bool lxcapi_freeze(struct lxc_container *c)
 
 	if (lxclock(c->slock, 0))
 		return false;
-	ret = lxc_freeze(c->name);
+	ret = lxc_freeze(c->name, c->config_path);
 	lxcunlock(c->slock);
 	if (ret)
 		return false;
@@ -210,7 +210,7 @@ static bool lxcapi_unfreeze(struct lxc_container *c)
 
 	if (lxclock(c->slock, 0))
 		return false;
-	ret = lxc_unfreeze(c->name);
+	ret = lxc_unfreeze(c->name, c->config_path);
 	lxcunlock(c->slock);
 	if (ret)
 		return false;

src/lxc/monitor.c

@@ -47,13 +47,23 @@ lxc_log_define(lxc_monitor, lxc);
 #define UNIX_PATH_MAX 108
 #endif
 
-static void lxc_monitor_send(struct lxc_msg *msg)
+static void lxc_monitor_send(struct lxc_msg *msg, const char *lxcpath)
 {
 	int fd;
 	struct sockaddr_un addr = { .sun_family = AF_UNIX };
 	char *offset = &addr.sun_path[1];
-
-	strcpy(offset, "lxc-monitor");
+	size_t ret, len;
+
+	/*
+	 * addr.sun_path is only 108 bytes.
+	 * should we take a hash of lxcpath?  a subset of it?
+	 */
+	len = sizeof(addr.sun_path) - 1;
+	ret = snprintf(offset, len, "%s/lxc-monitor", lxcpath);
+	if (ret < 0 || ret >= len) {
+		ERROR("lxcpath too long to open monitor");
+		return;
+	}
 
 	fd = socket(PF_UNIX, SOCK_DGRAM, 0);
 	if (fd < 0)
@@ -65,23 +75,33 @@ static void lxc_monitor_send(struct lxc_msg *msg)
 	close(fd);
 }
 
-void lxc_monitor_send_state(const char *name, lxc_state_t state)
+void lxc_monitor_send_state(const char *name, lxc_state_t state, const char *lxcpath)
 {
 	struct lxc_msg msg = { .type = lxc_msg_state,
 			       .value = state };
 	strncpy(msg.name, name, sizeof(msg.name));
 	msg.name[sizeof(msg.name) - 1] = 0;
 
-	lxc_monitor_send(&msg);
+	lxc_monitor_send(&msg, lxcpath);
 }
 
-int lxc_monitor_open(void)
+int lxc_monitor_open(const char *lxcpath)
 {
 	struct sockaddr_un addr = { .sun_family = AF_UNIX };
 	char *offset = &addr.sun_path[1];
 	int fd;
-
-	strcpy(offset, "lxc-monitor");
+	size_t ret, len;
+
+	/*
+	 * addr.sun_path is only 108 bytes.
+	 * should we take a hash of lxcpath?  a subset of it?
+	 */
+	len = sizeof(addr.sun_path) - 1;
+	ret = snprintf(offset, len, "%s/lxc-monitor", lxcpath);
+	if (ret < 0 || ret >= len) {
+		ERROR("lxcpath too long to open monitor");
+		return -1;
+	}
 
 	fd = socket(PF_UNIX, SOCK_DGRAM, 0);
 	if (fd < 0) {

src/lxc/monitor.h

@@ -36,8 +36,7 @@ struct lxc_msg {
 	int value;
 };
 
-void lxc_monitor_send_state(const char *name, lxc_state_t state);
-void lxc_monitor_send_priority(const char *name, int priority);
-void lxc_monitor_cleanup(const char *name);
+void lxc_monitor_send_state(const char *name, lxc_state_t state,
+			    const char *lxcpath);
 
 #endif

src/lxc/start.c

@@ -311,7 +311,7 @@ int lxc_clone_flags_callback(int fd, struct lxc_request *request,
 int lxc_set_state(const char *name, struct lxc_handler *handler, lxc_state_t state)
 {
 	handler->state = state;
-	lxc_monitor_send_state(name, state);
+	lxc_monitor_send_state(name, state, handler->lxcpath);
 	return 0;
 }
 
@@ -379,6 +379,7 @@ struct lxc_handler *lxc_init(const char *name, struct lxc_conf *conf, const char
 	memset(handler, 0, sizeof(*handler));
 
 	handler->conf = conf;
+	handler->lxcpath = lxcpath;
 
 	apparmor_handler_init(handler);
 	handler->name = strdup(name);

src/lxc/start.h

@@ -50,6 +50,7 @@ struct lxc_handler {
 	int aa_enabled;
 #endif
 	int pinfd;
+	const char *lxcpath;
 };
 
 extern struct lxc_handler *lxc_init(const char *name, struct lxc_conf *, const char *);

src/lxc/state.c

@@ -200,7 +200,7 @@ extern int lxc_wait(const char *lxcname, const char *states, int timeout, const
 	if (fillwaitedstates(states, s))
 		return -1;
 
-	fd = lxc_monitor_open();
+	fd = lxc_monitor_open(lxcpath);
 	if (fd < 0)
 		return -1;
 

src/lxc/stop.c

@@ -85,7 +85,7 @@ extern int lxc_stop_callback(int fd, struct lxc_request *request,
 
 	answer.ret = kill(handler->pid, SIGKILL);
 	if (!answer.ret) {
-		ret = lxc_unfreeze(handler->name);
+		ret = lxc_unfreeze(handler->name, handler->lxcpath);
 		if (!ret)
 			return 0;