From: Christian Brauner <christian.brauner@ubuntu.com>
Date: Wed, 23 Aug 2017 13:03:01 +0000 (+0200)
Subject: confile: add "lxc.cgroup.dir"
X-Git-Tag: lxc-2.1.0~17^2~13
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=43654d3475f61c239b6b800e0ece6b28f3bfaa2c;p=thirdparty%2Flxc.git

confile: add "lxc.cgroup.dir"

"lxc.cgroup.dir" can be used to set the name of the directory the container's
cgroup will be created in. For example, setting

    lxc.uts.name = c1
    lxc.cgroup.dir = lxd

would make liblxc create the cgroup

    lxd/c1

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---

diff --git a/src/lxc/cgroups/cgfs.c b/src/lxc/cgroups/cgfs.c
index 0e50dd3f5..bcbd66134 100644
--- a/src/lxc/cgroups/cgfs.c
+++ b/src/lxc/cgroups/cgfs.c
@@ -2343,7 +2343,7 @@ struct cgroup_ops *cgfs_ops_init(void)
 	return &cgfs_ops;
 }
 
-static void *cgfs_init(const char *name)
+static void *cgfs_init(struct lxc_handler *handler)
 {
 	struct cgfs_data *d;
 
@@ -2352,7 +2352,7 @@ static void *cgfs_init(const char *name)
 		return NULL;
 
 	memset(d, 0, sizeof(*d));
-	d->name = strdup(name);
+	d->name = strdup(handler->name);
 	if (!d->name)
 		goto err1;
 
diff --git a/src/lxc/cgroups/cgfsng.c b/src/lxc/cgroups/cgfsng.c
index 86679741d..fc658faf2 100644
--- a/src/lxc/cgroups/cgfsng.c
+++ b/src/lxc/cgroups/cgfsng.c
@@ -53,8 +53,9 @@
 #include "cgroup.h"
 #include "cgroup_utils.h"
 #include "commands.h"
+#include "conf.h"
 #include "log.h"
-#include "storage.h"
+#include "storage/storage.h"
 #include "utils.h"
 
 lxc_log_define(lxc_cgfsng, lxc);
@@ -81,17 +82,21 @@ struct hierarchy {
 
 /*
  * The cgroup data which is attached to the lxc_handler.
- * @cgroup_pattern - a copy of the lxc.cgroup.pattern
- * @container_cgroup - if not null, the cgroup which was created for
- *   the container.  For each hierarchy, it is created under the
- *   @hierarchy->base_cgroup directory.  Relative to the base_cgroup
- *   it is the same for all hierarchies.
- * @name - the container name
+ * @cgroup_pattern   : A copy of the lxc.cgroup.pattern
+ * @container_cgroup : If not null, the cgroup which was created for the
+ *                     container. For each hierarchy, it is created under the
+ *                     @hierarchy->base_cgroup directory. Relative to the
+ *                     base_cgroup it is the same for all hierarchies.
+ * @name             : The name of the container.
+ * @cgroup_meta      : A copy of the container's cgroup information. This
+ *                     overrides @cgroup_pattern.
  */
 struct cgfsng_handler_data {
 	char *cgroup_pattern;
 	char *container_cgroup; /* cgroup we created for the container */
 	char *name; /* container name */
+	/* per-container cgroup information */
+	struct lxc_cgroup cgroup_meta;
 };
 
 /*
@@ -220,6 +225,10 @@ static void free_handler_data(struct cgfsng_handler_data *d)
 	free(d->cgroup_pattern);
 	free(d->container_cgroup);
 	free(d->name);
+	if (d->cgroup_meta.dir)
+		free(d->cgroup_meta.dir);
+	if (d->cgroup_meta.controllers)
+		free(d->cgroup_meta.controllers);
 	free(d);
 }
 
@@ -986,8 +995,12 @@ static void lxc_cgfsng_print_handler_data(const struct cgfsng_handler_data *d)
 	printf("Cgroup information:\n");
 	printf("  container name: %s\n", d->name ? d->name : "(null)");
 	printf("  lxc.cgroup.use: %s\n", cgroup_use ? cgroup_use : "(null)");
-	printf("  lxc.cgroup.pattern: %s\n", d->cgroup_pattern ? d->cgroup_pattern : "(null)");
-	printf("  cgroup: %s\n", d->container_cgroup ? d->container_cgroup : "(null)");
+	printf("  lxc.cgroup.pattern: %s\n",
+	       d->cgroup_pattern ? d->cgroup_pattern : "(null)");
+	printf("  lxc.cgroup.dir: %s\n",
+	       d->cgroup_meta.dir ? d->cgroup_meta.dir : "(null)");
+	printf("  cgroup: %s\n",
+	       d->container_cgroup ? d->container_cgroup : "(null)");
 }
 
 static void lxc_cgfsng_print_hierarchies()
@@ -1150,18 +1163,25 @@ static bool collect_hierarchy_info(void)
 	return parse_hierarchies();
 }
 
-static void *cgfsng_init(const char *name)
+static void *cgfsng_init(struct lxc_handler *handler)
 {
-	struct cgfsng_handler_data *d;
 	const char *cgroup_pattern;
+	struct cgfsng_handler_data *d;
 
 	d = must_alloc(sizeof(*d));
 	memset(d, 0, sizeof(*d));
 
-	d->name = must_copy_string(name);
+	/* copy container name */
+	d->name = must_copy_string(handler->name);
+
+	/* copy per-container cgroup information */
+	d->cgroup_meta.dir = must_copy_string(handler->conf->cgroup_meta.dir);
+	d->cgroup_meta.controllers = must_copy_string(handler->conf->cgroup_meta.controllers);
 
+	/* copy system-wide cgroup information */
 	cgroup_pattern = lxc_global_config_value("lxc.cgroup.pattern");
-	if (!cgroup_pattern) { /* lxc.cgroup.pattern is only NULL on error */
+	if (!cgroup_pattern) {
+		/* lxc.cgroup.pattern is only NULL on error. */
 		ERROR("Error getting cgroup pattern");
 		goto out_free;
 	}
@@ -1324,12 +1344,16 @@ static inline bool cgfsng_create(void *hdata)
 
 	if (!d)
 		return false;
+
 	if (d->container_cgroup) {
 		WARN("cgfsng_create called a second time");
 		return false;
 	}
 
-	tmp = lxc_string_replace("%n", d->name, d->cgroup_pattern);
+	if (d->cgroup_meta.dir)
+		tmp = strdup(d->cgroup_meta.dir);
+	else
+		tmp = lxc_string_replace("%n", d->name, d->cgroup_pattern);
 	if (!tmp) {
 		ERROR("Failed expanding cgroup name pattern");
 		return false;
diff --git a/src/lxc/cgroups/cgmanager.c b/src/lxc/cgroups/cgmanager.c
index cb98ce7b7..6c6278e59 100644
--- a/src/lxc/cgroups/cgmanager.c
+++ b/src/lxc/cgroups/cgmanager.c
@@ -540,7 +540,7 @@ static void cgm_remove_cgroup(const char *controller, const char *path)
 		INFO("cgroup removal attempt: %s:%s did not exist", controller, path);
 }
 
-static void *cgm_init(const char *name)
+static void *cgm_init(struct lxc_handler *handler)
 {
 	struct cgm_data *d;
 
@@ -554,7 +554,7 @@ static void *cgm_init(const char *name)
 	}
 
 	memset(d, 0, sizeof(*d));
-	d->name = strdup(name);
+	d->name = strdup(handler->name);
 	if (!d->name) {
 		cgm_dbus_disconnect();
 		goto err1;
diff --git a/src/lxc/cgroups/cgroup.c b/src/lxc/cgroups/cgroup.c
index 085953342..674e30905 100644
--- a/src/lxc/cgroups/cgroup.c
+++ b/src/lxc/cgroups/cgroup.c
@@ -65,7 +65,7 @@ bool cgroup_init(struct lxc_handler *handler)
 
 	if (ops) {
 		INFO("cgroup driver %s initing for %s", ops->name, handler->name);
-		handler->cgroup_data = ops->init(handler->name);
+		handler->cgroup_data = ops->init(handler);
 	}
 
 	return handler->cgroup_data != NULL;
@@ -209,7 +209,8 @@ int lxc_cgroup_get(const char *filename, char *value, size_t len,
 	return -1;
 }
 
-void cgroup_disconnect(void) {
+void cgroup_disconnect(void)
+{
 	if (ops && ops->disconnect)
 		ops->disconnect();
 }
diff --git a/src/lxc/cgroups/cgroup.h b/src/lxc/cgroups/cgroup.h
index 11b251e69..f17a6abe0 100644
--- a/src/lxc/cgroups/cgroup.h
+++ b/src/lxc/cgroups/cgroup.h
@@ -41,7 +41,7 @@ typedef enum {
 struct cgroup_ops {
 	const char *name;
 
-	void *(*init)(const char *name);
+	void *(*init)(struct lxc_handler *handler);
 	void (*destroy)(void *hdata, struct lxc_conf *conf);
 	bool (*create)(void *hdata);
 	bool (*enter)(void *hdata, pid_t pid);
diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index 8f58ef541..93d4c1588 100644
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -2769,6 +2769,7 @@ struct lxc_conf *lxc_conf_init(void)
 	 * default to running as UID/GID 0 when using lxc-execute */
 	new->init_uid = 0;
 	new->init_gid = 0;
+	memset(&new->cgroup_meta, 0, sizeof(struct lxc_cgroup));
 
 	return new;
 }
@@ -4606,6 +4607,8 @@ void lxc_conf_free(struct lxc_conf *conf)
 	lxc_clear_aliens(conf);
 	lxc_clear_environment(conf);
 	lxc_clear_limits(conf, "lxc.prlimit");
+	free(conf->cgroup_meta.dir);
+	free(conf->cgroup_meta.controllers);
 	free(conf);
 }
 
diff --git a/src/lxc/conf.h b/src/lxc/conf.h
index b12b1afb9..f085bc94c 100644
--- a/src/lxc/conf.h
+++ b/src/lxc/conf.h
@@ -144,14 +144,29 @@ struct lxc_netdev {
 };
 
 /*
- * Defines a generic struct to configure the control group.
- * It is up to the programmer to specify the right subsystem.
+ * Defines a generic struct to configure the control group. It is up to the
+ * programmer to specify the right subsystem.
  * @subsystem : the targeted subsystem
  * @value     : the value to set
+ *
+ * @controllers : The controllers to use for this container.
+ * @dir         : The name of the directory containing the container's cgroup.
+ *                Not that this is a per-container setting.
  */
 struct lxc_cgroup {
-	char *subsystem;
-	char *value;
+	union {
+		/* information about a specific controller */
+		struct /* controller */ {
+			char *subsystem;
+			char *value;
+		};
+
+		/* meta information about cgroup configuration */
+		struct /* meta */ {
+			char *controllers;
+			char *dir;
+		};
+	};
 };
 
 #if !HAVE_SYS_RESOURCE_H
@@ -422,6 +437,13 @@ struct lxc_conf {
 	 * legacy configuration keys.
 	 */
 	bool contains_legacy_key;
+
+	/* Contains generic info about the cgroup configuration for this
+	 * container. Note that struct lxc_cgroup contains a union. It is only
+	 * valid to access the members of the anonymous "meta" struct within
+	 * that union.
+	 */
+	struct lxc_cgroup cgroup_meta;
 };
 
 #ifdef HAVE_TLS
@@ -459,7 +481,6 @@ extern int lxc_delete_autodev(struct lxc_handler *handler);
 extern void lxc_clear_includes(struct lxc_conf *conf);
 extern int do_rootfs_setup(struct lxc_conf *conf, const char *name,
 			   const char *lxcpath);
-struct cgroup_process_info;
 extern int lxc_setup(struct lxc_handler *handler);
 extern int setup_resource_limits(struct lxc_list *limits, pid_t pid);
 extern void lxc_restore_phys_nics_to_netns(int netnsfd, struct lxc_conf *conf);
diff --git a/src/lxc/confile.c b/src/lxc/confile.c
index ad74b8d1f..730ea1d24 100644
--- a/src/lxc/confile.c
+++ b/src/lxc/confile.c
@@ -82,7 +82,8 @@ lxc_config_define(tty_dir);
 lxc_config_define(apparmor_profile);
 lxc_config_define(apparmor_allow_incomplete);
 lxc_config_define(selinux_context);
-lxc_config_define(cgroup);
+lxc_config_define(cgroup_controller);
+lxc_config_define(cgroup_dir);
 lxc_config_define(idmaps);
 lxc_config_define(log_level);
 lxc_config_define(log_file);
@@ -142,7 +143,8 @@ static struct lxc_config_t config[] = {
 	{ "lxc.autodev",                   false,                  set_config_autodev,                     get_config_autodev,                     clr_config_autodev,                   },
 	{ "lxc.cap.drop",                  false,                  set_config_cap_drop,                    get_config_cap_drop,                    clr_config_cap_drop,                  },
 	{ "lxc.cap.keep",                  false,                  set_config_cap_keep,                    get_config_cap_keep,                    clr_config_cap_keep,                  },
-	{ "lxc.cgroup",                    false,                  set_config_cgroup,                      get_config_cgroup,                      clr_config_cgroup,                    },
+	{ "lxc.cgroup.dir",                false,                  set_config_cgroup_dir,                  get_config_cgroup_dir,                  clr_config_cgroup_dir,                },
+	{ "lxc.cgroup",                    false,                  set_config_cgroup_controller,           get_config_cgroup_controller,           clr_config_cgroup_controller,         },
 	{ "lxc.console.logfile",           false,                  set_config_console_logfile,             get_config_console_logfile,             clr_config_console_logfile,           },
 	{ "lxc.console.path",              false,                  set_config_console_path,                get_config_console_path,                clr_config_console_path,              },
 	{ "lxc.environment",               false,                  set_config_environment,                 get_config_environment,                 clr_config_environment,               },
@@ -1368,8 +1370,8 @@ static int set_config_signal_stop(const char *key, const char *value,
 	return 0;
 }
 
-static int set_config_cgroup(const char *key, const char *value,
-			     struct lxc_conf *lxc_conf, void *data)
+static int set_config_cgroup_controller(const char *key, const char *value,
+					struct lxc_conf *lxc_conf, void *data)
 {
 	char *subkey;
 	char *token = "lxc.cgroup.";
@@ -1423,6 +1425,18 @@ out:
 	return -1;
 }
 
+static int set_config_cgroup_dir(const char *key, const char *value,
+				 struct lxc_conf *lxc_conf, void *data)
+{
+	if (lxc_config_value_empty(value))
+		return clr_config_cgroup_dir(key, lxc_conf, NULL);
+
+	if (lxc_conf->cgroup_meta.dir)
+		clr_config_cgroup_dir(key, lxc_conf, NULL);
+
+	return set_config_string_item(&lxc_conf->cgroup_meta.dir, value);
+}
+
 static int set_config_prlimit(const char *key, const char *value,
 			    struct lxc_conf *lxc_conf, void *data)
 {
@@ -2624,8 +2638,8 @@ static int get_config_selinux_context(const char *key, char *retv, int inlen,
  * If you ask for 'lxc.cgroup", then all cgroup entries will be printed, in
  * 'lxc.cgroup.subsystem.key = value' format.
  */
-static int get_config_cgroup(const char *key, char *retv, int inlen,
-			     struct lxc_conf *c, void *data)
+static int get_config_cgroup_controller(const char *key, char *retv, int inlen,
+					struct lxc_conf *c, void *data)
 {
 	struct lxc_list *it;
 	int len;
@@ -2658,6 +2672,22 @@ static int get_config_cgroup(const char *key, char *retv, int inlen,
 	return fulllen;
 }
 
+static int get_config_cgroup_dir(const char *key, char *retv, int inlen,
+				 struct lxc_conf *lxc_conf, void *data)
+{
+	int len;
+	int fulllen = 0;
+
+	if (!retv)
+		inlen = 0;
+	else
+		memset(retv, 0, inlen);
+
+	strprint(retv, inlen, "%s", lxc_conf->cgroup_meta.dir);
+
+	return fulllen;
+}
+
 static int get_config_idmaps(const char *key, char *retv, int inlen,
 			     struct lxc_conf *c, void *data)
 {
@@ -3197,12 +3227,23 @@ static inline int clr_config_selinux_context(const char *key,
 	return 0;
 }
 
-static inline int clr_config_cgroup(const char *key, struct lxc_conf *c,
-				    void *data)
+static inline int clr_config_cgroup_controller(const char *key,
+					       struct lxc_conf *c, void *data)
 {
 	return lxc_clear_cgroups(c, key);
 }
 
+static int clr_config_cgroup_dir(const char *key, struct lxc_conf *lxc_conf,
+				 void *data)
+{
+	if (lxc_conf->cgroup_meta.dir) {
+		free(lxc_conf->cgroup_meta.dir);
+		lxc_conf->cgroup_meta.dir = NULL;
+	}
+
+	return 0;
+}
+
 static inline int clr_config_idmaps(const char *key, struct lxc_conf *c,
 				    void *data)
 {