From: Tom Hromatka <tom.hromatka@oracle.com>
Date: Wed, 15 Dec 2021 19:30:30 +0000 (+0000)
Subject: wrapper.c: Store the version in struct cgroup_controller
X-Git-Tag: v3.0~241
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=251ca6c987b0cc1c88119dd74cec4d9858050ac7;p=thirdparty%2Flibcgroup.git

wrapper.c: Store the version in struct cgroup_controller

Store the cgroup version in struct cgroup_controller.  Each
controller can be mounted separately, and thus the cgroup
version is applicable at the controller level.

Note that this commit requires cgroup_init() to be called by
cgconfigparser.  Storing the version in the cgroup_controller
struct requires the cg_mount_table[] to be populated.

Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>
Reviewed-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
---

diff --git a/src/libcgroup-internal.h b/src/libcgroup-internal.h
index 160a189f..dd390cc7 100644
--- a/src/libcgroup-internal.h
+++ b/src/libcgroup-internal.h
@@ -101,6 +101,7 @@ struct cgroup_controller {
 	struct control_value *values[CG_NV_MAX];
 	struct cgroup *cgroup;
 	int index;
+	enum cg_version_t version;
 };
 
 struct cgroup {
diff --git a/src/tools/cgconfig.c b/src/tools/cgconfig.c
index e8bb5a2e..b5058db4 100644
--- a/src/tools/cgconfig.c
+++ b/src/tools/cgconfig.c
@@ -94,6 +94,13 @@ int main(int argc, char *argv[])
 		return -1;
 	}
 
+	ret = cgroup_init();
+	if (ret) {
+		fprintf(stderr, "%s: libcgroup initialization failed: %s\n",
+			argv[0], cgroup_strerror(ret));
+		goto err;
+	}
+
 	error = cgroup_string_list_init(&cfg_files, argc/2);
 	if (error)
 		goto err;
diff --git a/src/tools/cgget.c b/src/tools/cgget.c
index e9e29fd2..01fae3c8 100644
--- a/src/tools/cgget.c
+++ b/src/tools/cgget.c
@@ -113,7 +113,9 @@ static int parse_a_flag(struct cgroup **cg_list[], int * const cg_list_len)
 		if (!cgc) {
 			cgc = cgroup_add_controller(cg, controller.name);
 			if (!cgc) {
-				ret = ECGCONTROLLERCREATEFAILED;
+				fprintf(stderr, "cgget: cannot find controller '%s'\n",
+					controller.name);
+				ret = ECGOTHER;
 				goto out;
 			}
 		}
@@ -163,7 +165,9 @@ static int parse_r_flag(struct cgroup **cg_list[], int * const cg_list_len,
 	if (!cgc) {
 		cgc = cgroup_add_controller(cg, cntl_value_controller);
 		if (!cgc) {
-			ret = ECGCONTROLLERCREATEFAILED;
+			fprintf(stderr, "cgget: cannot find controller '%s'\n",
+				cntl_value_controller);
+			ret = ECGOTHER;
 			goto out;
 		}
 	}
@@ -204,7 +208,9 @@ static int parse_g_flag_no_colon(struct cgroup **cg_list[],
 	if (!cgc) {
 		cgc = cgroup_add_controller(cg, ctrl_str);
 		if (!cgc) {
-			ret = ECGCONTROLLERCREATEFAILED;
+			fprintf(stderr, "cgget: cannot find controller '%s'\n",
+				ctrl_str);
+			ret = ECGOTHER;
 			goto out;
 		}
 	}
@@ -296,7 +302,9 @@ static int parse_g_flag_with_colon(struct cgroup **cg_list[],
 		if (!cgc) {
 			cgc = cgroup_add_controller(cg, controllers[i]);
 			if (!cgc) {
-				ret = ECGCONTROLLERCREATEFAILED;
+				fprintf(stderr, "cgget: cannot find controller '%s'\n",
+					controllers[i]);
+				ret = ECGOTHER;
 				goto out;
 			}
 		}
diff --git a/src/wrapper.c b/src/wrapper.c
index 98ebcc26..2b287656 100644
--- a/src/wrapper.c
+++ b/src/wrapper.c
@@ -56,7 +56,7 @@ struct cgroup *cgroup_new_cgroup(const char *name)
 struct cgroup_controller *cgroup_add_controller(struct cgroup *cgroup,
 							const char *name)
 {
-	int i;
+	int i, ret;
 	struct cgroup_controller *controller;
 
 	if (!cgroup)
@@ -86,6 +86,23 @@ struct cgroup_controller *cgroup_add_controller(struct cgroup *cgroup,
 	controller->cgroup = cgroup;
 	controller->index = 0;
 
+	if (strcmp(controller->name, CGROUP_FILE_PREFIX) == 0) {
+		/*
+		 * Operating on the "cgroup" controller is only allowed on
+		 * cgroup v2 systems
+		 */
+		controller->version = CGROUP_V2;
+	} else {
+		ret = cgroup_get_controller_version(controller->name,
+						    &controller->version);
+		if (ret) {
+			cgroup_dbg("failed to get cgroup version for controller %s\n",
+				   controller->name);
+			free(controller);
+			return NULL;
+		}
+	}
+
 	cgroup->controller[cgroup->index] = controller;
 	cgroup->index++;