Commit bf47300b authored by Yafang Shao's avatar Yafang Shao Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add a new cgroup helper get_cgroup_hierarchy_id() 



A new cgroup helper function, get_cgroup1_hierarchy_id(), has been
introduced to obtain the ID of a cgroup1 hierarchy based on the provided
cgroup name. This cgroup name can be obtained from the /proc/self/cgroup
file.

Signed-off-by: default avatarYafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20231111090034.4248-6-laoar.shao@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent c1dcc050

tools/testing/selftests/bpf/cgroup_helpers.c

+52 −0
Original line number Diff line number Diff line
@@ -637,3 +637,55 @@ unsigned long long get_classid_cgroup_id(void) 
	format_classid_path(cgroup_workdir);

	return get_cgroup_id_from_path(cgroup_workdir);

}



/**

 * get_cgroup1_hierarchy_id - Retrieves the ID of a cgroup1 hierarchy from the cgroup1 subsys name.

 * @subsys_name: The cgroup1 subsys name, which can be retrieved from /proc/self/cgroup. It can be

 * a named cgroup like "name=systemd", a controller name like "net_cls", or multi-contollers like

 * "net_cls,net_prio".

 */

int get_cgroup1_hierarchy_id(const char *subsys_name)

{

	char *c, *c2, *c3, *c4;

	bool found = false;

	char line[1024];

	FILE *file;

	int i, id;



	if (!subsys_name)

		return -1;



	file = fopen("/proc/self/cgroup", "r");

	if (!file) {

		log_err("fopen /proc/self/cgroup");

		return -1;

	}



	while (fgets(line, 1024, file)) {

		i = 0;

		for (c = strtok_r(line, ":", &c2); c && i < 2; c = strtok_r(NULL, ":", &c2)) {

			if (i == 0) {

				id = strtol(c, NULL, 10);

			} else if (i == 1) {

				if (!strcmp(c, subsys_name)) {

					found = true;

					break;

				}



				/* Multiple subsystems may share one single mount point */

				for (c3 = strtok_r(c, ",", &c4); c3;

				     c3 = strtok_r(NULL, ",", &c4)) {

					if (!strcmp(c, subsys_name)) {

						found = true;

						break;

					}

				}

			}

			i++;

		}

		if (found)

			break;

	}

	fclose(file);

	return found ? id : -1;

}

tools/testing/selftests/bpf/cgroup_helpers.h

+1 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ int get_root_cgroup(void); 
int create_and_get_cgroup(const char *relative_path);

void remove_cgroup(const char *relative_path);

unsigned long long get_cgroup_id(const char *relative_path);

int get_cgroup1_hierarchy_id(const char *subsys_name);



int join_cgroup(const char *relative_path);

int join_root_cgroup(void);