Commit 81427a62 authored by Alexei Starovoitov's avatar Alexei Starovoitov
Browse files

Merge branch 'bpf-add-support-for-cgroup1-bpf-part' 

Yafang Shao says:

====================
bpf: Add support for cgroup1, BPF part

This is the BPF part of the series "bpf, cgroup: Add BPF support for
cgroup1 hierarchy" with adjustment in the last two patches compared
to the previous one.

v3->v4:
  - use subsys_name instead of cgrp_name in get_cgroup_hierarchy_id()
    (Tejun)
  - use local bpf_link instead of modifying the skeleton in the
    selftests
v3: https://lwn.net/Articles/949264/
====================

Link: https://lore.kernel.org/r/20231111090034.4248-1-laoar.shao@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parents 727a92d6 36076923

kernel/bpf/helpers.c

+20 −0
Original line number Diff line number Diff line
@@ -2228,6 +2228,25 @@ __bpf_kfunc long bpf_task_under_cgroup(struct task_struct *task, 
	rcu_read_unlock();

	return ret;

}



/**

 * bpf_task_get_cgroup1 - Acquires the associated cgroup of a task within a

 * specific cgroup1 hierarchy. The cgroup1 hierarchy is identified by its

 * hierarchy ID.

 * @task: The target task

 * @hierarchy_id: The ID of a cgroup1 hierarchy

 *

 * On success, the cgroup is returen. On failure, NULL is returned.

 */

__bpf_kfunc struct cgroup *

bpf_task_get_cgroup1(struct task_struct *task, int hierarchy_id)

{

	struct cgroup *cgrp = task_get_cgroup1(task, hierarchy_id);



	if (IS_ERR(cgrp))

		return NULL;

	return cgrp;

}

#endif /* CONFIG_CGROUPS */



/**
@@ -2534,6 +2553,7 @@ BTF_ID_FLAGS(func, bpf_cgroup_release, KF_RELEASE) 
BTF_ID_FLAGS(func, bpf_cgroup_ancestor, KF_ACQUIRE | KF_RCU | KF_RET_NULL)

BTF_ID_FLAGS(func, bpf_cgroup_from_id, KF_ACQUIRE | KF_RET_NULL)

BTF_ID_FLAGS(func, bpf_task_under_cgroup, KF_RCU)

BTF_ID_FLAGS(func, bpf_task_get_cgroup1, KF_ACQUIRE | KF_RCU | KF_RET_NULL)

#endif

BTF_ID_FLAGS(func, bpf_task_from_pid, KF_ACQUIRE | KF_RET_NULL)

BTF_ID_FLAGS(func, bpf_throw)

tools/testing/selftests/bpf/cgroup_helpers.c

+99 −17
Original line number Diff line number Diff line
@@ -45,9 +45,12 @@ 
#define format_parent_cgroup_path(buf, path) \

	format_cgroup_path_pid(buf, path, getppid())



#define format_classid_path_pid(buf, pid)				\

	snprintf(buf, sizeof(buf), "%s%s%d", NETCLS_MOUNT_PATH,	\

		 CGROUP_WORK_DIR, pid)



#define format_classid_path(buf)	\

	snprintf(buf, sizeof(buf), "%s%s", NETCLS_MOUNT_PATH,	\

		 CGROUP_WORK_DIR)

	format_classid_path_pid(buf, getpid())



static __thread bool cgroup_workdir_mounted;
@@ -419,26 +422,23 @@ int create_and_get_cgroup(const char *relative_path) 
}



/**

 * get_cgroup_id() - Get cgroup id for a particular cgroup path

 * @relative_path: The cgroup path, relative to the workdir, to join

 * get_cgroup_id_from_path - Get cgroup id for a particular cgroup path

 * @cgroup_workdir: The absolute cgroup path

 *

 * On success, it returns the cgroup id. On failure it returns 0,

 * which is an invalid cgroup id.

 * If there is a failure, it prints the error to stderr.

 */

unsigned long long get_cgroup_id(const char *relative_path)

unsigned long long get_cgroup_id_from_path(const char *cgroup_workdir)

{

	int dirfd, err, flags, mount_id, fhsize;

	union {

		unsigned long long cgid;

		unsigned char raw_bytes[8];

	} id;

	char cgroup_workdir[PATH_MAX + 1];

	struct file_handle *fhp, *fhp2;

	unsigned long long ret = 0;



	format_cgroup_path(cgroup_workdir, relative_path);



	dirfd = AT_FDCWD;

	flags = 0;

	fhsize = sizeof(*fhp);
@@ -474,6 +474,14 @@ unsigned long long get_cgroup_id(const char *relative_path) 
	return ret;

}



unsigned long long get_cgroup_id(const char *relative_path)

{

	char cgroup_workdir[PATH_MAX + 1];



	format_cgroup_path(cgroup_workdir, relative_path);

	return get_cgroup_id_from_path(cgroup_workdir);

}



int cgroup_setup_and_join(const char *path) {

	int cg_fd;
@@ -523,12 +531,22 @@ int setup_classid_environment(void) 
		return 1;

	}



	if (mount("net_cls", NETCLS_MOUNT_PATH, "cgroup", 0, "net_cls") &&

	    errno != EBUSY) {

	if (mount("net_cls", NETCLS_MOUNT_PATH, "cgroup", 0, "net_cls")) {

		if (errno != EBUSY) {

			log_err("mount cgroup net_cls");

			return 1;

		}



		if (rmdir(NETCLS_MOUNT_PATH)) {

			log_err("rmdir cgroup net_cls");

			return 1;

		}

		if (umount(CGROUP_MOUNT_DFLT)) {

			log_err("umount cgroup base");

			return 1;

		}

	}



	cleanup_classid_environment();



	if (mkdir(cgroup_workdir, 0777) && errno != EEXIST) {
@@ -541,15 +559,16 @@ int setup_classid_environment(void) 


/**

 * set_classid() - Set a cgroupv1 net_cls classid

 * @id: the numeric classid

 *

 * Writes the passed classid into the cgroup work dir's net_cls.classid

 * Writes the classid into the cgroup work dir's net_cls.classid

 * file in order to later on trigger socket tagging.

 *

 * We leverage the current pid as the classid, ensuring unique identification.

 *

 * On success, it returns 0, otherwise on failure it returns 1. If there

 * is a failure, it prints the error to stderr.

 */

int set_classid(unsigned int id)

int set_classid(void)

{

	char cgroup_workdir[PATH_MAX - 42];

	char cgroup_classid_path[PATH_MAX + 1];
@@ -565,7 +584,7 @@ int set_classid(unsigned int id) 
		return 1;

	}



	if (dprintf(fd, "%u\n", id) < 0) {

	if (dprintf(fd, "%u\n", getpid()) < 0) {

		log_err("Setting cgroup classid");

		rc = 1;

	}
@@ -607,3 +626,66 @@ void cleanup_classid_environment(void) 
	join_cgroup_from_top(NETCLS_MOUNT_PATH);

	nftw(cgroup_workdir, nftwfunc, WALK_FD_LIMIT, FTW_DEPTH | FTW_MOUNT);

}



/**

 * get_classid_cgroup_id - Get the cgroup id of a net_cls cgroup

 */

unsigned long long get_classid_cgroup_id(void)

{

	char cgroup_workdir[PATH_MAX + 1];



	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

+3 −1
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);
@@ -29,8 +30,9 @@ int setup_cgroup_environment(void); 
void cleanup_cgroup_environment(void);



/* cgroupv1 related */

int set_classid(unsigned int id);

int set_classid(void);

int join_classid(void);

unsigned long long get_classid_cgroup_id(void);



int setup_classid_environment(void);

void cleanup_classid_environment(void);

tools/testing/selftests/bpf/prog_tests/cgroup1_hierarchy.c

0 → 100644
+158 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/* Copyright (C) 2023 Yafang Shao <laoar.shao@gmail.com> */



#include <sys/types.h>

#include <unistd.h>

#include <test_progs.h>

#include "cgroup_helpers.h"

#include "test_cgroup1_hierarchy.skel.h"



static void bpf_cgroup1(struct test_cgroup1_hierarchy *skel)

{

	struct bpf_link *lsm_link, *fentry_link;

	int err;



	/* Attach LSM prog first */

	lsm_link = bpf_program__attach_lsm(skel->progs.lsm_run);

	if (!ASSERT_OK_PTR(lsm_link, "lsm_attach"))

		return;



	/* LSM prog will be triggered when attaching fentry */

	fentry_link = bpf_program__attach_trace(skel->progs.fentry_run);

	ASSERT_NULL(fentry_link, "fentry_attach_fail");



	err = bpf_link__destroy(lsm_link);

	ASSERT_OK(err, "destroy_lsm");

}



static void bpf_cgroup1_sleepable(struct test_cgroup1_hierarchy *skel)

{

	struct bpf_link *lsm_link, *fentry_link;

	int err;



	/* Attach LSM prog first */

	lsm_link = bpf_program__attach_lsm(skel->progs.lsm_s_run);

	if (!ASSERT_OK_PTR(lsm_link, "lsm_attach"))

		return;



	/* LSM prog will be triggered when attaching fentry */

	fentry_link = bpf_program__attach_trace(skel->progs.fentry_run);

	ASSERT_NULL(fentry_link, "fentry_attach_fail");



	err = bpf_link__destroy(lsm_link);

	ASSERT_OK(err, "destroy_lsm");

}



static void bpf_cgroup1_invalid_id(struct test_cgroup1_hierarchy *skel)

{

	struct bpf_link *lsm_link, *fentry_link;

	int err;



	/* Attach LSM prog first */

	lsm_link = bpf_program__attach_lsm(skel->progs.lsm_run);

	if (!ASSERT_OK_PTR(lsm_link, "lsm_attach"))

		return;



	/* LSM prog will be triggered when attaching fentry */

	fentry_link = bpf_program__attach_trace(skel->progs.fentry_run);

	if (!ASSERT_OK_PTR(fentry_link, "fentry_attach_success"))

		goto cleanup;



	err = bpf_link__destroy(fentry_link);

	ASSERT_OK(err, "destroy_lsm");



cleanup:

	err = bpf_link__destroy(lsm_link);

	ASSERT_OK(err, "destroy_fentry");

}



void test_cgroup1_hierarchy(void)

{

	struct test_cgroup1_hierarchy *skel;

	__u64 current_cgid;

	int hid, err;



	skel = test_cgroup1_hierarchy__open();

	if (!ASSERT_OK_PTR(skel, "open"))

		return;



	skel->bss->target_pid = getpid();



	err = bpf_program__set_attach_target(skel->progs.fentry_run, 0, "bpf_fentry_test1");

	if (!ASSERT_OK(err, "fentry_set_target"))

		goto destroy;



	err = test_cgroup1_hierarchy__load(skel);

	if (!ASSERT_OK(err, "load"))

		goto destroy;



	/* Setup cgroup1 hierarchy */

	err = setup_classid_environment();

	if (!ASSERT_OK(err, "setup_classid_environment"))

		goto destroy;



	err = join_classid();

	if (!ASSERT_OK(err, "join_cgroup1"))

		goto cleanup;



	current_cgid = get_classid_cgroup_id();

	if (!ASSERT_GE(current_cgid, 0, "cgroup1 id"))

		goto cleanup;



	hid = get_cgroup1_hierarchy_id("net_cls");

	if (!ASSERT_GE(hid, 0, "cgroup1 id"))

		goto cleanup;

	skel->bss->target_hid = hid;



	if (test__start_subtest("test_cgroup1_hierarchy")) {

		skel->bss->target_ancestor_cgid = current_cgid;

		bpf_cgroup1(skel);

	}



	if (test__start_subtest("test_root_cgid")) {

		skel->bss->target_ancestor_cgid = 1;

		skel->bss->target_ancestor_level = 0;

		bpf_cgroup1(skel);

	}



	if (test__start_subtest("test_invalid_level")) {

		skel->bss->target_ancestor_cgid = 1;

		skel->bss->target_ancestor_level = 1;

		bpf_cgroup1_invalid_id(skel);

	}



	if (test__start_subtest("test_invalid_cgid")) {

		skel->bss->target_ancestor_cgid = 0;

		bpf_cgroup1_invalid_id(skel);

	}



	if (test__start_subtest("test_invalid_hid")) {

		skel->bss->target_ancestor_cgid = 1;

		skel->bss->target_ancestor_level = 0;

		skel->bss->target_hid = -1;

		bpf_cgroup1_invalid_id(skel);

	}



	if (test__start_subtest("test_invalid_cgrp_name")) {

		skel->bss->target_hid = get_cgroup1_hierarchy_id("net_cl");

		skel->bss->target_ancestor_cgid = current_cgid;

		bpf_cgroup1_invalid_id(skel);

	}



	if (test__start_subtest("test_invalid_cgrp_name2")) {

		skel->bss->target_hid = get_cgroup1_hierarchy_id("net_cls,");

		skel->bss->target_ancestor_cgid = current_cgid;

		bpf_cgroup1_invalid_id(skel);

	}



	if (test__start_subtest("test_sleepable_prog")) {

		skel->bss->target_hid = hid;

		skel->bss->target_ancestor_cgid = current_cgid;

		bpf_cgroup1_sleepable(skel);

	}



cleanup:

	cleanup_classid_environment();

destroy:

	test_cgroup1_hierarchy__destroy(skel);

}

tools/testing/selftests/bpf/prog_tests/cgroup_v1v2.c

+1 −1
Original line number Diff line number Diff line
@@ -71,7 +71,7 @@ void test_cgroup_v1v2(void) 
	}

	ASSERT_OK(run_test(cgroup_fd, server_fd, false), "cgroup-v2-only");

	setup_classid_environment();

	set_classid(42);

	set_classid();

	ASSERT_OK(run_test(cgroup_fd, server_fd, true), "cgroup-v1v2");

	cleanup_classid_environment();

	close(server_fd);