bpf: move cgroup_helpers from samples/bpf/ to tools/testing/selftesting/bpf/

The purpose of this move is to use these files in bpf tests.

Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 3 insertions, 197 deletions

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 6a9321e..5994075 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -46,6 +46,7 @@ hostprogs-y += syscall_tp
 
 # Libbpf dependencies
 LIBBPF := ../../tools/lib/bpf/bpf.o
+CGROUP_HELPERS := ../../tools/testing/selftests/bpf/cgroup_helpers.o
 
 test_lru_dist-objs := test_lru_dist.o $(LIBBPF)
 sock_example-objs := sock_example.o $(LIBBPF)
@@ -69,13 +70,13 @@ map_perf_test-objs := bpf_load.o $(LIBBPF) map_perf_test_user.o
 test_overhead-objs := bpf_load.o $(LIBBPF) test_overhead_user.o
 test_cgrp2_array_pin-objs := $(LIBBPF) test_cgrp2_array_pin.o
 test_cgrp2_attach-objs := $(LIBBPF) test_cgrp2_attach.o
-test_cgrp2_attach2-objs := $(LIBBPF) test_cgrp2_attach2.o cgroup_helpers.o
+test_cgrp2_attach2-objs := $(LIBBPF) test_cgrp2_attach2.o $(CGROUP_HELPERS)
 test_cgrp2_sock-objs := $(LIBBPF) test_cgrp2_sock.o
 test_cgrp2_sock2-objs := bpf_load.o $(LIBBPF) test_cgrp2_sock2.o
 xdp1-objs := bpf_load.o $(LIBBPF) xdp1_user.o
 # reuse xdp1 source intentionally
 xdp2-objs := bpf_load.o $(LIBBPF) xdp1_user.o
-test_current_task_under_cgroup-objs := bpf_load.o $(LIBBPF) cgroup_helpers.o \
+test_current_task_under_cgroup-objs := bpf_load.o $(LIBBPF) $(CGROUP_HELPERS) \
 				       test_current_task_under_cgroup_user.o
 trace_event-objs := bpf_load.o $(LIBBPF) trace_event_user.o
 sampleip-objs := bpf_load.o $(LIBBPF) sampleip_user.o
diff --git a/samples/bpf/cgroup_helpers.c b/samples/bpf/cgroup_helpers.c
deleted file mode 100644
index f3bca3a..0000000
--- a/samples/bpf/cgroup_helpers.c
+++ /dev/null
@@ -1,178 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#define _GNU_SOURCE
-#include <sched.h>
-#include <sys/mount.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <linux/limits.h>
-#include <stdio.h>
-#include <linux/sched.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <ftw.h>
-
-
-#include "cgroup_helpers.h"
-
-/*
- * To avoid relying on the system setup, when setup_cgroup_env is called
- * we create a new mount namespace, and cgroup namespace. The cgroup2
- * root is mounted at CGROUP_MOUNT_PATH
- *
- * Unfortunately, most people don't have cgroupv2 enabled at this point in time.
- * It's easier to create our own mount namespace and manage it ourselves.
- *
- * We assume /mnt exists.
- */
-
-#define WALK_FD_LIMIT			16
-#define CGROUP_MOUNT_PATH		"/mnt"
-#define CGROUP_WORK_DIR			"/cgroup-test-work-dir"
-#define format_cgroup_path(buf, path) \
-	snprintf(buf, sizeof(buf), "%s%s%s", CGROUP_MOUNT_PATH, \
-		 CGROUP_WORK_DIR, path)
-
-/**
- * setup_cgroup_environment() - Setup the cgroup environment
- *
- * After calling this function, cleanup_cgroup_environment should be called
- * once testing is complete.
- *
- * This function will print an error to stderr and return 1 if it is unable
- * to setup the cgroup environment. If setup is successful, 0 is returned.
- */
-int setup_cgroup_environment(void)
-{
-	char cgroup_workdir[PATH_MAX + 1];
-
-	format_cgroup_path(cgroup_workdir, "");
-
-	if (unshare(CLONE_NEWNS)) {
-		log_err("unshare");
-		return 1;
-	}
-
-	if (mount("none", "/", NULL, MS_REC | MS_PRIVATE, NULL)) {
-		log_err("mount fakeroot");
-		return 1;
-	}
-
-	if (mount("none", CGROUP_MOUNT_PATH, "cgroup2", 0, NULL) && errno != EBUSY) {
-		log_err("mount cgroup2");
-		return 1;
-	}
-
-	/* Cleanup existing failed runs, now that the environment is setup */
-	cleanup_cgroup_environment();
-
-	if (mkdir(cgroup_workdir, 0777) && errno != EEXIST) {
-		log_err("mkdir cgroup work dir");
-		return 1;
-	}
-
-	return 0;
-}
-
-static int nftwfunc(const char *filename, const struct stat *statptr,
-		    int fileflags, struct FTW *pfwt)
-{
-	if ((fileflags & FTW_D) && rmdir(filename))
-		log_err("Removing cgroup: %s", filename);
-	return 0;
-}
-
-
-static int join_cgroup_from_top(char *cgroup_path)
-{
-	char cgroup_procs_path[PATH_MAX + 1];
-	pid_t pid = getpid();
-	int fd, rc = 0;
-
-	snprintf(cgroup_procs_path, sizeof(cgroup_procs_path),
-		 "%s/cgroup.procs", cgroup_path);
-
-	fd = open(cgroup_procs_path, O_WRONLY);
-	if (fd < 0) {
-		log_err("Opening Cgroup Procs: %s", cgroup_procs_path);
-		return 1;
-	}
-
-	if (dprintf(fd, "%d\n", pid) < 0) {
-		log_err("Joining Cgroup");
-		rc = 1;
-	}
-
-	close(fd);
-	return rc;
-}
-
-/**
- * join_cgroup() - Join a cgroup
- * @path: The cgroup path, relative to the workdir, to join
- *
- * This function expects a cgroup to already be created, relative to the cgroup
- * work dir, and it joins it. For example, passing "/my-cgroup" as the path
- * would actually put the calling process into the cgroup
- * "/cgroup-test-work-dir/my-cgroup"
- *
- * On success, it returns 0, otherwise on failure it returns 1.
- */
-int join_cgroup(char *path)
-{
-	char cgroup_path[PATH_MAX + 1];
-
-	format_cgroup_path(cgroup_path, path);
-	return join_cgroup_from_top(cgroup_path);
-}
-
-/**
- * cleanup_cgroup_environment() - Cleanup Cgroup Testing Environment
- *
- * This is an idempotent function to delete all temporary cgroups that
- * have been created during the test, including the cgroup testing work
- * directory.
- *
- * At call time, it moves the calling process to the root cgroup, and then
- * runs the deletion process. It is idempotent, and should not fail, unless
- * a process is lingering.
- *
- * On failure, it will print an error to stderr, and try to continue.
- */
-void cleanup_cgroup_environment(void)
-{
-	char cgroup_workdir[PATH_MAX + 1];
-
-	format_cgroup_path(cgroup_workdir, "");
-	join_cgroup_from_top(CGROUP_MOUNT_PATH);
-	nftw(cgroup_workdir, nftwfunc, WALK_FD_LIMIT, FTW_DEPTH | FTW_MOUNT);
-}
-
-/**
- * create_and_get_cgroup() - Create a cgroup, relative to workdir, and get the FD
- * @path: The cgroup path, relative to the workdir, to join
- *
- * This function creates a cgroup under the top level workdir and returns the
- * file descriptor. It is idempotent.
- *
- * On success, it returns the file descriptor. On failure it returns 0.
- * If there is a failure, it prints the error to stderr.
- */
-int create_and_get_cgroup(char *path)
-{
-	char cgroup_path[PATH_MAX + 1];
-	int fd;
-
-	format_cgroup_path(cgroup_path, path);
-	if (mkdir(cgroup_path, 0777) && errno != EEXIST) {
-		log_err("mkdiring cgroup %s .. %s", path, cgroup_path);
-		return 0;
-	}
-
-	fd = open(cgroup_path, O_RDONLY);
-	if (fd < 0) {
-		log_err("Opening Cgroup");
-		return 0;
-	}
-
-	return fd;
-}
diff --git a/samples/bpf/cgroup_helpers.h b/samples/bpf/cgroup_helpers.h
deleted file mode 100644
index 06485e0..0000000
--- a/samples/bpf/cgroup_helpers.h
+++ /dev/null
@@ -1,17 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __CGROUP_HELPERS_H
-#define __CGROUP_HELPERS_H
-#include <errno.h>
-#include <string.h>
-
-#define clean_errno() (errno == 0 ? "None" : strerror(errno))
-#define log_err(MSG, ...) fprintf(stderr, "(%s:%d: errno: %s) " MSG "\n", \
-	__FILE__, __LINE__, clean_errno(), ##__VA_ARGS__)
-
-
-int create_and_get_cgroup(char *path);
-int join_cgroup(char *path);
-int setup_cgroup_environment(void);
-void cleanup_cgroup_environment(void);
-
-#endif