Commit f269099a authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov

tools/bpf: add a selftest for bpf_get_current_cgroup_id() helper

Syscall name_to_handle_at() can be used to get cgroup id
for a particular cgroup path in user space. The selftest
got cgroup id from both user and kernel, and compare to
ensure they are equal to each other.
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent c7ddbbaf
......@@ -18,3 +18,4 @@ urandom_read
test_btf
test_sockmap
test_lirc_mode2_user
get_cgroup_id_user
......@@ -24,7 +24,7 @@ urandom_read: urandom_read.c
# Order correspond to 'make run_tests' order
TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test_progs \
test_align test_verifier_log test_dev_cgroup test_tcpbpf_user \
test_sock test_btf test_sockmap test_lirc_mode2_user
test_sock test_btf test_sockmap test_lirc_mode2_user get_cgroup_id_user
TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test_obj_id.o \
test_pkt_md_access.o test_xdp_redirect.o test_xdp_meta.o sockmap_parse_prog.o \
......@@ -34,7 +34,8 @@ TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test
sockmap_tcp_msg_prog.o connect4_prog.o connect6_prog.o test_adjust_tail.o \
test_btf_haskv.o test_btf_nokv.o test_sockmap_kern.o test_tunnel_kern.o \
test_get_stack_rawtp.o test_sockmap_kern.o test_sockhash_kern.o \
test_lwt_seg6local.o sendmsg4_prog.o sendmsg6_prog.o test_lirc_mode2_kern.o
test_lwt_seg6local.o sendmsg4_prog.o sendmsg6_prog.o test_lirc_mode2_kern.o \
get_cgroup_id_kern.o
# Order correspond to 'make run_tests' order
TEST_PROGS := test_kmod.sh \
......@@ -63,6 +64,7 @@ $(OUTPUT)/test_sock: cgroup_helpers.c
$(OUTPUT)/test_sock_addr: cgroup_helpers.c
$(OUTPUT)/test_sockmap: cgroup_helpers.c
$(OUTPUT)/test_progs: trace_helpers.c
$(OUTPUT)/get_cgroup_id_user: cgroup_helpers.c
.PHONY: force
......
......@@ -6,6 +6,7 @@
#include <sys/types.h>
#include <linux/limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <linux/sched.h>
#include <fcntl.h>
#include <unistd.h>
......@@ -176,3 +177,59 @@ int create_and_get_cgroup(char *path)
return fd;
}
/**
* get_cgroup_id() - Get cgroup id for a particular cgroup path
* @path: The cgroup path, relative to the workdir, to join
*
* 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(char *path)
{
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, path);
dirfd = AT_FDCWD;
flags = 0;
fhsize = sizeof(*fhp);
fhp = calloc(1, fhsize);
if (!fhp) {
log_err("calloc");
return 0;
}
err = name_to_handle_at(dirfd, cgroup_workdir, fhp, &mount_id, flags);
if (err >= 0 || fhp->handle_bytes != 8) {
log_err("name_to_handle_at");
goto free_mem;
}
fhsize = sizeof(struct file_handle) + fhp->handle_bytes;
fhp2 = realloc(fhp, fhsize);
if (!fhp2) {
log_err("realloc");
goto free_mem;
}
err = name_to_handle_at(dirfd, cgroup_workdir, fhp2, &mount_id, flags);
fhp = fhp2;
if (err < 0) {
log_err("name_to_handle_at");
goto free_mem;
}
memcpy(id.raw_bytes, fhp->f_handle, 8);
ret = id.cgid;
free_mem:
free(fhp);
return ret;
}
......@@ -13,5 +13,6 @@ int create_and_get_cgroup(char *path);
int join_cgroup(char *path);
int setup_cgroup_environment(void);
void cleanup_cgroup_environment(void);
unsigned long long get_cgroup_id(char *path);
#endif
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2018 Facebook
#include <linux/bpf.h>
#include "bpf_helpers.h"
struct bpf_map_def SEC("maps") cg_ids = {
.type = BPF_MAP_TYPE_ARRAY,
.key_size = sizeof(__u32),
.value_size = sizeof(__u64),
.max_entries = 1,
};
SEC("tracepoint/syscalls/sys_enter_nanosleep")
int trace(void *ctx)
{
__u32 key = 0;
__u64 *val;
val = bpf_map_lookup_elem(&cg_ids, &key);
if (val)
*val = bpf_get_current_cgroup_id();
return 0;
}
char _license[] SEC("license") = "GPL";
__u32 _version SEC("version") = 1; /* ignored by tracepoints, required by libbpf.a */
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2018 Facebook
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <syscall.h>
#include <unistd.h>
#include <linux/perf_event.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <linux/bpf.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
#include "cgroup_helpers.h"
#include "bpf_rlimit.h"
#define CHECK(condition, tag, format...) ({ \
int __ret = !!(condition); \
if (__ret) { \
printf("%s:FAIL:%s ", __func__, tag); \
printf(format); \
} else { \
printf("%s:PASS:%s\n", __func__, tag); \
} \
__ret; \
})
static int bpf_find_map(const char *test, struct bpf_object *obj,
const char *name)
{
struct bpf_map *map;
map = bpf_object__find_map_by_name(obj, name);
if (!map)
return -1;
return bpf_map__fd(map);
}
#define TEST_CGROUP "/test-bpf-get-cgroup-id/"
int main(int argc, char **argv)
{
const char *probe_name = "syscalls/sys_enter_nanosleep";
const char *file = "get_cgroup_id_kern.o";
int err, bytes, efd, prog_fd, pmu_fd;
struct perf_event_attr attr = {};
int cgroup_fd, cgidmap_fd;
struct bpf_object *obj;
__u64 kcgid = 0, ucgid;
int exit_code = 1;
char buf[256];
__u32 key = 0;
err = setup_cgroup_environment();
if (CHECK(err, "setup_cgroup_environment", "err %d errno %d\n", err,
errno))
return 1;
cgroup_fd = create_and_get_cgroup(TEST_CGROUP);
if (CHECK(cgroup_fd < 0, "create_and_get_cgroup", "err %d errno %d\n",
cgroup_fd, errno))
goto cleanup_cgroup_env;
err = join_cgroup(TEST_CGROUP);
if (CHECK(err, "join_cgroup", "err %d errno %d\n", err, errno))
goto cleanup_cgroup_env;
err = bpf_prog_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj, &prog_fd);
if (CHECK(err, "bpf_prog_load", "err %d errno %d\n", err, errno))
goto cleanup_cgroup_env;
cgidmap_fd = bpf_find_map(__func__, obj, "cg_ids");
if (CHECK(cgidmap_fd < 0, "bpf_find_map", "err %d errno %d\n",
cgidmap_fd, errno))
goto close_prog;
snprintf(buf, sizeof(buf),
"/sys/kernel/debug/tracing/events/%s/id", probe_name);
efd = open(buf, O_RDONLY, 0);
if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno))
goto close_prog;
bytes = read(efd, buf, sizeof(buf));
close(efd);
if (CHECK(bytes <= 0 || bytes >= sizeof(buf), "read",
"bytes %d errno %d\n", bytes, errno))
goto close_prog;
attr.config = strtol(buf, NULL, 0);
attr.type = PERF_TYPE_TRACEPOINT;
attr.sample_type = PERF_SAMPLE_RAW;
attr.sample_period = 1;
attr.wakeup_events = 1;
/* attach to this pid so the all bpf invocations will be in the
* cgroup associated with this pid.
*/
pmu_fd = syscall(__NR_perf_event_open, &attr, getpid(), -1, -1, 0);
if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n", pmu_fd,
errno))
goto close_prog;
err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
if (CHECK(err, "perf_event_ioc_enable", "err %d errno %d\n", err,
errno))
goto close_pmu;
err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);
if (CHECK(err, "perf_event_ioc_set_bpf", "err %d errno %d\n", err,
errno))
goto close_pmu;
/* trigger some syscalls */
sleep(1);
err = bpf_map_lookup_elem(cgidmap_fd, &key, &kcgid);
if (CHECK(err, "bpf_map_lookup_elem", "err %d errno %d\n", err, errno))
goto close_pmu;
ucgid = get_cgroup_id(TEST_CGROUP);
if (CHECK(kcgid != ucgid, "compare_cgroup_id",
"kern cgid %llx user cgid %llx", kcgid, ucgid))
goto close_pmu;
exit_code = 0;
printf("%s:PASS\n", argv[0]);
close_pmu:
close(pmu_fd);
close_prog:
bpf_object__close(obj);
cleanup_cgroup_env:
cleanup_cgroup_environment();
return exit_code;
}
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment