1// SPDX-License-Identifier: GPL-2.0
  2// Copyright (c) 2018 Facebook
  3
  4#include <stdio.h>
  5#include <stdlib.h>
  6#include <string.h>
  7#include <errno.h>
  8#include <fcntl.h>
  9#include <syscall.h>
 10#include <unistd.h>
 11#include <linux/perf_event.h>
 12#include <sys/ioctl.h>
 13#include <sys/time.h>
 14#include <sys/types.h>
 15#include <sys/stat.h>
 16
 17#include <linux/bpf.h>
 18#include <bpf/bpf.h>
 19#include <bpf/libbpf.h>
 20
 21#include "cgroup_helpers.h"
 22#include "bpf_rlimit.h"
 23
 24#define CHECK(condition, tag, format...) ({		\
 25	int __ret = !!(condition);			\
 26	if (__ret) {					\
 27		printf("%s:FAIL:%s ", __func__, tag);	\
 28		printf(format);				\
 29	} else {					\
 30		printf("%s:PASS:%s\n", __func__, tag);	\
 31	}						\
 32	__ret;						\
 33})
 34
 35static int bpf_find_map(const char *test, struct bpf_object *obj,
 36			const char *name)
 37{
 38	struct bpf_map *map;
 39
 40	map = bpf_object__find_map_by_name(obj, name);
 41	if (!map)
 42		return -1;
 43	return bpf_map__fd(map);
 44}
 45
 46#define TEST_CGROUP "/test-bpf-get-cgroup-id/"
 47
 48int main(int argc, char **argv)
 49{
 50	const char *probe_name = "syscalls/sys_enter_nanosleep";
 51	const char *file = "get_cgroup_id_kern.o";
 52	int err, bytes, efd, prog_fd, pmu_fd;
 53	int cgroup_fd, cgidmap_fd, pidmap_fd;
 54	struct perf_event_attr attr = {};
 55	struct bpf_object *obj;
 56	__u64 kcgid = 0, ucgid;
 57	__u32 key = 0, pid;
 58	int exit_code = 1;
 59	char buf[256];
 60
 61	cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
 62	if (CHECK(cgroup_fd < 0, "cgroup_setup_and_join", "err %d errno %d\n", cgroup_fd, errno))
 63		return 1;
 64
 65	err = bpf_prog_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj, &prog_fd);
 66	if (CHECK(err, "bpf_prog_load", "err %d errno %d\n", err, errno))
 67		goto cleanup_cgroup_env;
 68
 69	cgidmap_fd = bpf_find_map(__func__, obj, "cg_ids");
 70	if (CHECK(cgidmap_fd < 0, "bpf_find_map", "err %d errno %d\n",
 71		  cgidmap_fd, errno))
 72		goto close_prog;
 73
 74	pidmap_fd = bpf_find_map(__func__, obj, "pidmap");
 75	if (CHECK(pidmap_fd < 0, "bpf_find_map", "err %d errno %d\n",
 76		  pidmap_fd, errno))
 77		goto close_prog;
 78
 79	pid = getpid();
 80	bpf_map_update_elem(pidmap_fd, &key, &pid, 0);
 81
 82	snprintf(buf, sizeof(buf),
 83		 "/sys/kernel/debug/tracing/events/%s/id", probe_name);
 84	efd = open(buf, O_RDONLY, 0);
 85	if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno))
 86		goto close_prog;
 87	bytes = read(efd, buf, sizeof(buf));
 88	close(efd);
 89	if (CHECK(bytes <= 0 || bytes >= sizeof(buf), "read",
 90		  "bytes %d errno %d\n", bytes, errno))
 91		goto close_prog;
 92
 93	attr.config = strtol(buf, NULL, 0);
 94	attr.type = PERF_TYPE_TRACEPOINT;
 95	attr.sample_type = PERF_SAMPLE_RAW;
 96	attr.sample_period = 1;
 97	attr.wakeup_events = 1;
 98
 99	/* attach to this pid so the all bpf invocations will be in the
100	 * cgroup associated with this pid.
101	 */
102	pmu_fd = syscall(__NR_perf_event_open, &attr, getpid(), -1, -1, 0);
103	if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n", pmu_fd,
104		  errno))
105		goto close_prog;
106
107	err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
108	if (CHECK(err, "perf_event_ioc_enable", "err %d errno %d\n", err,
109		  errno))
110		goto close_pmu;
111
112	err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);
113	if (CHECK(err, "perf_event_ioc_set_bpf", "err %d errno %d\n", err,
114		  errno))
115		goto close_pmu;
116
117	/* trigger some syscalls */
118	sleep(1);
119
120	err = bpf_map_lookup_elem(cgidmap_fd, &key, &kcgid);
121	if (CHECK(err, "bpf_map_lookup_elem", "err %d errno %d\n", err, errno))
122		goto close_pmu;
123
124	ucgid = get_cgroup_id(TEST_CGROUP);
125	if (CHECK(kcgid != ucgid, "compare_cgroup_id",
126		  "kern cgid %llx user cgid %llx", kcgid, ucgid))
127		goto close_pmu;
128
129	exit_code = 0;
130	printf("%s:PASS\n", argv[0]);
131
132close_pmu:
133	close(pmu_fd);
134close_prog:
135	bpf_object__close(obj);
136cleanup_cgroup_env:
137	cleanup_cgroup_environment();
138	return exit_code;
139}