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	const struct timespec req = {
 61		.tv_sec = 1,
 62		.tv_nsec = 0,
 63	};
 64
 65	cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
 66	if (CHECK(cgroup_fd < 0, "cgroup_setup_and_join", "err %d errno %d\n", cgroup_fd, errno))
 67		return 1;
 68
 69	err = bpf_prog_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj, &prog_fd);
 70	if (CHECK(err, "bpf_prog_load", "err %d errno %d\n", err, errno))
 71		goto cleanup_cgroup_env;
 72
 73	cgidmap_fd = bpf_find_map(__func__, obj, "cg_ids");
 74	if (CHECK(cgidmap_fd < 0, "bpf_find_map", "err %d errno %d\n",
 75		  cgidmap_fd, errno))
 76		goto close_prog;
 77
 78	pidmap_fd = bpf_find_map(__func__, obj, "pidmap");
 79	if (CHECK(pidmap_fd < 0, "bpf_find_map", "err %d errno %d\n",
 80		  pidmap_fd, errno))
 81		goto close_prog;
 82
 83	pid = getpid();
 84	bpf_map_update_elem(pidmap_fd, &key, &pid, 0);
 85
 86	snprintf(buf, sizeof(buf),
 87		 "/sys/kernel/debug/tracing/events/%s/id", probe_name);
 88	efd = open(buf, O_RDONLY, 0);
 89	if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno))
 90		goto close_prog;
 91	bytes = read(efd, buf, sizeof(buf));
 92	close(efd);
 93	if (CHECK(bytes <= 0 || bytes >= sizeof(buf), "read",
 94		  "bytes %d errno %d\n", bytes, errno))
 95		goto close_prog;
 96
 97	attr.config = strtol(buf, NULL, 0);
 98	attr.type = PERF_TYPE_TRACEPOINT;
 99	attr.sample_type = PERF_SAMPLE_RAW;
100	attr.sample_period = 1;
101	attr.wakeup_events = 1;
102
103	/* attach to this pid so the all bpf invocations will be in the
104	 * cgroup associated with this pid.
105	 */
106	pmu_fd = syscall(__NR_perf_event_open, &attr, getpid(), -1, -1, 0);
107	if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n", pmu_fd,
108		  errno))
109		goto close_prog;
110
111	err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
112	if (CHECK(err, "perf_event_ioc_enable", "err %d errno %d\n", err,
113		  errno))
114		goto close_pmu;
115
116	err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);
117	if (CHECK(err, "perf_event_ioc_set_bpf", "err %d errno %d\n", err,
118		  errno))
119		goto close_pmu;
120
121	/* trigger some syscalls */
122	syscall(__NR_nanosleep, &req, NULL);
123
124	err = bpf_map_lookup_elem(cgidmap_fd, &key, &kcgid);
125	if (CHECK(err, "bpf_map_lookup_elem", "err %d errno %d\n", err, errno))
126		goto close_pmu;
127
128	ucgid = get_cgroup_id(TEST_CGROUP);
129	if (CHECK(kcgid != ucgid, "compare_cgroup_id",
130		  "kern cgid %llx user cgid %llx", kcgid, ucgid))
131		goto close_pmu;
132
133	exit_code = 0;
134	printf("%s:PASS\n", argv[0]);
135
136close_pmu:
137	close(pmu_fd);
138close_prog:
139	bpf_object__close(obj);
140cleanup_cgroup_env:
141	cleanup_cgroup_environment();
142	return exit_code;
143}