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 "testing_helpers.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.bpf.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	/* Use libbpf 1.0 API mode */
 70	libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
 71
 72	err = bpf_prog_test_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj, &prog_fd);
 73	if (CHECK(err, "bpf_prog_test_load", "err %d errno %d\n", err, errno))
 74		goto cleanup_cgroup_env;
 75
 76	cgidmap_fd = bpf_find_map(__func__, obj, "cg_ids");
 77	if (CHECK(cgidmap_fd < 0, "bpf_find_map", "err %d errno %d\n",
 78		  cgidmap_fd, errno))
 79		goto close_prog;
 80
 81	pidmap_fd = bpf_find_map(__func__, obj, "pidmap");
 82	if (CHECK(pidmap_fd < 0, "bpf_find_map", "err %d errno %d\n",
 83		  pidmap_fd, errno))
 84		goto close_prog;
 85
 86	pid = getpid();
 87	bpf_map_update_elem(pidmap_fd, &key, &pid, 0);
 88
 89	if (access("/sys/kernel/tracing/trace", F_OK) == 0) {
 90		snprintf(buf, sizeof(buf),
 91			 "/sys/kernel/tracing/events/%s/id", probe_name);
 92	} else {
 93		snprintf(buf, sizeof(buf),
 94			 "/sys/kernel/debug/tracing/events/%s/id", probe_name);
 95	}
 96	efd = open(buf, O_RDONLY, 0);
 97	if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno))
 98		goto close_prog;
 99	bytes = read(efd, buf, sizeof(buf));
100	close(efd);
101	if (CHECK(bytes <= 0 || bytes >= sizeof(buf), "read",
102		  "bytes %d errno %d\n", bytes, errno))
103		goto close_prog;
104
105	attr.config = strtol(buf, NULL, 0);
106	attr.type = PERF_TYPE_TRACEPOINT;
107	attr.sample_type = PERF_SAMPLE_RAW;
108	attr.sample_period = 1;
109	attr.wakeup_events = 1;
110
111	/* attach to this pid so the all bpf invocations will be in the
112	 * cgroup associated with this pid.
113	 */
114	pmu_fd = syscall(__NR_perf_event_open, &attr, getpid(), -1, -1, 0);
115	if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n", pmu_fd,
116		  errno))
117		goto close_prog;
118
119	err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
120	if (CHECK(err, "perf_event_ioc_enable", "err %d errno %d\n", err,
121		  errno))
122		goto close_pmu;
123
124	err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);
125	if (CHECK(err, "perf_event_ioc_set_bpf", "err %d errno %d\n", err,
126		  errno))
127		goto close_pmu;
128
129	/* trigger some syscalls */
130	syscall(__NR_nanosleep, &req, NULL);
131
132	err = bpf_map_lookup_elem(cgidmap_fd, &key, &kcgid);
133	if (CHECK(err, "bpf_map_lookup_elem", "err %d errno %d\n", err, errno))
134		goto close_pmu;
135
136	ucgid = get_cgroup_id(TEST_CGROUP);
137	if (CHECK(kcgid != ucgid, "compare_cgroup_id",
138		  "kern cgid %llx user cgid %llx", kcgid, ucgid))
139		goto close_pmu;
140
141	exit_code = 0;
142	printf("%s:PASS\n", argv[0]);
143
144close_pmu:
145	close(pmu_fd);
146close_prog:
147	bpf_object__close(obj);
148cleanup_cgroup_env:
149	cleanup_cgroup_environment();
150	return exit_code;
151}