tools/testing/selftests/bpf/prog_tests/task_fd_query_tp.c

// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>

static void test_task_fd_query_tp_core(const char *probe_name,
				       const char *tp_name)
{
	const char *file = "./test_tracepoint.o";
	int err, bytes, efd, prog_fd, pmu_fd;
	struct perf_event_attr attr = {};
	__u64 probe_offset, probe_addr;
	__u32 len, prog_id, fd_type;
	struct bpf_object *obj = NULL;
	__u32 duration = 0;
	char buf[256];

	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 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;
	pmu_fd = syscall(__NR_perf_event_open, &attr, -1 /* pid */,
			 0 /* cpu 0 */, -1 /* group id */,
			 0 /* flags */);
	if (CHECK(err, "perf_event_open", "err %d errno %d\n", err, errno))
		goto close_pmu;

	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;

	/* query (getpid(), pmu_fd) */
	len = sizeof(buf);
	err = bpf_task_fd_query(getpid(), pmu_fd, 0, buf, &len, &prog_id,
				&fd_type, &probe_offset, &probe_addr);
	if (CHECK(err < 0, "bpf_task_fd_query", "err %d errno %d\n", err,
		  errno))
		goto close_pmu;

	err = (fd_type == BPF_FD_TYPE_TRACEPOINT) && !strcmp(buf, tp_name);
	if (CHECK(!err, "check_results", "fd_type %d tp_name %s\n",
		  fd_type, buf))
		goto close_pmu;

close_pmu:
	close(pmu_fd);
close_prog:
	bpf_object__close(obj);
}

void test_task_fd_query_tp(void)
{
	test_task_fd_query_tp_core("sched/sched_switch",
				   "sched_switch");
	test_task_fd_query_tp_core("syscalls/sys_enter_read",
				   "sys_enter_read");
}