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

// SPDX-License-Identifier: GPL-2.0
#include <ctype.h>
#include <fcntl.h>
#include <poll.h>
#include <signal.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include <test_progs.h>
#include "bpftool_helpers.h"
#include "bpftool_ringbuf.skel.h"

#define WAIT_STEPS 500
#define WAIT_US 10000

struct consumer {
	pid_t pid;
	int fd;
};

static void consumer_cleanup(struct consumer *child)
{
	if (child->pid > 0) {
		kill(child->pid, SIGKILL);
		while (waitpid(child->pid, NULL, 0) < 0 && errno == EINTR)
			;
		child->pid = -1;
	}
	if (child->fd >= 0) {
		close(child->fd);
		child->fd = -1;
	}
}

static bool consumer_start(struct consumer *child, int map_fd, const char *format,
			   const char *pin_path, const char *option,
			   bool pair, bool capture_errors)
{
	struct bpf_map_info info = {};
	__u32 len = sizeof(info);
	char path[PATH_MAX];
	char *argv[12], id[16];
	int out[2], ready[2], n = 0, err, err_fd;
	struct pollfd pfd;

	if (!ASSERT_OK(detect_bpftool_path(path, sizeof(path)), "bpftool path") ||
	    !ASSERT_OK(bpf_map_get_info_by_fd(map_fd, &info, &len), "map info"))
		return false;
	snprintf(id, sizeof(id), "%u", info.id);
	argv[n++] = path;
	if (format)
		argv[n++] = (char *)format;
	argv[n++] = "map";
	argv[n++] = "event_pipe";
	argv[n++] = pin_path ? "pinned" : "id";
	argv[n++] = pin_path ? (char *)pin_path : id;
	if (option) {
		argv[n++] = (char *)option;
		argv[n++] = "0";
		if (pair) {
			argv[n++] = "index";
			argv[n++] = "0";
		}
	}
	argv[n] = NULL;
	if (!ASSERT_OK(pipe2(out, O_CLOEXEC), "output pipe"))
		return false;
	if (!ASSERT_OK(pipe2(ready, O_CLOEXEC), "exec pipe")) {
		close(out[0]);
		close(out[1]);
		return false;
	}
	child->pid = fork();
	if (!child->pid) {
		close(out[0]);
		close(ready[0]);
		err_fd = capture_errors ? out[1] : open("/dev/null", O_WRONLY);
		if (dup2(out[1], STDOUT_FILENO) < 0 ||
		    dup2(err_fd, STDERR_FILENO) < 0)
			goto exec_fail;
		if (!capture_errors)
			close(err_fd);
		close(out[1]);
		execv(path, argv);
exec_fail:
		err = errno;
		if (write(ready[1], &err, sizeof(err)) != sizeof(err))
			_exit(126);
		_exit(127);
	}
	close(out[1]);
	close(ready[1]);
	child->fd = out[0];
	pfd = (struct pollfd) { .fd = ready[0], .events = POLLIN };
	/* EOF on the close-on-exec pipe distinguishes exec from inherited handlers. */
	err = child->pid > 0 ? poll(&pfd, 1, WAIT_STEPS * WAIT_US / 1000) : -1;
	if (!ASSERT_GT(child->pid, 0, "fork") ||
	    !ASSERT_GT(err, 0, "exec timeout") ||
	    !ASSERT_EQ(read(ready[0], &err, sizeof(err)), 0, "exec")) {
		close(ready[0]);
		consumer_cleanup(child);
		return false;
	}
	close(ready[0]);
	return true;
}

static bool consumer_finish(struct consumer *child, int signo, bool success,
			    char *output, size_t size)
{
	int status = 0, i;
	pid_t ret = 0;
	ssize_t n;
	size_t used = 0;

	if (!ASSERT_OK(fcntl(child->fd, F_SETFL, O_NONBLOCK), "nonblocking output"))
		return false;
	if (signo && !ASSERT_OK(kill(child->pid, signo), "signal consumer"))
		return false;
	for (i = 0; i < WAIT_STEPS; i++) {
		while (used < size - 1 &&
		       (n = read(child->fd, output + used, size - 1 - used)) > 0)
			used += n;
		ret = waitpid(child->pid, &status, WNOHANG);
		if (ret == child->pid)
			break;
		if (ret < 0 && errno != EINTR)
			break;
		usleep(WAIT_US);
	}
	if (!ASSERT_EQ(ret, child->pid, "bounded consumer exit"))
		return false;
	child->pid = -1;
	while (used < size - 1 && (n = read(child->fd, output + used, size - 1 - used)) > 0)
		used += n;
	output[used] = '\0';
	return ASSERT_TRUE(WIFEXITED(status), "normal exit") &&
	       ASSERT_EQ(WEXITSTATUS(status) == 0, success, "exit status");
}

static bool consumer_ready(struct consumer *child)
{
	unsigned long long caught;
	char path[64], line[256];
	int i;
	FILE *f;

	snprintf(path, sizeof(path), "/proc/%d/status", child->pid);
	for (i = 0; i < WAIT_STEPS; i++) {
		f = fopen(path, "r");
		if (!f)
			break;
		while (fgets(line, sizeof(line), f)) {
			if (sscanf(line, "SigCgt: %llx", &caught) == 1 &&
			    (caught & (1ULL << (SIGINT - 1))) &&
			    (caught & (1ULL << (SIGTERM - 1)))) {
				fclose(f);
				return true;
			}
		}
		fclose(f);
		usleep(WAIT_US);
	}
	return ASSERT_TRUE(false, "consumer signal handlers ready");
}

static bool emit_record(struct bpftool_ringbuf *skel, int record)
{
	char packet[64] = {};

	LIBBPF_OPTS(bpf_test_run_opts, opts,
		    .data_in = packet,
		    .data_size_in = sizeof(packet),
	);

	skel->bss->record = record;
	return ASSERT_OK(bpf_prog_test_run_opts(bpf_program__fd(skel->progs.produce),
					      &opts), "produce record") &&
	       ASSERT_OK(skel->bss->output_err, "ringbuf output");
}

static bool consumed(unsigned long *position, unsigned long expected)
{
	int i;

	for (i = 0; i < WAIT_STEPS; i++) {
		if (__atomic_load_n(position, __ATOMIC_ACQUIRE) == expected)
			return true;
		usleep(WAIT_US);
	}
	return ASSERT_EQ(*position, expected, "consumer position");
}

static void check_json(char *output, const char *expected)
{
	char *src = output, *dst = output;
	bool quoted = false, escaped = false;

	/* Ignore formatting whitespace while checking the entire JSON document. */
	while (*src) {
		if (quoted || !isspace((unsigned char)*src))
			*dst++ = *src;
		if (!escaped && *src == '"')
			quoted = !quoted;
		escaped = !escaped && quoted && *src == '\\';
		src++;
	}
	*dst = '\0';
	ASSERT_STREQ(output, expected, "JSON records");
}

static void test_consumer(const char *format, bool idle, int signo, bool pinned)
{
	struct consumer child = { .pid = -1, .fd = -1 };
	struct bpftool_ringbuf *skel;
	unsigned long *position = MAP_FAILED;
	int page_size = getpagesize(), fd;
	char pin_dir[] = "/sys/fs/bpf/bpftool_ringbuf_XXXXXX";
	char pin_path[sizeof(pin_dir) + sizeof("/map")];
	bool dir_created = false, map_pinned = false;
	char output[4096];
	struct pollfd pfd;

	skel = bpftool_ringbuf__open();
	if (!ASSERT_OK_PTR(skel, "open"))
		return;
	bpf_map__set_max_entries(skel->maps.ringbuf, page_size);
	if (!ASSERT_OK(bpftool_ringbuf__load(skel), "load"))
		goto out;
	fd = bpf_map__fd(skel->maps.ringbuf);
	if (pinned) {
		if (!ASSERT_OK_PTR(mkdtemp(pin_dir), "create pin directory"))
			goto out;
		dir_created = true;
		snprintf(pin_path, sizeof(pin_path), "%s/map", pin_dir);
		if (!ASSERT_OK(bpf_obj_pin(fd, pin_path), "pin ringbuf"))
			goto out;
		map_pinned = true;
	}
	position = mmap(NULL, page_size, PROT_READ, MAP_SHARED, fd, 0);
	if (!ASSERT_NEQ(position, MAP_FAILED, "consumer mmap"))
		goto out;
	if (!idle && (!emit_record(skel, 0) || !emit_record(skel, 1)))
		goto out;
	if (!consumer_start(&child, fd, format, pinned ? pin_path : NULL,
			    NULL, false, false) ||
	    !consumer_ready(&child))
		goto out;
	if (!idle) {
		/* Both prefilled records occupy 16 bytes including their headers. */
		if (!consumed(position, 32))
			goto out;
		pfd = (struct pollfd) { .fd = child.fd, .events = POLLIN };
		if (!ASSERT_GT(poll(&pfd, 1, WAIT_STEPS * WAIT_US / 1000), 0,
			       "records flushed before exit") ||
		    !ASSERT_TRUE(pfd.revents & POLLIN, "record output readable") ||
		    !emit_record(skel, 2) || !consumed(position, 64))
			goto out;
	}
	if (!consumer_finish(&child, signo, true, output, sizeof(output)))
		goto out;
	if (format && !strcmp(format, "-p"))
		ASSERT_STREQ(output, idle ? "[]\n" :
			     "[{\n"
			     "        \"size\": 2,\n"
			     "        \"data\": [0,255\n"
			     "        ]\n"
			     "    },{\n"
			     "        \"size\": 5,\n"
			     "        \"data\": [1,2,3,4,5\n"
			     "        ]\n"
			     "    },{\n"
			     "        \"size\": 17,\n"
			     "        \"data\": [16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32\n"
			     "        ]\n"
			     "    }\n"
			     "]\n", "pretty JSON records");
	else if (format)
		check_json(output, idle ? "[]" :
			   "[{\"size\":2,\"data\":[0,255]},"
			   "{\"size\":5,\"data\":[1,2,3,4,5]},"
			   "{\"size\":17,\"data\":[16,17,18,19,20,21,22,23,"
			   "24,25,26,27,28,29,30,31,32]}]");
	else
		ASSERT_STREQ(output, idle ? "" :
			     "== size: 2 =====\n00 ff\n"
			     "== size: 5 =====\n01 02 03 04 05\n"
			     "== size: 17 =====\n10 11 12 13 14 15 16 17  "
			     "18 19 1a 1b 1c 1d 1e 1f\n20\n", "plain records");
out:
	consumer_cleanup(&child);
	if (position != MAP_FAILED)
		munmap(position, page_size);
	if (map_pinned)
		ASSERT_OK(unlink(pin_path), "unpin ringbuf");
	if (dir_created)
		ASSERT_OK(rmdir(pin_dir), "remove pin directory");
	bpftool_ringbuf__destroy(skel);
}

static void test_perf_consumer(void)
{
	struct consumer child = { .pid = -1, .fd = -1 };
	unsigned long long seconds, nanoseconds;
	struct bpftool_ringbuf *skel;
	char output[16384], expected[16384];
	int nr_cpus, cpu, index, offset = 0, i, used = 0, fields;
	struct pollfd pfd;

	nr_cpus = libbpf_num_possible_cpus();
	if (!ASSERT_GT(nr_cpus, 0, "possible cpus"))
		return;
	skel = bpftool_ringbuf__open();
	if (!ASSERT_OK_PTR(skel, "open"))
		return;
	bpf_map__set_max_entries(skel->maps.ringbuf, getpagesize());
	bpf_map__set_max_entries(skel->maps.perfbuf, nr_cpus);
	if (!ASSERT_OK(bpftool_ringbuf__load(skel), "load") ||
	    !consumer_start(&child, bpf_map__fd(skel->maps.perfbuf), NULL,
			    NULL, NULL, false, false) || !consumer_ready(&child) ||
	    !emit_record(skel, 3))
		goto out;
	/* One large record flushes the existing buffered perf output callback. */
	pfd = (struct pollfd) { .fd = child.fd, .events = POLLIN };
	if (!ASSERT_GT(poll(&pfd, 1, WAIT_STEPS * WAIT_US / 1000), 0,
		       "perf record output") ||
	    !ASSERT_TRUE(pfd.revents & POLLIN, "perf output readable") ||
	    !consumer_finish(&child, SIGINT, true, output, sizeof(output)))
		goto out;
	fields = sscanf(output, "== @%llu.%llu CPU: %d index: %d =====\n%n",
			&seconds, &nanoseconds, &cpu, &index, &offset);
	if (!ASSERT_EQ(fields, 4, "perf header") ||
	    !ASSERT_GT(offset, 0, "perf payload offset"))
		goto out;
	ASSERT_GT(seconds * 1000000000ULL + nanoseconds, 0, "perf timestamp");
	ASSERT_LT(nanoseconds, 1000000000ULL, "perf timestamp nanoseconds");
	ASSERT_GE(cpu, 0, "perf cpu");
	ASSERT_LT(cpu, nr_cpus, "perf cpu range");
	ASSERT_EQ(index, cpu, "perf index");
	for (i = 0; i < sizeof(skel->rodata->perf_payload); i++) {
		const char *separator = !i ? "" : !(i % 16) ? "\n" :
					!(i % 8) ? "  " : " ";

		used += snprintf(expected + used, sizeof(expected) - used,
				 "%s%02x", separator, i == 1 ? 0xff : 0);
	}
	snprintf(expected + used, sizeof(expected) - used, "\n");
	ASSERT_STREQ(output + offset, expected, "perf payload");
out:
	consumer_cleanup(&child);
	bpftool_ringbuf__destroy(skel);
}

static void test_reject(enum bpf_map_type type, const char *option, bool pair, bool json)
{
	struct consumer child = { .pid = -1, .fd = -1 };
	bool ring = type == BPF_MAP_TYPE_RINGBUF || type == BPF_MAP_TYPE_USER_RINGBUF;
	const char *expected = option && !strcmp(option, "foobar") ?
		"{\"error\":\"what is 'foobar'?\"}" : option ?
		"{\"error\":\"ring buffer maps do not support cpu or index arguments\"}" :
		"{\"error\":\"map is not a perf event array or ring buffer\"}";
	char output[4096];
	int fd;

	fd = bpf_map_create(type, NULL, ring ? 0 : 4, ring ? 0 : 4,
			    ring ? getpagesize() : 1, NULL);
	if (!ASSERT_GE(fd, 0, "create map"))
		return;
	if (consumer_start(&child, fd, json ? "-j" : NULL, NULL, option, pair, true) &&
	    consumer_finish(&child, 0, false, output, sizeof(output))) {
		if (json)
			check_json(output, expected);
		else
			ASSERT_GT(strlen(output), 0, "error diagnostic");
	}
	consumer_cleanup(&child);
	close(fd);
}

void test_bpftool_ringbuf(void)
{
	if (test__start_subtest("perf_event_array"))
		test_perf_consumer();
	if (test__start_subtest("plain"))
		test_consumer(NULL, false, SIGINT, false);
	if (test__start_subtest("json"))
		test_consumer("-j", false, SIGTERM, false);
	if (test__start_subtest("pretty_json"))
		test_consumer("-p", false, SIGINT, false);
	if (test__start_subtest("pinned_plain"))
		test_consumer(NULL, false, SIGTERM, true);
	if (test__start_subtest("pinned_json"))
		test_consumer("-j", false, SIGINT, true);
	if (test__start_subtest("pinned_pretty_json"))
		test_consumer("-p", false, SIGTERM, true);
	if (test__start_subtest("idle_sigint"))
		test_consumer(NULL, true, SIGINT, false);
	if (test__start_subtest("idle_sigterm_json"))
		test_consumer("-j", true, SIGTERM, false);
	if (test__start_subtest("idle_sigint_pretty_json"))
		test_consumer("-p", true, SIGINT, false);
	if (test__start_subtest("reject_array"))
		test_reject(BPF_MAP_TYPE_ARRAY, NULL, false, false);
	if (test__start_subtest("reject_user_ringbuf"))
		test_reject(BPF_MAP_TYPE_USER_RINGBUF, NULL, false, false);
	if (test__start_subtest("reject_cpu"))
		test_reject(BPF_MAP_TYPE_RINGBUF, "cpu", false, false);
	if (test__start_subtest("reject_index"))
		test_reject(BPF_MAP_TYPE_RINGBUF, "index", false, false);
	if (test__start_subtest("reject_cpu_index"))
		test_reject(BPF_MAP_TYPE_RINGBUF, "cpu", true, false);
	if (test__start_subtest("reject_user_ringbuf_json"))
		test_reject(BPF_MAP_TYPE_USER_RINGBUF, NULL, false, true);
	if (test__start_subtest("reject_unknown_json"))
		test_reject(BPF_MAP_TYPE_RINGBUF, "foobar", false, true);
	if (test__start_subtest("reject_cpu_index_json"))
		test_reject(BPF_MAP_TYPE_RINGBUF, "cpu", true, true);
}