selftests/bpf: Add variable-length data concatenation pattern test

// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2020 Facebook */

#include <test_progs.h>

#include <time.h>

#include "test_varlen.skel.h"

#define CHECK_VAL(got, exp) \

	CHECK((got) != (exp), "check", "got %ld != exp %ld\n", \

	      (long)(got), (long)(exp))

void test_varlen(void)

{

	int duration = 0, err;

	struct test_varlen* skel;

	struct test_varlen__bss *bss;

	struct test_varlen__data *data;

	const char str1[] = "Hello, ";

	const char str2[] = "World!";

	const char exp_str[] = "Hello, \0World!\0";

	const int size1 = sizeof(str1);

	const int size2 = sizeof(str2);

	skel = test_varlen__open_and_load();

	if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))

		return;

	bss = skel->bss;

	data = skel->data;

	err = test_varlen__attach(skel);

	if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))

		goto cleanup;

	bss->test_pid = getpid();

	/* trigger everything */

	memcpy(bss->buf_in1, str1, size1);

	memcpy(bss->buf_in2, str2, size2);

	bss->capture = true;

	usleep(1);

	bss->capture = false;

	CHECK_VAL(bss->payload1_len1, size1);

	CHECK_VAL(bss->payload1_len2, size2);

	CHECK_VAL(bss->total1, size1 + size2);

	CHECK(memcmp(bss->payload1, exp_str, size1 + size2), "content_check",

	      "doesn't match!");

	CHECK_VAL(data->payload2_len1, size1);

	CHECK_VAL(data->payload2_len2, size2);

	CHECK_VAL(data->total2, size1 + size2);

	CHECK(memcmp(data->payload2, exp_str, size1 + size2), "content_check",

	      "doesn't match!");

cleanup:

	test_varlen__destroy(skel);

}

// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2020 Facebook */

#include "vmlinux.h"

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>

#include <bpf/bpf_core_read.h>

#define MAX_LEN 256

char buf_in1[MAX_LEN] = {};

char buf_in2[MAX_LEN] = {};

int test_pid = 0;

bool capture = false;

/* .bss */

long payload1_len1 = 0;

long payload1_len2 = 0;

long total1 = 0;

char payload1[MAX_LEN + MAX_LEN] = {};

/* .data */

int payload2_len1 = -1;

int payload2_len2 = -1;

int total2 = -1;

char payload2[MAX_LEN + MAX_LEN] = { 1 };

SEC("raw_tp/sys_enter")

int handler64(void *regs)

{

	int pid = bpf_get_current_pid_tgid() >> 32;

	void *payload = payload1;

	u64 len;

	/* ignore irrelevant invocations */

	if (test_pid != pid || !capture)

		return 0;

	len = bpf_probe_read_kernel_str(payload, MAX_LEN, &buf_in1[0]);

	if (len <= MAX_LEN) {

		payload += len;

		payload1_len1 = len;

	}

	len = bpf_probe_read_kernel_str(payload, MAX_LEN, &buf_in2[0]);

	if (len <= MAX_LEN) {

		payload += len;

		payload1_len2 = len;

	}

	total1 = payload - (void *)payload1;

	return 0;

}

SEC("tp_btf/sys_enter")

int handler32(void *regs)

{

	int pid = bpf_get_current_pid_tgid() >> 32;

	void *payload = payload2;

	u32 len;

	/* ignore irrelevant invocations */

	if (test_pid != pid || !capture)

		return 0;

	len = bpf_probe_read_kernel_str(payload, MAX_LEN, &buf_in1[0]);

	if (len <= MAX_LEN) {

		payload += len;

		payload2_len1 = len;

	}

	len = bpf_probe_read_kernel_str(payload, MAX_LEN, &buf_in2[0]);

	if (len <= MAX_LEN) {

		payload += len;

		payload2_len2 = len;

	}

	total2 = payload - (void *)payload2;

	return 0;

}

SEC("tp_btf/sys_exit")

int handler_exit(void *regs)

{

	long bla;

	if (bpf_probe_read_kernel(&bla, sizeof(bla), 0))

		return 1;

	else

		return 0;

}

char LICENSE[] SEC("license") = "GPL";