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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
#include "test_user_ringbuf.h"
char _license[] SEC("license") = "GPL";
struct {
__uint(type, BPF_MAP_TYPE_USER_RINGBUF);
} user_ringbuf SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_RINGBUF);
} kernel_ringbuf SEC(".maps");
/* inputs */
int pid, err, val;
int read = 0;
/* Counter used for end-to-end protocol test */
__u64 kern_mutated = 0;
__u64 user_mutated = 0;
__u64 expected_user_mutated = 0;
static int
is_test_process(void)
{
int cur_pid = bpf_get_current_pid_tgid() >> 32;
return cur_pid == pid;
}
static long
record_sample(struct bpf_dynptr *dynptr, void *context)
{
const struct sample *sample = NULL;
struct sample stack_sample;
int status;
static int num_calls;
if (num_calls++ % 2 == 0) {
status = bpf_dynptr_read(&stack_sample, sizeof(stack_sample), dynptr, 0, 0);
if (status) {
bpf_printk("bpf_dynptr_read() failed: %d\n", status);
err = 1;
return 1;
}
} else {
sample = bpf_dynptr_data(dynptr, 0, sizeof(*sample));
if (!sample) {
bpf_printk("Unexpectedly failed to get sample\n");
err = 2;
return 1;
}
stack_sample = *sample;
}
__sync_fetch_and_add(&read, 1);
return 0;
}
static void
handle_sample_msg(const struct test_msg *msg)
{
switch (msg->msg_op) {
case TEST_MSG_OP_INC64:
kern_mutated += msg->operand_64;
break;
case TEST_MSG_OP_INC32:
kern_mutated += msg->operand_32;
break;
case TEST_MSG_OP_MUL64:
kern_mutated *= msg->operand_64;
break;
case TEST_MSG_OP_MUL32:
kern_mutated *= msg->operand_32;
break;
default:
bpf_printk("Unrecognized op %d\n", msg->msg_op);
err = 2;
}
}
static long
read_protocol_msg(struct bpf_dynptr *dynptr, void *context)
{
const struct test_msg *msg = NULL;
msg = bpf_dynptr_data(dynptr, 0, sizeof(*msg));
if (!msg) {
err = 1;
bpf_printk("Unexpectedly failed to get msg\n");
return 0;
}
handle_sample_msg(msg);
return 0;
}
static int publish_next_kern_msg(__u32 index, void *context)
{
struct test_msg *msg = NULL;
int operand_64 = TEST_OP_64;
int operand_32 = TEST_OP_32;
msg = bpf_ringbuf_reserve(&kernel_ringbuf, sizeof(*msg), 0);
if (!msg) {
err = 4;
return 1;
}
switch (index % TEST_MSG_OP_NUM_OPS) {
case TEST_MSG_OP_INC64:
msg->operand_64 = operand_64;
msg->msg_op = TEST_MSG_OP_INC64;
expected_user_mutated += operand_64;
break;
case TEST_MSG_OP_INC32:
msg->operand_32 = operand_32;
msg->msg_op = TEST_MSG_OP_INC32;
expected_user_mutated += operand_32;
break;
case TEST_MSG_OP_MUL64:
msg->operand_64 = operand_64;
msg->msg_op = TEST_MSG_OP_MUL64;
expected_user_mutated *= operand_64;
break;
case TEST_MSG_OP_MUL32:
msg->operand_32 = operand_32;
msg->msg_op = TEST_MSG_OP_MUL32;
expected_user_mutated *= operand_32;
break;
default:
bpf_ringbuf_discard(msg, 0);
err = 5;
return 1;
}
bpf_ringbuf_submit(msg, 0);
return 0;
}
static void
publish_kern_messages(void)
{
if (expected_user_mutated != user_mutated) {
bpf_printk("%lu != %lu\n", expected_user_mutated, user_mutated);
err = 3;
return;
}
bpf_loop(8, publish_next_kern_msg, NULL, 0);
}
SEC("fentry/" SYS_PREFIX "sys_prctl")
int test_user_ringbuf_protocol(void *ctx)
{
long status = 0;
struct sample *sample = NULL;
struct bpf_dynptr ptr;
if (!is_test_process())
return 0;
status = bpf_user_ringbuf_drain(&user_ringbuf, read_protocol_msg, NULL, 0);
if (status < 0) {
bpf_printk("Drain returned: %ld\n", status);
err = 1;
return 0;
}
publish_kern_messages();
return 0;
}
SEC("fentry/" SYS_PREFIX "sys_getpgid")
int test_user_ringbuf(void *ctx)
{
int status = 0;
struct sample *sample = NULL;
struct bpf_dynptr ptr;
if (!is_test_process())
return 0;
err = bpf_user_ringbuf_drain(&user_ringbuf, record_sample, NULL, 0);
return 0;
}
static long
do_nothing_cb(struct bpf_dynptr *dynptr, void *context)
{
__sync_fetch_and_add(&read, 1);
return 0;
}
SEC("fentry/" SYS_PREFIX "sys_getrlimit")
int test_user_ringbuf_epoll(void *ctx)
{
long num_samples;
if (!is_test_process())
return 0;
num_samples = bpf_user_ringbuf_drain(&user_ringbuf, do_nothing_cb, NULL, 0);
if (num_samples <= 0)
err = 1;
return 0;
}
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