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// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2025. Huawei Technologies Co., Ltd */
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
char _license[] SEC("license") = "GPL";
struct {
__uint(type, BPF_MAP_TYPE_RINGBUF);
__uint(map_flags, BPF_F_RB_OVERWRITE);
} ringbuf SEC(".maps");
int pid;
const volatile unsigned long LEN1;
const volatile unsigned long LEN2;
const volatile unsigned long LEN3;
const volatile unsigned long LEN4;
const volatile unsigned long LEN5;
long reserve1_fail = 0;
long reserve2_fail = 0;
long reserve3_fail = 0;
long reserve4_fail = 0;
long reserve5_fail = 0;
unsigned long avail_data = 0;
unsigned long ring_size = 0;
unsigned long cons_pos = 0;
unsigned long prod_pos = 0;
unsigned long over_pos = 0;
SEC("fentry/" SYS_PREFIX "sys_getpgid")
int test_overwrite_ringbuf(void *ctx)
{
char *rec1, *rec2, *rec3, *rec4, *rec5;
int cur_pid = bpf_get_current_pid_tgid() >> 32;
if (cur_pid != pid)
return 0;
rec1 = bpf_ringbuf_reserve(&ringbuf, LEN1, 0);
if (!rec1) {
reserve1_fail = 1;
return 0;
}
rec2 = bpf_ringbuf_reserve(&ringbuf, LEN2, 0);
if (!rec2) {
bpf_ringbuf_discard(rec1, 0);
reserve2_fail = 1;
return 0;
}
rec3 = bpf_ringbuf_reserve(&ringbuf, LEN3, 0);
/* expect failure */
if (!rec3) {
reserve3_fail = 1;
} else {
bpf_ringbuf_discard(rec1, 0);
bpf_ringbuf_discard(rec2, 0);
bpf_ringbuf_discard(rec3, 0);
return 0;
}
rec4 = bpf_ringbuf_reserve(&ringbuf, LEN4, 0);
if (!rec4) {
reserve4_fail = 1;
bpf_ringbuf_discard(rec1, 0);
bpf_ringbuf_discard(rec2, 0);
return 0;
}
bpf_ringbuf_submit(rec1, 0);
bpf_ringbuf_submit(rec2, 0);
bpf_ringbuf_submit(rec4, 0);
rec5 = bpf_ringbuf_reserve(&ringbuf, LEN5, 0);
if (!rec5) {
reserve5_fail = 1;
return 0;
}
for (int i = 0; i < LEN3; i++)
rec5[i] = 0xdd;
bpf_ringbuf_submit(rec5, 0);
ring_size = bpf_ringbuf_query(&ringbuf, BPF_RB_RING_SIZE);
avail_data = bpf_ringbuf_query(&ringbuf, BPF_RB_AVAIL_DATA);
cons_pos = bpf_ringbuf_query(&ringbuf, BPF_RB_CONS_POS);
prod_pos = bpf_ringbuf_query(&ringbuf, BPF_RB_PROD_POS);
over_pos = bpf_ringbuf_query(&ringbuf, BPF_RB_OVERWRITE_POS);
return 0;
}
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