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// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2021. Huawei Technologies Co., Ltd */
#include <linux/types.h>
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#define STRNCMP_STR_SZ 4096
/* Will be updated by benchmark before program loading */
const volatile unsigned int cmp_str_len = 1;
const char target[STRNCMP_STR_SZ];
long hits = 0;
char str[STRNCMP_STR_SZ];
char _license[] SEC("license") = "GPL";
static __always_inline int local_strncmp(const char *s1, unsigned int sz,
const char *s2)
{
int ret = 0;
unsigned int i;
for (i = 0; i < sz; i++) {
/* E.g. 0xff > 0x31 */
ret = (unsigned char)s1[i] - (unsigned char)s2[i];
if (ret || !s1[i])
break;
}
return ret;
}
SEC("tp/syscalls/sys_enter_getpgid")
int strncmp_no_helper(void *ctx)
{
if (local_strncmp(str, cmp_str_len + 1, target) < 0)
__sync_add_and_fetch(&hits, 1);
return 0;
}
SEC("tp/syscalls/sys_enter_getpgid")
int strncmp_helper(void *ctx)
{
if (bpf_strncmp(str, cmp_str_len + 1, target) < 0)
__sync_add_and_fetch(&hits, 1);
return 0;
}
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