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