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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2021, 2024, Oracle and/or its affiliates.
*/
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include <stdint.h>
#include <dt_dctx.h>
#include <bpf-lib.h>
#ifndef noinline
# define noinline __attribute__((noinline))
#endif
extern uint64_t STBSZ;
extern uint64_t STRSZ;
noinline uint64_t dt_strlen(const dt_dctx_t *dctx, const char *str)
{
char *tmp = dctx->strtab + (uint64_t)&STBSZ;
int64_t len;
/*
* The bpf_probe_read_str() helper returns either a negative value (for
* error conditions) or a positive value (string length + 1 to account
* for the terminating 0-byte). It will never return 0, so it is safe
* to speculatively subtract 1. Any negative value will be converted
* into a 0.
*/
len = bpf_probe_read_str(tmp, (uint64_t)&STRSZ + 1, str) - 1;
set_not_neg_bound(len);
return len;
}
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