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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2021, 2024, Oracle and/or its affiliates.
*/
#include <bpf_asm_helpers.h>
/*
* void dt_strjoin(char *dst, const char *s1, const char *s2)
*/
.text
.align 4
.global dt_strjoin
.type dt_strjoin, @function
dt_strjoin:
mov %r9, %r1 /* %r9 = dst */
mov %r7, %r2 /* %r7 = s1 */
mov %r8, %r3 /* %r8 = s2 */
lddw %r6, STRSZ
add %r6, 1 /* cnt = STRSZ + 1 */
mov %r2, %r6
mov %r3, %r7
call BPF_FUNC_probe_read_str /* rc = probe_read_str(dst, cnt, s1); */
jsle %r0, 0, .Lexit /* if (rc s<= 0) goto .Lexit; */
mov %r7, %r0 /* len = rc */
jeq %r7, %r6, .Lexit /* if (len == cnt) goto .Lexit; */
sub %r7, 1 /* len-- */
mov %r1, %r9
add %r1, %r7
mov %r2, %r6
sub %r2, %r7
mov %r3, %r8
call BPF_FUNC_probe_read_str /*
* rc = probe_read_str(dst, cnt - len,
* s2);
*/
jsle %r0, 0, .Lexit /* if (rc s<= 0) goto .Lexit */
add %r7, %r0 /* len += rc */
.Lexit:
exit
.size dt_strjoin, .-dt_strjoin
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