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References: <20240311093526.1010158-1-dongmenglong.8@bytedance.com> <20240311093526.1010158-9-dongmenglong.8@bytedance.com>
In-Reply-To: <20240311093526.1010158-9-dongmenglong.8@bytedance.com>
From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date: Mon, 11 Mar 2024 18:56:18 -0700
Message-ID: <CAADnVQK+s3XgSYhpSdh7_9Qhq4DimmSO-D9d5+EsSZQMX4TxxA@mail.gmail.com>
Subject: Re: [PATCH bpf-next v2 8/9] libbpf: add support for the multi-link of tracing
To: Menglong Dong <dongmenglong.8@bytedance.com>
Cc: Andrii Nakryiko <andrii@kernel.org>, Alexei Starovoitov <ast@kernel.org>, 
	Daniel Borkmann <daniel@iogearbox.net>, Martin KaFai Lau <martin.lau@linux.dev>, Eddy Z <eddyz87@gmail.com>, 
	Song Liu <song@kernel.org>, Yonghong Song <yonghong.song@linux.dev>, 
	John Fastabend <john.fastabend@gmail.com>, KP Singh <kpsingh@kernel.org>, 
	Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>, 
	Alexander Gordeev <agordeev@linux.ibm.com>, Christian Borntraeger <borntraeger@linux.ibm.com>, 
	Sven Schnelle <svens@linux.ibm.com>, "David S. Miller" <davem@davemloft.net>, 
	David Ahern <dsahern@kernel.org>, Dave Hansen <dave.hansen@linux.intel.com>, 
	X86 ML <x86@kernel.org>, Steven Rostedt <rostedt@goodmis.org>, 
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>, Quentin Monnet <quentin@isovalent.com>, 
	bpf <bpf@vger.kernel.org>, 
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>, LKML <linux-kernel@vger.kernel.org>, 
	linux-riscv <linux-riscv@lists.infradead.org>, linux-s390 <linux-s390@vger.kernel.org>, 
	Network Development <netdev@vger.kernel.org>, linux-trace-kernel@vger.kernel.org, 
	"open list:KERNEL SELFTEST FRAMEWORK" <linux-kselftest@vger.kernel.org>, linux-stm32@st-md-mailman.stormreply.com
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On Mon, Mar 11, 2024 at 2:35=E2=80=AFAM Menglong Dong
<dongmenglong.8@bytedance.com> wrote:
>
>
> -               err =3D libbpf_find_attach_btf_id(prog, attach_name, &btf=
_obj_fd, &btf_type_id);
> +               name_end =3D strchr(attach_name, ',');
> +               /* for multi-link tracing, use the first target symbol du=
ring
> +                * loading.
> +                */
> +               if ((def & SEC_ATTACH_BTF_MULTI) && name_end) {
> +                       int len =3D name_end - attach_name + 1;
> +                       char *first_tgt;
> +
> +                       first_tgt =3D malloc(len);
> +                       if (!first_tgt)
> +                               return -ENOMEM;
> +                       strncpy(first_tgt, attach_name, len);
> +                       first_tgt[len - 1] =3D '\0';
> +                       err =3D libbpf_find_attach_btf_id(prog, first_tgt=
, &btf_obj_fd,
> +                                                       &btf_type_id);
> +                       free(first_tgt);
> +               } else {
> +                       err =3D libbpf_find_attach_btf_id(prog, attach_na=
me, &btf_obj_fd,
> +                                                       &btf_type_id);
> +               }

Pls use glob_match the way [ku]probe multi are doing
instead of exact match.