From: Alan Maguire <alan.maguire@oracle.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Alan Maguire <alan.maguire@oracle.com>,
Andrii Nakryiko <andrii@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>, Martin Lau <kafai@fb.com>,
Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
john fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
Yucong Sun <sunyucong@gmail.com>,
Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>
Subject: Re: [PATCH v3 bpf-next 2/4] libbpf: add auto-attach for uprobes based on section name
Date: Wed, 23 Feb 2022 09:32:46 +0000 (GMT) [thread overview]
Message-ID: <alpine.LRH.2.23.451.2202230924001.26488@MyRouter.home> (raw)
In-Reply-To: <CAEf4Bzb9xhpn5asJo7cwhL61DawqtuL_MakdU0YZwOeWuaRq6A@mail.gmail.com>
On Fri, 4 Feb 2022, Andrii Nakryiko wrote:
> On Mon, Jan 31, 2022 at 8:13 AM Alan Maguire <alan.maguire@oracle.com> wrote:
> >
> > Now that u[ret]probes can use name-based specification, it makes
> > sense to add support for auto-attach based on SEC() definition.
> > The format proposed is
> >
> > SEC("u[ret]probe//path/to/prog:[raw_offset|[function_name[+offset]]")
> >
> > For example, to trace malloc() in libc:
> >
> > SEC("uprobe//usr/lib64/libc.so.6:malloc")
>
> I assume that path to library can be relative path as well, right?
>
> Also, should be look at trying to locate library in the system if it's
> specified as "libc"? Or if the binary is "bash", for example. Just
> bringing this up, because I think it came up before in the context of
> one of libbpf-tools.
>
This is a great suggestion for usability, but I'm trying to puzzle
out how to carry out the location search for cases where the path
specified is not a relative or absolute path.
A few things we can can do - use search paths from PATH and
LD_LIBRARY_PATH, with an appended set of standard locations
such as /usr/bin, /usr/sbin for cases where those environment
variables are missing or incomplete.
However, when it comes to libraries, do we search in /usr/lib64 or
/usr/lib? We could use whether the version of libbpf is 64-bit or not I
suppose, but it's at least conceivable that the user might want to
instrument a 32-bit library from a 64-bit libbpf. Do you think that
approach is sufficient, or are there other things we should do? Thanks!
Alan
next prev parent reply other threads:[~2022-02-23 9:33 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-31 16:12 [PATCH v3 bpf-next 0/4] libbpf: name-based u[ret]probe attach Alan Maguire
2022-01-31 16:12 ` [PATCH v3 bpf-next 1/4] libbpf: support function name-based attach uprobes Alan Maguire
2022-02-04 19:17 ` Andrii Nakryiko
2022-02-25 16:12 ` Alan Maguire
2022-01-31 16:12 ` [PATCH v3 bpf-next 2/4] libbpf: add auto-attach for uprobes based on section name Alan Maguire
2022-02-04 19:22 ` Andrii Nakryiko
2022-02-23 9:32 ` Alan Maguire [this message]
2022-02-24 1:49 ` Andrii Nakryiko
2022-02-24 15:39 ` Alan Maguire
2022-03-01 1:45 ` Andrii Nakryiko
2022-01-31 16:12 ` [PATCH v3 bpf-next 3/4] selftests/bpf: add get_lib_path() helper Alan Maguire
2022-02-04 19:24 ` Andrii Nakryiko
2022-01-31 16:12 ` [PATCH v3 bpf-next 4/4] selftests/bpf: add tests for u[ret]probe attach by name Alan Maguire
2022-02-04 19:30 ` Andrii Nakryiko
2022-02-26 16:00 ` Jiri Olsa
2022-02-01 8:52 ` [PATCH v3 bpf-next 0/4] libbpf: name-based u[ret]probe attach Daniel Borkmann
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