Re: [PATCH bpf-next] libbpf: Allow Golang symbols in uprobe secdef

[Jiri Olsa <olsajiri@gmail.com>]

On Mon, Sep 25, 2023 at 02:57:22AM +0000, Hengqi Chen wrote:
> Golang symbols in ELF files are different from C/C++
> which contains special characters like '*', '(' and ')'.
> With generics, things get more complicated, there are
> symbols like:
> 
>   github.com/cilium/ebpf/internal.(*Deque[go.shape.interface {
>    Format(fmt.State, int32); TypeName() string;
>   github.com/cilium/ebpf/btf.copy() github.com/cilium/ebpf/btf.Type
>   }]).Grow
> 
> Add " ()*,-/;[]{}" (in alphabetical order) to support matching
> against such symbols. Note that ']' and '-' should be the first
> and last characters in the %m range as sscanf required.
> 
> A working example can be found at this repo ([0]).
> 
>   [0]: https://github.com/chenhengqi/libbpf-go-symbols
> 
> Suggested-by: Andrii Nakryiko <andrii@kernel.org>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
> ---
>  tools/lib/bpf/libbpf.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index b4758e54a815..de0e068195ab 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -11630,7 +11630,7 @@ static int attach_uprobe(const struct bpf_program *prog, long cookie, struct bpf
>  
>  	*link = NULL;
>  
> -	n = sscanf(prog->sec_name, "%m[^/]/%m[^:]:%m[a-zA-Z0-9_.@]+%li",
> +	n = sscanf(prog->sec_name, "%m[^/]/%m[^:]:%m[]a-zA-Z0-9 ()*,./;@[_{}-]+%li",
>  		   &probe_type, &binary_path, &func_name, &offset);

could you please make that work for uprobe.multi (attach_uprobe_multi)
as well?

it uses %ms at the moment and it seems it won't get pass the space
in the symbol name

thanks,
jirka

>  	switch (n) {
>  	case 1:
> -- 
> 2.34.1
> 
>