* [PATCH bpf-next] libbpf: Allow Golang symbols in uprobe secdef
@ 2023-09-25 2:57 Hengqi Chen
2023-09-25 8:19 ` Jiri Olsa
2023-09-25 23:15 ` Andrii Nakryiko
0 siblings, 2 replies; 5+ messages in thread
From: Hengqi Chen @ 2023-09-25 2:57 UTC (permalink / raw)
To: bpf; +Cc: ast, daniel, andrii, hengqi.chen, Arnaldo Carvalho de Melo
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);
switch (n) {
case 1:
--
2.34.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH bpf-next] libbpf: Allow Golang symbols in uprobe secdef
2023-09-25 2:57 [PATCH bpf-next] libbpf: Allow Golang symbols in uprobe secdef Hengqi Chen
@ 2023-09-25 8:19 ` Jiri Olsa
2023-09-27 2:12 ` Hengqi Chen
2023-09-25 23:15 ` Andrii Nakryiko
1 sibling, 1 reply; 5+ messages in thread
From: Jiri Olsa @ 2023-09-25 8:19 UTC (permalink / raw)
To: Hengqi Chen; +Cc: bpf, ast, daniel, andrii, Arnaldo Carvalho de Melo
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
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH bpf-next] libbpf: Allow Golang symbols in uprobe secdef
2023-09-25 8:19 ` Jiri Olsa
@ 2023-09-27 2:12 ` Hengqi Chen
0 siblings, 0 replies; 5+ messages in thread
From: Hengqi Chen @ 2023-09-27 2:12 UTC (permalink / raw)
To: Jiri Olsa; +Cc: bpf, ast, daniel, andrii, Arnaldo Carvalho de Melo
On Mon, Sep 25, 2023 at 4:19 PM Jiri Olsa <olsajiri@gmail.com> wrote:
>
> 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?
>
I haven't used uprobe.multi before, let me try.
> 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
> >
> >
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH bpf-next] libbpf: Allow Golang symbols in uprobe secdef
2023-09-25 2:57 [PATCH bpf-next] libbpf: Allow Golang symbols in uprobe secdef Hengqi Chen
2023-09-25 8:19 ` Jiri Olsa
@ 2023-09-25 23:15 ` Andrii Nakryiko
2023-09-27 2:17 ` Hengqi Chen
1 sibling, 1 reply; 5+ messages in thread
From: Andrii Nakryiko @ 2023-09-25 23:15 UTC (permalink / raw)
To: Hengqi Chen; +Cc: bpf, ast, daniel, andrii, Arnaldo Carvalho de Melo
On Sun, Sep 24, 2023 at 8:19 PM Hengqi Chen <hengqi.chen@gmail.com> 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",
This is almost incomprehensible now... wouldn't it be clearer to just
have a catch-all %ms at the end, and then internally checking if we
have '+%li'? I.e., once we match everything after
"uprobe/<path-to-binary>:", we can strchr('+'), if found, try
sscanf("%li") on the remaining suffix. If that doesn't parse properly,
then we have a choice -- either error out, or just assume that
`+<something>` part is just a part of ELF symbol name?
That way we don't hard-code any fixes set of symbols and avoid any
future crazy adjustments.
WDYT?
> &probe_type, &binary_path, &func_name, &offset);
> switch (n) {
> case 1:
> --
> 2.34.1
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH bpf-next] libbpf: Allow Golang symbols in uprobe secdef
2023-09-25 23:15 ` Andrii Nakryiko
@ 2023-09-27 2:17 ` Hengqi Chen
0 siblings, 0 replies; 5+ messages in thread
From: Hengqi Chen @ 2023-09-27 2:17 UTC (permalink / raw)
To: Andrii Nakryiko; +Cc: bpf, ast, daniel, andrii, Arnaldo Carvalho de Melo
On Tue, Sep 26, 2023 at 7:15 AM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Sun, Sep 24, 2023 at 8:19 PM Hengqi Chen <hengqi.chen@gmail.com> 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",
>
> This is almost incomprehensible now... wouldn't it be clearer to just
> have a catch-all %ms at the end, and then internally checking if we
> have '+%li'? I.e., once we match everything after
> "uprobe/<path-to-binary>:", we can strchr('+'), if found, try
> sscanf("%li") on the remaining suffix. If that doesn't parse properly,
> then we have a choice -- either error out, or just assume that
> `+<something>` part is just a part of ELF symbol name?
>
> That way we don't hard-code any fixes set of symbols and avoid any
> future crazy adjustments.
>
> WDYT?
Sounds good. This also solves the matching of unicode identifiers.
As Jiri mentioned above, %ms won't match whitespaces,
so I am wondering if %m[^\n] is acceptable.
>
> > &probe_type, &binary_path, &func_name, &offset);
> > switch (n) {
> > case 1:
> > --
> > 2.34.1
> >
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2023-09-27 2:17 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2023-09-25 2:57 [PATCH bpf-next] libbpf: Allow Golang symbols in uprobe secdef Hengqi Chen
2023-09-25 8:19 ` Jiri Olsa
2023-09-27 2:12 ` Hengqi Chen
2023-09-25 23:15 ` Andrii Nakryiko
2023-09-27 2:17 ` Hengqi Chen
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