diff mbox series

[PATCHv2,bpf-next,4/9] libbpf: Add support for uprobe multi session attach

Message ID 20240701164115.723677-5-jolsa@kernel.org (mailing list archive)
State Superseded
Headers show
Series uprobe, bpf: Add session support | expand

Commit Message

Jiri Olsa July 1, 2024, 4:41 p.m. UTC 
Adding support to attach program in uprobe session mode
with bpf_program__attach_uprobe_multi function.

Adding session bool to bpf_uprobe_multi_opts struct that allows
to load and attach the bpf program via uprobe session.
the attachment to create uprobe multi session.

Also adding new program loader section that allows:
  SEC("uprobe.session/bpf_fentry_test*")

and loads/attaches uprobe program as uprobe session.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/lib/bpf/bpf.c    |  1 +
 tools/lib/bpf/libbpf.c | 50 ++++++++++++++++++++++++++++++++++++++++--
 tools/lib/bpf/libbpf.h |  4 +++-
 3 files changed, 52 insertions(+), 3 deletions(-)

Comments

Andrii Nakryiko July 2, 2024, 9:34 p.m. UTC | #1 
On Mon, Jul 1, 2024 at 9:42 AM Jiri Olsa <jolsa@kernel.org> wrote:
>
> Adding support to attach program in uprobe session mode
> with bpf_program__attach_uprobe_multi function.
>
> Adding session bool to bpf_uprobe_multi_opts struct that allows
> to load and attach the bpf program via uprobe session.
> the attachment to create uprobe multi session.
>
> Also adding new program loader section that allows:
>   SEC("uprobe.session/bpf_fentry_test*")
>
> and loads/attaches uprobe program as uprobe session.
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>  tools/lib/bpf/bpf.c    |  1 +
>  tools/lib/bpf/libbpf.c | 50 ++++++++++++++++++++++++++++++++++++++++--
>  tools/lib/bpf/libbpf.h |  4 +++-
>  3 files changed, 52 insertions(+), 3 deletions(-)
>

[...]

> @@ -9362,6 +9363,7 @@ static const struct bpf_sec_def section_defs[] = {
>         SEC_DEF("kprobe.session+",      KPROBE, BPF_TRACE_KPROBE_SESSION, SEC_NONE, attach_kprobe_session),
>         SEC_DEF("uprobe.multi+",        KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_NONE, attach_uprobe_multi),
>         SEC_DEF("uretprobe.multi+",     KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_NONE, attach_uprobe_multi),
> +       SEC_DEF("uprobe.session+",      KPROBE, BPF_TRACE_UPROBE_SESSION, SEC_NONE, attach_uprobe_session),

sleepable ones as well?

>         SEC_DEF("uprobe.multi.s+",      KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_SLEEPABLE, attach_uprobe_multi),
>         SEC_DEF("uretprobe.multi.s+",   KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_SLEEPABLE, attach_uprobe_multi),
>         SEC_DEF("ksyscall+",            KPROBE, 0, SEC_NONE, attach_ksyscall),
> @@ -11698,6 +11700,40 @@ static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, stru
>         return ret;
>  }
>
> +static int attach_uprobe_session(const struct bpf_program *prog, long cookie, struct bpf_link **link)
> +{
> +       char *binary_path = NULL, *func_name = NULL;
> +       LIBBPF_OPTS(bpf_uprobe_multi_opts, opts,
> +               .session = true,
> +       );

nit: keep a single line?

> +       int n, ret = -EINVAL;
> +       const char *spec;
> +
> +       *link = NULL;
> +
> +       spec = prog->sec_name + sizeof("uprobe.session/") - 1;
> +       n = sscanf(spec, "%m[^:]:%m[^\n]",
> +                  &binary_path, &func_name);

single line, wrapping lines is a necessary evil, please

[...]
Jiri Olsa July 3, 2024, 5:14 p.m. UTC | #2 
On Tue, Jul 02, 2024 at 02:34:34PM -0700, Andrii Nakryiko wrote:
> On Mon, Jul 1, 2024 at 9:42 AM Jiri Olsa <jolsa@kernel.org> wrote:
> >
> > Adding support to attach program in uprobe session mode
> > with bpf_program__attach_uprobe_multi function.
> >
> > Adding session bool to bpf_uprobe_multi_opts struct that allows
> > to load and attach the bpf program via uprobe session.
> > the attachment to create uprobe multi session.
> >
> > Also adding new program loader section that allows:
> >   SEC("uprobe.session/bpf_fentry_test*")
> >
> > and loads/attaches uprobe program as uprobe session.
> >
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> >  tools/lib/bpf/bpf.c    |  1 +
> >  tools/lib/bpf/libbpf.c | 50 ++++++++++++++++++++++++++++++++++++++++--
> >  tools/lib/bpf/libbpf.h |  4 +++-
> >  3 files changed, 52 insertions(+), 3 deletions(-)
> >
> 
> [...]
> 
> > @@ -9362,6 +9363,7 @@ static const struct bpf_sec_def section_defs[] = {
> >         SEC_DEF("kprobe.session+",      KPROBE, BPF_TRACE_KPROBE_SESSION, SEC_NONE, attach_kprobe_session),
> >         SEC_DEF("uprobe.multi+",        KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_NONE, attach_uprobe_multi),
> >         SEC_DEF("uretprobe.multi+",     KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_NONE, attach_uprobe_multi),
> > +       SEC_DEF("uprobe.session+",      KPROBE, BPF_TRACE_UPROBE_SESSION, SEC_NONE, attach_uprobe_session),
> 
> sleepable ones as well?

ah right, forgot.. will add

> 
> >         SEC_DEF("uprobe.multi.s+",      KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_SLEEPABLE, attach_uprobe_multi),
> >         SEC_DEF("uretprobe.multi.s+",   KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_SLEEPABLE, attach_uprobe_multi),
> >         SEC_DEF("ksyscall+",            KPROBE, 0, SEC_NONE, attach_ksyscall),
> > @@ -11698,6 +11700,40 @@ static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, stru
> >         return ret;
> >  }
> >
> > +static int attach_uprobe_session(const struct bpf_program *prog, long cookie, struct bpf_link **link)
> > +{
> > +       char *binary_path = NULL, *func_name = NULL;
> > +       LIBBPF_OPTS(bpf_uprobe_multi_opts, opts,
> > +               .session = true,
> > +       );
> 
> nit: keep a single line?

ok

> 
> > +       int n, ret = -EINVAL;
> > +       const char *spec;
> > +
> > +       *link = NULL;
> > +
> > +       spec = prog->sec_name + sizeof("uprobe.session/") - 1;
> > +       n = sscanf(spec, "%m[^:]:%m[^\n]",
> > +                  &binary_path, &func_name);
> 
> single line, wrapping lines is a necessary evil, please

ok

thanks,
jirka
diff mbox series

Patch

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 2a4c71501a17..becdfa701c75 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -776,6 +776,7 @@  int bpf_link_create(int prog_fd, int target_fd,
 			return libbpf_err(-EINVAL);
 		break;
 	case BPF_TRACE_UPROBE_MULTI:
+	case BPF_TRACE_UPROBE_SESSION:
 		attr.link_create.uprobe_multi.flags = OPTS_GET(opts, uprobe_multi.flags, 0);
 		attr.link_create.uprobe_multi.cnt = OPTS_GET(opts, uprobe_multi.cnt, 0);
 		attr.link_create.uprobe_multi.path = ptr_to_u64(OPTS_GET(opts, uprobe_multi.path, 0));
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 4a28fac4908a..492a8eb4d047 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -9344,6 +9344,7 @@  static int attach_trace(const struct bpf_program *prog, long cookie, struct bpf_
 static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link);
 static int attach_kprobe_session(const struct bpf_program *prog, long cookie, struct bpf_link **link);
 static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link);
+static int attach_uprobe_session(const struct bpf_program *prog, long cookie, struct bpf_link **link);
 static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_link **link);
 static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_link **link);
 
@@ -9362,6 +9363,7 @@  static const struct bpf_sec_def section_defs[] = {
 	SEC_DEF("kprobe.session+",	KPROBE,	BPF_TRACE_KPROBE_SESSION, SEC_NONE, attach_kprobe_session),
 	SEC_DEF("uprobe.multi+",	KPROBE,	BPF_TRACE_UPROBE_MULTI, SEC_NONE, attach_uprobe_multi),
 	SEC_DEF("uretprobe.multi+",	KPROBE,	BPF_TRACE_UPROBE_MULTI, SEC_NONE, attach_uprobe_multi),
+	SEC_DEF("uprobe.session+",	KPROBE,	BPF_TRACE_UPROBE_SESSION, SEC_NONE, attach_uprobe_session),
 	SEC_DEF("uprobe.multi.s+",	KPROBE,	BPF_TRACE_UPROBE_MULTI, SEC_SLEEPABLE, attach_uprobe_multi),
 	SEC_DEF("uretprobe.multi.s+",	KPROBE,	BPF_TRACE_UPROBE_MULTI, SEC_SLEEPABLE, attach_uprobe_multi),
 	SEC_DEF("ksyscall+",		KPROBE,	0, SEC_NONE, attach_ksyscall),
@@ -11698,6 +11700,40 @@  static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, stru
 	return ret;
 }
 
+static int attach_uprobe_session(const struct bpf_program *prog, long cookie, struct bpf_link **link)
+{
+	char *binary_path = NULL, *func_name = NULL;
+	LIBBPF_OPTS(bpf_uprobe_multi_opts, opts,
+		.session = true,
+	);
+	int n, ret = -EINVAL;
+	const char *spec;
+
+	*link = NULL;
+
+	spec = prog->sec_name + sizeof("uprobe.session/") - 1;
+	n = sscanf(spec, "%m[^:]:%m[^\n]",
+		   &binary_path, &func_name);
+
+	switch (n) {
+	case 1:
+		/* but auto-attach is impossible. */
+		ret = 0;
+		break;
+	case 2:
+		*link = bpf_program__attach_uprobe_multi(prog, -1, binary_path, func_name, &opts);
+		ret = *link ? 0 : -errno;
+		break;
+	default:
+		pr_warn("prog '%s': invalid format of section definition '%s'\n", prog->name,
+			prog->sec_name);
+		break;
+	}
+	free(binary_path);
+	free(func_name);
+	return ret;
+}
+
 static void gen_uprobe_legacy_event_name(char *buf, size_t buf_sz,
 					 const char *binary_path, uint64_t offset)
 {
@@ -11932,10 +11968,12 @@  bpf_program__attach_uprobe_multi(const struct bpf_program *prog,
 	const unsigned long *ref_ctr_offsets = NULL, *offsets = NULL;
 	LIBBPF_OPTS(bpf_link_create_opts, lopts);
 	unsigned long *resolved_offsets = NULL;
+	enum bpf_attach_type attach_type;
 	int err = 0, link_fd, prog_fd;
 	struct bpf_link *link = NULL;
 	char errmsg[STRERR_BUFSIZE];
 	char full_path[PATH_MAX];
+	bool retprobe, session;
 	const __u64 *cookies;
 	const char **syms;
 	size_t cnt;
@@ -12006,12 +12044,20 @@  bpf_program__attach_uprobe_multi(const struct bpf_program *prog,
 		offsets = resolved_offsets;
 	}
 
+	retprobe = OPTS_GET(opts, retprobe, false);
+	session  = OPTS_GET(opts, session, false);
+
+	if (retprobe && session)
+		return libbpf_err_ptr(-EINVAL);
+
+	attach_type = session ? BPF_TRACE_UPROBE_SESSION : BPF_TRACE_UPROBE_MULTI;
+
 	lopts.uprobe_multi.path = path;
 	lopts.uprobe_multi.offsets = offsets;
 	lopts.uprobe_multi.ref_ctr_offsets = ref_ctr_offsets;
 	lopts.uprobe_multi.cookies = cookies;
 	lopts.uprobe_multi.cnt = cnt;
-	lopts.uprobe_multi.flags = OPTS_GET(opts, retprobe, false) ? BPF_F_UPROBE_MULTI_RETURN : 0;
+	lopts.uprobe_multi.flags = retprobe ? BPF_F_UPROBE_MULTI_RETURN : 0;
 
 	if (pid == 0)
 		pid = getpid();
@@ -12025,7 +12071,7 @@  bpf_program__attach_uprobe_multi(const struct bpf_program *prog,
 	}
 	link->detach = &bpf_link__detach_fd;
 
-	link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &lopts);
+	link_fd = bpf_link_create(prog_fd, 0, attach_type, &lopts);
 	if (link_fd < 0) {
 		err = -errno;
 		pr_warn("prog '%s': failed to attach multi-uprobe: %s\n",
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 64a6a3d323e3..f6a7835dc519 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -569,10 +569,12 @@  struct bpf_uprobe_multi_opts {
 	size_t cnt;
 	/* create return uprobes */
 	bool retprobe;
+	/* create session kprobes */
+	bool session;
 	size_t :0;
 };
 
-#define bpf_uprobe_multi_opts__last_field retprobe
+#define bpf_uprobe_multi_opts__last_field session
 
 /**
  * @brief **bpf_program__attach_uprobe_multi()** attaches a BPF program