netdev - [PATCH bpf-next v3 1/3] libbpf: use func name when pinning programs with LIBBPF_STRICT_SEC

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Message-Id: <20211020225005.2986729-2-sdf@google.com>
Date:   Wed, 20 Oct 2021 15:50:03 -0700
From:   Stanislav Fomichev <sdf@...gle.com>
To:     netdev@...r.kernel.org, bpf@...r.kernel.org
Cc:     ast@...nel.org, daniel@...earbox.net, andrii@...nel.org,
        Stanislav Fomichev <sdf@...gle.com>,
        Quentin Monnet <quentin@...valent.com>
Subject: [PATCH bpf-next v3 1/3] libbpf: use func name when pinning programs
 with LIBBPF_STRICT_SEC_NAME

We can't use section name anymore because they are not unique
and pinning objects with multiple programs with the same
progtype/secname will fail.

Closes: https://github.com/libbpf/libbpf/issues/273
Fixes: 33a2c75c55e2 ("libbpf: add internal pin_name"0
Cc: Quentin Monnet <quentin@...valent.com>
Signed-off-by: Stanislav Fomichev <sdf@...gle.com>
---
 tools/lib/bpf/libbpf.c        | 13 +++++++++++--
 tools/lib/bpf/libbpf_legacy.h |  3 +++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 760c7e346603..7f48eeb3ca82 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -285,7 +285,7 @@ struct bpf_program {
 	size_t sub_insn_off;
 
 	char *name;
-	/* sec_name with / replaced by _; makes recursive pinning
+	/* name with / replaced by _; makes recursive pinning
 	 * in bpf_object__pin_programs easier
 	 */
 	char *pin_name;
@@ -614,7 +614,16 @@ static char *__bpf_program__pin_name(struct bpf_program *prog)
 {
 	char *name, *p;
 
-	name = p = strdup(prog->sec_name);
+	if (libbpf_mode & LIBBPF_STRICT_SEC_NAME)
+		name = strdup(prog->name);
+	else
+		name = strdup(prog->sec_name);
+
+	if (!name)
+		return NULL;
+
+	p = name;
+
 	while ((p = strchr(p, '/')))
 		*p = '_';
 
diff --git a/tools/lib/bpf/libbpf_legacy.h b/tools/lib/bpf/libbpf_legacy.h
index 74e6f860f703..a51f34637442 100644
--- a/tools/lib/bpf/libbpf_legacy.h
+++ b/tools/lib/bpf/libbpf_legacy.h
@@ -52,6 +52,9 @@ enum libbpf_strict_mode {
 	 * allowed, with LIBBPF_STRICT_SEC_PREFIX this will become
 	 * unrecognized by libbpf and would have to be just SEC("xdp") and
 	 * SEC("xdp") and SEC("perf_event").
+	 *
+	 * Note, in this mode the program pin path will based on the
+	 * function name instead of section name.
 	 */
 	LIBBPF_STRICT_SEC_NAME = 0x04,
 
-- 
2.33.0.1079.g6e70778dc9-goog