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Message-Id: <20220729202727.3311806-1-jevburton.kernel@gmail.com>
Date: Fri, 29 Jul 2022 20:27:27 +0000
From: Joe Burton <jevburton.kernel@...il.com>
To: Andrii Nakryiko <andrii@...nel.org>,
Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Martin KaFai Lau <martin.lau@...ux.dev>,
Song Liu <song@...nel.org>, Yonghong Song <yhs@...com>,
John Fastabend <john.fastabend@...il.com>,
KP Singh <kpsingh@...nel.org>,
Stanislav Fomichev <sdf@...gle.com>,
Hao Luo <haoluo@...gle.com>, Jiri Olsa <jolsa@...nel.org>,
bpf@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: Joe Burton <jevburton@...gle.com>
Subject: [PATCH v3 bpf-next] libbpf: Add bpf_obj_get_opts()
From: Joe Burton <jevburton@...gle.com>
Add an extensible variant of bpf_obj_get() capable of setting the
`file_flags` parameter.
This parameter is needed to enable unprivileged access to BPF maps.
Without a method like this, users must manually make the syscall.
Signed-off-by: Joe Burton <jevburton@...gle.com>
---
tools/lib/bpf/bpf.c | 9 +++++++++
tools/lib/bpf/bpf.h | 11 +++++++++++
tools/lib/bpf/libbpf.map | 1 +
3 files changed, 21 insertions(+)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 5eb0df90eb2b..efcc06dafbd9 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -578,12 +578,21 @@ int bpf_obj_pin(int fd, const char *pathname)
}
int bpf_obj_get(const char *pathname)
+{
+ return bpf_obj_get_opts(pathname, NULL);
+}
+
+int bpf_obj_get_opts(const char *pathname, const struct bpf_obj_get_opts *opts)
{
union bpf_attr attr;
int fd;
+ if (!OPTS_VALID(opts, bpf_obj_get_opts))
+ return libbpf_err(-EINVAL);
+
memset(&attr, 0, sizeof(attr));
attr.pathname = ptr_to_u64((void *)pathname);
+ attr.file_flags = OPTS_GET(opts, file_flags, 0);
fd = sys_bpf_fd(BPF_OBJ_GET, &attr, sizeof(attr));
return libbpf_err_errno(fd);
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 88a7cc4bd76f..9c50beabdd14 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -270,8 +270,19 @@ LIBBPF_API int bpf_map_update_batch(int fd, const void *keys, const void *values
__u32 *count,
const struct bpf_map_batch_opts *opts);
+struct bpf_obj_get_opts {
+ size_t sz; /* size of this struct for forward/backward compatibility */
+
+ __u32 file_flags;
+
+ size_t :0;
+};
+#define bpf_obj_get_opts__last_field file_flags
+
LIBBPF_API int bpf_obj_pin(int fd, const char *pathname);
LIBBPF_API int bpf_obj_get(const char *pathname);
+LIBBPF_API int bpf_obj_get_opts(const char *pathname,
+ const struct bpf_obj_get_opts *opts);
struct bpf_prog_attach_opts {
size_t sz; /* size of this struct for forward/backward compatibility */
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 0625adb9e888..119e6e1ea7f1 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -355,6 +355,7 @@ LIBBPF_0.8.0 {
LIBBPF_1.0.0 {
global:
+ bpf_obj_get_opts;
bpf_prog_query_opts;
bpf_program__attach_ksyscall;
btf__add_enum64;
--
2.37.1.455.g008518b4e5-goog
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