lkml.org 
[lkml]   [2022]   [Sep]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC][PATCH 1/3] libbpf: Define bpf_get_fd_opts and introduce bpf_map_get_fd_by_id_opts()
Date
From: Roberto Sassu <roberto.sassu@huawei.com>

Define a new data structure called bpf_get_fd_opts, with the member
open_flags, to be used by callers of the _opts variants of
bpf_*_get_fd_by_id() to specify the permissions needed for the file
descriptor to be obtained.

Also, introduce bpf_map_get_fd_by_id_opts(), to let the caller pass a
bpf_get_fd_opts structure.

Finally, keep the existing bpf_map_get_fd_by_id(), and call
bpf_map_get_fd_by_id_opts() with NULL as opts argument, to request
read-write permissions (current behavior).

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
tools/lib/bpf/bpf.c | 12 +++++++++++-
tools/lib/bpf/bpf.h | 10 ++++++++++
tools/lib/bpf/libbpf.map | 3 ++-
3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 1d49a0352836..4b03063edf1d 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -948,19 +948,29 @@ int bpf_prog_get_fd_by_id(__u32 id)
return libbpf_err_errno(fd);
}

-int bpf_map_get_fd_by_id(__u32 id)
+int bpf_map_get_fd_by_id_opts(__u32 id,
+ const struct bpf_get_fd_opts *opts)
{
const size_t attr_sz = offsetofend(union bpf_attr, open_flags);
union bpf_attr attr;
int fd;

+ if (!OPTS_VALID(opts, bpf_get_fd_opts))
+ return libbpf_err(-EINVAL);
+
memset(&attr, 0, attr_sz);
attr.map_id = id;
+ attr.open_flags = OPTS_GET(opts, open_flags, 0);

fd = sys_bpf_fd(BPF_MAP_GET_FD_BY_ID, &attr, attr_sz);
return libbpf_err_errno(fd);
}

+int bpf_map_get_fd_by_id(__u32 id)
+{
+ return bpf_map_get_fd_by_id_opts(id, NULL);
+}
+
int bpf_btf_get_fd_by_id(__u32 id)
{
const size_t attr_sz = offsetofend(union bpf_attr, open_flags);
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 9c50beabdd14..38a1b7eccfc8 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -365,7 +365,17 @@ LIBBPF_API int bpf_prog_get_next_id(__u32 start_id, __u32 *next_id);
LIBBPF_API int bpf_map_get_next_id(__u32 start_id, __u32 *next_id);
LIBBPF_API int bpf_btf_get_next_id(__u32 start_id, __u32 *next_id);
LIBBPF_API int bpf_link_get_next_id(__u32 start_id, __u32 *next_id);
+
+struct bpf_get_fd_opts {
+ size_t sz; /* size of this struct for forward/backward compatibility */
+ __u32 open_flags; /* permissions requested for the operation on fd */
+ __u32 :0;
+};
+#define bpf_get_fd_opts__last_field open_flags
+
LIBBPF_API int bpf_prog_get_fd_by_id(__u32 id);
+LIBBPF_API int bpf_map_get_fd_by_id_opts(__u32 id,
+ const struct bpf_get_fd_opts *opts);
LIBBPF_API int bpf_map_get_fd_by_id(__u32 id);
LIBBPF_API int bpf_btf_get_fd_by_id(__u32 id);
LIBBPF_API int bpf_link_get_fd_by_id(__u32 id);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index c1d6aa7c82b6..2e665b21d84f 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -367,10 +367,11 @@ LIBBPF_1.0.0 {
libbpf_bpf_map_type_str;
libbpf_bpf_prog_type_str;
perf_buffer__buffer;
-};
+} LIBBPF_0.8.0;

LIBBPF_1.1.0 {
global:
+ bpf_map_get_fd_by_id_opts;
user_ring_buffer__discard;
user_ring_buffer__free;
user_ring_buffer__new;
--
2.25.1
\
 
 \ /
  Last update: 2022-09-26 18:53    [W:0.034 / U:0.420 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site