Introduce a new bpf_prog_attach_xattr function that accepts an
extendable struct bpf_prog_attach_opts and supports passing a new
attribute to BPF_PROG_ATTACH command: replace_prog_fd that is fd of
previously attached cgroup-bpf program to replace if recently introduced
BPF_F_REPLACE flag is used.
The new function is named to be consistent with other xattr-functions
(bpf_prog_test_run_xattr, bpf_create_map_xattr, bpf_load_program_xattr).
The struct bpf_prog_attach_opts is supposed to be used with
DECLARE_LIBBPF_OPTS framework.
The opts argument is used directly in bpf_prog_attach_xattr
implementation since at the time of adding all fields already exist in
the kernel. New fields, if added, will need to be used via OPTS_* macros
from libbpf_internal.h.
Signed-off-by: Andrey Ignatov <rdna@xxxxxx>
---
tools/lib/bpf/bpf.c | 21 +++++++++++++++++----
tools/lib/bpf/bpf.h | 12 ++++++++++++
tools/lib/bpf/libbpf.map | 2 ++
3 files changed, 31 insertions(+), 4 deletions(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 98596e15390f..9f4e42abd185 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -466,14 +466,27 @@ int bpf_obj_get(const char *pathname)
int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type,
unsigned int flags)
+{
+ DECLARE_LIBBPF_OPTS(bpf_prog_attach_opts, opts,
+ .target_fd = target_fd,
+ .prog_fd = prog_fd,
+ .type = type,
+ .flags = flags,
+ );
+
+ return bpf_prog_attach_xattr(&opts);
+}
+
+int bpf_prog_attach_xattr(const struct bpf_prog_attach_opts *opts)
{
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
- attr.target_fd = target_fd;
- attr.attach_bpf_fd = prog_fd;
- attr.attach_type = type;
- attr.attach_flags = flags;
+ attr.target_fd = opts->target_fd;
+ attr.attach_bpf_fd = opts->prog_fd;
+ attr.attach_type = opts->type;
+ attr.attach_flags = opts->flags;
+ attr.replace_bpf_fd = opts->replace_prog_fd;
return sys_bpf(BPF_PROG_ATTACH, &attr, sizeof(attr));
}
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 5cfe6e0a1aef..5b5f9b374074 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -150,8 +150,20 @@ LIBBPF_API int bpf_map_get_next_key(int fd, const void *key, void *next_key);
LIBBPF_API int bpf_map_freeze(int fd);
LIBBPF_API int bpf_obj_pin(int fd, const char *pathname);
LIBBPF_API int bpf_obj_get(const char *pathname);
+
+struct bpf_prog_attach_opts {
+ size_t sz; /* size of this struct for forward/backward compatibility */
+ int target_fd;
+ int prog_fd;
+ enum bpf_attach_type type;
+ unsigned int flags;
+ int replace_prog_fd;
+};
+#define bpf_prog_attach_opts__last_field replace_prog_fd
+
LIBBPF_API int bpf_prog_attach(int prog_fd, int attachable_fd,
enum bpf_attach_type type, unsigned int flags);
+LIBBPF_API int bpf_prog_attach_xattr(const struct bpf_prog_attach_opts *opts);
LIBBPF_API int bpf_prog_detach(int attachable_fd, enum bpf_attach_type type);
LIBBPF_API int bpf_prog_detach2(int prog_fd, int attachable_fd,
enum bpf_attach_type type);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 495df575f87f..42b065454031 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -210,4 +210,6 @@ LIBBPF_0.0.6 {
} LIBBPF_0.0.5;
LIBBPF_0.0.7 {
+ global:
+ bpf_prog_attach_xattr;
} LIBBPF_0.0.6;
--
2.17.1
