path: root/tools/lib
diff options
authorAndrey Ignatov <rdna@fb.com>2019-12-18 23:44:36 -0800
committerAlexei Starovoitov <ast@kernel.org>2019-12-19 21:22:25 -0800
commitcdbee3839cd91a4577425c43cf064b9523926159 (patch)
tree8125c9716ca2582a1251363a8cb2a5f4e709fd3d /tools/lib
parentbpf: Support replacing cgroup-bpf program in MULTI mode (diff)
libbpf: Introduce bpf_prog_attach_xattr
Introduce a new bpf_prog_attach_xattr function that, in addition to program fd, target fd and attach type, accepts an extendable struct bpf_prog_attach_opts. bpf_prog_attach_opts relies on DECLARE_LIBBPF_OPTS macro to maintain backward and forward compatibility and has the following "optional" attach attributes: * existing attach_flags, since it's not required when attaching in NONE mode. Even though it's quite often used in MULTI and OVERRIDE mode it seems to be a good idea to reduce number of arguments to bpf_prog_attach_xattr; * newly introduced attribute of BPF_PROG_ATTACH command: replace_prog_fd that is fd of previously attached cgroup-bpf program to replace if 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 macro. Signed-off-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/bd6e0732303eb14e4b79cb128268d9e9ad6db208.1576741281.git.rdna@fb.com
Diffstat (limited to 'tools/lib')
3 files changed, 28 insertions, 1 deletions
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 98596e15390f..a787d53699c8 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -467,13 +467,28 @@ 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,
+ .flags = flags,
+ );
+ return bpf_prog_attach_xattr(prog_fd, target_fd, type, &opts);
+int bpf_prog_attach_xattr(int prog_fd, int target_fd,
+ enum bpf_attach_type type,
+ const struct bpf_prog_attach_opts *opts)
union bpf_attr attr;
+ if (!OPTS_VALID(opts, bpf_prog_attach_opts))
+ return -EINVAL;
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.attach_flags = OPTS_GET(opts, flags, 0);
+ attr.replace_bpf_fd = OPTS_GET(opts, replace_prog_fd, 0);
return sys_bpf(BPF_PROG_ATTACH, &attr, sizeof(attr));
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 269807ce9ef5..f0ab8519986e 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -126,8 +126,19 @@ 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 */
+ 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(int prog_fd, int attachable_fd,
+ enum bpf_attach_type type,
+ 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 e3a471f38a71..e9713a574243 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -219,6 +219,7 @@ LIBBPF_0.0.7 {
+ bpf_prog_attach_xattr;