You can include an optional path after specifying the object name for the
'struct_ops register' subcommand.
Since the commit 226bc6ae6405 ("Merge branch 'Transit between BPF TCP
congestion controls.'") has been accepted, it is now possible to create a
link for a struct_ops. This can be done by defining a struct_ops in
SEC(".struct_ops.link") to make libbpf returns a real link. If we don't pin
the links before leaving bpftool, they will disappear. To instruct bpftool
to pin the links in a directory with the names of the maps, we need to
provide the path of that directory.
Signed-off-by: Kui-Feng Lee <kuifeng@xxxxxxxx>
---
tools/bpf/bpftool/common.c | 14 +++++++
tools/bpf/bpftool/main.h | 3 ++
tools/bpf/bpftool/prog.c | 13 ------
tools/bpf/bpftool/struct_ops.c | 76 ++++++++++++++++++++++++++++------
4 files changed, 80 insertions(+), 26 deletions(-)
diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index 5a73ccf14332..1360c82ae732 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -1091,3 +1091,17 @@ const char *bpf_attach_type_input_str(enum bpf_attach_type t)
default: return libbpf_bpf_attach_type_str(t);
}
}
+
+int pathname_concat(char *buf, int buf_sz, const char *path,
+ const char *name)
+{
+ int len;
+
+ len = snprintf(buf, buf_sz, "%s/%s", path, name);
+ if (len < 0)
+ return -EINVAL;
+ if (len >= buf_sz)
+ return -ENAMETOOLONG;
+
+ return 0;
+}
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 0ef373cef4c7..f09853f24422 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -262,4 +262,7 @@ static inline bool hashmap__empty(struct hashmap *map)
return map ? hashmap__size(map) == 0 : true;
}
+int pathname_concat(char *buf, int buf_sz, const char *path,
+ const char *name);
+
#endif
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index afbe3ec342c8..6024b7316875 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -1472,19 +1472,6 @@ auto_attach_program(struct bpf_program *prog, const char *path)
return err;
}
-static int pathname_concat(char *buf, size_t buf_sz, const char *path, const char *name)
-{
- int len;
-
- len = snprintf(buf, buf_sz, "%s/%s", path, name);
- if (len < 0)
- return -EINVAL;
- if ((size_t)len >= buf_sz)
- return -ENAMETOOLONG;
-
- return 0;
-}
-
static int
auto_attach_programs(struct bpf_object *obj, const char *path)
{
diff --git a/tools/bpf/bpftool/struct_ops.c b/tools/bpf/bpftool/struct_ops.c
index b389f4830e11..41643756e400 100644
--- a/tools/bpf/bpftool/struct_ops.c
+++ b/tools/bpf/bpftool/struct_ops.c
@@ -475,21 +475,48 @@ static int do_unregister(int argc, char **argv)
return cmd_retval(&res, true);
}
+static int pin_link(struct bpf_link *link, const char *pindir,
+ const char *name)
+{
+ char pinfile[PATH_MAX];
+ int err;
+
+ err = pathname_concat(pinfile, sizeof(pinfile), pindir, name);
+ if (err)
+ return -1;
+
+ err = bpf_link__pin(link, pinfile);
+ if (err)
+ return -1;
+
+ return 0;
+}
+
static int do_register(int argc, char **argv)
{
LIBBPF_OPTS(bpf_object_open_opts, open_opts);
+ __u32 link_info_len = sizeof(struct bpf_link_info);
+ struct bpf_link_info link_info = {};
struct bpf_map_info info = {};
__u32 info_len = sizeof(info);
int nr_errs = 0, nr_maps = 0;
+ const char *linkdir = NULL;
struct bpf_object *obj;
struct bpf_link *link;
struct bpf_map *map;
const char *file;
- if (argc != 1)
+ if (argc != 1 && argc != 2)
usage();
file = GET_ARG();
+ if (argc == 1)
+ linkdir = GET_ARG();
+
+ if (linkdir && mount_bpffs_for_pin(linkdir)) {
+ p_err("can't mount bpffs for pinning");
+ return -1;
+ }
if (verifier_logs)
/* log_level1 + log_level2 + stats, but not stable UAPI */
@@ -519,21 +546,44 @@ static int do_register(int argc, char **argv)
}
nr_maps++;
- bpf_link__disconnect(link);
- bpf_link__destroy(link);
-
- if (!bpf_map_get_info_by_fd(bpf_map__fd(map), &info,
- &info_len))
- p_info("Registered %s %s id %u",
- get_kern_struct_ops_name(&info),
- bpf_map__name(map),
- info.id);
- else
+ if (bpf_map_get_info_by_fd(bpf_map__fd(map), &info,
+ &info_len)) {
/* Not p_err. The struct_ops was attached
* successfully.
*/
p_info("Registered %s but can't find id: %s",
- bpf_map__name(map), strerror(errno));
+ bpf_map__name(map), strerror(errno));
+ goto clean_link;
+ }
+ if (!(bpf_map__map_flags(map) & BPF_F_LINK)) {
+ p_info("Registered %s %s id %u",
+ get_kern_struct_ops_name(&info),
+ info.name,
+ info.id);
+ goto clean_link;
+ }
+ if (bpf_link_get_info_by_fd(bpf_link__fd(link),
+ &link_info,
+ &link_info_len)) {
+ p_err("Registered %s but can't find link id: %s",
+ bpf_map__name(map), strerror(errno));
+ nr_errs++;
+ goto clean_link;
+ }
+ if (linkdir && pin_link(link, linkdir, info.name)) {
+ p_err("can't pin link %u for %s: %s",
+ link_info.id, info.name,
+ strerror(errno));
+ nr_errs++;
+ goto clean_link;
+ }
+ p_info("Registered %s %s map id %u link id %u",
+ get_kern_struct_ops_name(&info),
+ info.name, info.id, link_info.id);
+
+clean_link:
+ bpf_link__disconnect(link);
+ bpf_link__destroy(link);
}
bpf_object__close(obj);
@@ -562,7 +612,7 @@ static int do_help(int argc, char **argv)
fprintf(stderr,
"Usage: %1$s %2$s { show | list } [STRUCT_OPS_MAP]\n"
" %1$s %2$s dump [STRUCT_OPS_MAP]\n"
- " %1$s %2$s register OBJ\n"
+ " %1$s %2$s register OBJ [LINK_DIR]\n"
" %1$s %2$s unregister STRUCT_OPS_MAP\n"
" %1$s %2$s help\n"
"\n"
--
2.34.1
