The link query for bpf iterators is implemented.
Besides being shown to the user what bpf iterator
the link represents, the target_name is also used
to filter out what additional information should be
printed out, e.g., whether map_id should be shown or not.
The following is an example of bpf_iter link dump,
plain output or pretty output.
$ bpftool link show
11: iter prog 59 target_name task
pids test_progs(1749)
34: iter prog 173 target_name bpf_map_elem map_id 127
pids test_progs_1(1753)
$ bpftool -p link show
[{
"id": 11,
"type": "iter",
"prog_id": 59,
"target_name": "task",
"pids": [{
"pid": 1749,
"comm": "test_progs"
}
]
},{
"id": 34,
"type": "iter",
"prog_id": 173,
"target_name": "bpf_map_elem",
"map_id": 127,
"pids": [{
"pid": 1753,
"comm": "test_progs_1"
}
]
}
]
Signed-off-by: Yonghong Song <yhs@xxxxxx>
---
tools/bpf/bpftool/link.c | 44 +++++++++++++++++++++++++++++++++++++---
1 file changed, 41 insertions(+), 3 deletions(-)
diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
index a89f09e3c848..e77e1525d20a 100644
--- a/tools/bpf/bpftool/link.c
+++ b/tools/bpf/bpftool/link.c
@@ -77,6 +77,22 @@ static void show_link_attach_type_json(__u32 attach_type, json_writer_t *wtr)
jsonw_uint_field(wtr, "attach_type", attach_type);
}
+static bool is_iter_map_target(const char *target_name)
+{
+ return strcmp(target_name, "bpf_map_elem") == 0 ||
+ strcmp(target_name, "bpf_sk_storage_map") == 0;
+}
+
+static void show_iter_json(struct bpf_link_info *info, json_writer_t *wtr)
+{
+ const char *target_name = u64_to_ptr(info->iter.target_name);
+
+ jsonw_string_field(wtr, "target_name", target_name);
+
+ if (is_iter_map_target(target_name))
+ jsonw_uint_field(wtr, "map_id", info->iter.map.map_id);
+}
+
static int get_prog_info(int prog_id, struct bpf_prog_info *info)
{
__u32 len = sizeof(*info);
@@ -128,6 +144,9 @@ static int show_link_close_json(int fd, struct bpf_link_info *info)
info->cgroup.cgroup_id);
show_link_attach_type_json(info->cgroup.attach_type, json_wtr);
break;
+ case BPF_LINK_TYPE_ITER:
+ show_iter_json(info, json_wtr);
+ break;
case BPF_LINK_TYPE_NETNS:
jsonw_uint_field(json_wtr, "netns_ino",
info->netns.netns_ino);
@@ -175,6 +194,16 @@ static void show_link_attach_type_plain(__u32 attach_type)
printf("attach_type %u ", attach_type);
}
+static void show_iter_plain(struct bpf_link_info *info)
+{
+ const char *target_name = u64_to_ptr(info->iter.target_name);
+
+ printf("target_name %s ", target_name);
+
+ if (is_iter_map_target(target_name))
+ printf("map_id %u ", info->iter.map.map_id);
+}
+
static int show_link_close_plain(int fd, struct bpf_link_info *info)
{
struct bpf_prog_info prog_info;
@@ -204,6 +233,9 @@ static int show_link_close_plain(int fd, struct bpf_link_info *info)
printf("\n\tcgroup_id %zu ", (size_t)info->cgroup.cgroup_id);
show_link_attach_type_plain(info->cgroup.attach_type);
break;
+ case BPF_LINK_TYPE_ITER:
+ show_iter_plain(info);
+ break;
case BPF_LINK_TYPE_NETNS:
printf("\n\tnetns_ino %u ", info->netns.netns_ino);
show_link_attach_type_plain(info->netns.attach_type);
@@ -231,7 +263,7 @@ static int do_show_link(int fd)
{
struct bpf_link_info info;
__u32 len = sizeof(info);
- char raw_tp_name[256];
+ char buf[256];
int err;
memset(&info, 0, sizeof(info));
@@ -245,8 +277,14 @@ static int do_show_link(int fd)
}
if (info.type == BPF_LINK_TYPE_RAW_TRACEPOINT &&
!info.raw_tracepoint.tp_name) {
- info.raw_tracepoint.tp_name = (unsigned long)&raw_tp_name;
- info.raw_tracepoint.tp_name_len = sizeof(raw_tp_name);
+ info.raw_tracepoint.tp_name = (unsigned long)&buf;
+ info.raw_tracepoint.tp_name_len = sizeof(buf);
+ goto again;
+ }
+ if (info.type == BPF_LINK_TYPE_ITER &&
+ !info.iter.target_name) {
+ info.iter.target_name = (unsigned long)&buf;
+ info.iter.target_name_len = sizeof(buf);
goto again;
}
--
2.24.1
