[PATCH bpf-next 1/2] tools: bpftool: show frozen status for maps

[Quentin Monnet <quentin.monnet@xxxxxxxxxxxxx>]

When listing maps, read their "frozen" status from procfs, and tell if
maps are frozen.

As commit log for map freezing command mentions that the feature might
be extended with flags (e.g. for write-only instead of read-only) in the
future, use an integer and not a boolean for JSON output.

Signed-off-by: Quentin Monnet <quentin.monnet@xxxxxxxxxxxxx>
Reviewed-by: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx>
---
 tools/bpf/bpftool/map.c | 30 +++++++++++++++++++++++++++---
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index bfbbc6b4cb83..af2e9eb9747b 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -481,9 +481,11 @@ static int parse_elem(char **argv, struct bpf_map_info *info,
 
 static int show_map_close_json(int fd, struct bpf_map_info *info)
 {
-	char *memlock;
+	char *memlock, *frozen_str;
+	int frozen = 0;
 
 	memlock = get_fdinfo(fd, "memlock");
+	frozen_str = get_fdinfo(fd, "frozen");
 
 	jsonw_start_object(json_wtr);
 
@@ -533,6 +535,12 @@ static int show_map_close_json(int fd, struct bpf_map_info *info)
 	}
 	close(fd);
 
+	if (frozen_str) {
+		frozen = atoi(frozen_str);
+		free(frozen_str);
+	}
+	jsonw_int_field(json_wtr, "frozen", frozen);
+
 	if (info->btf_id)
 		jsonw_int_field(json_wtr, "btf_id", info->btf_id);
 
@@ -555,9 +563,11 @@ static int show_map_close_json(int fd, struct bpf_map_info *info)
 
 static int show_map_close_plain(int fd, struct bpf_map_info *info)
 {
-	char *memlock;
+	char *memlock, *frozen_str;
+	int frozen = 0;
 
 	memlock = get_fdinfo(fd, "memlock");
+	frozen_str = get_fdinfo(fd, "frozen");
 
 	printf("%u: ", info->id);
 	if (info->type < ARRAY_SIZE(map_type_name))
@@ -610,9 +620,23 @@ static int show_map_close_plain(int fd, struct bpf_map_info *info)
 				printf("\n\tpinned %s", obj->path);
 		}
 	}
+	printf("\n");
+
+	if (frozen_str) {
+		frozen = atoi(frozen_str);
+		free(frozen_str);
+	}
+
+	if (!info->btf_id && !frozen)
+		return 0;
+
+	printf("\t");
 
 	if (info->btf_id)
-		printf("\n\tbtf_id %d", info->btf_id);
+		printf("btf_id %d", info->btf_id);
+
+	if (frozen)
+		printf("%sfrozen", info->btf_id ? "  " : "");
 
 	printf("\n");
 	return 0;
-- 
2.17.1