bpftool: Do not expose and init hash maps for pinned path in main.c

BPF programs, maps, and links, can all be listed with their pinned paths
by bpftool, when the "-f" option is provided. To do so, bpftool builds
hash maps containing all pinned paths for each kind of objects.

These three hash maps are always initialised in main.c, and exposed
through main.h. There appear to be no particular reason to do so: we can
just as well make them static to the files that need them (prog.c,
map.c, and link.c respectively), and initialise them only when we want
to show objects and the "-f" switch is provided.

This may prevent unnecessary memory allocations if the implementation of
the hash maps was to change in the future.

Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211023205154.6710-3-quentin@isovalent.com

1 files changed, 8 insertions, 1 deletions

diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index 407071d54ab1..0085039d9610 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -56,6 +56,8 @@ const char * const map_type_name[] = {
 
 const size_t map_type_name_size = ARRAY_SIZE(map_type_name);
 
+static struct pinned_obj_table map_table;
+
 static bool map_is_per_cpu(__u32 type)
 {
 	return type == BPF_MAP_TYPE_PERCPU_HASH ||
@@ -694,8 +696,10 @@ static int do_show(int argc, char **argv)
 	int err;
 	int fd;
 
-	if (show_pinned)
+	if (show_pinned) {
+		hash_init(map_table.table);
 		build_pinned_obj_table(&map_table, BPF_OBJ_MAP);
+	}
 	build_obj_refs_table(&refs_table, BPF_OBJ_MAP);
 
 	if (argc == 2)
@@ -742,6 +746,9 @@ static int do_show(int argc, char **argv)
 
 	delete_obj_refs_table(&refs_table);
 
+	if (show_pinned)
+		delete_pinned_obj_table(&map_table);
+
 	return errno == ENOENT ? 0 : -1;
 }