libbpf: Introduce libbpf_bpf_map_type_str

This change introduces a new function, libbpf_bpf_map_type_str, to the
public libbpf API. The function allows users to get a string
representation for a bpf_map_type enum variant.
Signed-off-by: Daniel Müller <deso@posteo.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220523230428.3077108-5-deso@posteo.net

tools/lib/bpf/libbpf.c

@@ -72,6 +72,40 @@
 static struct bpf_map *bpf_object__add_map(struct bpf_object *obj);
 static bool prog_is_subprog(const struct bpf_object *obj, const struct bpf_program *prog);
 
+static const char * const map_type_name[] = {
+	[BPF_MAP_TYPE_UNSPEC]			= "unspec",
+	[BPF_MAP_TYPE_HASH]			= "hash",
+	[BPF_MAP_TYPE_ARRAY]			= "array",
+	[BPF_MAP_TYPE_PROG_ARRAY]		= "prog_array",
+	[BPF_MAP_TYPE_PERF_EVENT_ARRAY]		= "perf_event_array",
+	[BPF_MAP_TYPE_PERCPU_HASH]		= "percpu_hash",
+	[BPF_MAP_TYPE_PERCPU_ARRAY]		= "percpu_array",
+	[BPF_MAP_TYPE_STACK_TRACE]		= "stack_trace",
+	[BPF_MAP_TYPE_CGROUP_ARRAY]		= "cgroup_array",
+	[BPF_MAP_TYPE_LRU_HASH]			= "lru_hash",
+	[BPF_MAP_TYPE_LRU_PERCPU_HASH]		= "lru_percpu_hash",
+	[BPF_MAP_TYPE_LPM_TRIE]			= "lpm_trie",
+	[BPF_MAP_TYPE_ARRAY_OF_MAPS]		= "array_of_maps",
+	[BPF_MAP_TYPE_HASH_OF_MAPS]		= "hash_of_maps",
+	[BPF_MAP_TYPE_DEVMAP]			= "devmap",
+	[BPF_MAP_TYPE_DEVMAP_HASH]		= "devmap_hash",
+	[BPF_MAP_TYPE_SOCKMAP]			= "sockmap",
+	[BPF_MAP_TYPE_CPUMAP]			= "cpumap",
+	[BPF_MAP_TYPE_XSKMAP]			= "xskmap",
+	[BPF_MAP_TYPE_SOCKHASH]			= "sockhash",
+	[BPF_MAP_TYPE_CGROUP_STORAGE]		= "cgroup_storage",
+	[BPF_MAP_TYPE_REUSEPORT_SOCKARRAY]	= "reuseport_sockarray",
+	[BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE]	= "percpu_cgroup_storage",
+	[BPF_MAP_TYPE_QUEUE]			= "queue",
+	[BPF_MAP_TYPE_STACK]			= "stack",
+	[BPF_MAP_TYPE_SK_STORAGE]		= "sk_storage",
+	[BPF_MAP_TYPE_STRUCT_OPS]		= "struct_ops",
+	[BPF_MAP_TYPE_RINGBUF]			= "ringbuf",
+	[BPF_MAP_TYPE_INODE_STORAGE]		= "inode_storage",
+	[BPF_MAP_TYPE_TASK_STORAGE]		= "task_storage",
+	[BPF_MAP_TYPE_BLOOM_FILTER]		= "bloom_filter",
+};
+
 static const char * const prog_type_name[] = {
 	[BPF_PROG_TYPE_UNSPEC]			= "unspec",
 	[BPF_PROG_TYPE_SOCKET_FILTER]		= "socket_filter",
@@ -9335,6 +9369,14 @@ int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
 	return libbpf_err(-ESRCH);
 }
 
+const char *libbpf_bpf_map_type_str(enum bpf_map_type t)
+{
+	if (t < 0 || t >= ARRAY_SIZE(map_type_name))
+		return NULL;
+
+	return map_type_name[t];
+}
+
 const char *libbpf_bpf_prog_type_str(enum bpf_prog_type t)
 {
 	if (t < 0 || t >= ARRAY_SIZE(prog_type_name))

tools/lib/bpf/libbpf.h

@@ -51,6 +51,15 @@ enum libbpf_errno {
 
 LIBBPF_API int libbpf_strerror(int err, char *buf, size_t size);
 
+/**
+ * @brief **libbpf_bpf_map_type_str()** converts the provided map type value
+ * into a textual representation.
+ * @param t The map type.
+ * @return Pointer to a static string identifying the map type. NULL is
+ * returned for unknown **bpf_map_type** values.
+ */
+LIBBPF_API const char *libbpf_bpf_map_type_str(enum bpf_map_type t);
+
 /**
  * @brief **libbpf_bpf_prog_type_str()** converts the provided program type
  * value into a textual representation.

tools/lib/bpf/libbpf.map

@@ -462,6 +462,7 @@ LIBBPF_0.8.0 {
 
 LIBBPF_1.0.0 {
 	global:
+		libbpf_bpf_map_type_str;
 		libbpf_bpf_prog_type_str;
 
 	local: *;