bpftool: Use libbpf_bpf_map_type_str

This change switches bpftool over to using the recently introduced
libbpf_bpf_map_type_str function instead of maintaining its own string
representation for the bpf_map_type enum.
Signed-off-by: Daniel Müller <deso@posteo.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20220523230428.3077108-7-deso@posteo.net

tools/bpf/bpftool/feature.c

@@ -615,8 +615,8 @@ static bool probe_map_type_ifindex(enum bpf_map_type map_type, __u32 ifindex)
 }
 
 static void
-probe_map_type(enum bpf_map_type map_type, const char *define_prefix,
-	       __u32 ifindex)
+probe_map_type(enum bpf_map_type map_type, char const *map_type_str,
+	       const char *define_prefix, __u32 ifindex)
 {
 	char feat_name[128], plain_desc[128], define_name[128];
 	const char *plain_comment = "eBPF map_type ";
@@ -641,20 +641,16 @@ probe_map_type(enum bpf_map_type map_type, const char *define_prefix,
 	 * check required for unprivileged users
 	 */
 
-	if (!map_type_name[map_type]) {
-		p_info("map type name not found (type %d)", map_type);
-		return;
-	}
 	maxlen = sizeof(plain_desc) - strlen(plain_comment) - 1;
-	if (strlen(map_type_name[map_type]) > maxlen) {
+	if (strlen(map_type_str) > maxlen) {
 		p_info("map type name too long");
 		return;
 	}
 
-	sprintf(feat_name, "have_%s_map_type", map_type_name[map_type]);
-	sprintf(define_name, "%s_map_type", map_type_name[map_type]);
+	sprintf(feat_name, "have_%s_map_type", map_type_str);
+	sprintf(define_name, "%s_map_type", map_type_str);
 	uppercase(define_name, sizeof(define_name));
-	sprintf(plain_desc, "%s%s", plain_comment, map_type_name[map_type]);
+	sprintf(plain_desc, "%s%s", plain_comment, map_type_str);
 	print_bool_feature(feat_name, plain_desc, define_name, res,
 			   define_prefix);
 }
@@ -963,15 +959,23 @@ section_program_types(bool *supported_types, const char *define_prefix,
 
 static void section_map_types(const char *define_prefix, __u32 ifindex)
 {
-	unsigned int i;
+	unsigned int map_type = BPF_MAP_TYPE_UNSPEC;
+	const char *map_type_str;
 
 	print_start_section("map_types",
 			    "Scanning eBPF map types...",
 			    "/*** eBPF map types ***/",
 			    define_prefix);
 
-	for (i = BPF_MAP_TYPE_UNSPEC + 1; i < map_type_name_size; i++)
-		probe_map_type(i, define_prefix, ifindex);
+	while (true) {
+		map_type++;
+		map_type_str = libbpf_bpf_map_type_str(map_type);
+		/* libbpf will return NULL for variants unknown to it. */
+		if (!map_type_str)
+			break;
+
+		probe_map_type(map_type, map_type_str, define_prefix, ifindex);
+	}
 
 	print_end_section();
 }

tools/bpf/bpftool/main.h

@@ -65,9 +65,6 @@ static inline void *u64_to_ptr(__u64 ptr)
 
 extern const char * const attach_type_name[__MAX_BPF_ATTACH_TYPE];
 
-extern const char * const map_type_name[];
-extern const size_t map_type_name_size;
-
 /* keep in sync with the definition in skeleton/pid_iter.bpf.c */
 enum bpf_obj_type {
 	BPF_OBJ_UNKNOWN,

tools/bpf/bpftool/map.c

@@ -22,42 +22,6 @@
 #include "json_writer.h"
 #include "main.h"
 
-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",
-};
-
-const size_t map_type_name_size = ARRAY_SIZE(map_type_name);
-
 static struct hashmap *map_table;
 
 static bool map_is_per_cpu(__u32 type)
@@ -81,12 +45,18 @@ static bool map_is_map_of_progs(__u32 type)
 
 static int map_type_from_str(const char *type)
 {
+	const char *map_type_str;
 	unsigned int i;
 
-	for (i = 0; i < ARRAY_SIZE(map_type_name); i++)
+	for (i = 0; ; i++) {
+		map_type_str = libbpf_bpf_map_type_str(i);
+		if (!map_type_str)
+			break;
+
 		/* Don't allow prefixing in case of possible future shadowing */
-		if (map_type_name[i] && !strcmp(map_type_name[i], type))
+		if (!strcmp(map_type_str, type))
 			return i;
+	}
 	return -1;
 }
 
@@ -472,9 +442,12 @@ static int parse_elem(char **argv, struct bpf_map_info *info,
 
 static void show_map_header_json(struct bpf_map_info *info, json_writer_t *wtr)
 {
+	const char *map_type_str;
+
 	jsonw_uint_field(wtr, "id", info->id);
-	if (info->type < ARRAY_SIZE(map_type_name))
-		jsonw_string_field(wtr, "type", map_type_name[info->type]);
+	map_type_str = libbpf_bpf_map_type_str(info->type);
+	if (map_type_str)
+		jsonw_string_field(wtr, "type", map_type_str);
 	else
 		jsonw_uint_field(wtr, "type", info->type);
 
@@ -561,9 +534,13 @@ static int show_map_close_json(int fd, struct bpf_map_info *info)
 
 static void show_map_header_plain(struct bpf_map_info *info)
 {
+	const char *map_type_str;
+
 	printf("%u: ", info->id);
-	if (info->type < ARRAY_SIZE(map_type_name))
-		printf("%s  ", map_type_name[info->type]);
+
+	map_type_str = libbpf_bpf_map_type_str(info->type);
+	if (map_type_str)
+		printf("%s  ", map_type_str);
 	else
 		printf("type %u  ", info->type);
 
@@ -879,9 +856,13 @@ map_dump(int fd, struct bpf_map_info *info, json_writer_t *wtr,
 	}
 
 	if (info->type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY &&
-	    info->value_size != 8)
+	    info->value_size != 8) {
+		const char *map_type_str;
+
+		map_type_str = libbpf_bpf_map_type_str(info->type);
 		p_info("Warning: cannot read values from %s map with value_size != 8",
-		       map_type_name[info->type]);
+		       map_type_str);
+	}
 	while (true) {
 		err = bpf_map_get_next_key(fd, prev_key, key);
 		if (err) {

tools/testing/selftests/bpf/test_bpftool_synctypes.py

@@ -186,6 +186,27 @@ class FileExtractor(object):
         parser.search_block(start_marker)
         return parser.parse(pattern, end_marker)
 
+    def make_enum_map(self, names, enum_prefix):
+        """
+        Search for and parse an enum containing BPF_* members, just as get_enum
+        does. However, instead of just returning a set of the variant names,
+        also generate a textual representation from them by (assuming and)
+        removing a provided prefix and lowercasing the remainder. Then return a
+        dict mapping from name to textual representation.
+
+        @enum_values: a set of enum values; e.g., as retrieved by get_enum
+        @enum_prefix: the prefix to remove from each of the variants to infer
+        textual representation
+        """
+        mapping = {}
+        for name in names:
+            if not name.startswith(enum_prefix):
+                raise Exception(f"enum variant {name} does not start with {enum_prefix}")
+            text = name[len(enum_prefix):].lower()
+            mapping[name] = text
+
+        return mapping
+
     def __get_description_list(self, start_marker, pattern, end_marker):
         parser = InlineListParser(self.reader)
         parser.search_block(start_marker)
@@ -345,9 +366,6 @@ class MapFileExtractor(SourceFileExtractor):
     """
     filename = os.path.join(BPFTOOL_DIR, 'map.c')
 
-    def get_map_types(self):
-        return self.get_types_from_array('map_type_name')
-
     def get_map_help(self):
         return self.get_help_list('TYPE')
 
@@ -403,8 +421,9 @@ class BpfHeaderExtractor(FileExtractor):
     def get_prog_types(self):
         return self.get_enum('bpf_prog_type')
 
-    def get_map_types(self):
-        return self.get_enum('bpf_map_type')
+    def get_map_type_map(self):
+        names = self.get_enum('bpf_map_type')
+        return self.make_enum_map(names, 'BPF_MAP_TYPE_')
 
     def get_attach_types(self):
         return self.get_enum('bpf_attach_type')
@@ -492,21 +511,12 @@ def main():
     """)
     args = argParser.parse_args()
 
-    # Map types (enum)
-
     bpf_info = BpfHeaderExtractor()
-    ref = bpf_info.get_map_types()
-
-    map_info = MapFileExtractor()
-    source_map_items = map_info.get_map_types()
-    map_types_enum = set(source_map_items.keys())
-
-    verify(ref, map_types_enum,
-            f'Comparing BPF header (enum bpf_map_type) and {MapFileExtractor.filename} (map_type_name):')
 
     # Map types (names)
 
-    source_map_types = set(source_map_items.values())
+    map_info = MapFileExtractor()
+    source_map_types = set(bpf_info.get_map_type_map().values())
     source_map_types.discard('unspec')
 
     help_map_types = map_info.get_map_help()
@@ -522,13 +532,13 @@ def main():
     bashcomp_map_types = bashcomp_info.get_map_types()
 
     verify(source_map_types, help_map_types,
-            f'Comparing {MapFileExtractor.filename} (map_type_name) and {MapFileExtractor.filename} (do_help() TYPE):')
+            f'Comparing {BpfHeaderExtractor.filename} (bpf_map_type) and {MapFileExtractor.filename} (do_help() TYPE):')
     verify(source_map_types, man_map_types,
-            f'Comparing {MapFileExtractor.filename} (map_type_name) and {ManMapExtractor.filename} (TYPE):')
+            f'Comparing {BpfHeaderExtractor.filename} (bpf_map_type) and {ManMapExtractor.filename} (TYPE):')
     verify(help_map_options, man_map_options,
             f'Comparing {MapFileExtractor.filename} (do_help() OPTIONS) and {ManMapExtractor.filename} (OPTIONS):')
     verify(source_map_types, bashcomp_map_types,
-            f'Comparing {MapFileExtractor.filename} (map_type_name) and {BashcompExtractor.filename} (BPFTOOL_MAP_CREATE_TYPES):')
+            f'Comparing {BpfHeaderExtractor.filename} (bpf_map_type) and {BashcompExtractor.filename} (BPFTOOL_MAP_CREATE_TYPES):')
 
     # Attach types (enum)