bpftool: remove support of --legacy option for bpftool

Following:
  commit bd054102 ("libbpf: enforce strict libbpf 1.0 behaviors")
  commit 93b8952d ("libbpf: deprecate legacy BPF map definitions")

The --legacy option is no longer relevant as libbpf no longer supports
it. libbpf_set_strict_mode() is a no-op operation.
Signed-off-by: Sahid Orentino Ferdjaoui <sahid.ferdjaoui@industrialdiscipline.com>
Acked-by: Yonghong Song <yhs@fb.com>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/r/20221120112515.38165-2-sahid.ferdjaoui@industrialdiscipline.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

tools/bpf/bpftool/Documentation/common_options.rst

@@ -23,12 +23,3 @@
 	  Print all logs available, even debug-level information. This includes
 	  logs from libbpf as well as from the verifier, when attempting to
 	  load programs.
-
--l, --legacy
-	  Use legacy libbpf mode which has more relaxed BPF program
-	  requirements. By default, bpftool has more strict requirements
-	  about section names, changes pinning logic and doesn't support
-	  some of the older non-BTF map declarations.
-
-	  See https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0
-	  for details.

tools/bpf/bpftool/Documentation/substitutions.rst

 .. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
 
-.. |COMMON_OPTIONS| replace:: { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** } | { **-l** | **--legacy** }
+.. |COMMON_OPTIONS| replace:: { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** }

tools/bpf/bpftool/bash-completion/bpftool

@@ -261,7 +261,7 @@ _bpftool()
     # Deal with options
     if [[ ${words[cword]} == -* ]]; then
         local c='--version --json --pretty --bpffs --mapcompat --debug \
-	       --use-loader --base-btf --legacy'
+	       --use-loader --base-btf'
         COMPREPLY=( $( compgen -W "$c" -- "$cur" ) )
         return 0
     fi

tools/bpf/bpftool/main.c

@@ -31,7 +31,6 @@ bool block_mount;
 bool verifier_logs;
 bool relaxed_maps;
 bool use_loader;
-bool legacy_libbpf;
 struct btf *base_btf;
 struct hashmap *refs_table;
 
@@ -160,7 +159,6 @@ static int do_version(int argc, char **argv)
 		jsonw_start_object(json_wtr);	/* features */
 		jsonw_bool_field(json_wtr, "libbfd", has_libbfd);
 		jsonw_bool_field(json_wtr, "llvm", has_llvm);
-		jsonw_bool_field(json_wtr, "libbpf_strict", !legacy_libbpf);
 		jsonw_bool_field(json_wtr, "skeletons", has_skeletons);
 		jsonw_bool_field(json_wtr, "bootstrap", bootstrap);
 		jsonw_end_object(json_wtr);	/* features */
@@ -179,7 +177,6 @@ static int do_version(int argc, char **argv)
 		printf("features:");
 		print_feature("libbfd", has_libbfd, &nb_features);
 		print_feature("llvm", has_llvm, &nb_features);
-		print_feature("libbpf_strict", !legacy_libbpf, &nb_features);
 		print_feature("skeletons", has_skeletons, &nb_features);
 		print_feature("bootstrap", bootstrap, &nb_features);
 		printf("\n");
@@ -451,7 +448,6 @@ int main(int argc, char **argv)
 		{ "debug",	no_argument,	NULL,	'd' },
 		{ "use-loader",	no_argument,	NULL,	'L' },
 		{ "base-btf",	required_argument, NULL, 'B' },
-		{ "legacy",	no_argument,	NULL,	'l' },
 		{ 0 }
 	};
 	bool version_requested = false;
@@ -524,9 +520,6 @@ int main(int argc, char **argv)
 		case 'L':
 			use_loader = true;
 			break;
-		case 'l':
-			legacy_libbpf = true;
-			break;
 		default:
 			p_err("unrecognized option '%s'", argv[optind - 1]);
 			if (json_output)
@@ -536,14 +529,6 @@ int main(int argc, char **argv)
 		}
 	}
 
-	if (!legacy_libbpf) {
-		/* Allow legacy map definitions for skeleton generation.
-		 * It will still be rejected if users use LIBBPF_STRICT_ALL
-		 * mode for loading generated skeleton.
-		 */
-		libbpf_set_strict_mode(LIBBPF_STRICT_ALL & ~LIBBPF_STRICT_MAP_DEFINITIONS);
-	}
-
 	argc -= optind;
 	argv += optind;
 	if (argc < 0)

tools/bpf/bpftool/main.h

@@ -57,7 +57,7 @@ static inline void *u64_to_ptr(__u64 ptr)
 #define HELP_SPEC_PROGRAM						\
 	"PROG := { id PROG_ID | pinned FILE | tag PROG_TAG | name PROG_NAME }"
 #define HELP_SPEC_OPTIONS						\
-	"OPTIONS := { {-j|--json} [{-p|--pretty}] | {-d|--debug} | {-l|--legacy}"
+	"OPTIONS := { {-j|--json} [{-p|--pretty}] | {-d|--debug}"
 #define HELP_SPEC_MAP							\
 	"MAP := { id MAP_ID | pinned FILE | name MAP_NAME }"
 #define HELP_SPEC_LINK							\
@@ -82,7 +82,6 @@ extern bool block_mount;
 extern bool verifier_logs;
 extern bool relaxed_maps;
 extern bool use_loader;
-extern bool legacy_libbpf;
 extern struct btf *base_btf;
 extern struct hashmap *refs_table;
 

tools/bpf/bpftool/prog.c

@@ -1802,11 +1802,6 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
 	else
 		bpf_object__unpin_programs(obj, pinfile);
 err_close_obj:
-	if (!legacy_libbpf) {
-		p_info("Warning: bpftool is now running in libbpf strict mode and has more stringent requirements about BPF programs.\n"
-		       "If it used to work for this object file but now doesn't, see --legacy option for more details.\n");
-	}
-
 	bpf_object__close(obj);
 err_free_reuse_maps:
 	for (i = 0; i < old_map_fds; i++)

tools/testing/selftests/bpf/test_bpftool_synctypes.py

@@ -309,11 +309,11 @@ class MainHeaderFileExtractor(SourceFileExtractor):
         commands), which looks to the lists of options in other source files
         but has different start and end markers:
 
-            "OPTIONS := { {-j|--json} [{-p|--pretty}] | {-d|--debug} | {-l|--legacy}"
+            "OPTIONS := { {-j|--json} [{-p|--pretty}] | {-d|--debug}"
 
         Return a set containing all options, such as:
 
-            {'-p', '-d', '--legacy', '--pretty', '--debug', '--json', '-l', '-j'}
+            {'-p', '-d', '--pretty', '--debug', '--json', '-j'}
         """
         start_marker = re.compile(f'"OPTIONS :=')
         pattern = re.compile('([\w-]+) ?(?:\||}[ }\]"])')
@@ -336,7 +336,7 @@ class ManSubstitutionsExtractor(SourceFileExtractor):
 
         Return a set containing all options, such as:
 
-            {'-p', '-d', '--legacy', '--pretty', '--debug', '--json', '-l', '-j'}
+            {'-p', '-d', '--pretty', '--debug', '--json', '-j'}
         """
         start_marker = re.compile('\|COMMON_OPTIONS\| replace:: {')
         pattern = re.compile('\*\*([\w/-]+)\*\*')