[PATCH bpf-next v2 0/5] clean-up bpftool from legacy support

[PATCH bpf-next v2 0/5] clean-up bpftool from legacy support

[Sahid Orentino Ferdjaoui]

As part of commit 93b8952d223a ("libbpf: deprecate legacy BPF map
definitions") and commit bd054102a8c7 ("libbpf: enforce strict libbpf
1.0 behaviors") The --legacy option is not relevant anymore. #1 is
removing it. #4 is cleaning the code from using libbpf_get_error().

About patches #2 and #3 They are changes discovered while working on
this series (credits to Quentin Monnet). #2 is cleaning-up usage of an
unnecessary PTR_ERR(NULL), finally #3 is fixing an invalid value
passed to strerror().

v1 -> v2:
  - Addressed review comments from Yonghong Song on patch #4
  - Added a patch #5 that removes unwanted function noticed by
    Yonghong Song

Sahid Orentino Ferdjaoui (5):
  bpftool: remove support of --legacy option for bpftool
  bpftool: replace return value PTR_ERR(NULL) with 0
  bpftool: fix error message when function can't register struct_ops
  bpftool: clean-up usage of libbpf_get_error()
  bpftool: remove function free_btf_vmlinux()

 .../bpftool/Documentation/common_options.rst  |  9 --------
 .../bpftool/Documentation/substitutions.rst   |  2 +-
 tools/bpf/bpftool/bash-completion/bpftool     |  2 +-
 tools/bpf/bpftool/btf.c                       | 17 ++++++--------
 tools/bpf/bpftool/btf_dumper.c                |  2 +-
 tools/bpf/bpftool/gen.c                       | 11 ++++------
 tools/bpf/bpftool/iter.c                      |  6 ++---
 tools/bpf/bpftool/main.c                      | 22 +++----------------
 tools/bpf/bpftool/main.h                      |  3 +--
 tools/bpf/bpftool/map.c                       | 20 ++++++-----------
 tools/bpf/bpftool/prog.c                      | 15 +++++--------
 tools/bpf/bpftool/struct_ops.c                | 22 ++++++++-----------
 .../selftests/bpf/test_bpftool_synctypes.py   |  6 ++---
 13 files changed, 44 insertions(+), 93 deletions(-)

--
2.34.1

[PATCH bpf-next v2 1/5] bpftool: remove support of --legacy option for bpftool

[Sahid Orentino Ferdjaoui]

Following:
  commit bd054102a8c7 ("libbpf: enforce strict libbpf 1.0 behaviors")
  commit 93b8952d223a ("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>
---
 .../bpf/bpftool/Documentation/common_options.rst  |  9 ---------
 tools/bpf/bpftool/Documentation/substitutions.rst |  2 +-
 tools/bpf/bpftool/bash-completion/bpftool         |  2 +-
 tools/bpf/bpftool/main.c                          | 15 ---------------
 tools/bpf/bpftool/main.h                          |  3 +--
 tools/bpf/bpftool/prog.c                          |  5 -----
 .../selftests/bpf/test_bpftool_synctypes.py       |  6 +++---
 7 files changed, 6 insertions(+), 36 deletions(-)

diff --git a/tools/bpf/bpftool/Documentation/common_options.rst b/tools/bpf/bpftool/Documentation/common_options.rst
index 05350a1aadf9..30df7a707f02 100644
--- a/tools/bpf/bpftool/Documentation/common_options.rst
+++ b/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.
diff --git a/tools/bpf/bpftool/Documentation/substitutions.rst b/tools/bpf/bpftool/Documentation/substitutions.rst
index ccf1ffa0686c..827e3ffb1766 100644
--- a/tools/bpf/bpftool/Documentation/substitutions.rst
+++ b/tools/bpf/bpftool/Documentation/substitutions.rst
@@ -1,3 +1,3 @@
 .. 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** }
diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool
index 2957b42cab67..35f26f7c1124 100644
--- a/tools/bpf/bpftool/bash-completion/bpftool
+++ b/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
diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
index 741e50ee0b6c..87ceafa4b9b8 100644
--- a/tools/bpf/bpftool/main.c
+++ b/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)
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 467d8472df0c..2d1f4d7211cd 100644
--- a/tools/bpf/bpftool/main.h
+++ b/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;

diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index a858b907da16..b6b62b3ef49b 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -1804,11 +1804,6 @@ 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++)
diff --git a/tools/testing/selftests/bpf/test_bpftool_synctypes.py b/tools/testing/selftests/bpf/test_bpftool_synctypes.py
index 9fe4c9336c6f..0cfece7ff4f8 100755
--- a/tools/testing/selftests/bpf/test_bpftool_synctypes.py
+++ b/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/-]+)\*\*')
--
2.34.1

[PATCH bpf-next v2 2/5] bpftool: replace return value PTR_ERR(NULL) with 0

[Sahid Orentino Ferdjaoui]

There is no reasons to keep PTR_ERR() when kern_btf=NULL, let's just
return 0.

Signed-off-by: Sahid Orentino Ferdjaoui <sahid.ferdjaoui@industrialdiscipline.com>
---
 tools/bpf/bpftool/struct_ops.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/tools/bpf/bpftool/struct_ops.c b/tools/bpf/bpftool/struct_ops.c
index e08a6ff2866c..68281f9b7a0e 100644
--- a/tools/bpf/bpftool/struct_ops.c
+++ b/tools/bpf/bpftool/struct_ops.c
@@ -63,10 +63,8 @@ static __s32 get_map_info_type_id(void)
 		return map_info_type_id;

 	kern_btf = get_btf_vmlinux();
-	if (libbpf_get_error(kern_btf)) {
-		map_info_type_id = PTR_ERR(kern_btf);
-		return map_info_type_id;
-	}
+	if (libbpf_get_error(kern_btf))
+		return 0;

 	map_info_type_id = btf__find_by_name_kind(kern_btf, "bpf_map_info",
 						  BTF_KIND_STRUCT);
--
2.34.1

Re: [PATCH bpf-next v2 0/5] clean-up bpftool from legacy support

[Yonghong Song]

On 11/8/22 11:44 PM, Sahid Orentino Ferdjaoui wrote:
> As part of commit 93b8952d223a ("libbpf: deprecate legacy BPF map
> definitions") and commit bd054102a8c7 ("libbpf: enforce strict libbpf
> 1.0 behaviors") The --legacy option is not relevant anymore. #1 is
> removing it. #4 is cleaning the code from using libbpf_get_error().
> 
> About patches #2 and #3 They are changes discovered while working on
> this series (credits to Quentin Monnet). #2 is cleaning-up usage of an
> unnecessary PTR_ERR(NULL), finally #3 is fixing an invalid value
> passed to strerror().
> 
> v1 -> v2:
>    - Addressed review comments from Yonghong Song on patch #4
>    - Added a patch #5 that removes unwanted function noticed by
>      Yonghong Song
> 
> Sahid Orentino Ferdjaoui (5):
>    bpftool: remove support of --legacy option for bpftool
>    bpftool: replace return value PTR_ERR(NULL) with 0
>    bpftool: fix error message when function can't register struct_ops
>    bpftool: clean-up usage of libbpf_get_error()
>    bpftool: remove function free_btf_vmlinux()
> 
>   .../bpftool/Documentation/common_options.rst  |  9 --------
>   .../bpftool/Documentation/substitutions.rst   |  2 +-
>   tools/bpf/bpftool/bash-completion/bpftool     |  2 +-
>   tools/bpf/bpftool/btf.c                       | 17 ++++++--------
>   tools/bpf/bpftool/btf_dumper.c                |  2 +-
>   tools/bpf/bpftool/gen.c                       | 11 ++++------
>   tools/bpf/bpftool/iter.c                      |  6 ++---
>   tools/bpf/bpftool/main.c                      | 22 +++----------------
>   tools/bpf/bpftool/main.h                      |  3 +--
>   tools/bpf/bpftool/map.c                       | 20 ++++++-----------
>   tools/bpf/bpftool/prog.c                      | 15 +++++--------
>   tools/bpf/bpftool/struct_ops.c                | 22 ++++++++-----------
>   .../selftests/bpf/test_bpftool_synctypes.py   |  6 ++---
>   13 files changed, 44 insertions(+), 93 deletions(-)
> 
> --
> 2.34.1
> 

You can carry the 'Ack' if no significant change for
each patch.

Ack for the whole series.

Acked-by: Yonghong Song <yhs@fb.com>

Re: [PATCH bpf-next v2 2/5] bpftool: replace return value PTR_ERR(NULL) with 0

[Andrii Nakryiko]

On Tue, Nov 8, 2022 at 11:45 PM Sahid Orentino Ferdjaoui
<sahid.ferdjaoui@industrialdiscipline.com> wrote:
>
> There is no reasons to keep PTR_ERR() when kern_btf=NULL, let's just
> return 0.
>
> Signed-off-by: Sahid Orentino Ferdjaoui <sahid.ferdjaoui@industrialdiscipline.com>
> ---
>  tools/bpf/bpftool/struct_ops.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/tools/bpf/bpftool/struct_ops.c b/tools/bpf/bpftool/struct_ops.c
> index e08a6ff2866c..68281f9b7a0e 100644
> --- a/tools/bpf/bpftool/struct_ops.c
> +++ b/tools/bpf/bpftool/struct_ops.c
> @@ -63,10 +63,8 @@ static __s32 get_map_info_type_id(void)
>                 return map_info_type_id;
>
>         kern_btf = get_btf_vmlinux();
> -       if (libbpf_get_error(kern_btf)) {
> -               map_info_type_id = PTR_ERR(kern_btf);
> -               return map_info_type_id;
> -       }
> +       if (libbpf_get_error(kern_btf))
> +               return 0;
>

if (!kern_btf)
    return 0;

>         map_info_type_id = btf__find_by_name_kind(kern_btf, "bpf_map_info",
>                                                   BTF_KIND_STRUCT);
> --
> 2.34.1
>
>

Re: [PATCH bpf-next v2 0/5] clean-up bpftool from legacy support

[Sahid Orentino Ferdjaoui]

On 11/09/ , Yonghong Song wrote:
>
>
> On 11/8/22 11:44 PM, Sahid Orentino Ferdjaoui wrote:
> > As part of commit 93b8952d223a ("libbpf: deprecate legacy BPF map
> > definitions") and commit bd054102a8c7 ("libbpf: enforce strict libbpf
> > 1.0 behaviors") The --legacy option is not relevant anymore. #1 is
> > removing it. #4 is cleaning the code from using libbpf_get_error().
> >
> > About patches #2 and #3 They are changes discovered while working on
> > this series (credits to Quentin Monnet). #2 is cleaning-up usage of an
> > unnecessary PTR_ERR(NULL), finally #3 is fixing an invalid value
> > passed to strerror().
> >
> > v1 -> v2:
> >    - Addressed review comments from Yonghong Song on patch #4
> >    - Added a patch #5 that removes unwanted function noticed by
> >      Yonghong Song
> >
> > Sahid Orentino Ferdjaoui (5):
> >    bpftool: remove support of --legacy option for bpftool
> >    bpftool: replace return value PTR_ERR(NULL) with 0
> >    bpftool: fix error message when function can't register struct_ops
> >    bpftool: clean-up usage of libbpf_get_error()
> >    bpftool: remove function free_btf_vmlinux()
> >
> >   .../bpftool/Documentation/common_options.rst  |  9 --------
> >   .../bpftool/Documentation/substitutions.rst   |  2 +-
> >   tools/bpf/bpftool/bash-completion/bpftool     |  2 +-
> >   tools/bpf/bpftool/btf.c                       | 17 ++++++--------
> >   tools/bpf/bpftool/btf_dumper.c                |  2 +-
> >   tools/bpf/bpftool/gen.c                       | 11 ++++------
> >   tools/bpf/bpftool/iter.c                      |  6 ++---
> >   tools/bpf/bpftool/main.c                      | 22 +++----------------
> >   tools/bpf/bpftool/main.h                      |  3 +--
> >   tools/bpf/bpftool/map.c                       | 20 ++++++-----------
> >   tools/bpf/bpftool/prog.c                      | 15 +++++--------
> >   tools/bpf/bpftool/struct_ops.c                | 22 ++++++++-----------
> >   .../selftests/bpf/test_bpftool_synctypes.py   |  6 ++---
> >   13 files changed, 44 insertions(+), 93 deletions(-)
> >
> > --
> > 2.34.1
> >
>
> You can carry the 'Ack' if no significant change for
> each patch.

Thanks a lot for this advice. I will use this in my v3 when addressing
Andrii comments.

> Ack for the whole series.
>
> Acked-by: Yonghong Song <yhs@fb.com>