bpftool: Update doc (use susbtitutions) and test_bpftool_synctypes.py

test_bpftool_synctypes.py helps detecting inconsistencies in bpftool
between the different list of types and options scattered in the
sources, the documentation, and the bash completion. For options that
apply to all bpftool commands, the script had a hardcoded list of
values, and would use them to check whether the man pages are
up-to-date. When writing the script, it felt acceptable to have this
list in order to avoid to open and parse bpftool's main.h every time,
and because the list of global options in bpftool doesn't change so
often.

However, this is prone to omissions, and we recently added a new
-l|--legacy option which was described in common_options.rst, but not
listed in the options summary of each manual page. The script did not
complain, because it keeps comparing the hardcoded list to the (now)
outdated list in the header file.

To address the issue, this commit brings the following changes:

- Options that are common to all bpftool commands (--json, --pretty, and
  --debug) are moved to a dedicated file, and used in the definition of
  a RST substitution. This substitution is used in the sources of all
  the man pages.

- This list of common options is updated, with the addition of the new
  -l|--legacy option.

- The script test_bpftool_synctypes.py is updated to compare:
    - Options specific to a command, found in C files, for the
      interactive help messages, with the same specific options from the
      relevant man page for that command.
    - Common options, checked just once: the list in main.h is
      compared with the new list in substitutions.rst.
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211115225844.33943-3-quentin@isovalent.com

tools/bpf/bpftool/Documentation/bpftool-btf.rst

@@ -9,13 +9,14 @@ tool for inspection of BTF data
 
 :Manual section: 8
 
+.. include:: substitutions.rst
+
 SYNOPSIS
 ========
 
 	**bpftool** [*OPTIONS*] **btf** *COMMAND*
 
-	*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | {**-d** | **--debug** } |
-	{ **-B** | **--base-btf** } }
+	*OPTIONS* := { |COMMON_OPTIONS| | { **-B** | **--base-btf** } }
 
 	*COMMANDS* := { **dump** | **help** }
 

tools/bpf/bpftool/Documentation/bpftool-cgroup.rst

@@ -9,13 +9,14 @@ tool for inspection and simple manipulation of eBPF progs
 
 :Manual section: 8
 
+.. include:: substitutions.rst
+
 SYNOPSIS
 ========
 
 	**bpftool** [*OPTIONS*] **cgroup** *COMMAND*
 
-	*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** } |
-	{ **-f** | **--bpffs** } }
+	*OPTIONS* := { |COMMON_OPTIONS| | { **-f** | **--bpffs** } }
 
 	*COMMANDS* :=
 	{ **show** | **list** | **tree** | **attach** | **detach** | **help** }

tools/bpf/bpftool/Documentation/bpftool-feature.rst

@@ -9,12 +9,14 @@ tool for inspection of eBPF-related parameters for Linux kernel or net device
 
 :Manual section: 8
 
+.. include:: substitutions.rst
+
 SYNOPSIS
 ========
 
 	**bpftool** [*OPTIONS*] **feature** *COMMAND*
 
-	*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** } }
+	*OPTIONS* := { |COMMON_OPTIONS| }
 
 	*COMMANDS* := { **probe** | **help** }
 

tools/bpf/bpftool/Documentation/bpftool-gen.rst

@@ -9,13 +9,14 @@ tool for BPF code-generation
 
 :Manual section: 8
 
+.. include:: substitutions.rst
+
 SYNOPSIS
 ========
 
 	**bpftool** [*OPTIONS*] **gen** *COMMAND*
 
-	*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** } |
-	{ **-L** | **--use-loader** } }
+	*OPTIONS* := { |COMMON_OPTIONS| | { **-L** | **--use-loader** } }
 
 	*COMMAND* := { **object** | **skeleton** | **help** }
 

tools/bpf/bpftool/Documentation/bpftool-iter.rst

@@ -9,12 +9,14 @@ tool to create BPF iterators
 
 :Manual section: 8
 
+.. include:: substitutions.rst
+
 SYNOPSIS
 ========
 
 	**bpftool** [*OPTIONS*] **iter** *COMMAND*
 
-	*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** } }
+	*OPTIONS* := { |COMMON_OPTIONS| }
 
 	*COMMANDS* := { **pin** | **help** }
 

tools/bpf/bpftool/Documentation/bpftool-link.rst

@@ -9,13 +9,14 @@ tool for inspection and simple manipulation of eBPF links
 
 :Manual section: 8
 
+.. include:: substitutions.rst
+
 SYNOPSIS
 ========
 
 	**bpftool** [*OPTIONS*] **link** *COMMAND*
 
-	*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** } |
-	{ **-f** | **--bpffs** } | { **-n** | **--nomount** } }
+	*OPTIONS* := { |COMMON_OPTIONS| | { **-f** | **--bpffs** } | { **-n** | **--nomount** } }
 
 	*COMMANDS* := { **show** | **list** | **pin** | **help** }
 

tools/bpf/bpftool/Documentation/bpftool-map.rst

@@ -9,13 +9,14 @@ tool for inspection and simple manipulation of eBPF maps
 
 :Manual section: 8
 
+.. include:: substitutions.rst
+
 SYNOPSIS
 ========
 
 	**bpftool** [*OPTIONS*] **map** *COMMAND*
 
-	*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** } |
-	{ **-f** | **--bpffs** } | { **-n** | **--nomount** } }
+	*OPTIONS* := { |COMMON_OPTIONS| | { **-f** | **--bpffs** } | { **-n** | **--nomount** } }
 
 	*COMMANDS* :=
 	{ **show** | **list** | **create** | **dump** | **update** | **lookup** | **getnext** |

tools/bpf/bpftool/Documentation/bpftool-net.rst

@@ -9,12 +9,14 @@ tool for inspection of netdev/tc related bpf prog attachments
 
 :Manual section: 8
 
+.. include:: substitutions.rst
+
 SYNOPSIS
 ========
 
 	**bpftool** [*OPTIONS*] **net** *COMMAND*
 
-	*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** } }
+	*OPTIONS* := { |COMMON_OPTIONS| }
 
 	*COMMANDS* :=
 	{ **show** | **list** | **attach** | **detach** | **help** }

tools/bpf/bpftool/Documentation/bpftool-perf.rst

@@ -9,12 +9,14 @@ tool for inspection of perf related bpf prog attachments
 
 :Manual section: 8
 
+.. include:: substitutions.rst
+
 SYNOPSIS
 ========
 
 	**bpftool** [*OPTIONS*] **perf** *COMMAND*
 
-	*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** } }
+	*OPTIONS* := { |COMMON_OPTIONS| }
 
 	*COMMANDS* :=
 	{ **show** | **list** | **help** }

tools/bpf/bpftool/Documentation/bpftool-prog.rst

@@ -9,12 +9,14 @@ tool for inspection and simple manipulation of eBPF progs
 
 :Manual section: 8
 
+.. include:: substitutions.rst
+
 SYNOPSIS
 ========
 
 	**bpftool** [*OPTIONS*] **prog** *COMMAND*
 
-	*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** } |
+	*OPTIONS* := { |COMMON_OPTIONS| |
 	{ **-f** | **--bpffs** } | { **-m** | **--mapcompat** } | { **-n** | **--nomount** } |
 	{ **-L** | **--use-loader** } }
 

tools/bpf/bpftool/Documentation/bpftool-struct_ops.rst

@@ -9,12 +9,14 @@ tool to register/unregister/introspect BPF struct_ops
 
 :Manual section: 8
 
+.. include:: substitutions.rst
+
 SYNOPSIS
 ========
 
 	**bpftool** [*OPTIONS*] **struct_ops** *COMMAND*
 
-	*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** } }
+	*OPTIONS* := { |COMMON_OPTIONS| }
 
 	*COMMANDS* :=
 	{ **show** | **list** | **dump** | **register** | **unregister** | **help** }

tools/bpf/bpftool/Documentation/bpftool.rst

@@ -9,6 +9,8 @@ tool for inspection and simple manipulation of eBPF programs and maps
 
 :Manual section: 8
 
+.. include:: substitutions.rst
+
 SYNOPSIS
 ========
 
@@ -20,8 +22,7 @@ SYNOPSIS
 
 	*OBJECT* := { **map** | **program** | **cgroup** | **perf** | **net** | **feature** }
 
-	*OPTIONS* := { { **-V** | **--version** } |
-	{ **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** } }
+	*OPTIONS* := { { **-V** | **--version** } | |COMMON_OPTIONS| }
 
 	*MAP-COMMANDS* :=
 	{ **show** | **list** | **create** | **dump** | **update** | **lookup** | **getnext** |

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** }

tools/testing/selftests/bpf/test_bpftool_synctypes.py

@@ -242,12 +242,6 @@ class FileExtractor(object):
         end_marker = re.compile('}\\\\n')
         return self.__get_description_list(start_marker, pattern, end_marker)
 
-    def default_options(self):
-        """
-        Return the default options contained in HELP_SPEC_OPTIONS
-        """
-        return { '-j', '--json', '-p', '--pretty', '-d', '--debug' }
-
     def get_bashcomp_list(self, block_name):
         """
         Search for and parse a list of type names from a variable in bash
@@ -274,7 +268,56 @@ class SourceFileExtractor(FileExtractor):
     defined in children classes.
     """
     def get_options(self):
-        return self.default_options().union(self.get_help_list_macro('HELP_SPEC_OPTIONS'))
+        return self.get_help_list_macro('HELP_SPEC_OPTIONS')
+
+class MainHeaderFileExtractor(SourceFileExtractor):
+    """
+    An extractor for bpftool's main.h
+    """
+    filename = os.path.join(BPFTOOL_DIR, 'main.h')
+
+    def get_common_options(self):
+        """
+        Parse the list of common options in main.h (options that apply to all
+        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}"
+
+        Return a set containing all options, such as:
+
+            {'-p', '-d', '--legacy', '--pretty', '--debug', '--json', '-l', '-j'}
+        """
+        start_marker = re.compile(f'"OPTIONS :=')
+        pattern = re.compile('([\w-]+) ?(?:\||}[ }\]"])')
+        end_marker = re.compile('#define')
+
+        parser = InlineListParser(self.reader)
+        parser.search_block(start_marker)
+        return parser.parse(pattern, end_marker)
+
+class ManSubstitutionsExtractor(SourceFileExtractor):
+    """
+    An extractor for substitutions.rst
+    """
+    filename = os.path.join(BPFTOOL_DIR, 'Documentation/substitutions.rst')
+
+    def get_common_options(self):
+        """
+        Parse the list of common options in substitutions.rst (options that
+        apply to all commands).
+
+        Return a set containing all options, such as:
+
+            {'-p', '-d', '--legacy', '--pretty', '--debug', '--json', '-l', '-j'}
+        """
+        start_marker = re.compile('\|COMMON_OPTIONS\| replace:: {')
+        pattern = re.compile('\*\*([\w/-]+)\*\*')
+        end_marker = re.compile('}$')
+
+        parser = InlineListParser(self.reader)
+        parser.search_block(start_marker)
+        return parser.parse(pattern, end_marker)
 
 class ProgFileExtractor(SourceFileExtractor):
     """
@@ -580,6 +623,19 @@ def main():
     verify(help_main_options, man_main_options,
             f'Comparing {source_main_info.filename} (do_help() OPTIONS) and {man_main_info.filename} (OPTIONS):')
 
+    # Compare common options (options that apply to all commands)
+
+    main_hdr_info = MainHeaderFileExtractor()
+    source_common_options = main_hdr_info.get_common_options()
+    main_hdr_info.close()
+
+    man_substitutions = ManSubstitutionsExtractor()
+    man_common_options = man_substitutions.get_common_options()
+    man_substitutions.close()
+
+    verify(source_common_options, man_common_options,
+            f'Comparing common options from {main_hdr_info.filename} (HELP_SPEC_OPTIONS) and {man_substitutions.filename}:')
+
     sys.exit(retval)
 
 if __name__ == "__main__":