docs: kernel_feat.py: fix build error for missing files

If the directory passed to the '.. kernel-feat::' directive does not
exist or the get_feat.pl script does not find any files to extract
features from, Sphinx will report the following error:

Sphinx parallel build error:
UnboundLocalError: local variable 'fname' referenced before assignment
make[2]: *** [Documentation/Makefile:102: htmldocs] Error 2

This is due to how I changed the script in c48a7c44a1d0 ("docs:
kernel_feat.py: fix potential command injection"). Before that, the
filename passed along to self.nestedParse() in this case was weirdly
just the whole get_feat.pl invocation.

We can fix it by doing what kernel_abi.py does -- just pass
self.arguments[0] as 'fname'.

Fixes: c48a7c44a1d0 ("docs: kernel_feat.py: fix potential command injection")
Cc: Justin Forbes <jforbes@fedoraproject.org>
Cc: Salvatore Bonaccorso <carnil@debian.org>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Link: https://lore.kernel.org/r/20240205175133.774271-2-vegard.nossum@oracle.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

docs: kernel_feat.py: fix build error for missing files

If the directory passed to the '.. kernel-feat::' directive does not
exist or the get_feat.pl script does not find any files to extract
features from, Sphinx will report the following error:

Sphinx parallel build error:
UnboundLocalError: local variable 'fname' referenced before assignment
make[2]: *** [Documentation/Makefile:102: htmldocs] Error 2

This is due to how I changed the script in c48a7c44a1d0 ("docs:
kernel_feat.py: fix potential command injection"). Before that, the
filename passed along to self.nestedParse() in this case was weirdly
just the whole get_feat.pl invocation.

We can fix it by doing what kernel_abi.py does -- just pass
self.arguments[0] as 'fname'.

Fixes: c48a7c44a1d0 ("docs: kernel_feat.py: fix potential command injection")
Cc: Justin Forbes <jforbes@fedoraproject.org>
Cc: Salvatore Bonaccorso <carnil@debian.org>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Link: https://lore.kernel.org/r/20240205175133.774271-2-vegard.nossum@oracle.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

docs: kernel_feat.py: fix potential command injection

The kernel-feat directive passes its argument straight to the shell.
This is unfortunate and unnecessary.

Let's always use paths relative to $srctree/Documentation/ and use
subprocess.check_call() instead of subprocess.Popen(shell=True).

This also makes the code shorter.

This is analogous to commit 3231dd586277 ("docs: kernel_abi.py: fix
command injection") where we did exactly the same thing for
kernel_abi.py, somehow I completely missed this one.

Link: https://fosstodon.org/@jani/111676532203641247
Reported-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240110174758.3680506-1-vegard.nossum@oracle.com

Documentation/sphinx: fix Python string escapes

Python 3.6 introduced a DeprecationWarning for invalid escape sequences.
This is upgraded to a SyntaxWarning in Python 3.12, and will eventually
be a syntax error.

Fix these now to get ahead of it before it's an error.

Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Message-ID: <20230912060801.95533-3-bgray@linux.ibm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

docs: kernel_feat.py: add build dependencies

Ensure that the feature files will be regenerated if any
changes happen at the Documentation/features files that were
processed by gen_feat.pl.

Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Link: https://lore.kernel.org/r/5cdf7a8300019129dcc09d4c2557f75908754445.1648290305.git.mchehab@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/sphinx: fix typos of "its"

Use "its" for possessive form instead of the contraction "it's".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Link: https://lore.kernel.org/r/20211222062354.23224-1-rdunlap@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Move our minimum Sphinx version to 1.7

As promised, drop support for some ancient sphinx releases, along with a
lot of the cruft that was required to make that support work.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>

sphinx: kernel_feat.py: add a script to parse feature files

The feature files have a special well-defined format. Add
a script that parses them, allowing to search for a feature
and/or by an architecture and to produce ReST-compatible
outputs.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/bb2e51e5aa883e2583a4a6280f1c1b391bd8ef4c.1606748711.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>