lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Thu, 30 Sep 2021 12:24:17 -0700 From: Kees Cook <keescook@...omium.org> To: Jonathan Corbet <corbet@....net> Cc: Kees Cook <keescook@...omium.org>, Joe Perches <joe@...ches.com>, Alexey Dobriyan <adobriyan@...il.com>, Nick Desaulniers <ndesaulniers@...gle.com>, Linus Torvalds <torvalds@...ux-foundation.org>, Randy Dunlap <rdunlap@...radead.org>, Rasmus Villemoes <linux@...musvillemoes.dk>, Andrew Morton <akpm@...ux-foundation.org>, linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org, linux-hardening@...r.kernel.org Subject: [PATCH v2] docs: Explain the desired position of function attributes While discussing how to format the addition of various function attributes, some "unwritten rules" of ordering surfaced[1]. Capture as close as possible to Linus's preferences for future reference. (Though I note the dissent voiced by Joe Perches, Alexey Dobriyan, and others that would prefer all attributes live on a separate leading line.) [1] https://lore.kernel.org/mm-commits/CAHk-=wiOCLRny5aifWNhr621kYrJwhfURsa0vFPeUEm8mF0ufg@mail.gmail.com/ Signed-off-by: Kees Cook <keescook@...omium.org> --- Documentation/process/coding-style.rst | 30 ++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/Documentation/process/coding-style.rst b/Documentation/process/coding-style.rst index 42969ab37b34..6b4feb1c71e7 100644 --- a/Documentation/process/coding-style.rst +++ b/Documentation/process/coding-style.rst @@ -487,6 +487,36 @@ because it is a simple way to add valuable information for the reader. Do not use the ``extern`` keyword with function prototypes as this makes lines longer and isn't strictly necessary. +When writing a function declarations, please keep the `order of elements regular +<https://lore.kernel.org/mm-commits/CAHk-=wiOCLRny5aifWNhr621kYrJwhfURsa0vFPeUEm8mF0ufg@mail.gmail.com/>`_. +For example:: + + extern __init void * __must_check void action(enum magic value, size_t size, + u8 count, char *fmt, ...) __printf(4, 5) __malloc; + +The preferred order of elements for a function prototype is: + +- storage class (here, ``extern``, and things like ``static __always_inline`` even though + ``__always_inline`` is technically an attribute, it is treated like ``inline``) +- storage class attributes (here, ``__init`` -- i.e. section declarations, but also things like ``__cold``) +- return type (here, ``void *``) +- return type attributes (here, ``__must_check``) +- function name (here, ``action``) +- function parameters (here, ``(enum magic value, size_t size, u8 count, char *fmt, ...)``, noting that parameter names should always be included) +- function parameter attributes (here, ``__printf(4, 5)``) +- function behavior attributes (here, ``__malloc``) + +Note that for a function definition (e.g. ``static inline``), the compiler does +not allow function parameter attributes after the function parameters. In these +cases, they should go after the storage class attributes (e.g. note the changed +position of ``__printf(4, 5)``):: + + static __always_inline __init __printf(4, 5) void * __must_check void action( + enum magic value, size_t size, u8 count, char *fmt, ...) + __malloc + { + ... + } 7) Centralized exiting of functions ----------------------------------- -- 2.30.2
Powered by blists - more mailing lists