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From: Bruce Richardson <bruce.richardson@intel.com>
To: Nick Connolly <nick.connolly@mayadata.io>
Cc: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>,
	dev@dpdk.org, Tyler Retzlaff <roretzla@microsoft.com>,
	Jerin Jacob <jerinj@marvell.com>,
	Sunil Kumar Kori <skori@marvell.com>
Subject: Re: [dpdk-dev] [PATCH v2 1/7] eal: add wrappers for POSIX string functions
Date: Mon, 22 Feb 2021 14:26:25 +0000
Message-ID: <20210222142625.GA704@bricha3-MOBL.ger.corp.intel.com> (raw)
In-Reply-To: <64c1e6c5-ce80-b550-b8ea-ad2a6bfe7505@mayadata.io>

On Mon, Feb 22, 2021 at 12:48:39PM +0000, Nick Connolly wrote:
> Rather than defining "rte_" versions of these functions, is it possible
> just to provide the unprefixed definitions of them for internal use?
> While this probably won't work for any functions used in public headers,
> for any functions only used in C files, we can use meson to detect the
> presence of the standard function and set a macro flag for the compatiblity
> version if not present. This is something we already support for the
> strlcpy/strlcat functions from libbsd, and it basically allows the
> well-known (and loved?) functions to be used directly, and saves DPDK
> developers having to worry about what "standard" functions can be used
> directly, and which can't.
> 
>    Hi Bruce,
>    You're asking a really good question here that highlights a fundamental
>    issue:
>    Does the DPDK code base have an implied POSIX dependency, or should it
>    only
>    depend upon the standard C library and 'rte_ ' functions.  This hasn't
>    been an
>    issue before, but Windows isn't 'POSIX' based.
>    Using "well-known" names for missing functions is ok where the
>    definitions
>    are in private header files, but if the headers are public, or the
>    implementation
>    is better done in a C file, then there can be a clash with the
>    application which
>    is likely dealing with the same issues.
>    There seem to be two viable approaches to handling this:
>     1. Expect the platform to provide POSIX semantic (through an external
>        library
>        such as Cygwin). That way it becomes "an 'external' problem" and
>        the DPDK
>        can use the "well-known" names and expected behaviour.
>     2. Provide the missing functionality, but wrap it in 'internal' header
>        files
>        and 'rte_' versions to avoid link errors. This is the approach that
>        Dmitry has
>        taken based on the guidance we've received.
> 
>    For background, the approach I've taken with adding Windows support to
>    SPDK
>    is to create an 'external' library ([1]https://wpdk.github.io) with
>    header files that
>    provide the missing POSIX functionality and functions with a prefix to
>    avoid link
>    errors. As a result, the whole of SPDK can now build and run unchanged.
>    Regards,
>    Nick
> 

Whatever about the specific implementation, I'd very much like to get to
the point where we don't have to do search-replace for a bunch of functions
like this, not to mention that we'd need to have checkpatch rules in place
to ensure that further instances are not re-introduced.
As you say, though, the main issue will be whether we have instances in
public header files or not. I would hope that no static inline functions in
DPDK use any of the functions in question, but I'm not sure. Perhaps if
there are instances in public headers those could be reworked to not use
the problematic functions.

For any functions, such as strdup, which are not in a public header I would
suggest the following as a possible start point, based off what was done
for strlcpy.

* In DPDK (probably EAL), define an rte_strdup function for use as a
  fallback.
* Inside the meson build scripts, use "cc.has_function()" to check if the
  regular strdup function is available. If not, then add "-DRTE_NO_STRDUP"
  to the c_args for DPDK building
* Inside our DPDK header (rte_string_fns.h in the strdup case), we can add
  a conditional define such as:
   #ifdef RTE_NO_STRDUP
   #define strdup(s) rte_strdup(s)
   #endif

Thoughts on this?
/Bruce

  reply	other threads:[~2021-02-22 14:26 UTC|newest]

Thread overview: 132+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-20 23:29 [dpdk-dev] [PATCH 0/7] eal/windows: do not expose POSIX symbols Dmitry Kozlyuk
2021-02-20 23:29 ` [dpdk-dev] [PATCH 1/7] eal: add wrappers for POSIX string functions Dmitry Kozlyuk
2021-02-20 23:29 ` [dpdk-dev] [PATCH 2/7] eal: add macro for maximum path length Dmitry Kozlyuk
2021-02-20 23:29 ` [dpdk-dev] [PATCH 3/7] eal: add sleep API Dmitry Kozlyuk
2021-02-20 23:29 ` [dpdk-dev] [PATCH 4/7] eal: add asprintf() internal wrapper Dmitry Kozlyuk
2021-02-20 23:29 ` [dpdk-dev] [PATCH 5/7] lib: remove POSIX dependencies Dmitry Kozlyuk
2021-02-20 23:29 ` [dpdk-dev] [PATCH 6/7] drivers: " Dmitry Kozlyuk
2021-02-20 23:29 ` [dpdk-dev] [PATCH 7/7] eal/windows: do not expose POSIX symbols Dmitry Kozlyuk
2021-02-21  1:28 ` [dpdk-dev] [PATCH v2 0/7] " Dmitry Kozlyuk
2021-02-21  1:28   ` [dpdk-dev] [PATCH v2 1/7] eal: add wrappers for POSIX string functions Dmitry Kozlyuk
2021-02-22 11:47     ` Bruce Richardson
2021-02-22 12:48       ` Nick Connolly
2021-02-22 14:26         ` Bruce Richardson [this message]
2021-02-22 18:21           ` Nick Connolly
2021-02-22 22:57           ` Dmitry Kozlyuk
2021-02-23  9:45             ` Bruce Richardson
2021-02-27 20:23               ` Dmitry Kozlyuk
2021-03-01 21:31                 ` Nick Connolly
2021-03-02  0:22                   ` Dmitry Kozlyuk
2021-03-02 11:27                     ` Nick Connolly
2021-03-16  9:51                 ` Thomas Monjalon
2021-02-22 18:07         ` Tyler Retzlaff
2021-02-22 18:36           ` Nick Connolly
2021-02-21  1:28   ` [dpdk-dev] [PATCH v2 2/7] eal: add macro for maximum path length Dmitry Kozlyuk
2021-02-21  1:28   ` [dpdk-dev] [PATCH v2 3/7] eal: add sleep API Dmitry Kozlyuk
2021-02-21  8:58     ` Tal Shnaiderman
2021-02-21  1:28   ` [dpdk-dev] [PATCH v2 4/7] eal: add asprintf() internal wrapper Dmitry Kozlyuk
2021-02-21  1:28   ` [dpdk-dev] [PATCH v2 5/7] lib: remove POSIX dependencies Dmitry Kozlyuk
2021-02-21  1:28   ` [dpdk-dev] [PATCH v2 6/7] drivers: " Dmitry Kozlyuk
2021-02-21  8:59     ` Tal Shnaiderman
2021-02-21 15:54       ` Andrew Rybchenko
2021-02-21 17:05         ` Dmitry Kozlyuk
2021-02-21  1:28   ` [dpdk-dev] [PATCH v2 7/7] eal/windows: do not expose POSIX symbols Dmitry Kozlyuk
2021-02-21  8:59     ` Tal Shnaiderman
2021-02-21 10:24       ` Dmitry Kozlyuk
2021-02-21 11:58         ` Tal Shnaiderman
2021-02-21 14:33           ` Dmitry Kozlyuk
2021-02-21 14:28   ` [dpdk-dev] [PATCH v3 0/7] " Dmitry Kozlyuk
2021-02-21 14:28     ` [dpdk-dev] [PATCH v3 1/7] eal: add wrappers for POSIX string functions Dmitry Kozlyuk
2021-02-23  7:11       ` Andrew Rybchenko
2021-02-23 21:53         ` Nick Connolly
2021-02-24  7:21           ` Andrew Rybchenko
2021-03-04  6:47       ` [dpdk-dev] [EXTERNAL] " Khoa To
2021-02-21 14:28     ` [dpdk-dev] [PATCH v3 2/7] eal: add macro for maximum path length Dmitry Kozlyuk
2021-03-04  6:47       ` [dpdk-dev] [EXTERNAL] " Khoa To
2021-02-21 14:28     ` [dpdk-dev] [PATCH v3 3/7] eal: add sleep API Dmitry Kozlyuk
2021-02-23 22:06       ` Nick Connolly
2021-03-04  6:47       ` [dpdk-dev] [EXTERNAL] " Khoa To
2021-02-21 14:28     ` [dpdk-dev] [PATCH v3 4/7] eal: add asprintf() internal wrapper Dmitry Kozlyuk
2021-03-04  6:48       ` [dpdk-dev] [EXTERNAL] " Khoa To
2021-02-21 14:28     ` [dpdk-dev] [PATCH v3 5/7] lib: remove POSIX dependencies Dmitry Kozlyuk
2021-03-04  6:48       ` [dpdk-dev] [EXTERNAL] " Khoa To
2021-02-21 14:28     ` [dpdk-dev] [PATCH v3 6/7] drivers: " Dmitry Kozlyuk
2021-03-04  6:49       ` [dpdk-dev] [EXTERNAL] " Khoa To
2021-02-21 14:28     ` [dpdk-dev] [PATCH v3 7/7] eal/windows: do not expose POSIX symbols Dmitry Kozlyuk
2021-03-04  6:49       ` [dpdk-dev] [EXTERNAL] " Khoa To
2021-03-04  6:46     ` [dpdk-dev] [EXTERNAL] [PATCH v3 0/7] " Khoa To
2021-03-06  0:04     ` [dpdk-dev] [PATCH v4 0/4] " Dmitry Kozlyuk
2021-03-06  0:04       ` [dpdk-dev] [PATCH v4 1/4] eal: add sleep API Dmitry Kozlyuk
2021-03-06  0:04       ` [dpdk-dev] [PATCH v4 2/4] eal: add asprintf() internal wrapper Dmitry Kozlyuk
2021-03-06 15:27         ` Lance Richardson
2021-03-06  0:04       ` [dpdk-dev] [PATCH v4 3/4] build: indicate usage at build time for public headers Dmitry Kozlyuk
2021-03-16  9:59         ` Thomas Monjalon
2021-03-06  0:05       ` [dpdk-dev] [PATCH v4 4/4] eal/windows: do not expose POSIX symbols Dmitry Kozlyuk
2021-03-17 19:23       ` [dpdk-dev] [PATCH v4 0/4] " Ranjit Menon
2021-03-20 11:27       ` [dpdk-dev] [PATCH v5 0/5] " Dmitry Kozlyuk
2021-03-20 11:27         ` [dpdk-dev] [PATCH v5 1/5] eal: add sleep API Dmitry Kozlyuk
2021-03-22  8:57           ` Kinsella, Ray
2021-03-20 11:27         ` [dpdk-dev] [PATCH v5 2/5] eal/windows: hide asprintf() shim Dmitry Kozlyuk
2021-03-20 11:27         ` [dpdk-dev] [PATCH v5 3/5] eal: make OS shims internal Dmitry Kozlyuk
2021-03-20 11:27         ` [dpdk-dev] [PATCH v5 4/5] net: provide IP-related API on any OS Dmitry Kozlyuk
2021-03-20 11:27         ` [dpdk-dev] [PATCH v5 5/5] net: replace Windows networking shim Dmitry Kozlyuk
2021-03-20 13:05         ` [dpdk-dev] [PATCH v6 0/5] eal/windows: do not expose POSIX symbols Dmitry Kozlyuk
2021-03-20 13:05           ` [dpdk-dev] [PATCH v6 1/5] eal: add sleep API Dmitry Kozlyuk
2021-03-20 13:05           ` [dpdk-dev] [PATCH v6 2/5] eal/windows: hide asprintf() shim Dmitry Kozlyuk
2021-03-26  9:04             ` Thomas Monjalon
2021-03-20 13:05           ` [dpdk-dev] [PATCH v6 3/5] eal: make OS shims internal Dmitry Kozlyuk
2021-03-26  9:12             ` Thomas Monjalon
2021-03-31 21:05               ` Nick Connolly
2021-03-31 21:19                 ` Thomas Monjalon
2021-03-31 21:45                   ` Nick Connolly
2021-03-31 21:55                     ` Thomas Monjalon
2021-04-01 23:10                       ` Dmitry Kozlyuk
2021-04-01 23:18                         ` Thomas Monjalon
2021-03-20 13:05           ` [dpdk-dev] [PATCH v6 4/5] net: provide IP-related API on any OS Dmitry Kozlyuk
2021-03-26  9:22             ` Thomas Monjalon
2021-03-20 13:05           ` [dpdk-dev] [PATCH v6 5/5] net: replace Windows networking shim Dmitry Kozlyuk
2021-03-26  9:28             ` Thomas Monjalon
2021-04-01 23:03               ` Dmitry Kozlyuk
2021-04-03 23:41           ` [dpdk-dev] [PATCH v7 0/5] eal/windows: do not expose POSIX symbols Dmitry Kozlyuk
2021-04-03 23:41             ` [dpdk-dev] [PATCH v7 1/5] eal: add sleep API Dmitry Kozlyuk
2021-04-06 14:34               ` Morten Brørup
2021-04-06 23:29                 ` Dmitry Kozlyuk
2021-04-07  7:31                   ` Morten Brørup
2021-04-29 17:09                     ` Tyler Retzlaff
2021-04-03 23:41             ` [dpdk-dev] [PATCH v7 2/5] eal/windows: hide asprintf() shim Dmitry Kozlyuk
2021-04-10  7:05               ` Nick Connolly
2021-04-03 23:41             ` [dpdk-dev] [PATCH v7 3/5] eal: make OS shims internal Dmitry Kozlyuk
2021-04-03 23:41             ` [dpdk-dev] [PATCH v7 4/5] net: work around s_addr macro on Windows Dmitry Kozlyuk
2021-04-03 23:41             ` [dpdk-dev] [PATCH v7 5/5] net: provide IP-related API on any OS Dmitry Kozlyuk
2021-04-07 22:22             ` [dpdk-dev] [PATCH v8 0/4] eal/windows: do not expose POSIX symbols Dmitry Kozlyuk
2021-04-07 22:22               ` [dpdk-dev] [PATCH v8 1/4] eal/windows: hide asprintf() shim Dmitry Kozlyuk
2021-04-07 22:22               ` [dpdk-dev] [PATCH v8 2/4] eal: make OS shims internal Dmitry Kozlyuk
2021-04-07 22:22               ` [dpdk-dev] [PATCH v8 3/4] net: work around s_addr macro on Windows Dmitry Kozlyuk
2021-04-08 11:26                 ` Olivier Matz
2021-04-07 22:22               ` [dpdk-dev] [PATCH v8 4/4] net: provide IP-related API on any OS Dmitry Kozlyuk
2021-04-08 11:45                 ` Olivier Matz
2021-04-08 19:51                   ` Dmitry Kozlyuk
2021-04-09 13:33                     ` Olivier Matz
2021-04-14 21:47                   ` Thomas Monjalon
2021-04-10 22:47               ` [dpdk-dev] [PATCH v9 0/4] eal/windows: do not expose POSIX symbols Dmitry Kozlyuk
2021-04-10 22:47                 ` [dpdk-dev] [PATCH v9 1/4] eal/windows: hide asprintf() shim Dmitry Kozlyuk
2021-04-10 22:47                 ` [dpdk-dev] [PATCH v9 2/4] eal: make OS shims internal Dmitry Kozlyuk
2021-04-14 21:33                   ` Thomas Monjalon
2021-04-10 22:47                 ` [dpdk-dev] [PATCH v9 3/4] net: work around s_addr macro on Windows Dmitry Kozlyuk
2021-04-10 22:47                 ` [dpdk-dev] [PATCH v9 4/4] net: provide IP-related API on any OS Dmitry Kozlyuk
2021-04-13  4:46                 ` [dpdk-dev] [PATCH v9 0/4] eal/windows: do not expose POSIX symbols Ranjit Menon
2021-04-13  7:00                   ` Dmitry Kozlyuk
2021-04-14 21:12                     ` Thomas Monjalon
2021-04-14 21:34                       ` Ranjit Menon
2021-04-14 21:42                         ` Thomas Monjalon
2021-04-14 21:47                           ` Ranjit Menon
2021-04-14 22:08                             ` Dmitry Kozlyuk
2021-04-14 22:58                               ` Thomas Monjalon
2021-04-14 22:06                 ` [dpdk-dev] [PATCH v10 " Dmitry Kozlyuk
2021-04-14 22:06                   ` [dpdk-dev] [PATCH v10 1/4] eal/windows: hide asprintf() shim Dmitry Kozlyuk
2021-04-14 22:06                   ` [dpdk-dev] [PATCH v10 2/4] eal: make OS shims internal Dmitry Kozlyuk
2021-04-14 22:06                   ` [dpdk-dev] [PATCH v10 3/4] net: work around s_addr macro on Windows Dmitry Kozlyuk
2021-04-14 22:06                   ` [dpdk-dev] [PATCH v10 4/4] net: provide IP-related API on any OS Dmitry Kozlyuk
2021-04-14 22:50                   ` [dpdk-dev] [PATCH v10 0/4] eal/windows: do not expose POSIX symbols Ranjit Menon
2021-04-14 23:57                     ` Thomas Monjalon
2021-03-17 19:19 ` [dpdk-dev] [PATCH 0/7] " Ranjit Menon

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