Re: [PATCH] eal: fix API to get error string

[Jerin Jacob <jerin.jacob@caviumnetworks.com>]

-----Original Message-----
> Date: Wed, 31 Oct 2018 17:19:28 +0000
> From: Ferruh Yigit <ferruh.yigit@intel.com>
> To: Bruce Richardson <bruce.richardson@intel.com>
> CC: dev@dpdk.org, Ferruh Yigit <ferruh.yigit@intel.com>, stable@dpdk.org
> Subject: [dpdk-dev] [PATCH] eal: fix API to get error string
> X-Mailer: git-send-email 2.17.2
> 
> External Email
> 
> rte_strerror uses strerror_r(), and strerror_r() has two version of it.
> - XSI-compliant version, (_POSIX_C_SOURCE >= 200112L) && !  _GNU_SOURCE
> - GNU-specific version
> 
> Those two has different return types, so the exiting return type check
> is not correct for GNU-specific version.
> 
> And this is causing failure in errno_autotest unit test.
> 
> Adding different implementation for FreeBSD and Linux.
> 
> Fixes: 016c32bd3e3d ("eal: cleanup strerror function")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> ---
>  lib/librte_eal/common/eal_common_errno.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/lib/librte_eal/common/eal_common_errno.c b/lib/librte_eal/common/eal_common_errno.c
> index 56b492f5f..fbbc71b0b 100644
> --- a/lib/librte_eal/common/eal_common_errno.c
> +++ b/lib/librte_eal/common/eal_common_errno.c
> @@ -38,9 +38,17 @@ rte_strerror(int errnum)
>                 case E_RTE_NO_CONFIG:
>                         return "Missing rte_config structure";
>                 default:
> +#ifdef RTE_EXEC_ENV_BSDAPP
>                         if (strerror_r(errnum, ret, RETVAL_SZ) != 0)
>                                 snprintf(ret, RETVAL_SZ, "Unknown error%s %d",
>                                                 sep, errnum);
> +#else
> +                       /*
> +                        * _GNU_SOURCE version, error string is not always
> +                        * strored in "ret" buffer, need to use return value
> +                        */
> +                       ret = strerror_r(errnum, ret, RETVAL_SZ);

Probably this will fail in musl c version.
https://git.musl-libc.org/cgit/musl/tree/src/string/strerror_r.c

Another alternative of this patch.

http://patches.dpdk.org/patch/47706/

> +#endif
>                 }
> 
>         return ret;
> --
> 2.17.2
>