[5/5] radvd: add a patch to fix build failure on architectures without sysctl()

Modern architectures such as ARC do not provide the sysctl() system
call, since it is deprecated. However, uClibc still installs
<sys/sysctl.h> in such cases, which defeats radvd check for the
availability of sysctl(). This commit adds a patch to radvd which
improves the sysctl() checking.

Fixes:

  http://autobuild.buildroot.org/results/458/4581c4220adeaebbf6761e3b923088d8de8522d5/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
 ...0003-Improve-check-of-the-sysctl-function.patch | 49 ++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 package/radvd/0003-Improve-check-of-the-sysctl-function.patch

Thomas, All,

On 2014-11-23 18:36 +0100, Thomas Petazzoni spake thusly:
> Modern architectures such as ARC do not provide the sysctl() system
> call, since it is deprecated. However, uClibc still installs
> <sys/sysctl.h> in such cases, which defeats radvd check for the
> availability of sysctl(). This commit adds a patch to radvd which
> improves the sysctl() checking.
> 
> Fixes:
> 
>   http://autobuild.buildroot.org/results/458/4581c4220adeaebbf6761e3b923088d8de8522d5/
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

Regards,
Yann E. MORIN.

> ---
>  ...0003-Improve-check-of-the-sysctl-function.patch | 49 ++++++++++++++++++++++
>  1 file changed, 49 insertions(+)
>  create mode 100644 package/radvd/0003-Improve-check-of-the-sysctl-function.patch
> 
> diff --git a/package/radvd/0003-Improve-check-of-the-sysctl-function.patch b/package/radvd/0003-Improve-check-of-the-sysctl-function.patch
> new file mode 100644
> index 0000000..3053f7b
> --- /dev/null
> +++ b/package/radvd/0003-Improve-check-of-the-sysctl-function.patch
> @@ -0,0 +1,49 @@
> +From 4c86b3cbf52f810615d92835e98d83e9555a4d88 Mon Sep 17 00:00:00 2001
> +From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> +Date: Sun, 23 Nov 2014 12:13:47 +0100
> +Subject: [PATCH 3/3] Improve check of the sysctl() function
> +
> +Since sysctl is a deprecated system call, new architectures such as
> +ARC don't implement it. In such cases, uClibc installs the
> +<sys/sysctl.h> header, but dos not implement the sysctl()
> +function. This has the annoying side effect of breaking the sysctl
> +detection of radvd, which is purely based on the header file being
> +present.
> +
> +To fix this, this commit adds a check based on the existence of the
> +sysctl() function.
> +
> +Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> +---
> + configure.ac   | 1 +
> + device-linux.c | 2 +-
> + 2 files changed, 2 insertions(+), 1 deletion(-)
> +
> +diff --git a/configure.ac b/configure.ac
> +index 5dde3b2..5518f71 100644
> +--- a/configure.ac
> ++++ b/configure.ac
> +@@ -161,6 +161,7 @@ AC_CHECK_HEADERS( \
> + 	time.h \
> + )
> + AC_HEADER_TIME
> ++AC_CHECK_FUNCS([sysctl])
> + 
> + dnl Checks for typedefs, structures, and compiler characteristics.
> + AC_MSG_CHECKING(whether struct sockaddr_in6 has sin6_scope_id)
> +diff --git a/device-linux.c b/device-linux.c
> +index 1ecaa6b..d9b56b8 100644
> +--- a/device-linux.c
> ++++ b/device-linux.c
> +@@ -183,7 +183,7 @@ int check_ip6_forwarding(void)
> + 		value = -1;
> + 	}
> + 
> +-#ifdef HAVE_SYS_SYSCTL_H
> ++#if defined(HAVE_SYS_SYSCTL_H) && defined(HAVE_SYSCTL)
> + 	int forw_sysctl[] = { SYSCTL_IP6_FORWARDING };
> + 	size_t size = sizeof(value);
> + 	if (!fp && sysctl(forw_sysctl, sizeof(forw_sysctl) / sizeof(forw_sysctl[0]), &value, &size, NULL, 0) < 0) {
> +-- 
> +2.1.0
> +
> -- 
> 2.1.0
> 
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