[Buildroot] [PATCH 1/1] package/libcap: needs MMU

[Buildroot] [PATCH 1/1] package/libcap: needs MMU

[Fabrice Fontaine]

libcap uses fork() since version 2.33 and
https://git.kernel.org/pub/scm/linux/kernel/git/morgan/libcap.git/commit/?id=ef485973d5547431782f9e5f4323eabfebb38622

So add MMU dependency to avoid the following build failure on
applications using libcap without MMU such as ntp:

/tmp/instance-0/output-1/host/opt/ext-toolchain/arm-buildroot-uclinux-uclibcgnueabi/bin/ld.real: /tmp/instance-0/output-1/host/bin/../arm-buildroot-uclinux-uclibcgnueabi/sysroot/usr/lib/libcap.a(cap_proc.o): in function `cap_launch':
/tmp/instance-0/output-1/build/libcap-2.42/libcap/cap_proc.c:912: undefined reference to `fork'

Fixes:
 - http://autobuild.buildroot.org/results/89f39dae01c07977062b909079bfcd45a68060d3

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
---
 package/libcap/Config.in | 1 +
 1 file changed, 1 insertion(+)

diff --git a/package/libcap/Config.in b/package/libcap/Config.in
index 5b0c827191..1145ff0dd2 100644
--- a/package/libcap/Config.in
+++ b/package/libcap/Config.in
@@ -1,5 +1,6 @@
 config BR2_PACKAGE_LIBCAP
 	bool "libcap"
+	depends on BR2_USE_MMU # fork()
 	help
 	  This library implements the user-space interfaces to the
 	  POSIX 1003.1e capabilities available in Linux kernels. These
-- 
2.28.0

[Buildroot] [PATCH 1/1] package/libcap: needs MMU

[Baruch Siach]

Hi Fabric,

On Sun, Sep 13 2020, Fabrice Fontaine wrote:
> libcap uses fork() since version 2.33 and
> https://git.kernel.org/pub/scm/linux/kernel/git/morgan/libcap.git/commit/?id=ef485973d5547431782f9e5f4323eabfebb38622
>
> So add MMU dependency to avoid the following build failure on
> applications using libcap without MMU such as ntp:
>
> /tmp/instance-0/output-1/host/opt/ext-toolchain/arm-buildroot-uclinux-uclibcgnueabi/bin/ld.real: /tmp/instance-0/output-1/host/bin/../arm-buildroot-uclinux-uclibcgnueabi/sysroot/usr/lib/libcap.a(cap_proc.o): in function `cap_launch':
> /tmp/instance-0/output-1/build/libcap-2.42/libcap/cap_proc.c:912: undefined reference to `fork'
>
> Fixes:
>  - http://autobuild.buildroot.org/results/89f39dae01c07977062b909079bfcd45a68060d3

It might be worth noting that all current libcap reverse dependencies
depend on MMU already.

baruch

> Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
> ---
>  package/libcap/Config.in | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/package/libcap/Config.in b/package/libcap/Config.in
> index 5b0c827191..1145ff0dd2 100644
> --- a/package/libcap/Config.in
> +++ b/package/libcap/Config.in
> @@ -1,5 +1,6 @@
>  config BR2_PACKAGE_LIBCAP
>  	bool "libcap"
> +	depends on BR2_USE_MMU # fork()
>  	help
>  	  This library implements the user-space interfaces to the
>  	  POSIX 1003.1e capabilities available in Linux kernels. These


-- 
                                                     ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch at tkos.co.il - tel: +972.52.368.4656, http://www.tkos.co.il -

[Buildroot] [PATCH 1/1] package/libcap: needs MMU

[Thomas Petazzoni]

On Sun, 13 Sep 2020 18:50:48 +0200
Fabrice Fontaine <fontaine.fabrice@gmail.com> wrote:

> libcap uses fork() since version 2.33 and
> https://git.kernel.org/pub/scm/linux/kernel/git/morgan/libcap.git/commit/?id=ef485973d5547431782f9e5f4323eabfebb38622
> 
> So add MMU dependency to avoid the following build failure on
> applications using libcap without MMU such as ntp:
> 
> /tmp/instance-0/output-1/host/opt/ext-toolchain/arm-buildroot-uclinux-uclibcgnueabi/bin/ld.real: /tmp/instance-0/output-1/host/bin/../arm-buildroot-uclinux-uclibcgnueabi/sysroot/usr/lib/libcap.a(cap_proc.o): in function `cap_launch':
> /tmp/instance-0/output-1/build/libcap-2.42/libcap/cap_proc.c:912: undefined reference to `fork'
> 
> Fixes:
>  - http://autobuild.buildroot.org/results/89f39dae01c07977062b909079bfcd45a68060d3
> 
> Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>

I've applied, but after dropping the BR2_USE_MMU dependency on the
BR2_PACKAGE_LIBCAP_TOOLS option, since it was no longer needed. As
suggested by Baruch, I've added a note in the commit log to say that
all reverse dependencies of libcap already have a BR2_USE_MMU
dependency.

Thanks!

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com