[Buildroot] [PATCH 1/1] package/lxc: fix compilation with stub memfd_create

[Matthew Weber]

Patrick,

On Tue, Oct 22, 2019 at 7:42 AM Patrick Havelange
<patrick.havelange at essensium.com> wrote:
>
> This fixes compilation issue in case memfd_create is a stub in libc.
> Patch already merged in lxc master branch
> (344b8ee293f4d3730a70a6ccaa03d7e4a516ae95).
>
> Copy of the original commit log:
>
> In case the internal memfd_create has to be used, make sure we don't
> clash with the already existing memfd_create function from glibc.
>
> This can happen if this glibc function is a stub. In this case, at
> ./configure time, the test for this function will return false, however
> the declaration of that function is still available. This leads to
> compilation errors.
>
> Signed-off-by: Patrick Havelange <patrick.havelange at essensium.com>

Reviewed-by: Matt Weber <matthew.weber at rockwellcollins.com>


> ---
>  ...-rename-internal-memfd_create-to-mem.patch | 43 +++++++++++++++++++
>  1 file changed, 43 insertions(+)
>  create mode 100644 package/lxc/0001-syscall_wrappers-rename-internal-memfd_create-to-mem.patch
>
> diff --git a/package/lxc/0001-syscall_wrappers-rename-internal-memfd_create-to-mem.patch b/package/lxc/0001-syscall_wrappers-rename-internal-memfd_create-to-mem.patch
> new file mode 100644
> index 0000000000..6210591c09
> --- /dev/null
> +++ b/package/lxc/0001-syscall_wrappers-rename-internal-memfd_create-to-mem.patch
> @@ -0,0 +1,43 @@
> +From 2b23a1313f501423aecbe4ad4a988a9f6f832f1f Mon Sep 17 00:00:00 2001
> +From: Patrick Havelange <patrick.havelange at essensium.com>
> +Date: Tue, 22 Oct 2019 12:29:54 +0200
> +Subject: [PATCH 1/1] syscall_wrappers: rename internal memfd_create to
> + memfd_create_lxc
> +
> +In case the internal memfd_create has to be used, make sure we don't
> +clash with the already existing memfd_create function from glibc.
> +
> +This can happen if this glibc function is a stub. In this case, at
> +./configure time, the test for this function will return false, however
> +the declaration of that function is still available. This leads to
> +compilation errors.
> +
> +Signed-off-by: Patrick Havelange <patrick.havelange at essensium.com>
> +---
> + src/lxc/syscall_wrappers.h | 3 ++-
> + 1 file changed, 2 insertions(+), 1 deletion(-)
> +
> +diff --git a/src/lxc/syscall_wrappers.h b/src/lxc/syscall_wrappers.h
> +index 42d94db..bddf01b 100644
> +--- a/src/lxc/syscall_wrappers.h
> ++++ b/src/lxc/syscall_wrappers.h
> +@@ -59,7 +59,7 @@ static inline long __keyctl(int cmd, unsigned long arg2, unsigned long arg3,
> + #endif
> +
> + #ifndef HAVE_MEMFD_CREATE
> +-static inline int memfd_create(const char *name, unsigned int flags) {
> ++static inline int memfd_create_lxc(const char *name, unsigned int flags) {
> +       #ifndef __NR_memfd_create
> +               #if defined __i386__
> +                       #define __NR_memfd_create 356
> +@@ -98,6 +98,7 @@ static inline int memfd_create(const char *name, unsigned int flags) {
> +       return -1;
> +       #endif
> + }
> ++#define memfd_create memfd_create_lxc
> + #else
> + extern int memfd_create(const char *name, unsigned int flags);
> + #endif
> +--
> +2.20.1
> +
> --
> 2.20.1
>
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-- 

Matthew Weber | Associate Director Software Engineer | Commercial Avionics

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