[dm-devel] [PATCH] Makefiles: Fix function availability checks

[Christophe Varoqui]

Very nice, thanks.
Merged.

On Fri, Nov 18, 2016 at 8:52 PM, Bart Van Assche <bart.vanassche at sandisk.com
> wrote:

> The current implementation of the code that checks for function
> presence is not correct because it checks for a prefix match only.
> Introduce a function that checks for the exact function name.
> Additionally, report whether or not the function has been found.
> An example of the output produced by this function if 'make' is
> run:
>
> Checking for dm_task_no_flush in /usr/include/libdevmapper.h ... yes
> Checking for dm_task_set_cookie in /usr/include/libdevmapper.h ... yes
> Checking for udev_monitor_set_receive_buffer_size in
> /usr/include/libudev.h ... yes
> Checking for dm_task_deferred_remove in /usr/include/libdevmapper.h ... yes
>
> Signed-off-by: Bart Van Assche <bart.vanassche at sandisk.com>
> ---
>  Makefile.inc          | 14 ++++++++++++++
>  kpartx/Makefile       |  4 +---
>  libmultipath/Makefile | 16 ++++------------
>  3 files changed, 19 insertions(+), 15 deletions(-)
>
> diff --git a/Makefile.inc b/Makefile.inc
> index 1cc8f44..e7f4e05 100644
> --- a/Makefile.inc
> +++ b/Makefile.inc
> @@ -69,5 +69,19 @@ OPTFLAGS     = -O2 -g -pipe -Wall -Wextra -Wformat=2 \
>  CFLAGS         = $(OPTFLAGS) -fPIC -DLIB_STRING=\"${LIB}\"
> -DRUN_DIR=\"${RUN}\"
>  SHARED_FLAGS   = -shared
>
> +# Check whether a function with name $1 has been declared in header file
> $2.
> +check_func =
>     \
> +    $(shell
>      \
> +       if grep -Eq "^[^[:blank:]]+[[:blank:]]+$1[[:blank:]]*(.*)*" "$2";
> then \
> +          found=1;
>     \
> +          status="yes";
>      \
> +       else
>      \
> +          found=0;
>     \
> +          status="no";
>     \
> +       fi;
>     \
> +       echo 1>&2 "Checking for $1 in $2 ... $$status";
>     \
> +       echo "$$found"
>      \
> +    )
> +
>  %.o:   %.c
>         $(CC) $(CFLAGS) -c -o $@ $<
> diff --git a/kpartx/Makefile b/kpartx/Makefile
> index e8a59f2..9441a2b 100644
> --- a/kpartx/Makefile
> +++ b/kpartx/Makefile
> @@ -7,9 +7,7 @@ CFLAGS += -I. -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64
>
>  LIBDEPS += -ldevmapper
>
> -LIBDM_API_COOKIE = $(shell grep -Ecs '^[a-z]*[[:space:]]+dm_task_set_cookie'
> /usr/include/libdevmapper.h)
> -
> -ifneq ($(strip $(LIBDM_API_COOKIE)),0)
> +ifneq ($(call check_func,dm_task_set_cookie,/usr/include/libdevmapper.h),
> 0)
>         CFLAGS += -DLIBDM_API_COOKIE
>  endif
>
> diff --git a/libmultipath/Makefile b/libmultipath/Makefile
> index 495cebe..a11e483 100644
> --- a/libmultipath/Makefile
> +++ b/libmultipath/Makefile
> @@ -20,27 +20,19 @@ ifdef SYSTEMD
>         endif
>  endif
>
> -LIBDM_API_FLUSH = $(shell grep -Ecs '^[a-z]*[[:space:]]+dm_task_no_flush'
> /usr/include/libdevmapper.h)
> -
> -ifneq ($(strip $(LIBDM_API_FLUSH)),0)
> +ifneq ($(call check_func,dm_task_no_flush,/usr/include/libdevmapper.h),0)
>         CFLAGS += -DLIBDM_API_FLUSH -D_GNU_SOURCE
>  endif
>
> -LIBDM_API_COOKIE = $(shell grep -Ecs '^[a-z]*[[:space:]]+dm_task_set_cookie'
> /usr/include/libdevmapper.h)
> -
> -ifneq ($(strip $(LIBDM_API_COOKIE)),0)
> +ifneq ($(call check_func,dm_task_set_cookie,/usr/include/libdevmapper.h),
> 0)
>         CFLAGS += -DLIBDM_API_COOKIE
>  endif
>
> -LIBUDEV_API_RECVBUF = $(shell grep -Ecs '^[a-z]*[[:space:]]+udev_
> monitor_set_receive_buffer_size' /usr/include/libudev.h)
> -
> -ifneq ($(strip $(LIBUDEV_API_RECVBUF)),0)
> +ifneq ($(call check_func,udev_monitor_set_receive_buffer_size,/usr/
> include/libudev.h),0)
>         CFLAGS += -DLIBUDEV_API_RECVBUF
>  endif
>
> -LIBDM_API_DEFERRED = $(shell grep -Ecs '^[a-z]*[[:space:]]+dm_task_deferred_remove'
> /usr/include/libdevmapper.h)
> -
> -ifneq ($(strip $(LIBDM_API_DEFERRED)),0)
> +ifneq ($(call check_func,dm_task_deferred_remove,/usr/include/
> libdevmapper.h),0)
>         CFLAGS += -DLIBDM_API_DEFERRED
>  endif
>
> --
> 2.10.1
>
>
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