[PATCH] libselinux/utils: drop requirement to combine compiling and linking

[PATCH] libselinux/utils: drop requirement to combine compiling and linking

[Christian Göttsche]

The extra dependency of sefcontext_compile on its object file causes the
compile and link step to be separated.
During the link step the CFLAGS are not passed, which might contain
optimization or sanitizer flags.

Current behavior:

    gcc-11 **custom CFLAGS** -I../include -D_GNU_SOURCE     -c -o sefcontext_compile.o sefcontext_compile.c
    gcc-11 -L../src  sefcontext_compile.o ../src/regex.o  -lselinux  -lpcre ../src/libselinux.a -lsepol -o sefcontext_compile

Changed:

    gcc-11 **custom CFLAGS** -I../include -D_GNU_SOURCE    -L../src  sefcontext_compile.c ../src/regex.o  -lselinux  -lpcre ../src/libselinux.a -lsepol -o sefcontext_compile

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
---
 libselinux/utils/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libselinux/utils/Makefile b/libselinux/utils/Makefile
index b018a08a..f01295fd 100644
--- a/libselinux/utils/Makefile
+++ b/libselinux/utils/Makefile
@@ -54,7 +54,7 @@ endif
 
 sefcontext_compile: LDLIBS += $(PCRE_LDLIBS) ../src/libselinux.a -lsepol
 
-sefcontext_compile: sefcontext_compile.o ../src/regex.o
+sefcontext_compile: ../src/regex.o
 
 all: $(TARGETS)
 
-- 
2.32.0

Re: [PATCH] libselinux/utils: drop requirement to combine compiling and linking

[Nicolas Iooss]

On Wed, Jul 14, 2021 at 8:13 PM Christian Göttsche
<cgzones@googlemail.com> wrote:
>
> The extra dependency of sefcontext_compile on its object file causes the
> compile and link step to be separated.
> During the link step the CFLAGS are not passed, which might contain
> optimization or sanitizer flags.
>
> Current behavior:
>
>     gcc-11 **custom CFLAGS** -I../include -D_GNU_SOURCE     -c -o sefcontext_compile.o sefcontext_compile.c
>     gcc-11 -L../src  sefcontext_compile.o ../src/regex.o  -lselinux  -lpcre ../src/libselinux.a -lsepol -o sefcontext_compile
>
> Changed:
>
>     gcc-11 **custom CFLAGS** -I../include -D_GNU_SOURCE    -L../src  sefcontext_compile.c ../src/regex.o  -lselinux  -lpcre ../src/libselinux.a -lsepol -o sefcontext_compile
>
> Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
> ---
>  libselinux/utils/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/libselinux/utils/Makefile b/libselinux/utils/Makefile
> index b018a08a..f01295fd 100644
> --- a/libselinux/utils/Makefile
> +++ b/libselinux/utils/Makefile
> @@ -54,7 +54,7 @@ endif
>
>  sefcontext_compile: LDLIBS += $(PCRE_LDLIBS) ../src/libselinux.a -lsepol
>
> -sefcontext_compile: sefcontext_compile.o ../src/regex.o
> +sefcontext_compile: ../src/regex.o
>
>  all: $(TARGETS)
>

Hello,

In my humble opinion, this patch makes reading
ilbselinux/utils/Makefile harder: it is no longer clear that
sefcontext_compile depends on sefcontext_compile.c. While I prefer
adding an explicit rule (such as "$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^
$(LDLIBS)"), it seems that your issue can be fixed differently, by
completely removing "sefcontext_compile: sefcontext_compile.o
../src/regex.o". Indeed, as regex.o is included in
../src/libselinux.a, it does not need to be included again.

Could you please test that this patch works?

diff --git a/libselinux/utils/Makefile b/libselinux/utils/Makefile
index b018a08acbe0..086f9cbe91c4 100644
--- a/libselinux/utils/Makefile
+++ b/libselinux/utils/Makefile
@@ -54,8 +54,6 @@ endif

 sefcontext_compile: LDLIBS += $(PCRE_LDLIBS) ../src/libselinux.a -lsepol

-sefcontext_compile: sefcontext_compile.o ../src/regex.o
-
 all: $(TARGETS)

 install: all
--

(It would be even nicer if sefcontext_compile did not depend on
libselinux.a, but removing the dependency to libselinux.a is a much
harder topic).

Thanks,
Nicolas

[PATCH v2] libselinux/utils: drop requirement to combine compiling and linking

[Christian Göttsche]

The extra dependency of sefcontext_compile on its object file causes the
compile and link step to be separated.
During the link step the CFLAGS are not passed, which might contain
optimization or sanitizer flags.

Reorder the LDLIBS requirements to avoid the symbol 'pcre_fullinfo'
being unresolvable at link time.

Current behavior:

    gcc-11 **custom CFLAGS** -I../include -D_GNU_SOURCE     -c -o sefcontext_compile.o sefcontext_compile.c
    gcc-11 -L../src  sefcontext_compile.o ../src/regex.o  -lselinux  -lpcre ../src/libselinux.a -lsepol -o sefcontext_compile

Changed:

    gcc-11 **custom CFLAGS** -I../include -D_GNU_SOURCE    -L../src  sefcontext_compile.c  -lselinux  ../src/libselinux.a -lpcre -lsepol -o sefcontext_compile

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
---
v2:
  - drop line regarding regex.o, as suggested by Nicolas Iooss.
  - order -lpcre after libselinux.a


 libselinux/utils/Makefile | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/libselinux/utils/Makefile b/libselinux/utils/Makefile
index b018a08a..36816155 100644
--- a/libselinux/utils/Makefile
+++ b/libselinux/utils/Makefile
@@ -52,9 +52,7 @@ else
 TARGETS=$(patsubst %.c,%,$(sort $(wildcard *.c)))
 endif
 
-sefcontext_compile: LDLIBS += $(PCRE_LDLIBS) ../src/libselinux.a -lsepol
-
-sefcontext_compile: sefcontext_compile.o ../src/regex.o
+sefcontext_compile: LDLIBS += ../src/libselinux.a $(PCRE_LDLIBS) -lsepol
 
 all: $(TARGETS)
 
-- 
2.33.0

Re: [PATCH v2] libselinux/utils: drop requirement to combine compiling and linking

[Petr Lautrbach]

Christian Göttsche <cgzones@googlemail.com> writes:

> The extra dependency of sefcontext_compile on its object file causes the
> compile and link step to be separated.
> During the link step the CFLAGS are not passed, which might contain
> optimization or sanitizer flags.
>
> Reorder the LDLIBS requirements to avoid the symbol 'pcre_fullinfo'
> being unresolvable at link time.
>
> Current behavior:
>
>     gcc-11 **custom CFLAGS** -I../include -D_GNU_SOURCE     -c -o sefcontext_compile.o sefcontext_compile.c
>     gcc-11 -L../src  sefcontext_compile.o ../src/regex.o  -lselinux  -lpcre ../src/libselinux.a -lsepol -o sefcontext_compile
>
> Changed:
>
>     gcc-11 **custom CFLAGS** -I../include -D_GNU_SOURCE    -L../src  sefcontext_compile.c  -lselinux  ../src/libselinux.a -lpcre -lsepol -o sefcontext_compile
>
> Signed-off-by: Christian Göttsche <cgzones@googlemail.com>

Acked-by: Petr Lautrbach <plautrba@redhat.com>

Thanks!


> ---
> v2:
>   - drop line regarding regex.o, as suggested by Nicolas Iooss.
>   - order -lpcre after libselinux.a
>
>
>  libselinux/utils/Makefile | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/libselinux/utils/Makefile b/libselinux/utils/Makefile
> index b018a08a..36816155 100644
> --- a/libselinux/utils/Makefile
> +++ b/libselinux/utils/Makefile
> @@ -52,9 +52,7 @@ else
>  TARGETS=$(patsubst %.c,%,$(sort $(wildcard *.c)))
>  endif
>  
> -sefcontext_compile: LDLIBS += $(PCRE_LDLIBS) ../src/libselinux.a -lsepol
> -
> -sefcontext_compile: sefcontext_compile.o ../src/regex.o
> +sefcontext_compile: LDLIBS += ../src/libselinux.a $(PCRE_LDLIBS) -lsepol
>  
>  all: $(TARGETS)
>  
> -- 
> 2.33.0