Re: [fsverity-utils PATCH v2 2/2] Allow to build and run sign/digest on Windows

[Eric Biggers <ebiggers@kernel.org>]

On Thu, Dec 17, 2020 at 02:47:49PM +0000, luca.boccassi@gmail.com wrote:
> From: Luca Boccassi <luca.boccassi@microsoft.com>
> 
> Add some minimal compat type defs, and stub out the enable/measure
> sources. Also add a way to handle the fact that mingw adds a
> .exe extension automatically in the Makefile install rules, and
> that there is not pkg-config and the libcrypto linker flag is
> different.
> 
> Signed-off-by: Luca Boccassi <luca.boccassi@microsoft.com>
> ---
> v2: rework the stubbing out to detect mingw in the Makefile and remove
>     sources from compilation, instead of ifdefs.
>     add a new common/win32_defs.h for the compat definitions.
>     define strerror_r using strerror_s.
> 
>     To compile with mingw:
>       make CC=x86_64-w64-mingw32-gcc-8.3-win32
>     note that the openssl headers and a win32 libcrypto.dll need
>     to be available in the default search paths, and otherwise have
>     to be specified as expected via CPPFLAGS/LDFLAGS
> 

I got some warnings and an error when compiling:

$ make CC=x86_64-w64-mingw32-gcc
  CC       lib/compute_digest.o
  CC       lib/hash_algs.o
  CC       lib/sign_digest.o
  CC       lib/utils.o
lib/utils.c: In function ‘xmalloc’:
lib/utils.c:25:25: warning: unknown conversion type character ‘l’ in format [-Wformat=]
   25 |   libfsverity_error_msg("out of memory (tried to allocate %" SIZET_PF " bytes)",
      |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from lib/../common/win32_defs.h:24,
                 from lib/../common/common_defs.h:18,
                 from lib/lib_private.h:15,
                 from lib/utils.c:14:
/usr/x86_64-w64-mingw32/include/inttypes.h:36:18: note: format string is defined here
   36 | #define PRIu64 "llu"
      |                  ^
lib/utils.c:25:25: warning: too many arguments for format [-Wformat-extra-args]
   25 |   libfsverity_error_msg("out of memory (tried to allocate %" SIZET_PF " bytes)",
      |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  AR       libfsverity.a
  CC       lib/compute_digest.shlib.o
  CC       lib/hash_algs.shlib.o
  CC       lib/sign_digest.shlib.o
  CC       lib/utils.shlib.o
lib/utils.c: In function ‘xmalloc’:
lib/utils.c:25:25: warning: unknown conversion type character ‘l’ in format [-Wformat=]
   25 |   libfsverity_error_msg("out of memory (tried to allocate %" SIZET_PF " bytes)",
      |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from lib/../common/win32_defs.h:24,
                 from lib/../common/common_defs.h:18,
                 from lib/lib_private.h:15,
                 from lib/utils.c:14:
/usr/x86_64-w64-mingw32/include/inttypes.h:36:18: note: format string is defined here
   36 | #define PRIu64 "llu"
      |                  ^
lib/utils.c:25:25: warning: too many arguments for format [-Wformat-extra-args]
   25 |   libfsverity_error_msg("out of memory (tried to allocate %" SIZET_PF " bytes)",
      |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  CCLD     libfsverity.so.0
/usr/lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32/bin/ld: cannot find -l:libcrypto.dll
collect2: error: ld returned 1 exit status
make: *** [Makefile:137: libfsverity.so.0] Error 1



This is on Arch Linux with mingw-w64-gcc and mingw-w64-openssl installed.

So there's something wrong with the SIZET_PF format string, and also
-l:libcrypto.dll isn't correct; it should be just -lcrypto like it is on Linux.
(MinGW knows to look for a .dll file.)

- Eric