Re: [kvm-unit-tests PATCH v2 3/4] arm/arm64: populate argv[0] with prognam

[Thomas Huth <thuth@redhat.com>]

On 22.04.2016 16:54, Andrew Jones wrote:
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> ---
>  arm/Makefile.common |  6 +++++-
>  lib/argv.c          | 25 +++++++++++++++++++++----
>  lib/auxinfo.h       |  7 +++++++
>  scripts/auxinfo.mak |  7 +++++++
>  4 files changed, 40 insertions(+), 5 deletions(-)
>  create mode 100644 lib/auxinfo.h
>  create mode 100755 scripts/auxinfo.mak
> 
> diff --git a/arm/Makefile.common b/arm/Makefile.common
> index 9a2d61fc88a27..6b87a48b0066b 100644
> --- a/arm/Makefile.common
> +++ b/arm/Makefile.common
> @@ -26,6 +26,7 @@ CFLAGS += -I lib -I lib/libfdt
>  
>  asm-offsets = lib/$(ARCH)/asm-offsets.h
>  include scripts/asm-offsets.mak
> +include scripts/auxinfo.mak
>  
>  cflatobjs += lib/util.o
>  cflatobjs += lib/alloc.o
> @@ -49,9 +50,12 @@ start_addr := $(shell printf "%x\n" $$(( $(phys_base) + $(kernel_offset) )))
>  FLATLIBS = $(libcflat) $(LIBFDT_archive) $(libgcc) $(libeabi)
>  %.elf: LDFLAGS = $(CFLAGS) -nostdlib
>  %.elf: %.o $(FLATLIBS) arm/flat.lds
> +	$(call gen-auxinfo,$(@:.elf=.aux.c),$(@:.elf=.flat))
> +	$(CC) $(CFLAGS) -c -o $(@:.elf=.aux.o) $(@:.elf=.aux.c)
>  	$(CC) $(LDFLAGS) -o $@ \
>  		-Wl,-T,arm/flat.lds,--build-id=none,-Ttext=$(start_addr) \
> -		$(filter %.o, $^) $(FLATLIBS)
> +		$(filter %.o, $^) $(FLATLIBS) $(@:.elf=.aux.o)
> +	$(RM) $(@:.elf=.aux).*
>  
>  %.flat: %.elf
>  	$(OBJCOPY) -O binary $^ $@
> diff --git a/lib/argv.c b/lib/argv.c
> index c6ad5fcbc8cf4..66cd43f24d336 100644
> --- a/lib/argv.c
> +++ b/lib/argv.c
> @@ -1,4 +1,7 @@
>  #include "libcflat.h"
> +#include "auxinfo.h"
> +
> +static char *copy_ptr;
>  
>  int __argc;
>  char *__argv[100];
> @@ -21,26 +24,40 @@ void __setup_args(void)
>  {
>      char *args = __args;
>      char **argv = __argv;
> -    char *p = __args_copy;
> +
> +    copy_ptr = __args_copy;
>  
>      while (*(args = skip_blanks(args)) != '\0') {
> -        *argv++ = p;
> +        *argv++ = copy_ptr;
>          while (*args != '\0' && !isblank(*args))
> -            *p++ = *args++;
> -        *p++ = '\0';
> +            *copy_ptr++ = *args++;
> +        *copy_ptr++ = '\0';
>      }
>      __argc = argv - __argv;
>  }
>  
>  void setup_args(char *args)
>  {
> +#if defined(__arm__) || defined(__aarch64__)
> +    const char *p;
> +#endif
> +
>      if (args) {
>          __args = args;
>          __setup_args();
>  
>          for (int i = __argc; i > 0; --i)
>              __argv[i] = __argv[i-1];
> +    } else {
> +        copy_ptr = __args_copy;
>      }
> +#if defined(__arm__) || defined(__aarch64__)
> +    __argv[0] = copy_ptr;
> +    p = auxinfo.prognam;
> +    while ((*copy_ptr++ = *p++) != 0)
> +        ;

Could you also use strcpy() here? Or do you still need the updated
copy_ptr afterwards?

> +#else
>      __argv[0] = NULL; //HACK: just reserve argv[0] for now
> +#endif
>      ++__argc;
>  }
> diff --git a/lib/auxinfo.h b/lib/auxinfo.h
> new file mode 100644
> index 0000000000000..fc2d736aa63b1
> --- /dev/null
> +++ b/lib/auxinfo.h
> @@ -0,0 +1,7 @@
> +#ifndef _AUXINFO_H_
> +#define _AUXINFO_H_
> +struct auxinfo {
> +	const char *prognam;
> +};
> +extern struct auxinfo auxinfo;
> +#endif
> diff --git a/scripts/auxinfo.mak b/scripts/auxinfo.mak
> new file mode 100755
> index 0000000000000..dbb588e89fc6f
> --- /dev/null
> +++ b/scripts/auxinfo.mak
> @@ -0,0 +1,7 @@
> +
> +define gen-auxinfo
> +	(echo "#include <auxinfo.h>";		\
> +	 echo "struct auxinfo auxinfo = {";	\
> +	 echo "    .prognam = \"$(2)\",";	\
> +	 echo "};" ) > $(1)
> +endef

Looks sane. Not sure, whether it really makes sense to provide the name
to the unit test, but hey, why not?

Reviewed-by: Thomas Huth <thuth@redhat.com>