support/scripts/check-kernel-headers.sh: do not print error for loose checks

The C program inside check-kernel-headers.sh has two checking mode: a
strict and a loose one.

In strict mode, we want the kernel headers version declared by the
user to match exactly the one of the toolchain.

In loose mode, we want the kernel headers version of the toolchain to
be greater than or equal to the one declared by the user: this is used
when we have a toolchain that has newer headers than the latest
version known by Buildroot.

However, in loose mode, we continue to show the "Incorrect kernel
headers version" message, even though we then return a zero error
code. This is very confusing: you see an error displayed on the
terminal, but the build goes on.

We fix that by first doing the loose check first, and returning 0 if
it succeeds. And then we move on with the strict check where we want
the version to be identical.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
---
 support/scripts/check-kernel-headers.sh | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

Thomas, All,

On 2020-03-21 14:52 +0100, Thomas Petazzoni spake thusly:
> The C program inside check-kernel-headers.sh has two checking mode: a
> strict and a loose one.
> 
> In strict mode, we want the kernel headers version declared by the
> user to match exactly the one of the toolchain.
> 
> In loose mode, we want the kernel headers version of the toolchain to
> be greater than or equal to the one declared by the user: this is used
> when we have a toolchain that has newer headers than the latest
> version known by Buildroot.
> 
> However, in loose mode, we continue to show the "Incorrect kernel
> headers version" message, even though we then return a zero error
> code. This is very confusing: you see an error displayed on the
> terminal, but the build goes on.
> 
> We fix that by first doing the loose check first, and returning 0 if
> it succeeds. And then we move on with the strict check where we want
> the version to be identical.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

WhenVincent and I worked on this topic, I thought it would be better to
have the information about the version mismatch.

But I agree that the wording is confusing at best, so I applied to
master, thanks.

Regards,
Yann E. MORIN.

> ---
>  support/scripts/check-kernel-headers.sh | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/support/scripts/check-kernel-headers.sh b/support/scripts/check-kernel-headers.sh
> index 841df98b64..4e6dce5487 100755
> --- a/support/scripts/check-kernel-headers.sh
> +++ b/support/scripts/check-kernel-headers.sh
> @@ -49,18 +49,20 @@ ${HOSTCC} -imacros "${SYSROOT}/usr/include/linux/version.h" \
>  int main(int argc __attribute__((unused)),
>           char** argv __attribute__((unused)))
>  {
> -    int ret = 0;
>      int l = LINUX_VERSION_CODE & ~0xFF;
>      int h = KERNEL_VERSION(${HDR_M},${HDR_m},0);
>  
> +    if ((l >= h) && !strcmp("${CHECK}", "loose"))
> +        return 0;
> +
>      if (l != h) {
>          printf("Incorrect selection of kernel headers: ");
>          printf("expected %d.%d.x, got %d.%d.x\n", ${HDR_M}, ${HDR_m},
>                 ((LINUX_VERSION_CODE>>16) & 0xFF),
>                 ((LINUX_VERSION_CODE>>8) & 0xFF));
> -        ret = ((l >= h) && !strcmp("${CHECK}", "loose")) ? 0 : 1;
> +        return 1;
>      }
> -    return ret;
> +    return 0;
>  }
>  _EOF_
>  
> -- 
> 2.25.1
>

>>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni@bootlin.com> writes:

 > The C program inside check-kernel-headers.sh has two checking mode: a
 > strict and a loose one.

 > In strict mode, we want the kernel headers version declared by the
 > user to match exactly the one of the toolchain.

 > In loose mode, we want the kernel headers version of the toolchain to
 > be greater than or equal to the one declared by the user: this is used
 > when we have a toolchain that has newer headers than the latest
 > version known by Buildroot.

 > However, in loose mode, we continue to show the "Incorrect kernel
 > headers version" message, even though we then return a zero error
 > code. This is very confusing: you see an error displayed on the
 > terminal, but the build goes on.

 > We fix that by first doing the loose check first, and returning 0 if
 > it succeeds. And then we move on with the strict check where we want
 > the version to be identical.

 > Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

Committed to 2020.02.x, thanks.