XenServer uses quite long Xen version names, and encode such in the livepatch
filename, and it's currently running out of space in the file name.

Bump max filename size to 128, so it also matches the patch name length in the
hypervisor interface.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
 livepatch-build | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/livepatch-build b/livepatch-build
index cdb852cc7fea..78dd2d801048 100755
--- a/livepatch-build
+++ b/livepatch-build
@@ -72,8 +72,8 @@ function make_patch_name()
     fi
 
     # Only allow alphanumerics and '_' and '-' in the patch name.  Everything
-    # else is replaced with '-'.  Truncate to 48 chars.
-    echo ${PATCHNAME//[^a-zA-Z0-9_-]/-} |cut -c 1-48
+    # else is replaced with '-'.  Truncate to 128 chars.
+    echo ${PATCHNAME//[^a-zA-Z0-9_-]/-} |cut -c -128
 }
 
 # Do a full normal build
-- 
2.43.0

On Wed, Jan 31, 2024 at 4:58 PM Roger Pau Monne <roger.pau@citrix.com> wrote:
>
> XenServer uses quite long Xen version names, and encode such in the livepatch
> filename, and it's currently running out of space in the file name.
>
> Bump max filename size to 128, so it also matches the patch name length in the
> hypervisor interface.
>
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
> ---
>  livepatch-build | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/livepatch-build b/livepatch-build
> index cdb852cc7fea..78dd2d801048 100755
> --- a/livepatch-build
> +++ b/livepatch-build
> @@ -72,8 +72,8 @@ function make_patch_name()
>      fi
>
>      # Only allow alphanumerics and '_' and '-' in the patch name.  Everything
> -    # else is replaced with '-'.  Truncate to 48 chars.
> -    echo ${PATCHNAME//[^a-zA-Z0-9_-]/-} |cut -c 1-48
> +    # else is replaced with '-'.  Truncate to 128 chars.
> +    echo ${PATCHNAME//[^a-zA-Z0-9_-]/-} |cut -c -128
>  }

I think it should be XEN_LIVEPATCH_NAME_SIZE - 1 to match the hypervisor
since AFAICT the hypervisor expects the last character to be NUL.

In get_name(), it checks:

    if ( !name->size || name->size > XEN_LIVEPATCH_NAME_SIZE )
        return -EINVAL;

... and:

    if ( n[name->size - 1] )
        return -EINVAL;

Do you agree with that?

Ross

On Tue, Feb 27, 2024 at 01:32:05PM +0000, Ross Lagerwall wrote:
> On Wed, Jan 31, 2024 at 4:58 PM Roger Pau Monne <roger.pau@citrix.com> wrote:
> >
> > XenServer uses quite long Xen version names, and encode such in the livepatch
> > filename, and it's currently running out of space in the file name.
> >
> > Bump max filename size to 128, so it also matches the patch name length in the
> > hypervisor interface.
> >
> > Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
> > ---
> >  livepatch-build | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/livepatch-build b/livepatch-build
> > index cdb852cc7fea..78dd2d801048 100755
> > --- a/livepatch-build
> > +++ b/livepatch-build
> > @@ -72,8 +72,8 @@ function make_patch_name()
> >      fi
> >
> >      # Only allow alphanumerics and '_' and '-' in the patch name.  Everything
> > -    # else is replaced with '-'.  Truncate to 48 chars.
> > -    echo ${PATCHNAME//[^a-zA-Z0-9_-]/-} |cut -c 1-48
> > +    # else is replaced with '-'.  Truncate to 128 chars.
> > +    echo ${PATCHNAME//[^a-zA-Z0-9_-]/-} |cut -c -128
> >  }
> 
> I think it should be XEN_LIVEPATCH_NAME_SIZE - 1 to match the hypervisor
> since AFAICT the hypervisor expects the last character to be NUL.
> 
> In get_name(), it checks:
> 
>     if ( !name->size || name->size > XEN_LIVEPATCH_NAME_SIZE )
>         return -EINVAL;
> 
> ... and:
> 
>     if ( n[name->size - 1] )
>         return -EINVAL;
> 
> Do you agree with that?

Oh, I didn't catch that one.  xen-livepatch should also be adjusted
then, as get_name() there does:

static int get_name(int argc, char *argv[], char *name)
{
    ssize_t len = strlen(argv[0]);
    if ( len > XEN_LIVEPATCH_NAME_SIZE )

Which needs to be adjusted to len >= instead, and the error printed
should also mention that ID must be no more than
XEN_LIVEPATCH_NAME_SIZE - 1.

Thanks, Roger.