Matthew Maurer <mmaurer@xxxxxxxxxx> writes:
> Adds a new format for MODVERSIONS which stores each field in a separate
> ELF section. This initially adds support for variable length names, but
> could later be used to add additional fields to MODVERSIONS in a
> backwards compatible way if needed. Any new fields will be ignored by
> old user tooling, unlike the current format where user tooling cannot
> tolerate adjustments to the format (for example making the name field
> longer).
>
> Since PPC munges its version records to strip leading dots, we reproduce
> the munging for the new format. Other architectures do not appear to
> have architecture-specific usage of this information.
>
> Signed-off-by: Matthew Maurer <mmaurer@xxxxxxxxxx>
> ---
> arch/powerpc/kernel/module_64.c | 24 ++++++++++-
> kernel/module/internal.h | 11 +++++
> kernel/module/main.c | 92 +++++++++++++++++++++++++++++++++++++----
> kernel/module/version.c | 45 ++++++++++++++++++++
> 4 files changed, 162 insertions(+), 10 deletions(-)
>
> diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
> index e9bab599d0c2745e4d2b5cae04f2c56395c24654..02ada0b057cef6b2f29fa7519a5d52acac740ee5 100644
> --- a/arch/powerpc/kernel/module_64.c
> +++ b/arch/powerpc/kernel/module_64.c
> @@ -355,6 +355,24 @@ static void dedotify_versions(struct modversion_info *vers,
> }
> }
>
> +/* Same as normal versions, remove a leading dot if present. */
> +static void dedotify_ext_version_names(char *str_seq, unsigned long size)
> +{
> + unsigned long out = 0;
> + unsigned long in;
> + char last = '\0';
> +
> + for (in = 0; in < size; in++) {
> + /* Skip one leading dot */
> + if (last == '\0' && str_seq[in] == '.')
> + in++;
> + last = str_seq[in];
> + str_seq[out++] = last;
> + }
> + /* Zero the trailing portion of the names table for robustness */
> + memset(&str_seq[out], 0, size - out);
> +}
Sorry I realise it's version 7, but although the above looks correct it's
kind of dense.
I think the below would also work and is (I think) easier to follow, and
is more obviously similar to the existing code. I'm sure your version is
faster, but I don't think it's that performance critical.
static void dedotify_ext_version_names(char *str_seq, unsigned long size)
{
char *end = str_seq + size;
char *p = str_seq;
while (p < end) {
if (*p == '.')
memmove(p, p + 1, end - p - 1);
p += strlen(p) + 1;
}
}
The tail of str_seq will be filled with nulls as long as the last string
was null terminated.
cheers
