On Fri, Dec 25, 2020 at 10:30:43PM +0900, John Millikin wrote:
> The syntax for POSIX regexes technically doesn't allow empty branches in
> conditional match groups. GNU libc accepts them as equivalent to `()',
> but other libc implementations (e.g. macOS libc) reject them with a
> parse error.
>
> Changing to compliant syntax, `(|_sym)' to `(()|_sym)', lets the `relocs'
> tool run successfully when using a non-GNU platform as a build host for
> cross-compiling the kernel.
>
> Signed-off-by: John Millikin <j...@john-millikin.com>
> ---
>
> Helper binary to verify behavior for the current platform:
>
> #include <regex.h>
> #include <stdio.h>
> int main(int argc, char **argv) {
> regex_t compiled;
> int err = regcomp(&compiled, argv[1], REG_EXTENDED|REG_NOSUB);
> if (err != 0) {
> char errbuf[128];
> regerror(err, &compiled, errbuf, sizeof(errbuf));
> printf("regcomp(\"%s\"): %s\n", argv[1], errbuf);
> return 1;
> }
> printf("regcomp(\"%s\"): OK\n", argv[1]);
> return 0;
> }
>
> Output from GNU libc 2.28 and a fussier non-GNU libc:
>
> debian:~$ ./regcomp '^a(|b)$'
> regcomp("^a(|b)$"): OK
> debian:~$ ./regcomp '^a(()|b)$'
> regcomp("^a(()|b)$"): OK
>
> darwin:~$ ./regcomp '^a(|b)$'
> regcomp("^a(|b)$"): empty (sub)expression
> darwin:~$ ./regcomp '^a(()|b)$'
> regcomp("^a(()|b)$"): OK
>
I guess you can add those to the commit message as they explain in
detail what the situation is.
> arch/x86/tools/relocs.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
> index ce7188cbdae5..e6f28616a625 100644
> --- a/arch/x86/tools/relocs.c
> +++ b/arch/x86/tools/relocs.c
> @@ -57,12 +57,12 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] =
> {
> [S_REL] =
$ test-apply.sh /tmp/build.01
checking file arch/x86/tools/relocs.c
patch: **** malformed patch at line 67: [S_REL] =
Don't tell me the apple mangles patches...
:-)
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
