From nobody Tue Sep 9 12:57:55 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 202A3C001DC for ; Wed, 26 Jul 2023 07:11:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231230AbjGZHLV (ORCPT ); Wed, 26 Jul 2023 03:11:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46878 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232435AbjGZHKx (ORCPT ); Wed, 26 Jul 2023 03:10:53 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 5AB5D2727 for ; Wed, 26 Jul 2023 00:07:44 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6726011FB; Wed, 26 Jul 2023 00:07:47 -0700 (PDT) Received: from e125769.cambridge.arm.com (e125769.cambridge.arm.com [10.1.196.26]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 587463F5A1; Wed, 26 Jul 2023 00:07:03 -0700 (PDT) From: Ryan Roberts To: Willy Tarreau , Andrew Morton , Mark Brown , Naresh Kamboju Cc: Ryan Roberts , linux-kernel@vger.kernel.org, Linux Kernel Functional Testing Subject: [PATCH v1] tools/nolibc/stdio: add setvbuf() to set buffering mode Date: Wed, 26 Jul 2023 08:06:55 +0100 Message-Id: <20230726070655.2713530-1-ryan.roberts@arm.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Add a minimal implementation of setvbuf(), which error checks the mode argument (as required by spec) and returns. Since nolibc never buffers output, nothing needs to be done. The kselftest framework recently added a call to setvbuf(). As a result, any tests that use the kselftest framework and nolibc cause a compiler error due to missing function. This provides an urgent fix for the problem which is preventing arm64 testing on linux-next. Example: clang --target=3Daarch64-linux-gnu -fintegrated-as -Werror=3Dunknown-warning-option -Werror=3Dignored-optimization-argument -Werror=3Doption-ignored -Werror=3Dunused-command-line-argument --target=3Daarch64-linux-gnu -fintegrated-as -fno-asynchronous-unwind-tables -fno-ident -s -Os -nostdlib \ -include ../../../../include/nolibc/nolibc.h -I../..\ -static -ffreestanding -Wall za-fork.c build/kselftest/arm64/fp/za-fork-asm.o -o build/kselftest/arm64/fp/za-fork In file included from :1: In file included from ./../../../../include/nolibc/nolibc.h:97: In file included from ./../../../../include/nolibc/arch.h:25: ./../../../../include/nolibc/arch-aarch64.h:178:35: warning: unknown attribute 'optimize' ignored [-Wunknown-attributes] void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) __no_stack_protector _start(void) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from za-fork.c:12: ../../kselftest.h:123:2: error: call to undeclared function 'setvbuf'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] setvbuf(stdout, NULL, _IOLBF, 0); ^ ../../kselftest.h:123:24: error: use of undeclared identifier '_IOLBF' setvbuf(stdout, NULL, _IOLBF, 0); ^ 1 warning and 2 errors generated. Signed-off-by: Ryan Roberts Fixes: ecb7fe2cd610 ("selftests: line buffer test program's stdout") Reported-by: Linux Kernel Functional Testing Link: https://lore.kernel.org/linux-kselftest/CA+G9fYus3Z8r2cg3zLv8uH8MRrzL= FVWdnor02SNr=3DrCz+_WGVg@mail.gmail.com/ Reviewed-by: Mark Brown --- tools/include/nolibc/stdio.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h index 0eef91daf289..a3778aff4fa9 100644 --- a/tools/include/nolibc/stdio.h +++ b/tools/include/nolibc/stdio.h @@ -21,6 +21,11 @@ #define EOF (-1) #endif +/* Buffering mode used by setvbuf. */ +#define _IOFBF 0 /* Fully buffered. */ +#define _IOLBF 1 /* Line buffered. */ +#define _IONBF 2 /* No buffering. */ + /* just define FILE as a non-empty type. The value of the pointer gives * the FD: FILE=3D~fd for fd>=3D0 or NULL for fd<0. This way positive FILE * are immediately identified as abnormal entries (i.e. possible copies @@ -350,6 +355,25 @@ void perror(const char *msg) fprintf(stderr, "%s%serrno=3D%d\n", (msg && *msg) ? msg : "", (msg && *ms= g) ? ": " : "", errno); } +static __attribute__((unused)) +int setvbuf(FILE *stream, char *buf, int mode, size_t size) +{ + /* + * nolibc does not support buffering so this is a nop. Just check mode + * is valid as required by the spec. + */ + switch (mode) { + case _IOFBF: + case _IOLBF: + case _IONBF: + break; + default: + return EOF; + } + + return 0; +} + /* make sure to include all global symbols */ #include "nolibc.h" -- 2.25.1