kernel/linux.git/tools/include/nolibc/stdio.h, branch v6.12.80

tools/nolibc/stdio: let perror work when NOLIBC_IGNORE_ERRNO is set

2025-12-18T12:54:50+00:00

[ Upstream commit c485ca3aff2442adea4c08ceb5183e671ebed22a ] There is no errno variable when NOLIBC_IGNORE_ERRNO is defined. As such, simply print the message with "unknown error" rather than the integer value of errno. Fixes: acab7bcdb1bc ("tools/nolibc/stdio: add perror() to report the errno value") Signed-off-by: Benjamin Berg Signed-off-by: Thomas Weißschuh Signed-off-by: Sasha Levin

tools/nolibc: implement strerror()

2024-06-29T07:44:57+00:00

strerror() is commonly used. For example in kselftest which currently needs to do an #ifdef NOLIBC to handle the lack of strerror(). Keep it simple and reuse the output format of perror() for strerror(). Acked-by: Shuah Khan Signed-off-by: Thomas Weißschuh

tools/nolibc: annotate va_list printf formats

2023-12-11T21:38:32+00:00

__attribute__(format(printf)) can also be used for functions that take a va_list argument. As per the GCC docs: For functions where the arguments are not available to be checked (such as vprintf), specify the third parameter as zero. Link: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html Signed-off-by: Thomas Weißschuh

tools/nolibc: add stdarg.h header

2023-10-12T19:13:52+00:00

This allows nolic to work with `-nostdinc` avoiding any reliance on system headers. The implementation has been lifted from musl libc 1.2.4. There is already an implementation of stdarg.h in include/linux/stdarg.h but that is GPL licensed and therefore not suitable for nolibc. The used compiler builtins have been validated to be at least available since GCC 4.1.2 and clang 3.0.0. Signed-off-by: Thomas Weißschuh Signed-off-by: Willy Tarreau

tools/nolibc: setvbuf: avoid unused parameter warnings

2023-08-23T03:17:07+00:00

This warning will be enabled later so avoid triggering it. Signed-off-by: Thomas Weißschuh Signed-off-by: Willy Tarreau

tools/nolibc/stdio: add setvbuf() to set buffering mode

2023-08-23T02:40:22+00:00

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=aarch64-linux-gnu -fintegrated-as -Werror=unknown-warning-option -Werror=ignored-optimization-argument -Werror=option-ignored -Werror=unused-command-line-argument --target=aarch64-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 Reported-by: Linux Kernel Functional Testing Link: https://lore.kernel.org/linux-kselftest/CA+G9fYus3Z8r2cg3zLv8uH8MRrzLFVWdnor02SNr=rCz+_WGVg@mail.gmail.com/ Reviewed-by: Mark Brown Signed-off-by: Willy Tarreau

tools/nolibc: implement fd-based FILE streams

2023-06-09T18:33:05+00:00

This enables the usage of the stream APIs with arbitrary filedescriptors. It will be used by a future testcase. Signed-off-by: Thomas Weißschuh Signed-off-by: Willy Tarreau Signed-off-by: Paul E. McKenney

tools/nolibc/stdio: Implement vprintf()

2023-04-11T20:10:42+00:00

vprintf() is equivalent to vfprintf() to stdout so implement it as a simple wrapper for the existing vfprintf(), allowing us to build kselftest.h. Suggested-by: Willy Tarreau Signed-off-by: Mark Brown Acked-by: Willy Tarreau Acked-by: Paul E. McKenney Acked-by: Shuah Khan Signed-off-by: Shuah Khan

tools/nolibc: fix missing includes causing build issues at -O0

2023-01-09T17:36:05+00:00

After the nolibc includes were split to facilitate portability from standard libcs, programs that include only what they need may miss some symbols which are needed by libgcc. This is the case for raise() which is needed by the divide by zero code in some architectures for example. Regardless, being able to include only the apparently needed files is convenient. Instead of trying to move all exported definitions to a single file, since this can change over time, this patch takes another approach consisting in including the nolibc header at the end of all standard include files. This way their types and functions are already known at the moment of inclusion, and including any single one of them is sufficient to bring all the required ones. Signed-off-by: Willy Tarreau Signed-off-by: Paul E. McKenney

tools/nolibc/stdio: Add format attribute to enable printf warnings

2022-06-20T16:43:19+00:00

When we use printf and fprintf functions from the nolibc, we don't get any warning from the compiler if we have the wrong arguments. For example, the following calls will compile silently: ``` printf("%s %s\n", "aaa"); fprintf(stdout, "%s %s\n", "xxx", 1); ``` (Note the wrong arguments). Those calls are undefined behavior. The compiler can help us warn about the above mistakes by adding a `printf` format attribute to those functions declaration. This patch adds it, and now it yields these warnings for those mistakes: ``` warning: format `%s` expects a matching `char *` argument [-Wformat=] warning: format `%s` expects argument of type `char *`, but argument 4 has type `int` [-Wformat=] ``` [ ammarfaizi2: Simplify the attribute placement. ] Signed-off-by: Alviro Iskandar Setiawan Signed-off-by: Ammar Faizi Acked-by: Willy Tarreau Signed-off-by: Paul E. McKenney