kernel/linux.git/tools/include/nolibc/stdio.h, branch v6.18.22

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

2025-12-18T13:02:43+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

selftests/nolibc: correctly report errors from printf() and friends

2025-07-06T09:02:40+00:00

When an error is encountered by printf() it needs to be reported. errno() is already set by the callback. sprintf() is different, but that keeps working and is already tested. Also add a new test. Fixes: 7e4346f4a3a6 ("tools/nolibc/stdio: add a minimal [vf]printf() implementation") Signed-off-by: Thomas Weißschuh Acked-by: Willy Tarreau Link: https://lore.kernel.org/r/20250704-nolibc-printf-error-v1-2-74b7a092433b@linutronix.de Signed-off-by: Thomas Weißschuh

tools/nolibc: add fopen()

2025-05-21T13:32:14+00:00

This is used in various selftests and will be handy when integrating those with nolibc. Only the standard POSIX modes are supported. No extensions nor the (noop) "b" from ISO C are accepted. Signed-off-by: Thomas Weißschuh Acked-by: Willy Tarreau Link: https://lore.kernel.org/r/20250428-nolibc-misc-v2-13-3c043eeab06c@linutronix.de Signed-off-by: Thomas Weißschuh

tools/nolibc: add %m printf format

2025-05-21T13:32:01+00:00

The %m format can be used to format the current errno. It is non-standard but supported by other commonly used libcs like glibc and musl, so applications do rely on them. Signed-off-by: Thomas Weißschuh Acked-by: Willy Tarreau Link: https://lore.kernel.org/r/20250428-nolibc-misc-v2-2-3c043eeab06c@linutronix.de Signed-off-by: Thomas Weißschuh

tools/nolibc: include nolibc.h early from all header files

2025-05-21T13:31:50+00:00

Inclusion of any nolibc header file should also bring all other headers. On the other hand it should also be possible to include any nolibc header files in any order. Currently this is implemented by including the catch-all nolibc.h after the headers own definitions. This is problematic if one nolibc header depends on another one. The first header has to include the other one before defining any symbols. That in turn will include the rest of nolibc while the current header has not defined anything yet. If any other part of nolibc depends on definitions from the current header, errors are encountered. This is already the case today. Effectively nolibc can only be included in the order of nolibc.h. Restructure the way "nolibc.h" is included. Move it to the beginning of the header files and before the include guards. Now any header will behave exactly like "nolibc.h" while the include guards prevent any duplicate definitions. Signed-off-by: Thomas Weißschuh Acked-by: Willy Tarreau Link: https://lore.kernel.org/r/20250424-nolibc-header-check-v1-2-011576b6ed6f@linutronix.de

tools/nolibc: implement width padding in printf()

2025-04-22T08:59:06+00:00

printf can pad each argument to a certain width. Implement this for compatibility with the kselftest harness. Currently only padding with spaces is supported. Signed-off-by: Thomas Weißschuh Acked-by: Willy Tarreau

tools/nolibc: add snprintf() and friends

2025-04-22T08:59:04+00:00

Add more of the printf() functions. Signed-off-by: Thomas Weißschuh Acked-by: Willy Tarreau

tools/nolibc: allow limiting of printf destination size

2025-04-22T08:59:03+00:00

snprintf() allows limiting the output buffer, while still returning the number of all bytes that would have been written. Implement the limitation logic in preparation for snprintf(). Signed-off-by: Thomas Weißschuh Acked-by: Willy Tarreau

tools/nolibc: allow different write callbacks in printf

2025-04-22T08:59:02+00:00

Decouple the formatting logic from the writing logic to later enable writing straight to a buffer in sprintf(). Signed-off-by: Thomas Weißschuh Acked-by: Willy Tarreau

tools/nolibc: add dprintf() and vdprintf()

2025-04-22T08:58:22+00:00

dprintf() and vdprintf() are printf() variants printing directly into a filedescriptor. As FILE in nolibc is based directly on filedescriptors, the implementation is trivial. Signed-off-by: Thomas Weißschuh Acked-by: Willy Tarreau