linux.git/tools/include/nolibc, branch master

tools/nolibc: support UBSAN on gcc

2026-04-09T21:25:40+00:00

The UBSAN implementation in gcc requires a slightly different function
attribute to skip instrumentation.

Extend __nolibc_no_sanitize_undefined to also handle gcc.

Signed-off-by: Thomas Weißschuh 
Link: https://patch.msgid.link/20260408-nolibc-gcc-15-v1-2-330d0c40f894@weissschuh.net

tools/nolibc: create __nolibc_no_sanitize_ubsan

2026-04-09T21:25:35+00:00

The logic to disable UBSAN will become a bit more complicated.
Move it out into compiler.h, so crt.h stays readable.

Signed-off-by: Thomas Weißschuh 
Link: https://patch.msgid.link/20260408-nolibc-gcc-15-v1-1-330d0c40f894@weissschuh.net

tools/nolibc: add byteorder conversions

2026-04-07T07:27:25+00:00

Add some standard functions to convert between different byte orders.
Conveniently the UAPI headers provide all the necessary functionality.

Signed-off-by: Thomas Weißschuh 
Acked-by: Willy Tarreau 
Link: https://patch.msgid.link/20260405-nolibc-bswap-v1-1-f7699ca9cee0@weissschuh.net

tools/nolibc: add the _syscall() macro

2026-04-07T07:27:07+00:00

The standard syscall() function or macro uses the libc return value
convention. Errors returned from the kernel as negative values are
stored in errno and -1 is returned. Users who want to avoid using
errno don't have a way to call raw syscalls and check the returned
error.

Add a new macro _syscall() which works like the standard syscall()
but passes through the return value from the kernel unchanged.
The naming scheme and return values match the named _sys_foo()
system call wrappers already part of nolibc.

Signed-off-by: Thomas Weißschuh 
Acked-by: Willy Tarreau 
Link: https://patch.msgid.link/20260405-nolibc-syscall-v1-3-e5b12bc63211@weissschuh.net

tools/nolibc: move the call to __sysret() into syscall()

2026-04-07T07:27:02+00:00

__sysret() transforms the return value from the kernel into the libc
return value convention. There is no reason for it to be called in the
middle of the internals of the syscall() implementation macros.

Move the call up, directly into syscall(), to make the code simpler.

Signed-off-by: Thomas Weißschuh 
Acked-by: Willy Tarreau 
Link: https://patch.msgid.link/20260405-nolibc-syscall-v1-2-e5b12bc63211@weissschuh.net

tools/nolibc: rename the internal macros used in syscall()

2026-04-07T07:26:57+00:00

These macros are the internal implementation of syscall().
They can not be used by users. Align them with the standard naming
scheme for internal symbols.

The current name also prevents the addition of an application-usable
_syscall() symbol.

Signed-off-by: Thomas Weißschuh 
Acked-by: Willy Tarreau 
Link: https://patch.msgid.link/20260405-nolibc-syscall-v1-1-e5b12bc63211@weissschuh.net

tools/nolibc: check for overflow in calloc() without divisions

2026-04-06T17:46:52+00:00

On some architectures without native division instructions
the division can generate calls into libgcc/compiler-rt.
This library might not be available, so its use should be avoided.

Use the compiler builtin to check for overflows without needing a
division. The builtin has been available since GCC 3 and clang 3.8.

Signed-off-by: Thomas Weißschuh 
Acked-by: Willy Tarreau 
Link: https://patch.msgid.link/20260404-nolibc-asprintf-v2-1-17d2d0df9763@weissschuh.net

tools/nolibc: add support for asprintf()

2026-04-06T17:46:51+00:00

Add support for dynamically allocating formatted strings through
asprintf() and vasprintf().

Signed-off-by: Thomas Weißschuh 
Acked-by: Willy Tarreau 
Link: https://patch.msgid.link/20260401-nolibc-asprintf-v1-3-46292313439f@weissschuh.net

tools/nolibc: use __builtin_offsetof()

2026-04-04T08:48:14+00:00

The current custom implementation of offsetof() fails UBSAN:
runtime error: member access within null pointer of type 'struct ...'
This means that all its users, including container_of(), free() and
realloc(), fail.

Use __builtin_offsetof() instead which does not have this issue and
has been available since GCC 4 and clang 3.

Signed-off-by: Thomas Weißschuh 
Acked-by: Willy Tarreau 
Link: https://patch.msgid.link/20260401-nolibc-asprintf-v1-1-46292313439f@weissschuh.net

tools/nolibc: use makedev() in fstatat()

2026-04-04T08:29:07+00:00

fstatat() contains two open-coded copies of makedev() to handle minor
numbers >= 256. Now that the regular makedev() handles both large minor
and major numbers correctly use the common function.

Signed-off-by: Thomas Weißschuh 
Acked-by: Willy Tarreau 
Link: https://patch.msgid.link/20260404-nolibc-makedev-v2-6-456a429bf60c@weissschuh.net