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 <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260405-nolibc-syscall-v1-3-e5b12bc63211@weissschuh.net
__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 <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260405-nolibc-syscall-v1-2-e5b12bc63211@weissschuh.net
nolibc should work without libgcc to be compatible with as many
toolchains as possible. Currently the functionality tested by
nolibc-test does not contain any dependencies, make sure it stays
this way by not linking libgcc anymore.
On the ppc target GCC always emits references to '_restgpr_' functions,
so keep linking libgcc there.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260404-nolibc-libgcc-v1-1-eb3ecfe0e176@weissschuh.net
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 <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260404-nolibc-asprintf-v2-1-17d2d0df9763@weissschuh.net
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 <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260401-nolibc-asprintf-v1-1-46292313439f@weissschuh.net
statx() returns both 32-bit minor and major numbers. For both of them to
fit into the 'dev_t' in 'struct stat', that needs to be 64 bits wide.
The other uses of 'dev_t' in nolibc are makedev() and friends and
mknod(). makedev() and friends are going to be adapted in an upcoming
commit and mknod() will silently truncate 'dev_t' to 'unsigned int' in
the kernel, similar to other libcs.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260404-nolibc-makedev-v2-4-456a429bf60c@weissschuh.net
Functions make it easier to keep the input and output types straight and
avoid duplicate evaluations of their arguments.
Also these functions will become a bit more complex to handle full
64-bit 'dev_t' which is easier to read in a function.
Still stay compatible with code which expects these to be macros.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260404-nolibc-makedev-v2-3-456a429bf60c@weissschuh.net
For (eg) "%*.*s" treat a negative field width as a request to left align
the output (the same as the '-' flag), and a negative precision to
request the default precision.
Set the default precision to -1 (not INT_MAX) and add explicit checks
to the string handling for negative values (makes the tet unsigned).
For numeric output check for 'precision >= 0' instead of testing
_NOLIBC_PF_FLAGS_CONTAIN(flags, '.').
This needs an inverted test, some extra goto and removes an indentation.
The changed conditionals fix printf("%0-#o", 0) - but '0' and '-' shouldn't
both be specified.
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Link: https://patch.msgid.link/20260323112247.3196-1-david.laight.linux@gmail.com
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
The sys_foo() naming scheme used by the syscall wrappers may collide
with application symbols. Especially as 'sys_' is an obvious naming
scheme an application may choose for its own custom systemcall wrappers.
Avoid these conflicts by using an leading underscore which moves the
names into the implementation's namespace. This naming scheme was chosen
over a '__nolibc_' prefix, as these functions are not an implementation
detail but a documented interface meant to be used by applications.
While this may break some existing users, adapting them should be
straightforward. Given that nolibc is most-likely vendored, no
unexpected breakage should happen. No in-tree users are affected.
These conflicts happen when compiling some of the kernel selftests
with nolibc.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260319-nolibc-namespacing-v1-1-33c22eaddb5e@weissschuh.net
With -std=c89 the macro __STDC_VERSION__ is not defined.
While undefined identifiers in '#if' directives are assumed to be '0',
with -Wundef a warning is emitted.
Avoid the warning by explicitly falling back to '0' if __STDC_VERSION__
is not provided by the preprocessor.
Fixes: 37219aa5b1 ("tools/nolibc: add __nolibc_static_assert()")
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260318-nolibc-wundef-v1-1-fcb7f9ac7298@weissschuh.net
Add support for the GNU extensions 'program_invocation_name' and
'program_invocation_short_name'. These are useful to print error
messages, which by convention include the program name.
As these are global variables which take up memory even if not used,
similar to 'errno', gate them behind NOLIBC_IGNORE_ERRNO.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260318-nolibc-err-h-v4-1-08247a694bd9@weissschuh.net
Octal output isn't often used, but adding it costs very little.
Supporting "%#o" is mildly annoying, it has to add a leading '0' if
there isn't one present. In simple cases this is the same as adding a sign
of '0' - but that adds an extra '0' in a few places.
So you need 3 tests, %o, # and no leading '0' (which can only be checked
after the zero pad for precision).
If all the test are deferred until after zero padding then too many values
are 'live' across the call to _nolibc_u64toa_base() and get spilled to stack.
Hence the check that ignores the 'sign' if it is the same as the first
character of the output string.
Add tests for octal output.
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260308113742.12649-17-david.laight.linux@gmail.com
[Thomas: avoid a -Wsign-compare]
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Includes support for variable field widths (eg "%*.*d").
Zero padding is limited to 31 zero characters.
This is wider than the largest numeric field so shouldn't be a problem.
All the standard printf formats are now supported except octal
and floating point.
Add tests for new features
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260308113742.12649-16-david.laight.linux@gmail.com
[Thomas: fixup testcases for musl libc]
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
The output for %#x is almost the same as that for %p, both output in
hexadecimal with a leading "0x".
However for zero %#x should just output "0" (the same as decimal and ocal).
For %p match glibc and output "(nil)" rather than "0x0" or "0".
Add tests for "%#x", "% d", "%+d" and passing NULL to "%p".
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260308113742.12649-14-david.laight.linux@gmail.com
[Thomas: fix up testcases for musl libc]
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Length modifiers t (ptrdiff_t) and z (size_t) are aliases for l (long),
q and L are 64bit the same as j (intmax).
Format i is an alias for d and X similar to x but upper case.
Supporting them is mostly just adding the relevant bit to the bit
pattern used for matching characters.
Although %X is detected the output will be lower case.
Change/add tests to use conversions i and X, and length modifiers L and ll.
Use the correct minimum value for "%Li".
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260308113742.12649-10-david.laight.linux@gmail.com
[Thomas: Fix up testcases for musl libc]
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Use flags bits (1u << (ch & 31)) for the flags, length modifiers, and
conversion specifiers.
This makes it easy to test for multiple values at once.
Detect the conversion flags " #+-0" although they are currently all ignored.
Unconditionally generate the signed values (for %d) to remove a second
set of checks for the size.
Separate out the formatting of single characters from numbers.
Output the sign for negative values then negate and treat as unsigned.
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260308113742.12649-9-david.laight.linux@gmail.com
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Upcoming changes will need to use goto to jump to the code that
outputs characters.
Use 'goto do_output' to output a known number of characters.
Use 'goto do_strlen_output' to output a '\0' terminated string.
Removes a level of indentation from the format processing code.
The change is best reviewed using 'git diff -b' after applying it.
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260308113742.12649-8-david.laight.linux@gmail.com
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Move the check for the length modifiers into the format processing
between the field width and conversion specifier.
This lets the loop be simplified and a 'fast scan' for a format start
used.
If an error is detected (eg an invalid conversion specifier) then
copy the invalid format to the output buffer.
Reduces code size by about 10% on x86-64.
Some versions of gcc bloat this version by generating a jump table.
All goes away in the later patches.
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260308113742.12649-7-david.laight.linux@gmail.com
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
strerror() can be the only part of a program that has a .data section.
This requires 4k in the program file.
Add a simple implementation of strerror_r() and use that in strerror()
so that the "errno=" string is copied at run-time.
Use __builtin_memcpy() because that optimises away the input string
and just writes the required constants to the target buffer.
Code size change largely depends on whether the inlining decision for
strerror() changes.
Change the tests to use the normal EXPECT_VFPRINTF() when testing %m.
Skip the tests when !is_nolibc.
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260308113742.12649-4-david.laight.linux@gmail.com
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Instead of requiring the test cases specifying both the length and
expected output, take the length from the expected output.
Tests that expect the output be truncated are changed to specify
the un-truncated output.
Change the strncmp() to a memcmp() with an extra check that the
output is actually terminated.
Append a '+' to the printed output (after the final ") when the output
is truncated.
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260302101815.3043-6-david.laight.linux@gmail.com
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
