The guest formatter handed NaN to the host's snprintf, which prints
-nan for a negative NaN and +nan or " nan" with the + and space flags.
FreeBSD 11's vfprintf clears the sign of every NaN and prints nan (NAN
for the upper-case conversions), keeping the width and the - flag and
ignoring 0. The formatter now does the same for a, e, f and g and
their long double forms.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VZWLdTjf1S57iLgn2rcaFb
On Linux sscanf, vsscanf, fscanf and sscanf_s hand their conversions to
glibc. Since glibc 2.38, code built as GNU C++ calls the C23 entry
points (__isoc23_vsscanf, __isoc23_vfscanf, __isoc23_sscanf), whose %i
reads a 0b/0B binary prefix. On main,
sscanf("0b101 x", "%i%n%7s", &value, &end, rest) stores value 5 and
end 5 and leaves "x" for the %s; " -0B11" gives -3. TechnicalDebt
records this.
FreeBSD's %i knows only the 0 and 0x prefixes. FreeBSD 11.4
lib/libc/stdio/vfscanf.c, parseint, lines 345-353 and 371-380:
case '0':
if (base == 0) {
base = 8;
flags |= PFXOK;
}
...
/* letters ok iff hex */
case 'A': case 'B': case 'C':
case 'D': case 'E': case 'F':
case 'a': case 'b': case 'c':
case 'd': case 'e': case 'f':
/* no need to fix base here */
if (base <= 10)
break; /* not legal here */
so "0b101" stores 0, consumes the "0" and leaves "b101", as C17 does
and as the strtol family here already does.
With glibc the scanf family now calls __isoc99_vsscanf and
__isoc99_vfscanf, the entry points GNU C++ used before glibc 2.38
(exported since 2.7), which read %i without the binary prefix. Other
hosts keep std::vsscanf and std::vfscanf. The TechnicalDebt entry is
removed.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
FreeBSD's printf formats %m as the message for the errno value at the
time of the call. On Linux a format with %m went to glibc, which looks
the number up in Linux's table, so guest errno values above 34 got
another error's text: with errno 35 (EAGAIN) "[%m]" printed
"[Resource deadlock avoided]" instead of "[Resource temporarily
unavailable]", and errno 63 (ENAMETOOLONG) printed "Out of streams
resources". On Windows, and on Linux when the format also had a wide
argument, the guest formatter threw on %m.
FreeBSD 11.4, lib/libc/stdio/vfprintf.c:
saved_errno = errno;
...
case 'm':
cp = strerror(saved_errno);
size = (prec >= 0) ? strnlen(cp, prec) : strlen(cp);
sign = '\0';
break;
The guest formatter now saves errno when it starts and formats %m as a
string with the guest strerror_r text, so width, precision and the -
flag apply as FreeBSD's string path applies them. On Linux a format with
%m goes to the guest formatter like one with a wide argument.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The guest formatter threw on %n$ and *m$, which FreeBSD's vfprintf and
glibc accept. It now reads the arguments a numbered format names into a
table first, with the types their conversions give them, and follows
FreeBSD's rules for unnumbered conversions and unnamed arguments.
FreeBSD's vfprintf takes ' as the thousands-grouping flag. The Windows
formatter threw on it as an unsupported conversion. The guest's setlocale
only accepts the C locale, which has no thousands separator, so the flag
changes nothing: it is dropped before the host's printf sees it, and the
host's locale cannot add separators.
C and FreeBSD's vfprintf print a single 0 when # meets octal zero with a
precision of 0. The Windows formatter passed the conversion to the host's
printf, which printed nothing; it now asks for one digit instead.
C17 7.21.6.2p16 returns EOF only if input fails before the first conversion completes, and a suppressed conversion completes. FreeBSD counts it in nconversions (vfscanf.c, releng/11.4, lines 799-805). The host scanf returned EOF there, so sscanf("12", "%*d%d", &v) reported EOF instead of 0. Each suppressed conversion now records its end with a %n and a result of EOF becomes 0 when one was recorded.
The Windows formatter passed %p to the host CRT, which prints 16
zero-padded digits without a prefix. FreeBSD prints 0x followed by the
lowercase hex digits (0x0 for a null pointer), as if by %#lx.
guest_formatting called sprintf with four variadic arguments and
libc_printf with one, all in registers, and did not call sscanf, so only
snprintf had a check that fails with the old Linux register rebuild. sprintf
now formats six integers, sscanf converts eight fields and libc_printf prints
seven integers; on the old code the first gives "1 2 3 4 0 0" and the other
two crash.
Checks suggested by nauroth in #1435.
guest_formatting_tests was built on Linux but registered with ctest on
Windows only, so the Linux printf and scanf exports had no coverage: on main
the test fails there at its first vsnprintf check and then crashes in
snprintf with eight integers.
It is registered on every platform now. The %ls checks stay Windows-only,
as glibc reads %ls as 32-bit wchar_t; that gap is recorded in TechnicalDebt.
libkernel:
- direct memory keeps its contents per physical page across unmap and
remap; a page mapped at two live addresses at once throws
- sceKernelDirectMemoryQuery answers from tracked allocations
- SCE protections read back as set, GPU and AMPR bits included
- APR prefix path resolve, file size and stat by id, positional reads,
fsync/pread/pwrite; directories open as descriptors on Windows
- sceKernelCheckReachability, getpeername, shutdown
- Dinkumware C11 threads (_Mtx_*, _Cnd_*, _Thrd_*) in the title libc
layout; any pthread stack size, rounded at thread creation
libc:
- unaddressed guest mappings go to the system-managed area from
0x2_0000_0000, leaving the application area to fixed mappings
- the process starts in /app0
- guest sscanf on Windows; a null %s prints as (null) as on FreeBSD
- localeconv, _FNan, _FDtest, _FExp, __udivti3, wcsncpy_s, aligned
operator new, _Throw_Cpp_error
Tests: direct memory following physical pages, guest formatting.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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