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>
fflush() passed every stream to glibc's fflush(). For a stream that is
reading, glibc seeks the descriptor back and drops the read buffer, and
with a pushed-back character it gets the position wrong: after fgetc()
returned 'a' from "abcdef\n" and ungetc('Z'), fflush() returned 0 and
the next fread() returned "bcdef\n\n". The pushed-back 'Z' was lost and
the last byte came back twice.
FreeBSD's fflush() writes out only a stream that is writing and leaves
every other stream as it is, lib/libc/stdio/fflush.c:
if ((fp->_flags & (__SWR | __SRW)) == 0)
retval = 0;
else
retval = __sflush(fp);
and __sflush():
t = fp->_flags;
if ((t & __SWR) == 0)
return (0);
fflush() on Linux now returns 0 without calling the host for a stream
whose last operation was not a write (__fwriting() is 0). fflush(NULL)
and streams that are writing are unchanged.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
fopen and freopen leave an "a+" stream where the host CRT puts it, at
the start of the file. On main, after fopen(file, "a+") on a 7-byte
file, ftell returns 0 and the first fgetc returns the first byte of the
file. FreeBSD seeks every append-mode stream to the end when it opens
it, so ftell returns 7 and a read before any fseek returns EOF. Code
that opens a log or save file with "a+" and tests ftell(f) == 0 to see
whether the file is new treats every existing file as empty.
FreeBSD 11.4 lib/libc/stdio/fopen.c (fopen), and the same lines in
lib/libc/stdio/freopen.c (freopen):
if (oflags & O_APPEND) {
fp->_flags2 |= __S2OAP;
(void)_sseek(fp, (fpos_t)0, SEEK_END);
}
lib/libc/stdio/flags.c sets O_APPEND for every mode that starts with 'a':
case 'a': /* open for appending */
ret = __SWR;
m = O_WRONLY;
o = O_CREAT | O_APPEND;
fopen and freopen now seek a stream opened with an 'a' mode to the end
of the file, ignoring a failed seek as FreeBSD does. Writes still go to
the end through O_APPEND.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
fdopen only took a fixed list of 15 mode strings and failed with EINVAL
for any other, so "rt", "r+t", "re", "rbe" or "rw" gave NULL. FreeBSD's
fdopen parses the mode with __sflags (lib/libc/stdio/flags.c): after
r, w or a it takes b, +, x, e and v and stops at the first other
character ("default: known = 0;"), and only a bad first character or x
on a read-only mode fail with EINVAL. fopen and freopen already parse
modes this way through ParseFileMode (#2033).
fdopen now uses ParseFileMode as well and passes the host its normalised
mode without x, which FreeBSD's fdopen ignores.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The guest fgets handed the size straight to the host. With a size of 0
glibc and the Windows runtime return NULL without setting errno or the
stream error indicator, and a negative size goes to the Windows
invalid-parameter path. FreeBSD's fgets checks n <= 0 before reading:
it sets __SERR on the stream, sets errno to EINVAL and returns NULL,
leaving the buffer and the file position untouched.
fgets_nid_postfix now does the same before calling the host. The
FileStream flag it uses was only set for encoding errors so far and is
renamed from SetEncodingError/encodingError to SetError/guestError; it
already stays set until clearerr like __SERR.
guest_standard_streams checks sizes 0, -1 and INT_MIN (NULL, errno 22,
error indicator set and cleared by clearerr, buffer and position
untouched) and that a following read still returns the line; it fails
without the change.
Fixes#3084
AI-assisted: yes
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Porpoise PPSA99764 stops after pthread_attr_* (#3494) with the
predicted `FAIL: unresolved ELF import h05OHOMZNMw from
libSceLibcInternal.prx` (idx 311, call site 0x8EC37); RetroArch
PPSA99169 imports it at idx 448 (call site 0xA4A27). h05OHOMZNMw is
ftrylockfile by tools/nid_names.py and aerolib.csv (zecoxao/sce_symbols
2883963a); ps5-payload-dev/sdk f5d40f02 declares
`int ftrylockfile(FILE *)` in include/freebsd/stdio.h.
ftrylockfile tries the same host CRT stream lock that flockfile,
funlockfile and every locking host stdio call on the stream take, so
no second lock exists beside the one stdio uses. It returns 0 when the
lock is acquired or already owned by the caller (recursive, released by
as many funlockfile calls) and -1 when another thread holds it, as
FreeBSD 8c639945 lib/libc/stdio/_flock_stub.c:89-104 does. Linux calls
glibc ftrylockfile. UCRT has no try variant of _lock_file, so Windows
calls TryEnterCriticalSection on the CRITICAL_SECTION that _lock_file
enters (__crt_stdio_stream_data::_lock, ucrt/inc/corecrt_internal_stdio.h,
same layout in Windows SDK 10.0.19041, 10.0.22621 and 10.0.26100). A
null or closed stream throws. The UCRT layout dependency is recorded in
TechnicalDebt.
guest_standard_streams covers trylock on an unlocked stream, re-entry
by the owner, failure from another thread while held (also after one of
two unlocks and while another thread holds flockfile), stdio calls
from another thread blocking on the trylock-held lock, release order,
and null and closed streams.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
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.
Use unlocked POSIX EOF/error queries after unlocked byte operations so status synchronization cannot reacquire the stream lock. Keep the verified UCRT status calls on Windows, and cover byte, status, error, and held-lock behavior.
Co-authored-by: MarcZX100 <marczxrr@gmail.com>
FreeBSD's __sflags reads the access character, then b, +, x, e and v, and
stops at the first other character without failing, so "rt" opens for
reading. On Windows fopen inserted b after the first character and passed
the rest on, so "rt" became "rbt", the CRT rejected it with EINVAL, and
fopen threw. vkQuake opens history.txt with "rt" at startup. freopen
accepted only a fixed list of modes.
Both now parse the mode like __sflags. An unknown access character, or x
on a read-only stream, returns NULL with EINVAL; x on an existing file
returns NULL with EEXIST; e and v are accepted and ignored.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
FreeBSD's setvbuf takes a zero size with _IOFBF or _IOLBF as "pick the
buffer size". The UCRT rejects sizes below 2 for those modes through
its invalid parameter handler, so the call failed on Windows and a test
process was terminated. A zero size now drops the given buffer and
asks the host for one of BUFSIZ bytes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
David
Dean
milescoviello
fablevoid
David
Hussein Kadhim
Romans Pokrovskis
MarcZX100
Adrià Franch
Hannah Lyons
Scott Schuster
LeandroLP23
Ethan Barr
Nicolas Abosch
asimplestray
SamG-Coder