stdio source code

contracts/musl/src/stdio/__fclose_ca.c

+#include "stdio_impl.h"
+
+int __fclose_ca(FILE *f)
+{
+	return f->close(f);
+}

contracts/musl/src/stdio/__lockfile.c

+#include "stdio_impl.h"
+#include "pthread_impl.h"
+
+int __lockfile(FILE *f)
+{
+   /*
+	int owner, tid = __pthread_self()->tid;
+	if (f->lock == tid)
+		return 0;
+	while ((owner = a_cas(&f->lock, 0, tid)))
+		__wait(&f->lock, &f->waiters, owner, 1);
+	return 1;
+   */
+}
+
+void __unlockfile(FILE *f)
+{
+   //a_store(&f->lock, 0);
+
+	/* The following read is technically invalid under situations
+	 * of self-synchronized destruction. Another thread may have
+	 * called fclose as soon as the above store has completed.
+	 * Nonetheless, since FILE objects always live in memory
+	 * obtained by malloc from the heap, it's safe to assume
+	 * the dereferences below will not fault. In the worst case,
+	 * a spurious syscall will be made. If the implementation of
+	 * malloc changes, this assumption needs revisiting. */
+
+   //if (f->waiters) __wake(&f->lock, 1, 1);
+        
+}

contracts/musl/src/stdio/__overflow.c

+#include "stdio_impl.h"
+
+int __overflow(FILE *f, int _c)
+{
+	unsigned char c = _c;
+	if (!f->wend && __towrite(f)) return EOF;
+	if (f->wpos < f->wend && c != f->lbf) return *f->wpos++ = c;
+	if (f->write(f, &c, 1)!=1) return EOF;
+	return c;
+}

contracts/musl/src/stdio/__stdio_close.c

+#include "stdio_impl.h"
+
+static int dummy(int fd)
+{
+	return fd;
+}
+
+weak_alias(dummy, __aio_close);
+
+int __stdio_close(FILE *f)
+{
+   /*
+	return syscall(SYS_close, __aio_close(f->fd));
+   */
+}

contracts/musl/src/stdio/__stdio_exit.c

+#include "stdio_impl.h"
+
+static FILE *volatile dummy_file = 0;
+weak_alias(dummy_file, __stdin_used);
+weak_alias(dummy_file, __stdout_used);
+weak_alias(dummy_file, __stderr_used);
+
+static void close_file(FILE *f)
+{
+	if (!f) return;
+	FFINALLOCK(f);
+	if (f->wpos > f->wbase) f->write(f, 0, 0);
+	if (f->rpos < f->rend) f->seek(f, f->rpos-f->rend, SEEK_CUR);
+}
+
+void __stdio_exit(void)
+{
+	FILE *f;
+	for (f=*__ofl_lock(); f; f=f->next) close_file(f);
+	close_file(__stdin_used);
+	close_file(__stdout_used);
+}
+
+weak_alias(__stdio_exit, __stdio_exit_needed);

contracts/musl/src/stdio/__stdio_read.c

+#include "stdio_impl.h"
+//include <sys/uio.h>
+
+size_t __stdio_read(FILE *f, unsigned char *buf, size_t len)
+{
+   /*
+	struct iovec iov[2] = {
+		{ .iov_base = buf, .iov_len = len - !!f->buf_size },
+		{ .iov_base = f->buf, .iov_len = f->buf_size }
+	};
+	ssize_t cnt;
+
+	cnt = syscall(SYS_readv, f->fd, iov, 2);
+	if (cnt <= 0) {
+		f->flags |= F_EOF ^ ((F_ERR^F_EOF) & cnt);
+		return cnt;
+	}
+	if (cnt <= iov[0].iov_len) return cnt;
+	cnt -= iov[0].iov_len;
+	f->rpos = f->buf;
+	f->rend = f->buf + cnt;
+	if (f->buf_size) buf[len-1] = *f->rpos++;
+	return len;
+   */
+}

contracts/musl/src/stdio/__stdio_seek.c

+#include "stdio_impl.h"
+
+off_t __stdio_seek(FILE *f, off_t off, int whence)
+{
+   abort();
+        /*
+	off_t ret;
+#ifdef SYS__llseek
+	if (syscall(SYS__llseek, f->fd, off>>32, off, &ret, whence)<0)
+		ret = -1;
+#else
+	ret = syscall(SYS_lseek, f->fd, off, whence);
+#endif
+	return ret;
+        */
+}

contracts/musl/src/stdio/__stdio_write.c

+#include "stdio_impl.h"
+//include <sys/uio.h>
+
+size_t __stdio_write(FILE *f, const unsigned char *buf, size_t len)
+{
+   /*
+	struct iovec iovs[2] = {
+		{ .iov_base = f->wbase, .iov_len = f->wpos-f->wbase },
+		{ .iov_base = (void *)buf, .iov_len = len }
+	};
+	struct iovec *iov = iovs;
+	size_t rem = iov[0].iov_len + iov[1].iov_len;
+	int iovcnt = 2;
+	ssize_t cnt;
+	for (;;) {
+		cnt = syscall(SYS_writev, f->fd, iov, iovcnt);
+		if (cnt == rem) {
+			f->wend = f->buf + f->buf_size;
+			f->wpos = f->wbase = f->buf;
+			return len;
+		}
+		if (cnt < 0) {
+			f->wpos = f->wbase = f->wend = 0;
+			f->flags |= F_ERR;
+			return iovcnt == 2 ? 0 : len-iov[0].iov_len;
+		}
+		rem -= cnt;
+		if (cnt > iov[0].iov_len) {
+			cnt -= iov[0].iov_len;
+			iov++; iovcnt--;
+		}
+		iov[0].iov_base = (char *)iov[0].iov_base + cnt;
+		iov[0].iov_len -= cnt;
+	}
+   */
+}

contracts/musl/src/stdio/__stdout_write.c

+#include "stdio_impl.h"
+//include <sys/ioctl.h>
+
+size_t __stdout_write(FILE *f, const unsigned char *buf, size_t len)
+{
+   /*
+	struct winsize wsz;
+	f->write = __stdio_write;
+	if (!(f->flags & F_SVB) && __syscall(SYS_ioctl, f->fd, TIOCGWINSZ, &wsz))
+		f->lbf = -1;
+	return __stdio_write(f, buf, len);
+   */
+}

contracts/musl/src/stdio/__string_read.c

+#include "stdio_impl.h"
+#include <string.h>
+
+size_t __string_read(FILE *f, unsigned char *buf, size_t len)
+{
+	char *src = f->cookie;
+	size_t k = len+256;
+	char *end = memchr(src, 0, k);
+	if (end) k = end-src;
+	if (k < len) len = k;
+	memcpy(buf, src, len);
+	f->rpos = (void *)(src+len);
+	f->rend = (void *)(src+k);
+	f->cookie = src+k;
+	return len;
+}

contracts/musl/src/stdio/__toread.c

+#include <stdio_impl.h>
+
+int __toread(FILE *f)
+{
+	f->mode |= f->mode-1;
+	if (f->wpos > f->wbase) f->write(f, 0, 0);
+	f->wpos = f->wbase = f->wend = 0;
+	if (f->flags & F_NORD) {
+		f->flags |= F_ERR;
+		return EOF;
+	}
+	f->rpos = f->rend = f->buf + f->buf_size;
+	return (f->flags & F_EOF) ? EOF : 0;
+}
+
+void __stdio_exit_needed(void);
+
+void __toread_needs_stdio_exit()
+{
+	__stdio_exit_needed();
+}

contracts/musl/src/stdio/__towrite.c

+#include "stdio_impl.h"
+
+int __towrite(FILE *f)
+{
+	f->mode |= f->mode-1;
+	if (f->flags & (F_NOWR)) {
+		f->flags |= F_ERR;
+		return EOF;
+	}
+	/* Clear read buffer (easier than summoning nasal demons) */
+	f->rpos = f->rend = 0;
+
+	/* Activate write through the buffer. */
+	f->wpos = f->wbase = f->buf;
+	f->wend = f->buf + f->buf_size;
+
+	return 0;
+}
+
+void __stdio_exit_needed(void);
+
+void __towrite_needs_stdio_exit()
+{
+	__stdio_exit_needed();
+}

contracts/musl/src/stdio/__uflow.c

+#include "stdio_impl.h"
+
+/* This function assumes it will never be called if there is already
+ * data buffered for reading. */
+
+int __uflow(FILE *f)
+{
+	unsigned char c;
+	if (!__toread(f) && f->read(f, &c, 1)==1) return c;
+	return EOF;
+}

contracts/musl/src/stdio/asprintf.c

+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdarg.h>
+
+int asprintf(char **s, const char *fmt, ...)
+{
+	int ret;
+	va_list ap;
+	va_start(ap, fmt);
+	ret = vasprintf(s, fmt, ap);
+	va_end(ap);
+	return ret;
+}

contracts/musl/src/stdio/clearerr.c

+#include "stdio_impl.h"
+
+void clearerr(FILE *f)
+{
+	FLOCK(f);
+	f->flags &= ~(F_EOF|F_ERR);
+	FUNLOCK(f);
+}
+
+weak_alias(clearerr, clearerr_unlocked);

contracts/musl/src/stdio/dprintf.c

+#include <stdio.h>
+#include <stdarg.h>
+
+int dprintf(int fd, const char *restrict fmt, ...)
+{
+	int ret;
+	va_list ap;
+	va_start(ap, fmt);
+	ret = vdprintf(fd, fmt, ap);
+	va_end(ap);
+	return ret;
+}

contracts/musl/src/stdio/ext.c

+#define _GNU_SOURCE
+#include "stdio_impl.h"
+#include <stdio_ext.h>
+
+void _flushlbf(void)
+{
+	fflush(0);
+}
+
+int __fsetlocking(FILE *f, int type)
+{
+	return 0;
+}
+
+int __fwriting(FILE *f)
+{
+	return (f->flags & F_NORD) || f->wend;
+}
+
+int __freading(FILE *f)
+{
+	return (f->flags & F_NOWR) || f->rend;
+}
+
+int __freadable(FILE *f)
+{
+	return !(f->flags & F_NORD);
+}
+
+int __fwritable(FILE *f)
+{
+	return !(f->flags & F_NOWR);
+}
+
+int __flbf(FILE *f)
+{
+	return f->lbf >= 0;
+}
+
+size_t __fbufsize(FILE *f)
+{
+	return f->buf_size;
+}
+
+size_t __fpending(FILE *f)
+{
+	return f->wend ? f->wpos - f->wbase : 0;
+}
+
+int __fpurge(FILE *f)
+{
+	f->wpos = f->wbase = f->wend = 0;
+	f->rpos = f->rend = 0;
+	return 0;
+}
+
+weak_alias(__fpurge, fpurge);

contracts/musl/src/stdio/ext2.c

+#include "stdio_impl.h"
+
+size_t __freadahead(FILE *f)
+{
+	return f->rend - f->rpos;
+}
+
+const char *__freadptr(FILE *f, size_t *sizep)
+{
+	size_t size = f->rend - f->rpos;
+	if (!size) return 0;
+	*sizep = size;
+	return (const char *)f->rpos;
+}
+
+void __freadptrinc(FILE *f, size_t inc)
+{
+	f->rpos += inc;
+}
+
+void __fseterr(FILE *f)
+{
+	f->flags |= F_ERR;
+}

contracts/musl/src/stdio/fclose.c

+#include "stdio_impl.h"
+#include "libc.h"
+
+static void dummy(FILE *f) { }
+weak_alias(dummy, __unlist_locked_file);
+
+int fclose(FILE *f)
+{
+	int r;
+	int perm;
+	
+	FLOCK(f);
+
+	__unlist_locked_file(f);
+
+	if (!(perm = f->flags & F_PERM)) {
+		FILE **head = __ofl_lock();
+		if (f->prev) f->prev->next = f->next;
+		if (f->next) f->next->prev = f->prev;
+		if (*head == f) *head = f->next;
+		__ofl_unlock();
+	}
+
+	r = fflush(f);
+	r |= f->close(f);
+
+	if (f->getln_buf) free(f->getln_buf);
+	if (!perm) free(f);
+	else FUNLOCK(f);
+
+	return r;
+}

contracts/musl/src/stdio/feof.c

+#include "stdio_impl.h"
+
+#undef feof
+
+int feof(FILE *f)
+{
+	FLOCK(f);
+	int ret = !!(f->flags & F_EOF);
+	FUNLOCK(f);
+	return ret;
+}
+
+weak_alias(feof, feof_unlocked);
+weak_alias(feof, _IO_feof_unlocked);

contracts/musl/src/stdio/ferror.c

+#include "stdio_impl.h"
+
+#undef ferror
+
+int ferror(FILE *f)
+{
+	FLOCK(f);
+	int ret = !!(f->flags & F_ERR);
+	FUNLOCK(f);
+	return ret;
+}
+
+weak_alias(ferror, ferror_unlocked);
+weak_alias(ferror, _IO_ferror_unlocked);

contracts/musl/src/stdio/fflush.c

+#include "stdio_impl.h"
+
+/* stdout.c will override this if linked */
+static FILE *volatile dummy = 0;
+weak_alias(dummy, __stdout_used);
+
+int fflush(FILE *f)
+{
+	if (!f) {
+		int r = __stdout_used ? fflush(__stdout_used) : 0;
+
+		for (f=*__ofl_lock(); f; f=f->next) {
+			FLOCK(f);
+			if (f->wpos > f->wbase) r |= fflush(f);
+			FUNLOCK(f);
+		}
+		__ofl_unlock();
+
+		return r;
+	}
+
+	FLOCK(f);
+
+	/* If writing, flush output */
+	if (f->wpos > f->wbase) {
+		f->write(f, 0, 0);
+		if (!f->wpos) {
+			FUNLOCK(f);
+			return EOF;
+		}
+	}
+
+	/* If reading, sync position, per POSIX */
+	if (f->rpos < f->rend) f->seek(f, f->rpos-f->rend, SEEK_CUR);
+
+	/* Clear read and write modes */
+	f->wpos = f->wbase = f->wend = 0;
+	f->rpos = f->rend = 0;
+
+	FUNLOCK(f);
+	return 0;
+}
+
+weak_alias(fflush, fflush_unlocked);

contracts/musl/src/stdio/fgetc.c

+#include "stdio_impl.h"
+
+int fgetc(FILE *f)
+{
+	int c;
+	if (f->lock < 0 || !__lockfile(f))
+		return getc_unlocked(f);
+	c = getc_unlocked(f);
+	__unlockfile(f);
+	return c;
+}

contracts/musl/src/stdio/fgetln.c

+#define _GNU_SOURCE
+#include "stdio_impl.h"
+#include <string.h>
+
+char *fgetln(FILE *f, size_t *plen)
+{
+	char *ret = 0, *z;
+	ssize_t l;
+	FLOCK(f);
+	ungetc(getc_unlocked(f), f);
+	if ((z=memchr(f->rpos, '\n', f->rend - f->rpos))) {
+		ret = (char *)f->rpos;
+		*plen = ++z - ret;
+		f->rpos = (void *)z;
+	} else if ((l = getline(&f->getln_buf, (size_t[]){0}, f)) > 0) {
+		*plen = l;
+		ret = f->getln_buf;
+	}
+	FUNLOCK(f);
+	return ret;
+}

contracts/musl/src/stdio/fgetpos.c

+#include "stdio_impl.h"
+
+int fgetpos(FILE *restrict f, fpos_t *restrict pos)
+{
+	off_t off = __ftello(f);
+	if (off < 0) return -1;
+	*(off_t *)pos = off;
+	return 0;
+}
+
+LFS64(fgetpos);

contracts/musl/src/stdio/fgets.c

+#include "stdio_impl.h"
+#include <string.h>
+
+#define MIN(a,b) ((a)<(b) ? (a) : (b))
+
+char *fgets(char *restrict s, int n, FILE *restrict f)
+{
+	char *p = s;
+	unsigned char *z;
+	size_t k;
+	int c;
+
+	FLOCK(f);
+
+	if (n--<=1) {
+		f->mode |= f->mode-1;
+		FUNLOCK(f);
+		if (n) return 0;
+		*s = 0;
+		return s;
+	}
+
+	while (n) {
+		z = memchr(f->rpos, '\n', f->rend - f->rpos);
+		k = z ? z - f->rpos + 1 : f->rend - f->rpos;
+		k = MIN(k, n);
+		memcpy(p, f->rpos, k);
+		f->rpos += k;
+		p += k;
+		n -= k;
+		if (z || !n) break;
+		if ((c = getc_unlocked(f)) < 0) {
+			if (p==s || !feof(f)) s = 0;
+			break;
+		}
+		n--;
+		if ((*p++ = c) == '\n') break;
+	}
+	if (s) *p = 0;
+
+	FUNLOCK(f);
+
+	return s;
+}
+
+weak_alias(fgets, fgets_unlocked);

contracts/musl/src/stdio/fgetwc.c

+#include "stdio_impl.h"
+#include "locale_impl.h"
+#include <wchar.h>
+#include <errno.h>
+
+static wint_t __fgetwc_unlocked_internal(FILE *f)
+{
+	wchar_t wc;
+	int c;
+	size_t l;
+
+	/* Convert character from buffer if possible */
+	if (f->rpos < f->rend) {
+		l = mbtowc(&wc, (void *)f->rpos, f->rend - f->rpos);
+		if (l+1 >= 1) {
+			f->rpos += l + !l; /* l==0 means 1 byte, null */
+			return wc;
+		}
+	}
+
+	/* Convert character byte-by-byte */
+	mbstate_t st = { 0 };
+	unsigned char b;
+	int first = 1;
+	do {
+		b = c = getc_unlocked(f);
+		if (c < 0) {
+			if (!first) errno = EILSEQ;
+			return WEOF;
+		}
+		l = mbrtowc(&wc, (void *)&b, 1, &st);
+		if (l == -1) {
+			if (!first) ungetc(b, f);
+			return WEOF;
+		}
+		first = 0;
+	} while (l == -2);
+
+	return wc;
+}
+
+wint_t __fgetwc_unlocked(FILE *f)
+{
+	locale_t *ploc = &CURRENT_LOCALE, loc = *ploc;
+	if (f->mode <= 0) fwide(f, 1);
+	*ploc = f->locale;
+	wchar_t wc = __fgetwc_unlocked_internal(f);
+	*ploc = loc;
+	return wc;
+}
+
+wint_t fgetwc(FILE *f)
+{
+	wint_t c;
+	FLOCK(f);
+	c = __fgetwc_unlocked(f);
+	FUNLOCK(f);
+	return c;
+}
+
+weak_alias(__fgetwc_unlocked, fgetwc_unlocked);
+weak_alias(__fgetwc_unlocked, getwc_unlocked);

contracts/musl/src/stdio/fgetws.c

+#include "stdio_impl.h"
+#include <wchar.h>
+#include <errno.h>
+
+wint_t __fgetwc_unlocked(FILE *);
+
+wchar_t *fgetws(wchar_t *restrict s, int n, FILE *restrict f)
+{
+	wchar_t *p = s;
+
+	if (!n--) return s;
+
+	FLOCK(f);
+
+	/* Setup a dummy errno so we can detect EILSEQ. This is
+	 * the only way to catch encoding errors in the form of a
+	 * partial character just before EOF. */
+	errno = EAGAIN;
+	for (; n; n--) {
+		wint_t c = __fgetwc_unlocked(f);
+		if (c == WEOF) break;
+		*p++ = c;
+		if (c == '\n') break;
+	}
+	*p = 0;
+	if (ferror(f) || errno==EILSEQ) p = s;
+
+	FUNLOCK(f);
+
+	return (p == s) ? NULL : s;
+}
+
+weak_alias(fgetws, fgetws_unlocked);

contracts/musl/src/stdio/fileno.c

+#include "stdio_impl.h"
+
+int fileno(FILE *f)
+{
+	/* f->fd never changes, but the lock must be obtained and released
+	 * anyway since this function cannot return while another thread
+	 * holds the lock. */
+	FLOCK(f);
+	FUNLOCK(f);
+	return f->fd;
+}
+
+weak_alias(fileno, fileno_unlocked);

contracts/musl/src/stdio/fmemopen.c

+#include "stdio_impl.h"
+#include <errno.h>
+#include <string.h>
+#include <inttypes.h>
+
+struct cookie {
+	size_t pos, len, size;
+	unsigned char *buf;
+	int mode;
+};
+
+static off_t mseek(FILE *f, off_t off, int whence)
+{
+	ssize_t base;
+	struct cookie *c = f->cookie;
+	if (whence>2U) {
+fail:
+		errno = EINVAL;
+		return -1;
+	}
+	base = (size_t [3]){0, c->pos, c->len}[whence];
+	if (off < -base || off > (ssize_t)c->size-base) goto fail;
+	return c->pos = base+off;
+}
+
+static size_t mread(FILE *f, unsigned char *buf, size_t len)
+{
+	struct cookie *c = f->cookie;
+	size_t rem = c->len - c->pos;
+	if (c->pos > c->len) rem = 0;
+	if (len > rem) {
+		len = rem;
+		f->flags |= F_EOF;
+	}
+	memcpy(buf, c->buf+c->pos, len);
+	c->pos += len;
+	rem -= len;
+	if (rem > f->buf_size) rem = f->buf_size;
+	f->rpos = f->buf;
+	f->rend = f->buf + rem;
+	memcpy(f->rpos, c->buf+c->pos, rem);
+	c->pos += rem;
+	return len;
+}
+
+static size_t mwrite(FILE *f, const unsigned char *buf, size_t len)
+{
+	struct cookie *c = f->cookie;
+	size_t rem;
+	size_t len2 = f->wpos - f->wbase;
+	if (len2) {
+		f->wpos = f->wbase;
+		if (mwrite(f, f->wpos, len2) < len2) return 0;
+	}
+	if (c->mode == 'a') c->pos = c->len;
+	rem = c->size - c->pos;
+	if (len > rem) len = rem;
+	memcpy(c->buf+c->pos, buf, len);
+	c->pos += len;
+	if (c->pos > c->len) {
+		c->len = c->pos;
+		if (c->len < c->size) c->buf[c->len] = 0;
+		else if ((f->flags&F_NORD) && c->size) c->buf[c->size-1] = 0;
+	}
+	return len;
+}
+
+static int mclose(FILE *m)
+{
+	return 0;
+}
+
+FILE *fmemopen(void *restrict buf, size_t size, const char *restrict mode)
+{
+	FILE *f;
+	struct cookie *c;
+	int plus = !!strchr(mode, '+');
+	
+	if (!size || !strchr("rwa", *mode)) {
+		errno = EINVAL;
+		return 0;
+	}
+
+	if (!buf && size > SIZE_MAX-sizeof(FILE)-BUFSIZ-UNGET) {
+		errno = ENOMEM;
+		return 0;
+	}
+
+	f = calloc(sizeof *f + sizeof *c + UNGET + BUFSIZ + (buf?0:size), 1);
+	if (!f) return 0;
+	f->cookie = c = (void *)(f+1);
+	f->fd = -1;
+	f->lbf = EOF;
+	f->buf = (unsigned char *)(c+1) + UNGET;
+	f->buf_size = BUFSIZ;
+	if (!buf) buf = f->buf + BUFSIZ;
+
+	c->buf = buf;
+	c->size = size;
+	c->mode = *mode;
+	
+	if (!plus) f->flags = (*mode == 'r') ? F_NOWR : F_NORD;
+	if (*mode == 'r') c->len = size;
+	else if (*mode == 'a') c->len = c->pos = strnlen(buf, size);
+
+	f->read = mread;
+	f->write = mwrite;
+	f->seek = mseek;
+	f->close = mclose;
+
+	if (!libc.threaded) f->lock = -1;
+
+	return __ofl_add(f);
+}

contracts/musl/src/stdio/fopencookie.c

+#define _GNU_SOURCE
+#include "stdio_impl.h"
+#include <stdlib.h>
+//include <sys/ioctl.h>
+//include <fcntl.h>
+#include <errno.h>
+#include <string.h>
+
+struct fcookie {
+	void *cookie;
+	cookie_io_functions_t iofuncs;
+};
+
+struct cookie_FILE {
+	FILE f;
+	struct fcookie fc;
+	unsigned char buf[UNGET+BUFSIZ];
+};
+
+static size_t cookieread(FILE *f, unsigned char *buf, size_t len)
+{
+	struct fcookie *fc = f->cookie;
+	ssize_t ret = -1;
+	size_t remain = len, readlen = 0;
+	size_t len2 = len - !!f->buf_size;
+
+	if (!fc->iofuncs.read) goto bail;
+
+	if (len2) {
+		ret = fc->iofuncs.read(fc->cookie, (char *) buf, len2);
+		if (ret <= 0) goto bail;
+
+		readlen += ret;
+		remain -= ret;
+	}
+
+	if (!f->buf_size || remain > !!f->buf_size) return readlen;
+
+	f->rpos = f->buf;
+	ret = fc->iofuncs.read(fc->cookie, (char *) f->rpos, f->buf_size);
+	if (ret <= 0) goto bail;
+	f->rend = f->rpos + ret;
+
+	buf[readlen++] = *f->rpos++;
+
+	return readlen;
+
+bail:
+	f->flags |= ret == 0 ? F_EOF : F_ERR;
+	f->rpos = f->rend = f->buf;
+	return readlen;
+}
+
+static size_t cookiewrite(FILE *f, const unsigned char *buf, size_t len)
+{
+	struct fcookie *fc = f->cookie;
+	ssize_t ret;
+	size_t len2 = f->wpos - f->wbase;
+	if (!fc->iofuncs.write) return len;
+	if (len2) {
+		f->wpos = f->wbase;
+		if (cookiewrite(f, f->wpos, len2) < len2) return 0;
+	}
+	ret = fc->iofuncs.write(fc->cookie, (const char *) buf, len);
+	if (ret < 0) {
+		f->wpos = f->wbase = f->wend = 0;
+		f->flags |= F_ERR;
+		return 0;
+	}
+	return ret;
+}
+
+static off_t cookieseek(FILE *f, off_t off, int whence)
+{
+	struct fcookie *fc = f->cookie;
+	int res;
+	if (whence > 2U) {
+		errno = EINVAL;
+		return -1;
+	}
+	if (!fc->iofuncs.seek) {
+		errno = ENOTSUP;
+		return -1;
+	}
+	res = fc->iofuncs.seek(fc->cookie, &off, whence);
+	if (res < 0)
+		return res;
+	return off;
+}
+
+static int cookieclose(FILE *f)
+{
+	struct fcookie *fc = f->cookie;
+	if (fc->iofuncs.close) return fc->iofuncs.close(fc->cookie);
+	return 0;
+}
+
+FILE *fopencookie(void *cookie, const char *mode, cookie_io_functions_t iofuncs)
+{
+	struct cookie_FILE *f;
+
+	/* Check for valid initial mode character */
+	if (!strchr("rwa", *mode)) {
+		errno = EINVAL;
+		return 0;
+	}
+
+	/* Allocate FILE+fcookie+buffer or fail */
+	if (!(f=malloc(sizeof *f))) return 0;
+
+	/* Zero-fill only the struct, not the buffer */
+	memset(&f->f, 0, sizeof f->f);
+
+	/* Impose mode restrictions */
+	if (!strchr(mode, '+')) f->f.flags = (*mode == 'r') ? F_NOWR : F_NORD;
+
+	/* Set up our fcookie */
+	f->fc.cookie = cookie;
+	f->fc.iofuncs.read = iofuncs.read;
+	f->fc.iofuncs.write = iofuncs.write;
+	f->fc.iofuncs.seek = iofuncs.seek;
+	f->fc.iofuncs.close = iofuncs.close;
+
+	f->f.fd = -1;
+	f->f.cookie = &f->fc;
+	f->f.buf = f->buf + UNGET;
+	f->f.buf_size = BUFSIZ;
+	f->f.lbf = EOF;
+
+	/* Initialize op ptrs. No problem if some are unneeded. */
+	f->f.read = cookieread;
+	f->f.write = cookiewrite;
+	f->f.seek = cookieseek;
+	f->f.close = cookieclose;
+
+	/* Add new FILE to open file list */
+	return __ofl_add(&f->f);
+}

contracts/musl/src/stdio/fprintf.c

+#include <stdio.h>
+#include <stdarg.h>
+
+int fprintf(FILE *restrict f, const char *restrict fmt, ...)
+{
+	int ret;
+	va_list ap;
+	va_start(ap, fmt);
+	ret = vfprintf(f, fmt, ap);
+	va_end(ap);
+	return ret;
+}

contracts/musl/src/stdio/fputc.c

+#include "stdio_impl.h"
+
+int fputc(int c, FILE *f)
+{
+	if (f->lock < 0 || !__lockfile(f))
+		return putc_unlocked(c, f);
+	c = putc_unlocked(c, f);
+	__unlockfile(f);
+	return c;
+}

contracts/musl/src/stdio/fputs.c

+#include "stdio_impl.h"
+#include <string.h>
+
+int fputs(const char *restrict s, FILE *restrict f)
+{
+	size_t l = strlen(s);
+	return (fwrite(s, 1, l, f)==l) - 1;
+}
+
+weak_alias(fputs, fputs_unlocked);

contracts/musl/src/stdio/fputwc.c

+#include "stdio_impl.h"
+#include "locale_impl.h"
+#include <wchar.h>
+#include <limits.h>
+#include <ctype.h>
+
+wint_t __fputwc_unlocked(wchar_t c, FILE *f)
+{
+	char mbc[MB_LEN_MAX];
+	int l;
+	locale_t *ploc = &CURRENT_LOCALE, loc = *ploc;
+
+	if (f->mode <= 0) fwide(f, 1);
+	*ploc = f->locale;
+
+	if (isascii(c)) {
+		c = putc_unlocked(c, f);
+	} else if (f->wpos + MB_LEN_MAX < f->wend) {
+		l = wctomb((void *)f->wpos, c);
+		if (l < 0) c = WEOF;
+		else f->wpos += l;
+	} else {
+		l = wctomb(mbc, c);
+		if (l < 0 || __fwritex((void *)mbc, l, f) < l) c = WEOF;
+	}
+	if (c==WEOF) f->flags |= F_ERR;
+	*ploc = loc;
+	return c;
+}
+
+wint_t fputwc(wchar_t c, FILE *f)
+{
+	FLOCK(f);
+	c = __fputwc_unlocked(c, f);
+	FUNLOCK(f);
+	return c;
+}
+
+weak_alias(__fputwc_unlocked, fputwc_unlocked);
+weak_alias(__fputwc_unlocked, putwc_unlocked);

contracts/musl/src/stdio/fputws.c

+#include "stdio_impl.h"
+#include "locale_impl.h"
+#include <wchar.h>
+
+int fputws(const wchar_t *restrict ws, FILE *restrict f)
+{
+	unsigned char buf[BUFSIZ];
+	size_t l=0;
+	locale_t *ploc = &CURRENT_LOCALE, loc = *ploc;
+
+	FLOCK(f);
+
+	fwide(f, 1);
+	*ploc = f->locale;
+
+	while (ws && (l = wcsrtombs((void *)buf, (void*)&ws, sizeof buf, 0))+1 > 1)
+		if (__fwritex(buf, l, f) < l) {
+			FUNLOCK(f);
+			*ploc = loc;
+			return -1;
+		}
+
+	FUNLOCK(f);
+
+	*ploc = loc;
+	return l; /* 0 or -1 */
+}
+
+weak_alias(fputws, fputws_unlocked);

contracts/musl/src/stdio/fread.c

+#include "stdio_impl.h"
+#include <string.h>
+
+#define MIN(a,b) ((a)<(b) ? (a) : (b))
+
+size_t fread(void *restrict destv, size_t size, size_t nmemb, FILE *restrict f)
+{
+	unsigned char *dest = destv;
+	size_t len = size*nmemb, l = len, k;
+	if (!size) nmemb = 0;
+
+	FLOCK(f);
+
+	f->mode |= f->mode-1;
+
+	if (f->rend - f->rpos > 0) {
+		/* First exhaust the buffer. */
+		k = MIN(f->rend - f->rpos, l);
+		memcpy(dest, f->rpos, k);
+		f->rpos += k;
+		dest += k;
+		l -= k;
+	}
+	
+	/* Read the remainder directly */
+	for (; l; l-=k, dest+=k) {
+		k = __toread(f) ? 0 : f->read(f, dest, l);
+		if (k+1<=1) {
+			FUNLOCK(f);
+			return (len-l)/size;
+		}
+	}
+
+	FUNLOCK(f);
+	return nmemb;
+}
+
+weak_alias(fread, fread_unlocked);

contracts/musl/src/stdio/fscanf.c

+#include <stdio.h>
+#include <stdarg.h>
+#include "libc.h"
+
+int fscanf(FILE *restrict f, const char *restrict fmt, ...)
+{
+	int ret;
+	va_list ap;
+	va_start(ap, fmt);
+	ret = vfscanf(f, fmt, ap);
+	va_end(ap);
+	return ret;
+}
+
+weak_alias(fscanf, __isoc99_fscanf);

contracts/musl/src/stdio/fseek.c

+#include "stdio_impl.h"
+
+int __fseeko_unlocked(FILE *f, off_t off, int whence)
+{
+	/* Adjust relative offset for unread data in buffer, if any. */
+	if (whence == SEEK_CUR) off -= f->rend - f->rpos;
+
+	/* Flush write buffer, and report error on failure. */
+	if (f->wpos > f->wbase) {
+		f->write(f, 0, 0);
+		if (!f->wpos) return -1;
+	}
+
+	/* Leave writing mode */
+	f->wpos = f->wbase = f->wend = 0;
+
+	/* Perform the underlying seek. */
+	if (f->seek(f, off, whence) < 0) return -1;
+
+	/* If seek succeeded, file is seekable and we discard read buffer. */
+	f->rpos = f->rend = 0;
+	f->flags &= ~F_EOF;
+	
+	return 0;
+}
+
+int __fseeko(FILE *f, off_t off, int whence)
+{
+	int result;
+	FLOCK(f);
+	result = __fseeko_unlocked(f, off, whence);
+	FUNLOCK(f);
+	return result;
+}
+
+int fseek(FILE *f, long off, int whence)
+{
+	return __fseeko(f, off, whence);
+}
+
+weak_alias(__fseeko, fseeko);
+
+LFS64(fseeko);

contracts/musl/src/stdio/fsetpos.c

+#include "stdio_impl.h"
+
+int fsetpos(FILE *f, const fpos_t *pos)
+{
+	return __fseeko(f, *(const off_t *)pos, SEEK_SET);
+}
+
+LFS64(fsetpos);

contracts/musl/src/stdio/ftell.c

+#include "stdio_impl.h"
+#include <limits.h>
+#include <errno.h>
+
+off_t __ftello_unlocked(FILE *f)
+{
+	off_t pos = f->seek(f, 0,
+		(f->flags & F_APP) && f->wpos > f->wbase
+		? SEEK_END : SEEK_CUR);
+	if (pos < 0) return pos;
+
+	/* Adjust for data in buffer. */
+	return pos - (f->rend - f->rpos) + (f->wpos - f->wbase);
+}
+
+off_t __ftello(FILE *f)
+{
+	off_t pos;
+	FLOCK(f);
+	pos = __ftello_unlocked(f);
+	FUNLOCK(f);
+	return pos;
+}
+
+long ftell(FILE *f)
+{
+	off_t pos = __ftello(f);
+	if (pos > LONG_MAX) {
+		errno = EOVERFLOW;
+		return -1;
+	}
+	return pos;
+}
+
+weak_alias(__ftello, ftello);
+
+LFS64(ftello);

contracts/musl/src/stdio/funlockfile.c

+#include "stdio_impl.h"
+#include "pthread_impl.h"
+
+void __unlist_locked_file(FILE *);
+
+void funlockfile(FILE *f)
+{
+	if (f->lockcount == 1) {
+		__unlist_locked_file(f);
+		f->lockcount = 0;
+		__unlockfile(f);
+	} else {
+		f->lockcount--;
+	}
+}

contracts/musl/src/stdio/fwide.c

+#include "stdio_impl.h"
+#include "locale_impl.h"
+
+int fwide(FILE *f, int mode)
+{
+	FLOCK(f);
+	if (mode) {
+		if (!f->locale) f->locale = MB_CUR_MAX==1
+			? C_LOCALE : UTF8_LOCALE;
+		if (!f->mode) f->mode = mode>0 ? 1 : -1;
+	}
+	mode = f->mode;
+	FUNLOCK(f);
+	return mode;
+}

contracts/musl/src/stdio/fwprintf.c

+#include <stdio.h>
+#include <stdarg.h>
+#include <wchar.h>
+
+int fwprintf(FILE *restrict f, const wchar_t *restrict fmt, ...)
+{
+	int ret;
+	va_list ap;
+	va_start(ap, fmt);
+	ret = vfwprintf(f, fmt, ap);
+	va_end(ap);
+	return ret;
+}

contracts/musl/src/stdio/fwrite.c

+#include "stdio_impl.h"
+#include <string.h>
+
+size_t __fwritex(const unsigned char *restrict s, size_t l, FILE *restrict f)
+{
+	size_t i=0;
+
+	if (!f->wend && __towrite(f)) return 0;
+
+	if (l > f->wend - f->wpos) return f->write(f, s, l);
+
+	if (f->lbf >= 0) {
+		/* Match /^(.*\n|)/ */
+		for (i=l; i && s[i-1] != '\n'; i--);
+		if (i) {
+			size_t n = f->write(f, s, i);
+			if (n < i) return n;
+			s += i;
+			l -= i;
+		}
+	}
+
+	memcpy(f->wpos, s, l);
+	f->wpos += l;
+	return l+i;
+}
+
+size_t fwrite(const void *restrict src, size_t size, size_t nmemb, FILE *restrict f)
+{
+	size_t k, l = size*nmemb;
+	if (!size) nmemb = 0;
+	FLOCK(f);
+	k = __fwritex(src, l, f);
+	FUNLOCK(f);
+	return k==l ? nmemb : k/size;
+}
+
+weak_alias(fwrite, fwrite_unlocked);

contracts/musl/src/stdio/fwscanf.c

+#include <stdio.h>
+#include <stdarg.h>
+#include <wchar.h>
+#include "libc.h"
+
+int fwscanf(FILE *restrict f, const wchar_t *restrict fmt, ...)
+{
+	int ret;
+	va_list ap;
+	va_start(ap, fmt);
+	ret = vfwscanf(f, fmt, ap);
+	va_end(ap);
+	return ret;
+}
+
+weak_alias(fwscanf,__isoc99_fwscanf);

contracts/musl/src/stdio/getc.c

+#include "stdio_impl.h"
+
+int getc(FILE *f)
+{
+	int c;
+	if (f->lock < 0 || !__lockfile(f))
+		return getc_unlocked(f);
+	c = getc_unlocked(f);
+	__unlockfile(f);
+	return c;
+}
+
+weak_alias(getc, _IO_getc);

contracts/musl/src/stdio/getc_unlocked.c

+#include "stdio_impl.h"
+
+int (getc_unlocked)(FILE *f)
+{
+	return getc_unlocked(f);
+}
+
+weak_alias (getc_unlocked, fgetc_unlocked);
+weak_alias (getc_unlocked, _IO_getc_unlocked);

contracts/musl/src/stdio/getchar.c

+#include <stdio.h>
+
+int getchar(void)
+{
+	return fgetc(stdin);
+}

contracts/musl/src/stdio/getchar_unlocked.c

+#include "stdio_impl.h"
+
+int getchar_unlocked(void)
+{
+	return getc_unlocked(stdin);
+}

contracts/musl/src/stdio/getdelim.c

+#include "stdio_impl.h"
+#include <string.h>
+#include <inttypes.h>
+#include <errno.h>
+
+#define MIN(a,b) ((a)<(b) ? (a) : (b))
+
+ssize_t getdelim(char **restrict s, size_t *restrict n, int delim, FILE *restrict f)
+{
+	char *tmp;
+	unsigned char *z;
+	size_t k;
+	size_t i=0;
+	int c;
+
+	FLOCK(f);
+
+	if (!n || !s) {
+		f->flags |= F_ERR;
+		FUNLOCK(f);
+		errno = EINVAL;
+		return -1;
+	}
+
+	if (!*s) *n=0;
+
+	for (;;) {
+		z = memchr(f->rpos, delim, f->rend - f->rpos);
+		k = z ? z - f->rpos + 1 : f->rend - f->rpos;
+		if (i+k+1 >= *n) {
+			if (k >= SIZE_MAX/2-i) goto oom;
+			size_t m = i+k+2;
+			if (!z && m < SIZE_MAX/4) m += m/2;
+			tmp = realloc(*s, m);
+			if (!tmp) {
+				m = i+k+2;
+				tmp = realloc(*s, m);
+				if (!tmp) goto oom;
+			}
+			*s = tmp;
+			*n = m;
+		}
+		memcpy(*s+i, f->rpos, k);
+		f->rpos += k;
+		i += k;
+		if (z) break;
+		if ((c = getc_unlocked(f)) == EOF) {
+			if (!i || !feof(f)) {
+				FUNLOCK(f);
+				return -1;
+			}
+			break;
+		}
+		if (((*s)[i++] = c) == delim) break;
+	}
+	(*s)[i] = 0;
+
+	FUNLOCK(f);
+
+	return i;
+oom:
+	f->flags |= F_ERR;
+	FUNLOCK(f);
+	errno = ENOMEM;
+	return -1;
+}
+
+weak_alias(getdelim, __getdelim);

contracts/musl/src/stdio/getline.c

+#include <stdio.h>
+
+ssize_t getline(char **restrict s, size_t *restrict n, FILE *restrict f)
+{
+	return getdelim(s, n, '\n', f);
+}

contracts/musl/src/stdio/gets.c

+#include "stdio_impl.h"
+#include <limits.h>
+#include <string.h>
+
+char *gets(char *s)
+{
+	char *ret = fgets(s, INT_MAX, stdin);
+	if (ret && s[strlen(s)-1] == '\n') s[strlen(s)-1] = 0;
+	return ret;
+}

contracts/musl/src/stdio/getw.c

+#define _GNU_SOURCE
+#include <stdio.h>
+
+int getw(FILE *f)
+{
+	int x;
+	return fread(&x, sizeof x, 1, f) ? x : EOF;
+}

contracts/musl/src/stdio/getwc.c

+#include "stdio_impl.h"
+#include <wchar.h>
+
+wint_t getwc(FILE *f)
+{
+	return fgetwc(f);
+}

contracts/musl/src/stdio/getwchar.c

+#include "stdio_impl.h"
+#include <wchar.h>
+
+wint_t getwchar(void)
+{
+	return fgetwc(stdin);
+}
+
+weak_alias(getwchar, getwchar_unlocked);

contracts/musl/src/stdio/ofl.c

+#include "stdio_impl.h"
+#include "libc.h"
+
+static FILE *ofl_head;
+static volatile int ofl_lock[2];
+
+FILE **__ofl_lock()
+{
+	LOCK(ofl_lock);
+	return &ofl_head;
+}
+
+void __ofl_unlock()
+{
+	UNLOCK(ofl_lock);
+}

contracts/musl/src/stdio/ofl_add.c

+#include "stdio_impl.h"
+
+FILE *__ofl_add(FILE *f)
+{
+	FILE **head = __ofl_lock();
+	f->next = *head;
+	if (*head) (*head)->prev = f;
+	*head = f;
+	__ofl_unlock();
+	return f;
+}

contracts/musl/src/stdio/open_memstream.c

+#include "stdio_impl.h"
+#include <errno.h>
+#include <limits.h>
+#include <string.h>
+
+struct cookie {
+	char **bufp;
+	size_t *sizep;
+	size_t pos;
+	char *buf;
+	size_t len;
+	size_t space;
+};
+
+static off_t ms_seek(FILE *f, off_t off, int whence)
+{
+	ssize_t base;
+	struct cookie *c = f->cookie;
+	if (whence>2U) {
+fail:
+		errno = EINVAL;
+		return -1;
+	}
+	base = (size_t [3]){0, c->pos, c->len}[whence];
+	if (off < -base || off > SSIZE_MAX-base) goto fail;
+	return c->pos = base+off;
+}
+
+static size_t ms_write(FILE *f, const unsigned char *buf, size_t len)
+{
+	struct cookie *c = f->cookie;
+	size_t len2 = f->wpos - f->wbase;
+	char *newbuf;
+	if (len2) {
+		f->wpos = f->wbase;
+		if (ms_write(f, f->wbase, len2) < len2) return 0;
+	}
+	if (len + c->pos >= c->space) {
+		len2 = 2*c->space+1 | c->pos+len+1;
+		newbuf = realloc(c->buf, len2);
+		if (!newbuf) return 0;
+		*c->bufp = c->buf = newbuf;
+		memset(c->buf + c->space, 0, len2 - c->space);
+		c->space = len2;
+	}
+	memcpy(c->buf+c->pos, buf, len);
+	c->pos += len;
+	if (c->pos >= c->len) c->len = c->pos;
+	*c->sizep = c->pos;
+	return len;
+}
+
+static int ms_close(FILE *f)
+{
+	return 0;
+}
+
+FILE *open_memstream(char **bufp, size_t *sizep)
+{
+	FILE *f;
+	struct cookie *c;
+	char *buf;
+
+	if (!(f=malloc(sizeof *f + sizeof *c + BUFSIZ))) return 0;
+	if (!(buf=malloc(sizeof *buf))) {
+		free(f);
+		return 0;
+	}
+	memset(f, 0, sizeof *f + sizeof *c);
+	f->cookie = c = (void *)(f+1);
+
+	c->bufp = bufp;
+	c->sizep = sizep;
+	c->pos = c->len = c->space = *sizep = 0;
+	c->buf = *bufp = buf;
+	*buf = 0;
+
+	f->flags = F_NORD;
+	f->fd = -1;
+	f->buf = (void *)(c+1);
+	f->buf_size = BUFSIZ;
+	f->lbf = EOF;
+	f->write = ms_write;
+	f->seek = ms_seek;
+	f->close = ms_close;
+
+	if (!libc.threaded) f->lock = -1;
+
+	return __ofl_add(f);
+}

contracts/musl/src/stdio/open_wmemstream.c

+#include "stdio_impl.h"
+#include <wchar.h>
+#include <errno.h>
+#include <limits.h>
+#include <string.h>
+
+struct cookie {
+	wchar_t **bufp;
+	size_t *sizep;
+	size_t pos;
+	wchar_t *buf;
+	size_t len;
+	size_t space;
+	mbstate_t mbs;
+};
+
+static off_t wms_seek(FILE *f, off_t off, int whence)
+{
+	ssize_t base;
+	struct cookie *c = f->cookie;
+	if (whence>2U) {
+fail:
+		errno = EINVAL;
+		return -1;
+	}
+	base = (size_t [3]){0, c->pos, c->len}[whence];
+	if (off < -base || off > SSIZE_MAX/4-base) goto fail;
+	memset(&c->mbs, 0, sizeof c->mbs);
+	return c->pos = base+off;
+}
+
+static size_t wms_write(FILE *f, const unsigned char *buf, size_t len)
+{
+	struct cookie *c = f->cookie;
+	size_t len2;
+	wchar_t *newbuf;
+	if (len + c->pos >= c->space) {
+		len2 = 2*c->space+1 | c->pos+len+1;
+		if (len2 > SSIZE_MAX/4) return 0;
+		newbuf = realloc(c->buf, len2*4);
+		if (!newbuf) return 0;
+		*c->bufp = c->buf = newbuf;
+		memset(c->buf + c->space, 0, 4*(len2 - c->space));
+		c->space = len2;
+	}
+	
+	len2 = mbsnrtowcs(c->buf+c->pos, (void *)&buf, len, c->space-c->pos, &c->mbs);
+	if (len2 == -1) return 0;
+	c->pos += len2;
+	if (c->pos >= c->len) c->len = c->pos;
+	*c->sizep = c->pos;
+	return len;
+}
+
+static int wms_close(FILE *f)
+{
+	return 0;
+}
+
+FILE *open_wmemstream(wchar_t **bufp, size_t *sizep)
+{
+	FILE *f;
+	struct cookie *c;
+	wchar_t *buf;
+
+	if (!(f=malloc(sizeof *f + sizeof *c))) return 0;
+	if (!(buf=malloc(sizeof *buf))) {
+		free(f);
+		return 0;
+	}
+	memset(f, 0, sizeof *f + sizeof *c);
+	f->cookie = c = (void *)(f+1);
+
+	c->bufp = bufp;
+	c->sizep = sizep;
+	c->pos = c->len = c->space = *sizep = 0;
+	c->buf = *bufp = buf;
+	*buf = 0;
+
+	f->flags = F_NORD;
+	f->fd = -1;
+	f->buf = (void *)(c+1);
+	f->buf_size = 0;
+	f->lbf = EOF;
+	f->write = wms_write;
+	f->seek = wms_seek;
+	f->close = wms_close;
+
+	if (!libc.threaded) f->lock = -1;
+
+	return __ofl_add(f);
+}

contracts/musl/src/stdio/perror.c

+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include "stdio_impl.h"
+
+void perror(const char *msg)
+{
+	FILE *f = stderr;
+	char *errstr = strerror(errno);
+
+	FLOCK(f);
+	
+	if (msg && *msg) {
+		fwrite(msg, strlen(msg), 1, f);
+		fputc(':', f);
+		fputc(' ', f);
+	}
+	fwrite(errstr, strlen(errstr), 1, f);
+	fputc('\n', f);
+
+	FUNLOCK(f);
+}

contracts/musl/src/stdio/printf.c

+#include <stdio.h>
+#include <stdarg.h>
+
+int printf(const char *restrict fmt, ...)
+{
+	int ret;
+	va_list ap;
+	va_start(ap, fmt);
+	ret = vfprintf(stdout, fmt, ap);
+	va_end(ap);
+	return ret;
+}

contracts/musl/src/stdio/putc.c

+#include "stdio_impl.h"
+
+int putc(int c, FILE *f)
+{
+	if (f->lock < 0 || !__lockfile(f))
+		return putc_unlocked(c, f);
+	c = putc_unlocked(c, f);
+	__unlockfile(f);
+	return c;
+}
+
+weak_alias(putc, _IO_putc);

contracts/musl/src/stdio/putc_unlocked.c

+#include "stdio_impl.h"
+
+int (putc_unlocked)(int c, FILE *f)
+{
+	return putc_unlocked(c, f);
+}
+
+weak_alias(putc_unlocked, fputc_unlocked);
+weak_alias(putc_unlocked, _IO_putc_unlocked);

contracts/musl/src/stdio/putchar.c

+#include <stdio.h>
+
+int putchar(int c)
+{
+	return fputc(c, stdout);
+}

contracts/musl/src/stdio/putchar_unlocked.c

+#include "stdio_impl.h"
+
+int putchar_unlocked(int c)
+{
+	return putc_unlocked(c, stdout);
+}

contracts/musl/src/stdio/puts.c

+#include "stdio_impl.h"
+
+int puts(const char *s)
+{
+	int r;
+	FLOCK(stdout);
+	r = -(fputs(s, stdout) < 0 || putc_unlocked('\n', stdout) < 0);
+	FUNLOCK(stdout);
+	return r;
+}

contracts/musl/src/stdio/putw.c

+#define _GNU_SOURCE
+#include <stdio.h>
+
+int putw(int x, FILE *f)
+{
+	return (int)fwrite(&x, sizeof x, 1, f)-1;
+}

contracts/musl/src/stdio/putwc.c

+#include "stdio_impl.h"
+#include <wchar.h>
+
+wint_t putwc(wchar_t c, FILE *f)
+{
+	return fputwc(c, f);
+}

contracts/musl/src/stdio/putwchar.c

+#include "stdio_impl.h"
+#include <wchar.h>
+
+wint_t putwchar(wchar_t c)
+{
+	return fputwc(c, stdout);
+}
+
+weak_alias(putwchar, putwchar_unlocked);

contracts/musl/src/stdio/rewind.c

+#include "stdio_impl.h"
+
+void rewind(FILE *f)
+{
+	FLOCK(f);
+	__fseeko_unlocked(f, 0, SEEK_SET);
+	f->flags &= ~F_ERR;
+	FUNLOCK(f);
+}

contracts/musl/src/stdio/scanf.c

+#include <stdio.h>
+#include <stdarg.h>
+#include "libc.h"
+
+int scanf(const char *restrict fmt, ...)
+{
+	int ret;
+	va_list ap;
+	va_start(ap, fmt);
+	ret = vscanf(fmt, ap);
+	va_end(ap);
+	return ret;
+}
+
+weak_alias(scanf,__isoc99_scanf);

contracts/musl/src/stdio/setbuf.c

+#include <stdio.h>
+
+void setbuf(FILE *restrict f, char *restrict buf)
+{
+	setvbuf(f, buf, buf ? _IOFBF : _IONBF, BUFSIZ);
+}

contracts/musl/src/stdio/setbuffer.c

+#define _GNU_SOURCE
+#include <stdio.h>
+
+void setbuffer(FILE *f, char *buf, size_t size)
+{
+	setvbuf(f, buf, buf ? _IOFBF : _IONBF, size);
+}

contracts/musl/src/stdio/setlinebuf.c

+#define _GNU_SOURCE
+#include <stdio.h>
+
+void setlinebuf(FILE *f)
+{
+	setvbuf(f, 0, _IOLBF, 0);
+}

contracts/musl/src/stdio/setvbuf.c

+#include "stdio_impl.h"
+
+/* This function makes no attempt to protect the user from his/her own
+ * stupidity. If called any time but when then ISO C standard specifically
+ * allows it, all hell can and will break loose, especially with threads!
+ *
+ * This implementation ignores all arguments except the buffering type,
+ * and uses the existing buffer allocated alongside the FILE object.
+ * In the case of stderr where the preexisting buffer is length 1, it
+ * is not possible to set line buffering or full buffering. */
+
+int setvbuf(FILE *restrict f, char *restrict buf, int type, size_t size)
+{
+	f->lbf = EOF;
+
+	if (type == _IONBF)
+		f->buf_size = 0;
+	else if (type == _IOLBF)
+		f->lbf = '\n';
+
+	f->flags |= F_SVB;
+
+	return 0;
+}

contracts/musl/src/stdio/snprintf.c

+#include <stdio.h>
+#include <stdarg.h>
+
+int snprintf(char *restrict s, size_t n, const char *restrict fmt, ...)
+{
+	int ret;
+	va_list ap;
+	va_start(ap, fmt);
+	ret = vsnprintf(s, n, fmt, ap);
+	va_end(ap);
+	return ret;
+}
+

contracts/musl/src/stdio/sprintf.c

+#include <stdio.h>
+#include <stdarg.h>
+
+int sprintf(char *restrict s, const char *restrict fmt, ...)
+{
+	int ret;
+	va_list ap;
+	va_start(ap, fmt);
+	ret = vsprintf(s, fmt, ap);
+	va_end(ap);
+	return ret;
+}

contracts/musl/src/stdio/sscanf.c

+#include <stdio.h>
+#include <stdarg.h>
+#include "libc.h"
+
+int sscanf(const char *restrict s, const char *restrict fmt, ...)
+{
+	int ret;
+	va_list ap;
+	va_start(ap, fmt);
+	ret = vsscanf(s, fmt, ap);
+	va_end(ap);
+	return ret;
+}
+
+weak_alias(sscanf,__isoc99_sscanf);

contracts/musl/src/stdio/stderr.c

+#include "stdio_impl.h"
+
+static unsigned char buf[UNGET];
+static FILE f = {
+	.buf = buf+UNGET,
+	.buf_size = 0,
+	.fd = 2,
+	.flags = F_PERM | F_NORD,
+	.lbf = -1,
+	.write = __stdio_write,
+	.seek = __stdio_seek,
+	.close = __stdio_close,
+	.lock = -1,
+};
+FILE *const stderr = &f;
+FILE *volatile __stderr_used = &f;

contracts/musl/src/stdio/stdin.c

+#include "stdio_impl.h"
+
+static unsigned char buf[BUFSIZ+UNGET];
+static FILE f = {
+	.buf = buf+UNGET,
+	.buf_size = sizeof buf-UNGET,
+	.fd = 0,
+	.flags = F_PERM | F_NOWR,
+	.read = __stdio_read,
+	.seek = __stdio_seek,
+	.close = __stdio_close,
+	.lock = -1,
+};
+FILE *const stdin = &f;
+FILE *volatile __stdin_used = &f;

contracts/musl/src/stdio/stdout.c

+#include "stdio_impl.h"
+
+static unsigned char buf[BUFSIZ+UNGET];
+static FILE f = {
+	.buf = buf+UNGET,
+	.buf_size = sizeof buf-UNGET,
+	.fd = 1,
+	.flags = F_PERM | F_NORD,
+	.lbf = '\n',
+	.write = __stdout_write,
+	.seek = __stdio_seek,
+	.close = __stdio_close,
+	.lock = -1,
+};
+FILE *const stdout = &f;
+FILE *volatile __stdout_used = &f;

contracts/musl/src/stdio/swprintf.c

+#include <stdarg.h>
+#include <wchar.h>
+
+int swprintf(wchar_t *restrict s, size_t n, const wchar_t *restrict fmt, ...)
+{
+	int ret;
+	va_list ap;
+	va_start(ap, fmt);
+	ret = vswprintf(s, n, fmt, ap);
+	va_end(ap);
+	return ret;
+}
+

contracts/musl/src/stdio/swscanf.c

+#include <stdarg.h>
+#include <wchar.h>
+#include "libc.h"
+
+int swscanf(const wchar_t *restrict s, const wchar_t *restrict fmt, ...)
+{
+	int ret;
+	va_list ap;
+	va_start(ap, fmt);
+	ret = vswscanf(s, fmt, ap);
+	va_end(ap);
+	return ret;
+}
+
+weak_alias(swscanf,__isoc99_swscanf);

contracts/musl/src/stdio/ungetc.c

+#include "stdio_impl.h"
+
+int ungetc(int c, FILE *f)
+{
+	if (c == EOF) return c;
+
+	FLOCK(f);
+
+	if (!f->rpos) __toread(f);
+	if (!f->rpos || f->rpos <= f->buf - UNGET) {
+		FUNLOCK(f);
+		return EOF;
+	}
+
+	*--f->rpos = c;
+	f->flags &= ~F_EOF;
+
+	FUNLOCK(f);
+	return c;
+}

contracts/musl/src/stdio/ungetwc.c

+#include "stdio_impl.h"
+#include "locale_impl.h"
+#include <wchar.h>
+#include <limits.h>
+#include <ctype.h>
+#include <string.h>
+
+wint_t ungetwc(wint_t c, FILE *f)
+{
+	unsigned char mbc[MB_LEN_MAX];
+	int l;
+	locale_t *ploc = &CURRENT_LOCALE, loc = *ploc;
+
+	FLOCK(f);
+
+	if (f->mode <= 0) fwide(f, 1);
+	*ploc = f->locale;
+
+	if (!f->rpos) __toread(f);
+	if (!f->rpos || c == WEOF || (l = wcrtomb((void *)mbc, c, 0)) < 0 ||
+	    f->rpos < f->buf - UNGET + l) {
+		FUNLOCK(f);
+		*ploc = loc;
+		return WEOF;
+	}
+
+	if (isascii(c)) *--f->rpos = c;
+	else memcpy(f->rpos -= l, mbc, l);
+
+	f->flags &= ~F_EOF;
+
+	FUNLOCK(f);
+	*ploc = loc;
+	return c;
+}

contracts/musl/src/stdio/vasprintf.c

+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+
+int vasprintf(char **s, const char *fmt, va_list ap)
+{
+	va_list ap2;
+	va_copy(ap2, ap);
+	int l = vsnprintf(0, 0, fmt, ap2);
+	va_end(ap2);
+
+	if (l<0 || !(*s=malloc(l+1U))) return -1;
+	return vsnprintf(*s, l+1U, fmt, ap);
+}

contracts/musl/src/stdio/vdprintf.c

+#include "stdio_impl.h"
+
+static size_t wrap_write(FILE *f, const unsigned char *buf, size_t len)
+{
+	return __stdio_write(f, buf, len);
+}
+
+int vdprintf(int fd, const char *restrict fmt, va_list ap)
+{
+	FILE f = {
+		.fd = fd, .lbf = EOF, .write = wrap_write,
+		.buf = (void *)fmt, .buf_size = 0,
+		.lock = -1
+	};
+	return vfprintf(&f, fmt, ap);
+}

contracts/musl/src/stdio/vfprintf.c

+#include "stdio_impl.h"
+#include <errno.h>
+#include <ctype.h>
+#include <limits.h>
+#include <string.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <wchar.h>
+#include <inttypes.h>
+#include <math.h>
+#include <float.h>
+
+/* Some useful macros */
+
+#define MAX(a,b) ((a)>(b) ? (a) : (b))
+#define MIN(a,b) ((a)<(b) ? (a) : (b))
+
+/* Convenient bit representation for modifier flags, which all fall
+ * within 31 codepoints of the space character. */
+
+#define ALT_FORM   (1U<<'#'-' ')
+#define ZERO_PAD   (1U<<'0'-' ')
+#define LEFT_ADJ   (1U<<'-'-' ')
+#define PAD_POS    (1U<<' '-' ')
+#define MARK_POS   (1U<<'+'-' ')
+#define GROUPED    (1U<<'\''-' ')
+
+#define FLAGMASK (ALT_FORM|ZERO_PAD|LEFT_ADJ|PAD_POS|MARK_POS|GROUPED)
+
+/* State machine to accept length modifiers + conversion specifiers.
+ * Result is 0 on failure, or an argument type to pop on success. */
+
+enum {
+	BARE, LPRE, LLPRE, HPRE, HHPRE, BIGLPRE,
+	ZTPRE, JPRE,
+	STOP,
+	PTR, INT, UINT, ULLONG,
+	LONG, ULONG,
+	SHORT, USHORT, CHAR, UCHAR,
+	LLONG, SIZET, IMAX, UMAX, PDIFF, UIPTR,
+	DBL, LDBL,
+	NOARG,
+	MAXSTATE
+};
+
+#define S(x) [(x)-'A']
+
+static const unsigned char states[]['z'-'A'+1] = {
+	{ /* 0: bare types */
+		S('d') = INT, S('i') = INT,
+		S('o') = UINT, S('u') = UINT, S('x') = UINT, S('X') = UINT,
+		S('e') = DBL, S('f') = DBL, S('g') = DBL, S('a') = DBL,
+		S('E') = DBL, S('F') = DBL, S('G') = DBL, S('A') = DBL,
+		S('c') = CHAR, S('C') = INT,
+		S('s') = PTR, S('S') = PTR, S('p') = UIPTR, S('n') = PTR,
+		S('m') = NOARG,
+		S('l') = LPRE, S('h') = HPRE, S('L') = BIGLPRE,
+		S('z') = ZTPRE, S('j') = JPRE, S('t') = ZTPRE,
+	}, { /* 1: l-prefixed */
+		S('d') = LONG, S('i') = LONG,
+		S('o') = ULONG, S('u') = ULONG, S('x') = ULONG, S('X') = ULONG,
+		S('e') = DBL, S('f') = DBL, S('g') = DBL, S('a') = DBL,
+		S('E') = DBL, S('F') = DBL, S('G') = DBL, S('A') = DBL,
+		S('c') = INT, S('s') = PTR, S('n') = PTR,
+		S('l') = LLPRE,
+	}, { /* 2: ll-prefixed */
+		S('d') = LLONG, S('i') = LLONG,
+		S('o') = ULLONG, S('u') = ULLONG,
+		S('x') = ULLONG, S('X') = ULLONG,
+		S('n') = PTR,
+	}, { /* 3: h-prefixed */
+		S('d') = SHORT, S('i') = SHORT,
+		S('o') = USHORT, S('u') = USHORT,
+		S('x') = USHORT, S('X') = USHORT,
+		S('n') = PTR,
+		S('h') = HHPRE,
+	}, { /* 4: hh-prefixed */
+		S('d') = CHAR, S('i') = CHAR,
+		S('o') = UCHAR, S('u') = UCHAR,
+		S('x') = UCHAR, S('X') = UCHAR,
+		S('n') = PTR,
+	}, { /* 5: L-prefixed */
+		S('e') = LDBL, S('f') = LDBL, S('g') = LDBL, S('a') = LDBL,
+		S('E') = LDBL, S('F') = LDBL, S('G') = LDBL, S('A') = LDBL,
+		S('n') = PTR,
+	}, { /* 6: z- or t-prefixed (assumed to be same size) */
+		S('d') = PDIFF, S('i') = PDIFF,
+		S('o') = SIZET, S('u') = SIZET,
+		S('x') = SIZET, S('X') = SIZET,
+		S('n') = PTR,
+	}, { /* 7: j-prefixed */
+		S('d') = IMAX, S('i') = IMAX,
+		S('o') = UMAX, S('u') = UMAX,
+		S('x') = UMAX, S('X') = UMAX,
+		S('n') = PTR,
+	}
+};
+
+#define OOB(x) ((unsigned)(x)-'A' > 'z'-'A')
+
+union arg
+{
+	uintmax_t i;
+	long double f;
+	void *p;
+};
+
+static void pop_arg(union arg *arg, int type, va_list *ap)
+{
+	switch (type) {
+	       case PTR:	arg->p = va_arg(*ap, void *);
+	break; case INT:	arg->i = va_arg(*ap, int);
+	break; case UINT:	arg->i = va_arg(*ap, unsigned int);
+	break; case LONG:	arg->i = va_arg(*ap, long);
+	break; case ULONG:	arg->i = va_arg(*ap, unsigned long);
+	break; case ULLONG:	arg->i = va_arg(*ap, unsigned long long);
+	break; case SHORT:	arg->i = (short)va_arg(*ap, int);
+	break; case USHORT:	arg->i = (unsigned short)va_arg(*ap, int);
+	break; case CHAR:	arg->i = (signed char)va_arg(*ap, int);
+	break; case UCHAR:	arg->i = (unsigned char)va_arg(*ap, int);
+	break; case LLONG:	arg->i = va_arg(*ap, long long);
+	break; case SIZET:	arg->i = va_arg(*ap, size_t);
+	break; case IMAX:	arg->i = va_arg(*ap, intmax_t);
+	break; case UMAX:	arg->i = va_arg(*ap, uintmax_t);
+	break; case PDIFF:	arg->i = va_arg(*ap, ptrdiff_t);
+	break; case UIPTR:	arg->i = (uintptr_t)va_arg(*ap, void *);
+	break; case DBL:	arg->f = va_arg(*ap, double);
+	break; case LDBL:	arg->f = va_arg(*ap, long double);
+	}
+}
+
+static void out(FILE *f, const char *s, size_t l)
+{
+	if (!(f->flags & F_ERR)) __fwritex((void *)s, l, f);
+}
+
+static void pad(FILE *f, char c, int w, int l, int fl)
+{
+	char pad[256];
+	if (fl & (LEFT_ADJ | ZERO_PAD) || l >= w) return;
+	l = w - l;
+	memset(pad, c, l>sizeof pad ? sizeof pad : l);
+	for (; l >= sizeof pad; l -= sizeof pad)
+		out(f, pad, sizeof pad);
+	out(f, pad, l);
+}
+
+static const char xdigits[16] = {
+	"0123456789ABCDEF"
+};
+
+static char *fmt_x(uintmax_t x, char *s, int lower)
+{
+	for (; x; x>>=4) *--s = xdigits[(x&15)]|lower;
+	return s;
+}
+
+static char *fmt_o(uintmax_t x, char *s)
+{
+	for (; x; x>>=3) *--s = '0' + (x&7);
+	return s;
+}
+
+static char *fmt_u(uintmax_t x, char *s)
+{
+	unsigned long y;
+	for (   ; x>ULONG_MAX; x/=10) *--s = '0' + x%10;
+	for (y=x;           y; y/=10) *--s = '0' + y%10;
+	return s;
+}
+
+/* Do not override this check. The floating point printing code below
+ * depends on the float.h constants being right. If they are wrong, it
+ * may overflow the stack. */
+#if LDBL_MANT_DIG == 53
+typedef char compiler_defines_long_double_incorrectly[9-(int)sizeof(long double)];
+#endif
+
+static int fmt_fp(FILE *f, long double y, int w, int p, int fl, int t)
+{
+	uint32_t big[(LDBL_MANT_DIG+28)/29 + 1          // mantissa expansion
+		+ (LDBL_MAX_EXP+LDBL_MANT_DIG+28+8)/9]; // exponent expansion
+	uint32_t *a, *d, *r, *z;
+	int e2=0, e, i, j, l;
+	char buf[9+LDBL_MANT_DIG/4], *s;
+	const char *prefix="-0X+0X 0X-0x+0x 0x";
+	int pl;
+	char ebuf0[3*sizeof(int)], *ebuf=&ebuf0[3*sizeof(int)], *estr;
+
+	pl=1;
+	if (signbit(y)) {
+		y=-y;
+	} else if (fl & MARK_POS) {
+		prefix+=3;
+	} else if (fl & PAD_POS) {
+		prefix+=6;
+	} else prefix++, pl=0;
+
+	if (!isfinite(y)) {
+		char *s = (t&32)?"inf":"INF";
+		if (y!=y) s=(t&32)?"nan":"NAN";
+		pad(f, ' ', w, 3+pl, fl&~ZERO_PAD);
+		out(f, prefix, pl);
+		out(f, s, 3);
+		pad(f, ' ', w, 3+pl, fl^LEFT_ADJ);
+		return MAX(w, 3+pl);
+	}
+
+	y = frexpl(y, &e2) * 2;
+	if (y) e2--;
+
+	if ((t|32)=='a') {
+		long double round = 8.0;
+		int re;
+
+		if (t&32) prefix += 9;
+		pl += 2;
+
+		if (p<0 || p>=LDBL_MANT_DIG/4-1) re=0;
+		else re=LDBL_MANT_DIG/4-1-p;
+
+		if (re) {
+			while (re--) round*=16;
+			if (*prefix=='-') {
+				y=-y;
+				y-=round;
+				y+=round;
+				y=-y;
+			} else {
+				y+=round;
+				y-=round;
+			}
+		}
+
+		estr=fmt_u(e2<0 ? -e2 : e2, ebuf);
+		if (estr==ebuf) *--estr='0';
+		*--estr = (e2<0 ? '-' : '+');
+		*--estr = t+('p'-'a');
+
+		s=buf;
+		do {
+			int x=y;
+			*s++=xdigits[x]|(t&32);
+			y=16*(y-x);
+			if (s-buf==1 && (y||p>0||(fl&ALT_FORM))) *s++='.';
+		} while (y);
+
+		if (p > INT_MAX-2-(ebuf-estr)-pl)
+			return -1;
+		if (p && s-buf-2 < p)
+			l = (p+2) + (ebuf-estr);
+		else
+			l = (s-buf) + (ebuf-estr);
+
+		pad(f, ' ', w, pl+l, fl);
+		out(f, prefix, pl);
+		pad(f, '0', w, pl+l, fl^ZERO_PAD);
+		out(f, buf, s-buf);
+		pad(f, '0', l-(ebuf-estr)-(s-buf), 0, 0);
+		out(f, estr, ebuf-estr);
+		pad(f, ' ', w, pl+l, fl^LEFT_ADJ);
+		return MAX(w, pl+l);
+	}
+	if (p<0) p=6;
+
+	if (y) y *= 0x1p28, e2-=28;
+
+	if (e2<0) a=r=z=big;
+	else a=r=z=big+sizeof(big)/sizeof(*big) - LDBL_MANT_DIG - 1;
+
+	do {
+		*z = y;
+		y = 1000000000*(y-*z++);
+	} while (y);
+
+	while (e2>0) {
+		uint32_t carry=0;
+		int sh=MIN(29,e2);
+		for (d=z-1; d>=a; d--) {
+			uint64_t x = ((uint64_t)*d<<sh)+carry;
+			*d = x % 1000000000;
+			carry = x / 1000000000;
+		}
+		if (carry) *--a = carry;
+		while (z>a && !z[-1]) z--;
+		e2-=sh;
+	}
+	while (e2<0) {
+		uint32_t carry=0, *b;
+		int sh=MIN(9,-e2), need=1+(p+LDBL_MANT_DIG/3U+8)/9;
+		for (d=a; d<z; d++) {
+			uint32_t rm = *d & (1<<sh)-1;
+			*d = (*d>>sh) + carry;
+			carry = (1000000000>>sh) * rm;
+		}
+		if (!*a) a++;
+		if (carry) *z++ = carry;
+		/* Avoid (slow!) computation past requested precision */
+		b = (t|32)=='f' ? r : a;
+		if (z-b > need) z = b+need;
+		e2+=sh;
+	}
+
+	if (a<z) for (i=10, e=9*(r-a); *a>=i; i*=10, e++);
+	else e=0;
+
+	/* Perform rounding: j is precision after the radix (possibly neg) */
+	j = p - ((t|32)!='f')*e - ((t|32)=='g' && p);
+	if (j < 9*(z-r-1)) {
+		uint32_t x;
+		/* We avoid C's broken division of negative numbers */
+		d = r + 1 + ((j+9*LDBL_MAX_EXP)/9 - LDBL_MAX_EXP);
+		j += 9*LDBL_MAX_EXP;
+		j %= 9;
+		for (i=10, j++; j<9; i*=10, j++);
+		x = *d % i;
+		/* Are there any significant digits past j? */
+		if (x || d+1!=z) {
+			long double round = 2/LDBL_EPSILON;
+			long double small;
+			if ((*d/i & 1) || (i==1000000000 && d>a && (d[-1]&1)))
+				round += 2;
+			if (x<i/2) small=0x0.8p0;
+			else if (x==i/2 && d+1==z) small=0x1.0p0;
+			else small=0x1.8p0;
+			if (pl && *prefix=='-') round*=-1, small*=-1;
+			*d -= x;
+			/* Decide whether to round by probing round+small */
+			if (round+small != round) {
+				*d = *d + i;
+				while (*d > 999999999) {
+					*d--=0;
+					if (d<a) *--a=0;
+					(*d)++;
+				}
+				for (i=10, e=9*(r-a); *a>=i; i*=10, e++);
+			}
+		}
+		if (z>d+1) z=d+1;
+	}
+	for (; z>a && !z[-1]; z--);
+	
+	if ((t|32)=='g') {
+		if (!p) p++;
+		if (p>e && e>=-4) {
+			t--;
+			p-=e+1;
+		} else {
+			t-=2;
+			p--;
+		}
+		if (!(fl&ALT_FORM)) {
+			/* Count trailing zeros in last place */
+			if (z>a && z[-1]) for (i=10, j=0; z[-1]%i==0; i*=10, j++);
+			else j=9;
+			if ((t|32)=='f')
+				p = MIN(p,MAX(0,9*(z-r-1)-j));
+			else
+				p = MIN(p,MAX(0,9*(z-r-1)+e-j));
+		}
+	}
+	if (p > INT_MAX-1-(p || (fl&ALT_FORM)))
+		return -1;
+	l = 1 + p + (p || (fl&ALT_FORM));
+	if ((t|32)=='f') {
+		if (e > INT_MAX-l) return -1;
+		if (e>0) l+=e;
+	} else {
+		estr=fmt_u(e<0 ? -e : e, ebuf);
+		while(ebuf-estr<2) *--estr='0';
+		*--estr = (e<0 ? '-' : '+');
+		*--estr = t;
+		if (ebuf-estr > INT_MAX-l) return -1;
+		l += ebuf-estr;
+	}
+
+	if (l > INT_MAX-pl) return -1;
+	pad(f, ' ', w, pl+l, fl);
+	out(f, prefix, pl);
+	pad(f, '0', w, pl+l, fl^ZERO_PAD);
+
+	if ((t|32)=='f') {
+		if (a>r) a=r;
+		for (d=a; d<=r; d++) {
+			char *s = fmt_u(*d, buf+9);
+			if (d!=a) while (s>buf) *--s='0';
+			else if (s==buf+9) *--s='0';
+			out(f, s, buf+9-s);
+		}
+		if (p || (fl&ALT_FORM)) out(f, ".", 1);
+		for (; d<z && p>0; d++, p-=9) {
+			char *s = fmt_u(*d, buf+9);
+			while (s>buf) *--s='0';
+			out(f, s, MIN(9,p));
+		}
+		pad(f, '0', p+9, 9, 0);
+	} else {
+		if (z<=a) z=a+1;
+		for (d=a; d<z && p>=0; d++) {
+			char *s = fmt_u(*d, buf+9);
+			if (s==buf+9) *--s='0';
+			if (d!=a) while (s>buf) *--s='0';
+			else {
+				out(f, s++, 1);
+				if (p>0||(fl&ALT_FORM)) out(f, ".", 1);
+			}
+			out(f, s, MIN(buf+9-s, p));
+			p -= buf+9-s;
+		}
+		pad(f, '0', p+18, 18, 0);
+		out(f, estr, ebuf-estr);
+	}
+
+	pad(f, ' ', w, pl+l, fl^LEFT_ADJ);
+
+	return MAX(w, pl+l);
+}
+
+static int getint(char **s) {
+	int i;
+	for (i=0; isdigit(**s); (*s)++) {
+		if (i > INT_MAX/10U || **s-'0' > INT_MAX-10*i) i = -1;
+		else i = 10*i + (**s-'0');
+	}
+	return i;
+}
+
+static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg, int *nl_type)
+{
+	char *a, *z, *s=(char *)fmt;
+	unsigned l10n=0, fl;
+	int w, p, xp;
+	union arg arg;
+	int argpos;
+	unsigned st, ps;
+	int cnt=0, l=0;
+	size_t i;
+	char buf[sizeof(uintmax_t)*3+3+LDBL_MANT_DIG/4];
+	const char *prefix;
+	int t, pl;
+	wchar_t wc[2], *ws;
+	char mb[4];
+
+	for (;;) {
+		/* This error is only specified for snprintf, but since it's
+		 * unspecified for other forms, do the same. Stop immediately
+		 * on overflow; otherwise %n could produce wrong results. */
+		if (l > INT_MAX - cnt) goto overflow;
+
+		/* Update output count, end loop when fmt is exhausted */
+		cnt += l;
+		if (!*s) break;
+
+		/* Handle literal text and %% format specifiers */
+		for (a=s; *s && *s!='%'; s++);
+		for (z=s; s[0]=='%' && s[1]=='%'; z++, s+=2);
+		if (z-a > INT_MAX-cnt) goto overflow;
+		l = z-a;
+		if (f) out(f, a, l);
+		if (l) continue;
+
+		if (isdigit(s[1]) && s[2]=='$') {
+			l10n=1;
+			argpos = s[1]-'0';
+			s+=3;
+		} else {
+			argpos = -1;
+			s++;
+		}
+
+		/* Read modifier flags */
+		for (fl=0; (unsigned)*s-' '<32 && (FLAGMASK&(1U<<*s-' ')); s++)
+			fl |= 1U<<*s-' ';
+
+		/* Read field width */
+		if (*s=='*') {
+			if (isdigit(s[1]) && s[2]=='$') {
+				l10n=1;
+				nl_type[s[1]-'0'] = INT;
+				w = nl_arg[s[1]-'0'].i;
+				s+=3;
+			} else if (!l10n) {
+				w = f ? va_arg(*ap, int) : 0;
+				s++;
+			} else goto inval;
+			if (w<0) fl|=LEFT_ADJ, w=-w;
+		} else if ((w=getint(&s))<0) goto overflow;
+
+		/* Read precision */
+		if (*s=='.' && s[1]=='*') {
+			if (isdigit(s[2]) && s[3]=='$') {
+				nl_type[s[2]-'0'] = INT;
+				p = nl_arg[s[2]-'0'].i;
+				s+=4;
+			} else if (!l10n) {
+				p = f ? va_arg(*ap, int) : 0;
+				s+=2;
+			} else goto inval;
+			xp = (p>=0);
+		} else if (*s=='.') {
+			s++;
+			p = getint(&s);
+			xp = 1;
+		} else {
+			p = -1;
+			xp = 0;
+		}
+
+		/* Format specifier state machine */
+		st=0;
+		do {
+			if (OOB(*s)) goto inval;
+			ps=st;
+			st=states[st]S(*s++);
+		} while (st-1<STOP);
+		if (!st) goto inval;
+
+		/* Check validity of argument type (nl/normal) */
+		if (st==NOARG) {
+			if (argpos>=0) goto inval;
+		} else {
+			if (argpos>=0) nl_type[argpos]=st, arg=nl_arg[argpos];
+			else if (f) pop_arg(&arg, st, ap);
+			else return 0;
+		}
+
+		if (!f) continue;
+
+		z = buf + sizeof(buf);
+		prefix = "-+   0X0x";
+		pl = 0;
+		t = s[-1];
+
+		/* Transform ls,lc -> S,C */
+		if (ps && (t&15)==3) t&=~32;
+
+		/* - and 0 flags are mutually exclusive */
+		if (fl & LEFT_ADJ) fl &= ~ZERO_PAD;
+
+		switch(t) {
+		case 'n':
+			switch(ps) {
+			case BARE: *(int *)arg.p = cnt; break;
+			case LPRE: *(long *)arg.p = cnt; break;
+			case LLPRE: *(long long *)arg.p = cnt; break;
+			case HPRE: *(unsigned short *)arg.p = cnt; break;
+			case HHPRE: *(unsigned char *)arg.p = cnt; break;
+			case ZTPRE: *(size_t *)arg.p = cnt; break;
+			case JPRE: *(uintmax_t *)arg.p = cnt; break;
+			}
+			continue;
+		case 'p':
+			p = MAX(p, 2*sizeof(void*));
+			t = 'x';
+			fl |= ALT_FORM;
+		case 'x': case 'X':
+			a = fmt_x(arg.i, z, t&32);
+			if (arg.i && (fl & ALT_FORM)) prefix+=(t>>4), pl=2;
+			if (0) {
+		case 'o':
+			a = fmt_o(arg.i, z);
+			if ((fl&ALT_FORM) && p<z-a+1) prefix+=5, pl=1;
+			} if (0) {
+		case 'd': case 'i':
+			pl=1;
+			if (arg.i>INTMAX_MAX) {
+				arg.i=-arg.i;
+			} else if (fl & MARK_POS) {
+				prefix++;
+			} else if (fl & PAD_POS) {
+				prefix+=2;
+			} else pl=0;
+		case 'u':
+			a = fmt_u(arg.i, z);
+			}
+			if (xp && p<0) goto overflow;
+			if (p>=0) fl &= ~ZERO_PAD;
+			if (!arg.i && !p) {
+				a=z;
+				break;
+			}
+			p = MAX(p, z-a + !arg.i);
+			break;
+		case 'c':
+			*(a=z-(p=1))=arg.i;
+			fl &= ~ZERO_PAD;
+			break;
+		case 'm':
+			if (1) a = strerror(errno); else
+		case 's':
+			a = arg.p ? arg.p : "(null)";
+			z = a + strnlen(a, p<0 ? INT_MAX : p);
+			if (p<0 && *z) goto overflow;
+			p = z-a;
+			fl &= ~ZERO_PAD;
+			break;
+		case 'C':
+			wc[0] = arg.i;
+			wc[1] = 0;
+			arg.p = wc;
+			p = -1;
+		case 'S':
+			ws = arg.p;
+			for (i=l=0; i<p && *ws && (l=wctomb(mb, *ws++))>=0 && l<=p-i; i+=l);
+			if (l<0) return -1;
+			if (i > INT_MAX) goto overflow;
+			p = i;
+			pad(f, ' ', w, p, fl);
+			ws = arg.p;
+			for (i=0; i<0U+p && *ws && i+(l=wctomb(mb, *ws++))<=p; i+=l)
+				out(f, mb, l);
+			pad(f, ' ', w, p, fl^LEFT_ADJ);
+			l = w>p ? w : p;
+			continue;
+		case 'e': case 'f': case 'g': case 'a':
+		case 'E': case 'F': case 'G': case 'A':
+			if (xp && p<0) goto overflow;
+			l = fmt_fp(f, arg.f, w, p, fl, t);
+			if (l<0) goto overflow;
+			continue;
+		}
+
+		if (p < z-a) p = z-a;
+		if (p > INT_MAX-pl) goto overflow;
+		if (w < pl+p) w = pl+p;
+		if (w > INT_MAX-cnt) goto overflow;
+
+		pad(f, ' ', w, pl+p, fl);
+		out(f, prefix, pl);
+		pad(f, '0', w, pl+p, fl^ZERO_PAD);
+		pad(f, '0', p, z-a, 0);
+		out(f, a, z-a);
+		pad(f, ' ', w, pl+p, fl^LEFT_ADJ);
+
+		l = w;
+	}
+
+	if (f) return cnt;
+	if (!l10n) return 0;
+
+	for (i=1; i<=NL_ARGMAX && nl_type[i]; i++)
+		pop_arg(nl_arg+i, nl_type[i], ap);
+	for (; i<=NL_ARGMAX && !nl_type[i]; i++);
+	if (i<=NL_ARGMAX) goto inval;
+	return 1;
+
+inval:
+	errno = EINVAL;
+	return -1;
+overflow:
+	errno = EOVERFLOW;
+	return -1;
+}
+
+int vfprintf(FILE *restrict f, const char *restrict fmt, va_list ap)
+{
+	va_list ap2;
+	int nl_type[NL_ARGMAX+1] = {0};
+	union arg nl_arg[NL_ARGMAX+1];
+	unsigned char internal_buf[80], *saved_buf = 0;
+	int olderr;
+	int ret;
+
+	/* the copy allows passing va_list* even if va_list is an array */
+	va_copy(ap2, ap);
+	if (printf_core(0, fmt, &ap2, nl_arg, nl_type) < 0) {
+		va_end(ap2);
+		return -1;
+	}
+
+	FLOCK(f);
+	olderr = f->flags & F_ERR;
+	if (f->mode < 1) f->flags &= ~F_ERR;
+	if (!f->buf_size) {
+		saved_buf = f->buf;
+		f->wpos = f->wbase = f->buf = internal_buf;
+		f->buf_size = sizeof internal_buf;
+		f->wend = internal_buf + sizeof internal_buf;
+	}
+	ret = printf_core(f, fmt, &ap2, nl_arg, nl_type);
+	if (saved_buf) {
+		f->write(f, 0, 0);
+		if (!f->wpos) ret = -1;
+		f->buf = saved_buf;
+		f->buf_size = 0;
+		f->wpos = f->wbase = f->wend = 0;
+	}
+	if (f->flags & F_ERR) ret = -1;
+	f->flags |= olderr;
+	FUNLOCK(f);
+	va_end(ap2);
+	return ret;
+}

contracts/musl/src/stdio/vfscanf.c

+#include <stdlib.h>
+#include <stdarg.h>
+#include <ctype.h>
+#include <wchar.h>
+#include <wctype.h>
+#include <limits.h>
+#include <string.h>
+#include <stdint.h>
+
+#include "stdio_impl.h"
+#include "shgetc.h"
+#include "intscan.h"
+#include "floatscan.h"
+
+#define SIZE_hh -2
+#define SIZE_h  -1
+#define SIZE_def 0
+#define SIZE_l   1
+#define SIZE_L   2
+#define SIZE_ll  3
+
+static void store_int(void *dest, int size, unsigned long long i)
+{
+	if (!dest) return;
+	switch (size) {
+	case SIZE_hh:
+		*(char *)dest = i;
+		break;
+	case SIZE_h:
+		*(short *)dest = i;
+		break;
+	case SIZE_def:
+		*(int *)dest = i;
+		break;
+	case SIZE_l:
+		*(long *)dest = i;
+		break;
+	case SIZE_ll:
+		*(long long *)dest = i;
+		break;
+	}
+}
+
+static void *arg_n(va_list ap, unsigned int n)
+{
+	void *p;
+	unsigned int i;
+	va_list ap2;
+	va_copy(ap2, ap);
+	for (i=n; i>1; i--) va_arg(ap2, void *);
+	p = va_arg(ap2, void *);
+	va_end(ap2);
+	return p;
+}
+
+int vfscanf(FILE *restrict f, const char *restrict fmt, va_list ap)
+{
+	int width;
+	int size;
+	int alloc;
+	int base;
+	const unsigned char *p;
+	int c, t;
+	char *s;
+	wchar_t *wcs;
+	mbstate_t st;
+	void *dest=NULL;
+	int invert;
+	int matches=0;
+	unsigned long long x;
+	long double y;
+	off_t pos = 0;
+	unsigned char scanset[257];
+	size_t i, k;
+	wchar_t wc;
+
+	FLOCK(f);
+
+	for (p=(const unsigned char *)fmt; *p; p++) {
+
+		alloc = 0;
+
+		if (isspace(*p)) {
+			while (isspace(p[1])) p++;
+			shlim(f, 0);
+			while (isspace(shgetc(f)));
+			shunget(f);
+			pos += shcnt(f);
+			continue;
+		}
+		if (*p != '%' || p[1] == '%') {
+			shlim(f, 0);
+			if (*p == '%') {
+				p++;
+				while (isspace((c=shgetc(f))));
+			} else {
+				c = shgetc(f);
+			}
+			if (c!=*p) {
+				shunget(f);
+				if (c<0) goto input_fail;
+				goto match_fail;
+			}
+			pos += shcnt(f);
+			continue;
+		}
+
+		p++;
+		if (*p=='*') {
+			dest = 0; p++;
+		} else if (isdigit(*p) && p[1]=='$') {
+			dest = arg_n(ap, *p-'0'); p+=2;
+		} else {
+			dest = va_arg(ap, void *);
+		}
+
+		for (width=0; isdigit(*p); p++) {
+			width = 10*width + *p - '0';
+		}
+
+		if (*p=='m') {
+			wcs = 0;
+			s = 0;
+			alloc = !!dest;
+			p++;
+		} else {
+			alloc = 0;
+		}
+
+		size = SIZE_def;
+		switch (*p++) {
+		case 'h':
+			if (*p == 'h') p++, size = SIZE_hh;
+			else size = SIZE_h;
+			break;
+		case 'l':
+			if (*p == 'l') p++, size = SIZE_ll;
+			else size = SIZE_l;
+			break;
+		case 'j':
+			size = SIZE_ll;
+			break;
+		case 'z':
+		case 't':
+			size = SIZE_l;
+			break;
+		case 'L':
+			size = SIZE_L;
+			break;
+		case 'd': case 'i': case 'o': case 'u': case 'x':
+		case 'a': case 'e': case 'f': case 'g':
+		case 'A': case 'E': case 'F': case 'G': case 'X':
+		case 's': case 'c': case '[':
+		case 'S': case 'C':
+		case 'p': case 'n':
+			p--;
+			break;
+		default:
+			goto fmt_fail;
+		}
+
+		t = *p;
+
+		/* C or S */
+		if ((t&0x2f) == 3) {
+			t |= 32;
+			size = SIZE_l;
+		}
+
+		switch (t) {
+		case 'c':
+			if (width < 1) width = 1;
+		case '[':
+			break;
+		case 'n':
+			store_int(dest, size, pos);
+			/* do not increment match count, etc! */
+			continue;
+		default:
+			shlim(f, 0);
+			while (isspace(shgetc(f)));
+			shunget(f);
+			pos += shcnt(f);
+		}
+
+		shlim(f, width);
+		if (shgetc(f) < 0) goto input_fail;
+		shunget(f);
+
+		switch (t) {
+		case 's':
+		case 'c':
+		case '[':
+			if (t == 'c' || t == 's') {
+				memset(scanset, -1, sizeof scanset);
+				scanset[0] = 0;
+				if (t == 's') {
+					scanset[1+'\t'] = 0;
+					scanset[1+'\n'] = 0;
+					scanset[1+'\v'] = 0;
+					scanset[1+'\f'] = 0;
+					scanset[1+'\r'] = 0;
+					scanset[1+' '] = 0;
+				}
+			} else {
+				if (*++p == '^') p++, invert = 1;
+				else invert = 0;
+				memset(scanset, invert, sizeof scanset);
+				scanset[0] = 0;
+				if (*p == '-') p++, scanset[1+'-'] = 1-invert;
+				else if (*p == ']') p++, scanset[1+']'] = 1-invert;
+				for (; *p != ']'; p++) {
+					if (!*p) goto fmt_fail;
+					if (*p=='-' && p[1] && p[1] != ']')
+						for (c=p++[-1]; c<*p; c++)
+							scanset[1+c] = 1-invert;
+					scanset[1+*p] = 1-invert;
+				}
+			}
+			wcs = 0;
+			s = 0;
+			i = 0;
+			k = t=='c' ? width+1U : 31;
+			if (size == SIZE_l) {
+				if (alloc) {
+					wcs = malloc(k*sizeof(wchar_t));
+					if (!wcs) goto alloc_fail;
+				} else {
+					wcs = dest;
+				}
+				st = (mbstate_t){0};
+				while (scanset[(c=shgetc(f))+1]) {
+					switch (mbrtowc(&wc, &(char){c}, 1, &st)) {
+					case -1:
+						goto input_fail;
+					case -2:
+						continue;
+					}
+					if (wcs) wcs[i++] = wc;
+					if (alloc && i==k) {
+						k+=k+1;
+						wchar_t *tmp = realloc(wcs, k*sizeof(wchar_t));
+						if (!tmp) goto alloc_fail;
+						wcs = tmp;
+					}
+				}
+				if (!mbsinit(&st)) goto input_fail;
+			} else if (alloc) {
+				s = malloc(k);
+				if (!s) goto alloc_fail;
+				while (scanset[(c=shgetc(f))+1]) {
+					s[i++] = c;
+					if (i==k) {
+						k+=k+1;
+						char *tmp = realloc(s, k);
+						if (!tmp) goto alloc_fail;
+						s = tmp;
+					}
+				}
+			} else if ((s = dest)) {
+				while (scanset[(c=shgetc(f))+1])
+					s[i++] = c;
+			} else {
+				while (scanset[(c=shgetc(f))+1]);
+			}
+			shunget(f);
+			if (!shcnt(f)) goto match_fail;
+			if (t == 'c' && shcnt(f) != width) goto match_fail;
+			if (alloc) {
+				if (size == SIZE_l) *(wchar_t **)dest = wcs;
+				else *(char **)dest = s;
+			}
+			if (t != 'c') {
+				if (wcs) wcs[i] = 0;
+				if (s) s[i] = 0;
+			}
+			break;
+		case 'p':
+		case 'X':
+		case 'x':
+			base = 16;
+			goto int_common;
+		case 'o':
+			base = 8;
+			goto int_common;
+		case 'd':
+		case 'u':
+			base = 10;
+			goto int_common;
+		case 'i':
+			base = 0;
+		int_common:
+			x = __intscan(f, base, 0, ULLONG_MAX);
+			if (!shcnt(f)) goto match_fail;
+			if (t=='p' && dest) *(void **)dest = (void *)(uintptr_t)x;
+			else store_int(dest, size, x);
+			break;
+		case 'a': case 'A':
+		case 'e': case 'E':
+		case 'f': case 'F':
+		case 'g': case 'G':
+			y = __floatscan(f, size, 0);
+			if (!shcnt(f)) goto match_fail;
+			if (dest) switch (size) {
+			case SIZE_def:
+				*(float *)dest = y;
+				break;
+			case SIZE_l:
+				*(double *)dest = y;
+				break;
+			case SIZE_L:
+				*(long double *)dest = y;
+				break;
+			}
+			break;
+		}
+
+		pos += shcnt(f);
+		if (dest) matches++;
+	}
+	if (0) {
+fmt_fail:
+alloc_fail:
+input_fail:
+		if (!matches) matches--;
+match_fail:
+		if (alloc) {
+			free(s);
+			free(wcs);
+		}
+	}
+	FUNLOCK(f);
+	return matches;
+}
+
+weak_alias(vfscanf,__isoc99_vfscanf);

contracts/musl/src/stdio/vfwprintf.c

+#include "stdio_impl.h"
+#include <errno.h>
+#include <ctype.h>
+#include <limits.h>
+#include <string.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <wchar.h>
+#include <inttypes.h>
+
+/* Convenient bit representation for modifier flags, which all fall
+ * within 31 codepoints of the space character. */
+
+#define ALT_FORM   (1U<<'#'-' ')
+#define ZERO_PAD   (1U<<'0'-' ')
+#define LEFT_ADJ   (1U<<'-'-' ')
+#define PAD_POS    (1U<<' '-' ')
+#define MARK_POS   (1U<<'+'-' ')
+#define GROUPED    (1U<<'\''-' ')
+
+#define FLAGMASK (ALT_FORM|ZERO_PAD|LEFT_ADJ|PAD_POS|MARK_POS|GROUPED)
+
+/* State machine to accept length modifiers + conversion specifiers.
+ * Result is 0 on failure, or an argument type to pop on success. */
+
+enum {
+	BARE, LPRE, LLPRE, HPRE, HHPRE, BIGLPRE,
+	ZTPRE, JPRE,
+	STOP,
+	PTR, INT, UINT, ULLONG,
+	LONG, ULONG,
+	SHORT, USHORT, CHAR, UCHAR,
+	LLONG, SIZET, IMAX, UMAX, PDIFF, UIPTR,
+	DBL, LDBL,
+	NOARG,
+	MAXSTATE
+};
+
+#define S(x) [(x)-'A']
+
+static const unsigned char states[]['z'-'A'+1] = {
+	{ /* 0: bare types */
+		S('d') = INT, S('i') = INT,
+		S('o') = UINT, S('u') = UINT, S('x') = UINT, S('X') = UINT,
+		S('e') = DBL, S('f') = DBL, S('g') = DBL, S('a') = DBL,
+		S('E') = DBL, S('F') = DBL, S('G') = DBL, S('A') = DBL,
+		S('c') = CHAR, S('C') = INT,
+		S('s') = PTR, S('S') = PTR, S('p') = UIPTR, S('n') = PTR,
+		S('m') = NOARG,
+		S('l') = LPRE, S('h') = HPRE, S('L') = BIGLPRE,
+		S('z') = ZTPRE, S('j') = JPRE, S('t') = ZTPRE,
+	}, { /* 1: l-prefixed */
+		S('d') = LONG, S('i') = LONG,
+		S('o') = ULONG, S('u') = ULONG, S('x') = ULONG, S('X') = ULONG,
+		S('c') = INT, S('s') = PTR, S('n') = PTR,
+		S('l') = LLPRE,
+	}, { /* 2: ll-prefixed */
+		S('d') = LLONG, S('i') = LLONG,
+		S('o') = ULLONG, S('u') = ULLONG,
+		S('x') = ULLONG, S('X') = ULLONG,
+		S('n') = PTR,
+	}, { /* 3: h-prefixed */
+		S('d') = SHORT, S('i') = SHORT,
+		S('o') = USHORT, S('u') = USHORT,
+		S('x') = USHORT, S('X') = USHORT,
+		S('n') = PTR,
+		S('h') = HHPRE,
+	}, { /* 4: hh-prefixed */
+		S('d') = CHAR, S('i') = CHAR,
+		S('o') = UCHAR, S('u') = UCHAR,
+		S('x') = UCHAR, S('X') = UCHAR,
+		S('n') = PTR,
+	}, { /* 5: L-prefixed */
+		S('e') = LDBL, S('f') = LDBL, S('g') = LDBL, S('a') = LDBL,
+		S('E') = LDBL, S('F') = LDBL, S('G') = LDBL, S('A') = LDBL,
+		S('n') = PTR,
+	}, { /* 6: z- or t-prefixed (assumed to be same size) */
+		S('d') = PDIFF, S('i') = PDIFF,
+		S('o') = SIZET, S('u') = SIZET,
+		S('x') = SIZET, S('X') = SIZET,
+		S('n') = PTR,
+	}, { /* 7: j-prefixed */
+		S('d') = IMAX, S('i') = IMAX,
+		S('o') = UMAX, S('u') = UMAX,
+		S('x') = UMAX, S('X') = UMAX,
+		S('n') = PTR,
+	}
+};
+
+#define OOB(x) ((unsigned)(x)-'A' > 'z'-'A')
+
+union arg
+{
+	uintmax_t i;
+	long double f;
+	void *p;
+};
+
+static void pop_arg(union arg *arg, int type, va_list *ap)
+{
+	switch (type) {
+	       case PTR:	arg->p = va_arg(*ap, void *);
+	break; case INT:	arg->i = va_arg(*ap, int);
+	break; case UINT:	arg->i = va_arg(*ap, unsigned int);
+	break; case LONG:	arg->i = va_arg(*ap, long);
+	break; case ULONG:	arg->i = va_arg(*ap, unsigned long);
+	break; case ULLONG:	arg->i = va_arg(*ap, unsigned long long);
+	break; case SHORT:	arg->i = (short)va_arg(*ap, int);
+	break; case USHORT:	arg->i = (unsigned short)va_arg(*ap, int);
+	break; case CHAR:	arg->i = (signed char)va_arg(*ap, int);
+	break; case UCHAR:	arg->i = (unsigned char)va_arg(*ap, int);
+	break; case LLONG:	arg->i = va_arg(*ap, long long);
+	break; case SIZET:	arg->i = va_arg(*ap, size_t);
+	break; case IMAX:	arg->i = va_arg(*ap, intmax_t);
+	break; case UMAX:	arg->i = va_arg(*ap, uintmax_t);
+	break; case PDIFF:	arg->i = va_arg(*ap, ptrdiff_t);
+	break; case UIPTR:	arg->i = (uintptr_t)va_arg(*ap, void *);
+	break; case DBL:	arg->f = va_arg(*ap, double);
+	break; case LDBL:	arg->f = va_arg(*ap, long double);
+	}
+}
+
+static void out(FILE *f, const wchar_t *s, size_t l)
+{
+	while (l-- && !(f->flags & F_ERR)) fputwc(*s++, f);
+}
+
+static int getint(wchar_t **s) {
+	int i;
+	for (i=0; iswdigit(**s); (*s)++) {
+		if (i > INT_MAX/10U || **s-'0' > INT_MAX-10*i) i = -1;
+		else i = 10*i + (**s-'0');
+	}
+	return i;
+}
+
+static const char sizeprefix['y'-'a'] = {
+['a'-'a']='L', ['e'-'a']='L', ['f'-'a']='L', ['g'-'a']='L',
+['d'-'a']='j', ['i'-'a']='j', ['o'-'a']='j', ['u'-'a']='j', ['x'-'a']='j',
+['p'-'a']='j'
+};
+
+static int wprintf_core(FILE *f, const wchar_t *fmt, va_list *ap, union arg *nl_arg, int *nl_type)
+{
+	wchar_t *a, *z, *s=(wchar_t *)fmt;
+	unsigned l10n=0, fl;
+	int w, p, xp;
+	union arg arg;
+	int argpos;
+	unsigned st, ps;
+	int cnt=0, l=0;
+	int i;
+	int t;
+	char *bs;
+	char charfmt[16];
+	wchar_t wc;
+
+	for (;;) {
+		/* This error is only specified for snprintf, but since it's
+		 * unspecified for other forms, do the same. Stop immediately
+		 * on overflow; otherwise %n could produce wrong results. */
+		if (l > INT_MAX - cnt) goto overflow;
+
+		/* Update output count, end loop when fmt is exhausted */
+		cnt += l;
+		if (!*s) break;
+
+		/* Handle literal text and %% format specifiers */
+		for (a=s; *s && *s!='%'; s++);
+		for (z=s; s[0]=='%' && s[1]=='%'; z++, s+=2);
+		if (z-a > INT_MAX-cnt) goto overflow;
+		l = z-a;
+		if (f) out(f, a, l);
+		if (l) continue;
+
+		if (iswdigit(s[1]) && s[2]=='$') {
+			l10n=1;
+			argpos = s[1]-'0';
+			s+=3;
+		} else {
+			argpos = -1;
+			s++;
+		}
+
+		/* Read modifier flags */
+		for (fl=0; (unsigned)*s-' '<32 && (FLAGMASK&(1U<<*s-' ')); s++)
+			fl |= 1U<<*s-' ';
+
+		/* Read field width */
+		if (*s=='*') {
+			if (iswdigit(s[1]) && s[2]=='$') {
+				l10n=1;
+				nl_type[s[1]-'0'] = INT;
+				w = nl_arg[s[1]-'0'].i;
+				s+=3;
+			} else if (!l10n) {
+				w = f ? va_arg(*ap, int) : 0;
+				s++;
+			} else goto inval;
+			if (w<0) fl|=LEFT_ADJ, w=-w;
+		} else if ((w=getint(&s))<0) goto overflow;
+
+		/* Read precision */
+		if (*s=='.' && s[1]=='*') {
+			if (isdigit(s[2]) && s[3]=='$') {
+				nl_type[s[2]-'0'] = INT;
+				p = nl_arg[s[2]-'0'].i;
+				s+=4;
+			} else if (!l10n) {
+				p = f ? va_arg(*ap, int) : 0;
+				s+=2;
+			} else goto inval;
+			xp = (p>=0);
+		} else if (*s=='.') {
+			s++;
+			p = getint(&s);
+			xp = 1;
+		} else {
+			p = -1;
+			xp = 0;
+		}
+
+		/* Format specifier state machine */
+		st=0;
+		do {
+			if (OOB(*s)) goto inval;
+			ps=st;
+			st=states[st]S(*s++);
+		} while (st-1<STOP);
+		if (!st) goto inval;
+
+		/* Check validity of argument type (nl/normal) */
+		if (st==NOARG) {
+			if (argpos>=0) goto inval;
+		} else {
+			if (argpos>=0) nl_type[argpos]=st, arg=nl_arg[argpos];
+			else if (f) pop_arg(&arg, st, ap);
+			else return 0;
+		}
+
+		if (!f) continue;
+		t = s[-1];
+		if (ps && (t&15)==3) t&=~32;
+
+		switch (t) {
+		case 'n':
+			switch(ps) {
+			case BARE: *(int *)arg.p = cnt; break;
+			case LPRE: *(long *)arg.p = cnt; break;
+			case LLPRE: *(long long *)arg.p = cnt; break;
+			case HPRE: *(unsigned short *)arg.p = cnt; break;
+			case HHPRE: *(unsigned char *)arg.p = cnt; break;
+			case ZTPRE: *(size_t *)arg.p = cnt; break;
+			case JPRE: *(uintmax_t *)arg.p = cnt; break;
+			}
+			continue;
+		case 'c':
+			fputwc(btowc(arg.i), f);
+			l = 1;
+			continue;
+		case 'C':
+			fputwc(arg.i, f);
+			l = 1;
+			continue;
+		case 'S':
+			a = arg.p;
+			z = a + wcsnlen(a, p<0 ? INT_MAX : p);
+			if (p<0 && *z) goto overflow;
+			p = z-a;
+			if (w<p) w=p;
+			if (!(fl&LEFT_ADJ)) fprintf(f, "%*s", w-p, "");
+			out(f, a, p);
+			if ((fl&LEFT_ADJ)) fprintf(f, "%*s", w-p, "");
+			l=w;
+			continue;
+		case 'm':
+			arg.p = strerror(errno);
+		case 's':
+			if (!arg.p) arg.p = "(null)";
+			bs = arg.p;
+			for (i=l=0; l<(p<0?INT_MAX:p) && (i=mbtowc(&wc, bs, MB_LEN_MAX))>0; bs+=i, l++);
+			if (i<0) return -1;
+			if (p<0 && *bs) goto overflow;
+			p=l;
+			if (w<p) w=p;
+			if (!(fl&LEFT_ADJ)) fprintf(f, "%*s", w-p, "");
+			bs = arg.p;
+			while (l--) {
+				i=mbtowc(&wc, bs, MB_LEN_MAX);
+				bs+=i;
+				fputwc(wc, f);
+			}
+			if ((fl&LEFT_ADJ)) fprintf(f, "%*s", w-p, "");
+			l=w;
+			continue;
+		}
+
+		if (xp && p<0) goto overflow;
+		snprintf(charfmt, sizeof charfmt, "%%%s%s%s%s%s*.*%c%c",
+			"#"+!(fl & ALT_FORM),
+			"+"+!(fl & MARK_POS),
+			"-"+!(fl & LEFT_ADJ),
+			" "+!(fl & PAD_POS),
+			"0"+!(fl & ZERO_PAD),
+			sizeprefix[(t|32)-'a'], t);
+
+		switch (t|32) {
+		case 'a': case 'e': case 'f': case 'g':
+			l = fprintf(f, charfmt, w, p, arg.f);
+			break;
+		case 'd': case 'i': case 'o': case 'u': case 'x': case 'p':
+			l = fprintf(f, charfmt, w, p, arg.i);
+			break;
+		}
+	}
+
+	if (f) return cnt;
+	if (!l10n) return 0;
+
+	for (i=1; i<=NL_ARGMAX && nl_type[i]; i++)
+		pop_arg(nl_arg+i, nl_type[i], ap);
+	for (; i<=NL_ARGMAX && !nl_type[i]; i++);
+	if (i<=NL_ARGMAX) return -1;
+	return 1;
+
+inval:
+	errno = EINVAL;
+	return -1;
+overflow:
+	errno = EOVERFLOW;
+	return -1;
+}
+
+int vfwprintf(FILE *restrict f, const wchar_t *restrict fmt, va_list ap)
+{
+	va_list ap2;
+	int nl_type[NL_ARGMAX] = {0};
+	union arg nl_arg[NL_ARGMAX];
+	int olderr;
+	int ret;
+
+	/* the copy allows passing va_list* even if va_list is an array */
+	va_copy(ap2, ap);
+	if (wprintf_core(0, fmt, &ap2, nl_arg, nl_type) < 0) {
+		va_end(ap2);
+		return -1;
+	}
+
+	FLOCK(f);
+	fwide(f, 1);
+	olderr = f->flags & F_ERR;
+	f->flags &= ~F_ERR;
+	ret = wprintf_core(f, fmt, &ap2, nl_arg, nl_type);
+	if (f->flags & F_ERR) ret = -1;
+	f->flags |= olderr;
+	FUNLOCK(f);
+	va_end(ap2);
+	return ret;
+}

contracts/musl/src/stdio/vfwscanf.c

+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <ctype.h>
+#include <wchar.h>
+#include <wctype.h>
+#include <limits.h>
+#include <string.h>
+
+#include "stdio_impl.h"
+#include "shgetc.h"
+#include "intscan.h"
+#include "floatscan.h"
+#include "libc.h"
+
+#define SIZE_hh -2
+#define SIZE_h  -1
+#define SIZE_def 0
+#define SIZE_l   1
+#define SIZE_L   2
+#define SIZE_ll  3
+
+static void store_int(void *dest, int size, unsigned long long i)
+{
+	if (!dest) return;
+	switch (size) {
+	case SIZE_hh:
+		*(char *)dest = i;
+		break;
+	case SIZE_h:
+		*(short *)dest = i;
+		break;
+	case SIZE_def:
+		*(int *)dest = i;
+		break;
+	case SIZE_l:
+		*(long *)dest = i;
+		break;
+	case SIZE_ll:
+		*(long long *)dest = i;
+		break;
+	}
+}
+
+static void *arg_n(va_list ap, unsigned int n)
+{
+	void *p;
+	unsigned int i;
+	va_list ap2;
+	va_copy(ap2, ap);
+	for (i=n; i>1; i--) va_arg(ap2, void *);
+	p = va_arg(ap2, void *);
+	va_end(ap2);
+	return p;
+}
+
+static int in_set(const wchar_t *set, int c)
+{
+	int j;
+	const wchar_t *p = set;
+	if (*p == '-') {
+		if (c=='-') return 1;
+		p++;
+	} else if (*p == ']') {
+		if (c==']') return 1;
+		p++;
+	}
+	for (; *p && *p != ']'; p++) {
+		if (*p=='-' && p[1] && p[1] != ']')
+			for (j=p++[-1]; j<*p; j++)
+				if (c==j) return 1;
+		if (c==*p) return 1;
+	}
+	return 0;
+}
+
+#if 1
+#undef getwc
+#define getwc(f) \
+	((f)->rpos < (f)->rend && *(f)->rpos < 128 ? *(f)->rpos++ : (getwc)(f))
+
+#undef ungetwc
+#define ungetwc(c,f) \
+	((f)->rend && (c)<128U ? *--(f)->rpos : ungetwc((c),(f)))
+#endif
+
+int vfwscanf(FILE *restrict f, const wchar_t *restrict fmt, va_list ap)
+{
+	int width;
+	int size;
+	int alloc;
+	const wchar_t *p;
+	int c, t;
+	char *s;
+	wchar_t *wcs;
+	void *dest=NULL;
+	int invert;
+	int matches=0;
+	off_t pos = 0, cnt;
+	static const char size_pfx[][3] = { "hh", "h", "", "l", "L", "ll" };
+	char tmp[3*sizeof(int)+10];
+	const wchar_t *set;
+	size_t i, k;
+
+	FLOCK(f);
+
+	fwide(f, 1);
+
+	for (p=fmt; *p; p++) {
+
+		alloc = 0;
+
+		if (iswspace(*p)) {
+			while (iswspace(p[1])) p++;
+			while (iswspace((c=getwc(f)))) pos++;
+			ungetwc(c, f);
+			continue;
+		}
+		if (*p != '%' || p[1] == '%') {
+			if (*p == '%') {
+				p++;
+				while (iswspace((c=getwc(f)))) pos++;
+			} else {
+				c = getwc(f);
+			}
+			if (c!=*p) {
+				ungetwc(c, f);
+				if (c<0) goto input_fail;
+				goto match_fail;
+			}
+			pos++;
+			continue;
+		}
+
+		p++;
+		if (*p=='*') {
+			dest = 0; p++;
+		} else if (iswdigit(*p) && p[1]=='$') {
+			dest = arg_n(ap, *p-'0'); p+=2;
+		} else {
+			dest = va_arg(ap, void *);
+		}
+
+		for (width=0; iswdigit(*p); p++) {
+			width = 10*width + *p - '0';
+		}
+
+		if (*p=='m') {
+			wcs = 0;
+			s = 0;
+			alloc = !!dest;
+			p++;
+		} else {
+			alloc = 0;
+		}
+
+		size = SIZE_def;
+		switch (*p++) {
+		case 'h':
+			if (*p == 'h') p++, size = SIZE_hh;
+			else size = SIZE_h;
+			break;
+		case 'l':
+			if (*p == 'l') p++, size = SIZE_ll;
+			else size = SIZE_l;
+			break;
+		case 'j':
+			size = SIZE_ll;
+			break;
+		case 'z':
+		case 't':
+			size = SIZE_l;
+			break;
+		case 'L':
+			size = SIZE_L;
+			break;
+		case 'd': case 'i': case 'o': case 'u': case 'x':
+		case 'a': case 'e': case 'f': case 'g':
+		case 'A': case 'E': case 'F': case 'G': case 'X':
+		case 's': case 'c': case '[':
+		case 'S': case 'C':
+		case 'p': case 'n':
+			p--;
+			break;
+		default:
+			goto fmt_fail;
+		}
+
+		t = *p;
+
+		/* Transform S,C -> ls,lc */
+		if ((t&0x2f)==3) {
+			size = SIZE_l;
+			t |= 32;
+		}
+
+		if (t != 'n') {
+			if (t != '[' && (t|32) != 'c')
+				while (iswspace((c=getwc(f)))) pos++;
+			else
+				c=getwc(f);
+			if (c < 0) goto input_fail;
+			ungetwc(c, f);
+		}
+
+		switch (t) {
+		case 'n':
+			store_int(dest, size, pos);
+			/* do not increment match count, etc! */
+			continue;
+
+		case 's':
+		case 'c':
+		case '[':
+			if (t == 'c') {
+				if (width<1) width = 1;
+				invert = 1;
+				set = L"";
+			} else if (t == 's') {
+				invert = 1;
+				static const wchar_t spaces[] = {
+					' ', '\t', '\n', '\r', 11, 12,  0x0085,
+					0x2000, 0x2001, 0x2002, 0x2003, 0x2004, 0x2005,
+					0x2006, 0x2008, 0x2009, 0x200a,
+					0x2028, 0x2029, 0x205f, 0x3000, 0 };
+				set = spaces;
+			} else {
+				if (*++p == '^') p++, invert = 1;
+				else invert = 0;
+				set = p;
+				if (*p==']') p++;
+				while (*p!=']') {
+					if (!*p) goto fmt_fail;
+					p++;
+				}
+			}
+
+			s = (size == SIZE_def) ? dest : 0;
+			wcs = (size == SIZE_l) ? dest : 0;
+
+			int gotmatch = 0;
+
+			if (width < 1) width = -1;
+
+			i = 0;
+			if (alloc) {
+				k = t=='c' ? width+1U : 31;
+				if (size == SIZE_l) {
+					wcs = malloc(k*sizeof(wchar_t));
+					if (!wcs) goto alloc_fail;
+				} else {
+					s = malloc(k);
+					if (!s) goto alloc_fail;
+				}
+			}
+			while (width) {
+				if ((c=getwc(f))<0) break;
+				if (in_set(set, c) == invert)
+					break;
+				if (wcs) {
+					wcs[i++] = c;
+					if (alloc && i==k) {
+						k += k+1;
+						wchar_t *tmp = realloc(wcs, k*sizeof(wchar_t));
+						if (!tmp) goto alloc_fail;
+						wcs = tmp;
+					}
+				} else if (size != SIZE_l) {
+					int l = wctomb(s?s+i:tmp, c);
+					if (l<0) goto input_fail;
+					i += l;
+					if (alloc && i > k-4) {
+						k += k+1;
+						char *tmp = realloc(s, k);
+						if (!tmp) goto alloc_fail;
+						s = tmp;
+					}
+				}
+				pos++;
+				width-=(width>0);
+				gotmatch=1;
+			}
+			if (width) {
+				ungetwc(c, f);
+				if (t == 'c' || !gotmatch) goto match_fail;
+			}
+
+			if (alloc) {
+				if (size == SIZE_l) *(wchar_t **)dest = wcs;
+				else *(char **)dest = s;
+			}
+			if (t != 'c') {
+				if (wcs) wcs[i] = 0;
+				if (s) s[i] = 0;
+			}
+			break;
+
+		case 'd': case 'i': case 'o': case 'u': case 'x':
+		case 'a': case 'e': case 'f': case 'g':
+		case 'A': case 'E': case 'F': case 'G': case 'X':
+		case 'p':
+			if (width < 1) width = 0;
+			snprintf(tmp, sizeof tmp, "%.*s%.0d%s%c%%lln",
+				1+!dest, "%*", width, size_pfx[size+2], t);
+			cnt = 0;
+			if (fscanf(f, tmp, dest?dest:&cnt, &cnt) == -1)
+				goto input_fail;
+			else if (!cnt)
+				goto match_fail;
+			pos += cnt;
+			break;
+		default:
+			goto fmt_fail;
+		}
+
+		if (dest) matches++;
+	}
+	if (0) {
+fmt_fail:
+alloc_fail:
+input_fail:
+		if (!matches) matches--;
+match_fail:
+		if (alloc) {
+			free(s);
+			free(wcs);
+		}
+	}
+	FUNLOCK(f);
+	return matches;
+}
+
+weak_alias(vfwscanf,__isoc99_vfwscanf);

contracts/musl/src/stdio/vprintf.c

+#include <stdio.h>
+
+int vprintf(const char *restrict fmt, va_list ap)
+{
+	return vfprintf(stdout, fmt, ap);
+}

contracts/musl/src/stdio/vscanf.c

+#include <stdio.h>
+#include <stdarg.h>
+#include "libc.h"
+
+int vscanf(const char *restrict fmt, va_list ap)
+{
+	return vfscanf(stdin, fmt, ap);
+}
+
+weak_alias(vscanf,__isoc99_vscanf);

contracts/musl/src/stdio/vsnprintf.c

+#include "stdio_impl.h"
+#include <limits.h>
+#include <string.h>
+#include <errno.h>
+#include <stdint.h>
+
+struct cookie {
+	char *s;
+	size_t n;
+};
+
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+
+static size_t sn_write(FILE *f, const unsigned char *s, size_t l)
+{
+	struct cookie *c = f->cookie;
+	size_t k = MIN(c->n, f->wpos - f->wbase);
+	if (k) {
+		memcpy(c->s, f->wbase, k);
+		c->s += k;
+		c->n -= k;
+	}
+	k = MIN(c->n, l);
+	if (k) {
+		memcpy(c->s, s, k);
+		c->s += k;
+		c->n -= k;
+	}
+	*c->s = 0;
+	f->wpos = f->wbase = f->buf;
+	/* pretend to succeed, even if we discarded extra data */
+	return l;
+}
+
+int vsnprintf(char *restrict s, size_t n, const char *restrict fmt, va_list ap)
+{
+	unsigned char buf[1];
+	char dummy[1];
+	struct cookie c = { .s = n ? s : dummy, .n = n ? n-1 : 0 };
+	FILE f = {
+		.lbf = EOF,
+		.write = sn_write,
+		.lock = -1,
+		.buf = buf,
+		.cookie = &c,
+	};
+
+	if (n > INT_MAX) {
+		errno = EOVERFLOW;
+		return -1;
+	}
+
+	*c.s = 0;
+	return vfprintf(&f, fmt, ap);
+}

contracts/musl/src/stdio/vsprintf.c

+#include <stdio.h>
+#include <limits.h>
+
+int vsprintf(char *restrict s, const char *restrict fmt, va_list ap)
+{
+	return vsnprintf(s, INT_MAX, fmt, ap);
+}

contracts/musl/src/stdio/vsscanf.c

+#include "stdio_impl.h"
+#include "libc.h"
+
+static size_t do_read(FILE *f, unsigned char *buf, size_t len)
+{
+	return __string_read(f, buf, len);
+}
+
+int vsscanf(const char *restrict s, const char *restrict fmt, va_list ap)
+{
+	FILE f = {
+		.buf = (void *)s, .cookie = (void *)s,
+		.read = do_read, .lock = -1
+	};
+	return vfscanf(&f, fmt, ap);
+}
+
+weak_alias(vsscanf,__isoc99_vsscanf);

contracts/musl/src/stdio/vswprintf.c

+#include "stdio_impl.h"
+#include <limits.h>
+#include <string.h>
+#include <errno.h>
+#include <stdint.h>
+#include <wchar.h>
+
+struct cookie {
+	wchar_t *ws;
+	size_t l;
+};
+
+static size_t sw_write(FILE *f, const unsigned char *s, size_t l)
+{
+	size_t l0 = l;
+	int i = 0;
+	struct cookie *c = f->cookie;
+	if (s!=f->wbase && sw_write(f, f->wbase, f->wpos-f->wbase)==-1)
+		return -1;
+	while (c->l && l && (i=mbtowc(c->ws, (void *)s, l))>=0) {
+		s+=i;
+		l-=i;
+		c->l--;
+		c->ws++;
+	}
+	*c->ws = 0;
+	if (i < 0) {
+		f->wpos = f->wbase = f->wend = 0;
+		f->flags |= F_ERR;
+		return i;
+	}
+	f->wend = f->buf + f->buf_size;
+	f->wpos = f->wbase = f->buf;
+	return l0;
+}
+
+int vswprintf(wchar_t *restrict s, size_t n, const wchar_t *restrict fmt, va_list ap)
+{
+	int r;
+	FILE f;
+	unsigned char buf[256];
+	struct cookie c = { s, n-1 };
+
+	memset(&f, 0, sizeof(FILE));
+	f.lbf = EOF;
+	f.write = sw_write;
+	f.buf_size = sizeof buf;
+	f.buf = buf;
+	f.lock = -1;
+	f.cookie = &c;
+	if (!n) {
+		return -1;
+	} else if (n > INT_MAX) {
+		errno = EOVERFLOW;
+		return -1;
+	}
+	r = vfwprintf(&f, fmt, ap);
+	sw_write(&f, 0, 0);
+	return r>=n ? -1 : r;
+}

contracts/musl/src/stdio/vswscanf.c

+#include "stdio_impl.h"
+#include "libc.h"
+#include <wchar.h>
+
+static size_t wstring_read(FILE *f, unsigned char *buf, size_t len)
+{
+	const wchar_t *src = f->cookie;
+	size_t k;
+
+	if (!src) return 0;
+
+	k = wcsrtombs((void *)f->buf, &src, f->buf_size, 0);
+	if (k==(size_t)-1) {
+		f->rpos = f->rend = 0;
+		return 0;
+	}
+
+	f->rpos = f->buf;
+	f->rend = f->buf + k;
+	f->cookie = (void *)src;
+
+	if (!len || !k) return 0;
+
+	*buf = *f->rpos++;
+	return 1;
+}
+
+int vswscanf(const wchar_t *restrict s, const wchar_t *restrict fmt, va_list ap)
+{
+	unsigned char buf[256];
+	FILE f = {
+		.buf = buf, .buf_size = sizeof buf,
+		.cookie = (void *)s,
+		.read = wstring_read, .lock = -1
+	};
+	return vfwscanf(&f, fmt, ap);
+}
+
+weak_alias(vswscanf,__isoc99_vswscanf);

contracts/musl/src/stdio/vwprintf.c

+#include <stdio.h>
+#include <wchar.h>
+
+int vwprintf(const wchar_t *restrict fmt, va_list ap)
+{
+	return vfwprintf(stdout, fmt, ap);
+}