Add mksh from CVS 2010/08/24 as system/core/mksh module

Both shells (ash from system/core/sh, and mksh) are built by
default but only the one where $(TARGET_SHELL) is set to is
actually installed (the shell and the mkshrc configuration
file are tagged shell_mksh for this to work).

Signed-off-by: Thorsten Glaser <tg@mirbsd.org>
diff --git a/mksh/src/shf.c b/mksh/src/shf.c
new file mode 100644
index 0000000..0962752
--- /dev/null
+++ b/mksh/src/shf.c
@@ -0,0 +1,1042 @@
+/*	$OpenBSD: shf.c,v 1.15 2006/04/02 00:48:33 deraadt Exp $	*/
+
+/*-
+ * Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009
+ *	Thorsten Glaser <tg@mirbsd.org>
+ *
+ * Provided that these terms and disclaimer and all copyright notices
+ * are retained or reproduced in an accompanying document, permission
+ * is granted to deal in this work without restriction, including un-
+ * limited rights to use, publicly perform, distribute, sell, modify,
+ * merge, give away, or sublicence.
+ *
+ * This work is provided "AS IS" and WITHOUT WARRANTY of any kind, to
+ * the utmost extent permitted by applicable law, neither express nor
+ * implied; without malicious intent or gross negligence. In no event
+ * may a licensor, author or contributor be held liable for indirect,
+ * direct, other damage, loss, or other issues arising in any way out
+ * of dealing in the work, even if advised of the possibility of such
+ * damage or existence of a defect, except proven that it results out
+ * of said person's immediate fault when using the work as intended.
+ */
+
+#include "sh.h"
+
+__RCSID("$MirOS: src/bin/mksh/shf.c,v 1.36 2010/07/19 22:41:04 tg Exp $");
+
+/* flags to shf_emptybuf() */
+#define EB_READSW	0x01	/* about to switch to reading */
+#define EB_GROW		0x02	/* grow buffer if necessary (STRING+DYNAMIC) */
+
+/*
+ * Replacement stdio routines. Stdio is too flakey on too many machines
+ * to be useful when you have multiple processes using the same underlying
+ * file descriptors.
+ */
+
+static int shf_fillbuf(struct shf *);
+static int shf_emptybuf(struct shf *, int);
+
+/* Open a file. First three args are for open(), last arg is flags for
+ * this package. Returns NULL if file could not be opened, or if a dup
+ * fails.
+ */
+struct shf *
+shf_open(const char *name, int oflags, int mode, int sflags)
+{
+	struct shf *shf;
+	int bsize = sflags & SHF_UNBUF ? (sflags & SHF_RD ? 1 : 0) : SHF_BSIZE;
+	int fd;
+
+	/* Done before open so if alloca fails, fd won't be lost. */
+	shf = alloc(sizeof(struct shf) + bsize, ATEMP);
+	shf->areap = ATEMP;
+	shf->buf = (unsigned char *)&shf[1];
+	shf->bsize = bsize;
+	shf->flags = SHF_ALLOCS;
+	/* Rest filled in by reopen. */
+
+	fd = open(name, oflags, mode);
+	if (fd < 0) {
+		afree(shf, shf->areap);
+		return (NULL);
+	}
+	if ((sflags & SHF_MAPHI) && fd < FDBASE) {
+		int nfd;
+
+		nfd = fcntl(fd, F_DUPFD, FDBASE);
+		close(fd);
+		if (nfd < 0) {
+			afree(shf, shf->areap);
+			return (NULL);
+		}
+		fd = nfd;
+	}
+	sflags &= ~SHF_ACCMODE;
+	sflags |= (oflags & O_ACCMODE) == O_RDONLY ? SHF_RD :
+	    ((oflags & O_ACCMODE) == O_WRONLY ? SHF_WR : SHF_RDWR);
+
+	return (shf_reopen(fd, sflags, shf));
+}
+
+/* Set up the shf structure for a file descriptor. Doesn't fail. */
+struct shf *
+shf_fdopen(int fd, int sflags, struct shf *shf)
+{
+	int bsize = sflags & SHF_UNBUF ? (sflags & SHF_RD ? 1 : 0) : SHF_BSIZE;
+
+	/* use fcntl() to figure out correct read/write flags */
+	if (sflags & SHF_GETFL) {
+		int flags = fcntl(fd, F_GETFL, 0);
+
+		if (flags < 0)
+			/* will get an error on first read/write */
+			sflags |= SHF_RDWR;
+		else {
+			switch (flags & O_ACCMODE) {
+			case O_RDONLY:
+				sflags |= SHF_RD;
+				break;
+			case O_WRONLY:
+				sflags |= SHF_WR;
+				break;
+			case O_RDWR:
+				sflags |= SHF_RDWR;
+				break;
+			}
+		}
+	}
+
+	if (!(sflags & (SHF_RD | SHF_WR)))
+		internal_errorf("shf_fdopen: missing read/write");
+
+	if (shf) {
+		if (bsize) {
+			shf->buf = alloc(bsize, ATEMP);
+			sflags |= SHF_ALLOCB;
+		} else
+			shf->buf = NULL;
+	} else {
+		shf = alloc(sizeof(struct shf) + bsize, ATEMP);
+		shf->buf = (unsigned char *)&shf[1];
+		sflags |= SHF_ALLOCS;
+	}
+	shf->areap = ATEMP;
+	shf->fd = fd;
+	shf->rp = shf->wp = shf->buf;
+	shf->rnleft = 0;
+	shf->rbsize = bsize;
+	shf->wnleft = 0; /* force call to shf_emptybuf() */
+	shf->wbsize = sflags & SHF_UNBUF ? 0 : bsize;
+	shf->flags = sflags;
+	shf->errno_ = 0;
+	shf->bsize = bsize;
+	if (sflags & SHF_CLEXEC)
+		fcntl(fd, F_SETFD, FD_CLOEXEC);
+	return (shf);
+}
+
+/* Set up an existing shf (and buffer) to use the given fd */
+struct shf *
+shf_reopen(int fd, int sflags, struct shf *shf)
+{
+	int bsize = sflags & SHF_UNBUF ? (sflags & SHF_RD ? 1 : 0) : SHF_BSIZE;
+
+	/* use fcntl() to figure out correct read/write flags */
+	if (sflags & SHF_GETFL) {
+		int flags = fcntl(fd, F_GETFL, 0);
+
+		if (flags < 0)
+			/* will get an error on first read/write */
+			sflags |= SHF_RDWR;
+		else {
+			switch (flags & O_ACCMODE) {
+			case O_RDONLY:
+				sflags |= SHF_RD;
+				break;
+			case O_WRONLY:
+				sflags |= SHF_WR;
+				break;
+			case O_RDWR:
+				sflags |= SHF_RDWR;
+				break;
+			}
+		}
+	}
+
+	if (!(sflags & (SHF_RD | SHF_WR)))
+		internal_errorf("shf_reopen: missing read/write");
+	if (!shf || !shf->buf || shf->bsize < bsize)
+		internal_errorf("shf_reopen: bad shf/buf/bsize");
+
+	/* assumes shf->buf and shf->bsize already set up */
+	shf->fd = fd;
+	shf->rp = shf->wp = shf->buf;
+	shf->rnleft = 0;
+	shf->rbsize = bsize;
+	shf->wnleft = 0; /* force call to shf_emptybuf() */
+	shf->wbsize = sflags & SHF_UNBUF ? 0 : bsize;
+	shf->flags = (shf->flags & (SHF_ALLOCS | SHF_ALLOCB)) | sflags;
+	shf->errno_ = 0;
+	if (sflags & SHF_CLEXEC)
+		fcntl(fd, F_SETFD, FD_CLOEXEC);
+	return (shf);
+}
+
+/* Open a string for reading or writing. If reading, bsize is the number
+ * of bytes that can be read. If writing, bsize is the maximum number of
+ * bytes that can be written. If shf is not null, it is filled in and
+ * returned, if it is null, shf is allocated. If writing and buf is null
+ * and SHF_DYNAMIC is set, the buffer is allocated (if bsize > 0, it is
+ * used for the initial size). Doesn't fail.
+ * When writing, a byte is reserved for a trailing null - see shf_sclose().
+ */
+struct shf *
+shf_sopen(char *buf, int bsize, int sflags, struct shf *shf)
+{
+	/* can't have a read+write string */
+	if (!(!(sflags & SHF_RD) ^ !(sflags & SHF_WR)))
+		internal_errorf("shf_sopen: flags 0x%x", sflags);
+
+	if (!shf) {
+		shf = alloc(sizeof(struct shf), ATEMP);
+		sflags |= SHF_ALLOCS;
+	}
+	shf->areap = ATEMP;
+	if (!buf && (sflags & SHF_WR) && (sflags & SHF_DYNAMIC)) {
+		if (bsize <= 0)
+			bsize = 64;
+		sflags |= SHF_ALLOCB;
+		buf = alloc(bsize, shf->areap);
+	}
+	shf->fd = -1;
+	shf->buf = shf->rp = shf->wp = (unsigned char *)buf;
+	shf->rnleft = bsize;
+	shf->rbsize = bsize;
+	shf->wnleft = bsize - 1;	/* space for a '\0' */
+	shf->wbsize = bsize;
+	shf->flags = sflags | SHF_STRING;
+	shf->errno_ = 0;
+	shf->bsize = bsize;
+
+	return (shf);
+}
+
+/* Flush and close file descriptor, free the shf structure */
+int
+shf_close(struct shf *shf)
+{
+	int ret = 0;
+
+	if (shf->fd >= 0) {
+		ret = shf_flush(shf);
+		if (close(shf->fd) < 0)
+			ret = EOF;
+	}
+	if (shf->flags & SHF_ALLOCS)
+		afree(shf, shf->areap);
+	else if (shf->flags & SHF_ALLOCB)
+		afree(shf->buf, shf->areap);
+
+	return (ret);
+}
+
+/* Flush and close file descriptor, don't free file structure */
+int
+shf_fdclose(struct shf *shf)
+{
+	int ret = 0;
+
+	if (shf->fd >= 0) {
+		ret = shf_flush(shf);
+		if (close(shf->fd) < 0)
+			ret = EOF;
+		shf->rnleft = 0;
+		shf->rp = shf->buf;
+		shf->wnleft = 0;
+		shf->fd = -1;
+	}
+
+	return (ret);
+}
+
+/* Close a string - if it was opened for writing, it is null terminated;
+ * returns a pointer to the string and frees shf if it was allocated
+ * (does not free string if it was allocated).
+ */
+char *
+shf_sclose(struct shf *shf)
+{
+	unsigned char *s = shf->buf;
+
+	/* null terminate */
+	if (shf->flags & SHF_WR) {
+		shf->wnleft++;
+		shf_putc('\0', shf);
+	}
+	if (shf->flags & SHF_ALLOCS)
+		afree(shf, shf->areap);
+	return ((char *)s);
+}
+
+/* Un-read what has been read but not examined, or write what has been
+ * buffered. Returns 0 for success, EOF for (write) error.
+ */
+int
+shf_flush(struct shf *shf)
+{
+	if (shf->flags & SHF_STRING)
+		return ((shf->flags & SHF_WR) ? EOF : 0);
+
+	if (shf->fd < 0)
+		internal_errorf("shf_flush: no fd");
+
+	if (shf->flags & SHF_ERROR) {
+		errno = shf->errno_;
+		return (EOF);
+	}
+
+	if (shf->flags & SHF_READING) {
+		shf->flags &= ~(SHF_EOF | SHF_READING);
+		if (shf->rnleft > 0) {
+			lseek(shf->fd, (off_t)-shf->rnleft, SEEK_CUR);
+			shf->rnleft = 0;
+			shf->rp = shf->buf;
+		}
+		return (0);
+	} else if (shf->flags & SHF_WRITING)
+		return (shf_emptybuf(shf, 0));
+
+	return (0);
+}
+
+/* Write out any buffered data. If currently reading, flushes the read
+ * buffer. Returns 0 for success, EOF for (write) error.
+ */
+static int
+shf_emptybuf(struct shf *shf, int flags)
+{
+	int ret = 0;
+
+	if (!(shf->flags & SHF_STRING) && shf->fd < 0)
+		internal_errorf("shf_emptybuf: no fd");
+
+	if (shf->flags & SHF_ERROR) {
+		errno = shf->errno_;
+		return (EOF);
+	}
+
+	if (shf->flags & SHF_READING) {
+		if (flags & EB_READSW) /* doesn't happen */
+			return (0);
+		ret = shf_flush(shf);
+		shf->flags &= ~SHF_READING;
+	}
+	if (shf->flags & SHF_STRING) {
+		unsigned char *nbuf;
+
+		/* Note that we assume SHF_ALLOCS is not set if SHF_ALLOCB
+		 * is set... (changing the shf pointer could cause problems)
+		 */
+		if (!(flags & EB_GROW) || !(shf->flags & SHF_DYNAMIC) ||
+		    !(shf->flags & SHF_ALLOCB))
+			return (EOF);
+		/* allocate more space for buffer */
+		nbuf = aresize(shf->buf, 2 * shf->wbsize, shf->areap);
+		shf->rp = nbuf + (shf->rp - shf->buf);
+		shf->wp = nbuf + (shf->wp - shf->buf);
+		shf->rbsize += shf->wbsize;
+		shf->wnleft += shf->wbsize;
+		shf->wbsize *= 2;
+		shf->buf = nbuf;
+	} else {
+		if (shf->flags & SHF_WRITING) {
+			int ntowrite = shf->wp - shf->buf;
+			unsigned char *buf = shf->buf;
+			int n;
+
+			while (ntowrite > 0) {
+				n = write(shf->fd, buf, ntowrite);
+				if (n < 0) {
+					if (errno == EINTR &&
+					    !(shf->flags & SHF_INTERRUPT))
+						continue;
+					shf->flags |= SHF_ERROR;
+					shf->errno_ = errno;
+					shf->wnleft = 0;
+					if (buf != shf->buf) {
+						/* allow a second flush
+						 * to work */
+						memmove(shf->buf, buf,
+						    ntowrite);
+						shf->wp = shf->buf + ntowrite;
+					}
+					return (EOF);
+				}
+				buf += n;
+				ntowrite -= n;
+			}
+			if (flags & EB_READSW) {
+				shf->wp = shf->buf;
+				shf->wnleft = 0;
+				shf->flags &= ~SHF_WRITING;
+				return (0);
+			}
+		}
+		shf->wp = shf->buf;
+		shf->wnleft = shf->wbsize;
+	}
+	shf->flags |= SHF_WRITING;
+
+	return (ret);
+}
+
+/* Fill up a read buffer. Returns EOF for a read error, 0 otherwise. */
+static int
+shf_fillbuf(struct shf *shf)
+{
+	if (shf->flags & SHF_STRING)
+		return (0);
+
+	if (shf->fd < 0)
+		internal_errorf("shf_fillbuf: no fd");
+
+	if (shf->flags & (SHF_EOF | SHF_ERROR)) {
+		if (shf->flags & SHF_ERROR)
+			errno = shf->errno_;
+		return (EOF);
+	}
+
+	if ((shf->flags & SHF_WRITING) && shf_emptybuf(shf, EB_READSW) == EOF)
+		return (EOF);
+
+	shf->flags |= SHF_READING;
+
+	shf->rp = shf->buf;
+	while (1) {
+		shf->rnleft = blocking_read(shf->fd, (char *) shf->buf,
+		    shf->rbsize);
+		if (shf->rnleft < 0 && errno == EINTR &&
+		    !(shf->flags & SHF_INTERRUPT))
+			continue;
+		break;
+	}
+	if (shf->rnleft <= 0) {
+		if (shf->rnleft < 0) {
+			shf->flags |= SHF_ERROR;
+			shf->errno_ = errno;
+			shf->rnleft = 0;
+			shf->rp = shf->buf;
+			return (EOF);
+		}
+		shf->flags |= SHF_EOF;
+	}
+	return (0);
+}
+
+/* Read a buffer from shf. Returns the number of bytes read into buf,
+ * if no bytes were read, returns 0 if end of file was seen, EOF if
+ * a read error occurred.
+ */
+int
+shf_read(char *buf, int bsize, struct shf *shf)
+{
+	int orig_bsize = bsize;
+	int ncopy;
+
+	if (!(shf->flags & SHF_RD))
+		internal_errorf("shf_read: flags %x", shf->flags);
+
+	if (bsize <= 0)
+		internal_errorf("shf_read: bsize %d", bsize);
+
+	while (bsize > 0) {
+		if (shf->rnleft == 0 &&
+		    (shf_fillbuf(shf) == EOF || shf->rnleft == 0))
+			break;
+		ncopy = shf->rnleft;
+		if (ncopy > bsize)
+			ncopy = bsize;
+		memcpy(buf, shf->rp, ncopy);
+		buf += ncopy;
+		bsize -= ncopy;
+		shf->rp += ncopy;
+		shf->rnleft -= ncopy;
+	}
+	/* Note: fread(3S) returns 0 for errors - this doesn't */
+	return (orig_bsize == bsize ? (shf_error(shf) ? EOF : 0) :
+	    orig_bsize - bsize);
+}
+
+/* Read up to a newline or EOF. The newline is put in buf; buf is always
+ * null terminated. Returns NULL on read error or if nothing was read before
+ * end of file, returns a pointer to the null byte in buf otherwise.
+ */
+char *
+shf_getse(char *buf, int bsize, struct shf *shf)
+{
+	unsigned char *end;
+	int ncopy;
+	char *orig_buf = buf;
+
+	if (!(shf->flags & SHF_RD))
+		internal_errorf("shf_getse: flags %x", shf->flags);
+
+	if (bsize <= 0)
+		return (NULL);
+
+	--bsize;	/* save room for null */
+	do {
+		if (shf->rnleft == 0) {
+			if (shf_fillbuf(shf) == EOF)
+				return (NULL);
+			if (shf->rnleft == 0) {
+				*buf = '\0';
+				return (buf == orig_buf ? NULL : buf);
+			}
+		}
+		end = (unsigned char *)memchr((char *) shf->rp, '\n',
+		    shf->rnleft);
+		ncopy = end ? end - shf->rp + 1 : shf->rnleft;
+		if (ncopy > bsize)
+			ncopy = bsize;
+		memcpy(buf, (char *) shf->rp, ncopy);
+		shf->rp += ncopy;
+		shf->rnleft -= ncopy;
+		buf += ncopy;
+		bsize -= ncopy;
+	} while (!end && bsize);
+	*buf = '\0';
+	return (buf);
+}
+
+/* Returns the char read. Returns EOF for error and end of file. */
+int
+shf_getchar(struct shf *shf)
+{
+	if (!(shf->flags & SHF_RD))
+		internal_errorf("shf_getchar: flags %x", shf->flags);
+
+	if (shf->rnleft == 0 && (shf_fillbuf(shf) == EOF || shf->rnleft == 0))
+		return (EOF);
+	--shf->rnleft;
+	return (*shf->rp++);
+}
+
+/* Put a character back in the input stream. Returns the character if
+ * successful, EOF if there is no room.
+ */
+int
+shf_ungetc(int c, struct shf *shf)
+{
+	if (!(shf->flags & SHF_RD))
+		internal_errorf("shf_ungetc: flags %x", shf->flags);
+
+	if ((shf->flags & SHF_ERROR) || c == EOF ||
+	    (shf->rp == shf->buf && shf->rnleft))
+		return (EOF);
+
+	if ((shf->flags & SHF_WRITING) && shf_emptybuf(shf, EB_READSW) == EOF)
+		return (EOF);
+
+	if (shf->rp == shf->buf)
+		shf->rp = shf->buf + shf->rbsize;
+	if (shf->flags & SHF_STRING) {
+		/* Can unget what was read, but not something different - we
+		 * don't want to modify a string.
+		 */
+		if (shf->rp[-1] != c)
+			return (EOF);
+		shf->flags &= ~SHF_EOF;
+		shf->rp--;
+		shf->rnleft++;
+		return (c);
+	}
+	shf->flags &= ~SHF_EOF;
+	*--(shf->rp) = c;
+	shf->rnleft++;
+	return (c);
+}
+
+/* Write a character. Returns the character if successful, EOF if
+ * the char could not be written.
+ */
+int
+shf_putchar(int c, struct shf *shf)
+{
+	if (!(shf->flags & SHF_WR))
+		internal_errorf("shf_putchar: flags %x", shf->flags);
+
+	if (c == EOF)
+		return (EOF);
+
+	if (shf->flags & SHF_UNBUF) {
+		unsigned char cc = (unsigned char)c;
+		int n;
+
+		if (shf->fd < 0)
+			internal_errorf("shf_putchar: no fd");
+		if (shf->flags & SHF_ERROR) {
+			errno = shf->errno_;
+			return (EOF);
+		}
+		while ((n = write(shf->fd, &cc, 1)) != 1)
+			if (n < 0) {
+				if (errno == EINTR &&
+				    !(shf->flags & SHF_INTERRUPT))
+					continue;
+				shf->flags |= SHF_ERROR;
+				shf->errno_ = errno;
+				return (EOF);
+			}
+	} else {
+		/* Flush deals with strings and sticky errors */
+		if (shf->wnleft == 0 && shf_emptybuf(shf, EB_GROW) == EOF)
+			return (EOF);
+		shf->wnleft--;
+		*shf->wp++ = c;
+	}
+
+	return (c);
+}
+
+/* Write a string. Returns the length of the string if successful, EOF if
+ * the string could not be written.
+ */
+int
+shf_puts(const char *s, struct shf *shf)
+{
+	if (!s)
+		return (EOF);
+
+	return (shf_write(s, strlen(s), shf));
+}
+
+/* Write a buffer. Returns nbytes if successful, EOF if there is an error. */
+int
+shf_write(const char *buf, int nbytes, struct shf *shf)
+{
+	int n, ncopy, orig_nbytes = nbytes;
+
+	if (!(shf->flags & SHF_WR))
+		internal_errorf("shf_write: flags %x", shf->flags);
+
+	if (nbytes < 0)
+		internal_errorf("shf_write: nbytes %d", nbytes);
+
+	/* Don't buffer if buffer is empty and we're writting a large amount. */
+	if ((ncopy = shf->wnleft) &&
+	    (shf->wp != shf->buf || nbytes < shf->wnleft)) {
+		if (ncopy > nbytes)
+			ncopy = nbytes;
+		memcpy(shf->wp, buf, ncopy);
+		nbytes -= ncopy;
+		buf += ncopy;
+		shf->wp += ncopy;
+		shf->wnleft -= ncopy;
+	}
+	if (nbytes > 0) {
+		if (shf->flags & SHF_STRING) {
+			/* resize buffer until there's enough space left */
+			while (nbytes > shf->wnleft)
+				if (shf_emptybuf(shf, EB_GROW) == EOF)
+					return (EOF);
+			/* then write everything into the buffer */
+		} else {
+			/* flush deals with sticky errors */
+			if (shf_emptybuf(shf, EB_GROW) == EOF)
+				return (EOF);
+			/* write chunks larger than window size directly */
+			if (nbytes > shf->wbsize) {
+				ncopy = nbytes;
+				if (shf->wbsize)
+					ncopy -= nbytes % shf->wbsize;
+				nbytes -= ncopy;
+				while (ncopy > 0) {
+					n = write(shf->fd, buf, ncopy);
+					if (n < 0) {
+						if (errno == EINTR &&
+						    !(shf->flags & SHF_INTERRUPT))
+							continue;
+						shf->flags |= SHF_ERROR;
+						shf->errno_ = errno;
+						shf->wnleft = 0;
+						/*
+						 * Note: fwrite(3) returns 0
+						 * for errors - this doesn't
+						 */
+						return (EOF);
+					}
+					buf += n;
+					ncopy -= n;
+				}
+			}
+			/* ... and buffer the rest */
+		}
+		if (nbytes > 0) {
+			/* write remaining bytes to buffer */
+			memcpy(shf->wp, buf, nbytes);
+			shf->wp += nbytes;
+			shf->wnleft -= nbytes;
+		}
+	}
+
+	return (orig_nbytes);
+}
+
+int
+shf_fprintf(struct shf *shf, const char *fmt, ...)
+{
+	va_list args;
+	int n;
+
+	va_start(args, fmt);
+	n = shf_vfprintf(shf, fmt, args);
+	va_end(args);
+
+	return (n);
+}
+
+int
+shf_snprintf(char *buf, int bsize, const char *fmt, ...)
+{
+	struct shf shf;
+	va_list args;
+	int n;
+
+	if (!buf || bsize <= 0)
+		internal_errorf("shf_snprintf: buf %p, bsize %d", buf, bsize);
+
+	shf_sopen(buf, bsize, SHF_WR, &shf);
+	va_start(args, fmt);
+	n = shf_vfprintf(&shf, fmt, args);
+	va_end(args);
+	shf_sclose(&shf); /* null terminates */
+	return (n);
+}
+
+char *
+shf_smprintf(const char *fmt, ...)
+{
+	struct shf shf;
+	va_list args;
+
+	shf_sopen(NULL, 0, SHF_WR|SHF_DYNAMIC, &shf);
+	va_start(args, fmt);
+	shf_vfprintf(&shf, fmt, args);
+	va_end(args);
+	return (shf_sclose(&shf)); /* null terminates */
+}
+
+#undef FP			/* if you want floating point stuff */
+
+#ifndef DMAXEXP
+# define DMAXEXP	128	/* should be big enough */
+#endif
+
+#define BUF_SIZE	128
+/* must be > MAX(DMAXEXP, log10(pow(2, DSIGNIF))) + ceil(log10(DMAXEXP)) + 8
+ * (I think); since it's hard to express as a constant, just use a large buffer
+ */
+#define FPBUF_SIZE	(DMAXEXP+16)
+
+#define	FL_HASH		0x001	/* '#' seen */
+#define FL_PLUS		0x002	/* '+' seen */
+#define FL_RIGHT	0x004	/* '-' seen */
+#define FL_BLANK	0x008	/* ' ' seen */
+#define FL_SHORT	0x010	/* 'h' seen */
+#define FL_LONG		0x020	/* 'l' seen */
+#define FL_ZERO		0x040	/* '0' seen */
+#define FL_DOT		0x080	/* '.' seen */
+#define FL_UPPER	0x100	/* format character was uppercase */
+#define FL_NUMBER	0x200	/* a number was formated %[douxefg] */
+
+
+int
+shf_vfprintf(struct shf *shf, const char *fmt, va_list args)
+{
+	const char *s;
+	char c, *cp;
+	int tmp = 0, field, precision, len, flags;
+	unsigned long lnum;
+	/* %#o produces the longest output */
+	char numbuf[(8 * sizeof(long) + 2) / 3 + 1];
+	/* this stuff for dealing with the buffer */
+	int nwritten = 0;
+
+	if (!fmt)
+		return (0);
+
+	while ((c = *fmt++)) {
+		if (c != '%') {
+			shf_putc(c, shf);
+			nwritten++;
+			continue;
+		}
+		/*
+		 * This will accept flags/fields in any order - not
+		 * just the order specified in printf(3), but this is
+		 * the way _doprnt() seems to work (on bsd and sysV).
+		 * The only restriction is that the format character must
+		 * come last :-).
+		 */
+		flags = field = precision = 0;
+		for ( ; (c = *fmt++) ; ) {
+			switch (c) {
+			case '#':
+				flags |= FL_HASH;
+				continue;
+
+			case '+':
+				flags |= FL_PLUS;
+				continue;
+
+			case '-':
+				flags |= FL_RIGHT;
+				continue;
+
+			case ' ':
+				flags |= FL_BLANK;
+				continue;
+
+			case '0':
+				if (!(flags & FL_DOT))
+					flags |= FL_ZERO;
+				continue;
+
+			case '.':
+				flags |= FL_DOT;
+				precision = 0;
+				continue;
+
+			case '*':
+				tmp = va_arg(args, int);
+				if (flags & FL_DOT)
+					precision = tmp;
+				else if ((field = tmp) < 0) {
+					field = -field;
+					flags |= FL_RIGHT;
+				}
+				continue;
+
+			case 'l':
+				flags |= FL_LONG;
+				continue;
+
+			case 'h':
+				flags |= FL_SHORT;
+				continue;
+			}
+			if (ksh_isdigit(c)) {
+				tmp = c - '0';
+				while (c = *fmt++, ksh_isdigit(c))
+					tmp = tmp * 10 + c - '0';
+				--fmt;
+				if (tmp < 0)		/* overflow? */
+					tmp = 0;
+				if (flags & FL_DOT)
+					precision = tmp;
+				else
+					field = tmp;
+				continue;
+			}
+			break;
+		}
+
+		if (precision < 0)
+			precision = 0;
+
+		if (!c)		/* nasty format */
+			break;
+
+		if (c >= 'A' && c <= 'Z') {
+			flags |= FL_UPPER;
+			c = ksh_tolower(c);
+		}
+
+		switch (c) {
+		case 'p': /* pointer */
+			flags &= ~(FL_LONG | FL_SHORT);
+			flags |= (sizeof(char *) > sizeof(int)) ?
+			    /* hope it fits.. */ FL_LONG : 0;
+			/* aaahhh... */
+		case 'd':
+		case 'i':
+		case 'o':
+		case 'u':
+		case 'x':
+			flags |= FL_NUMBER;
+			cp = numbuf + sizeof(numbuf);
+			/*-
+			 * XXX any better way to do this?
+			 * XXX hopefully the compiler optimises this out
+			 *
+			 * For shorts, we want sign extend for %d but not
+			 * for %[oxu] - on 16 bit machines it doesn't matter.
+			 * Assumes C compiler has converted shorts to ints
+			 * before pushing them. XXX optimise this -tg
+			 */
+			if (flags & FL_LONG)
+				lnum = va_arg(args, unsigned long);
+			else if ((sizeof(int) < sizeof(long)) && (c == 'd'))
+				lnum = (long)va_arg(args, int);
+			else
+				lnum = va_arg(args, unsigned int);
+			switch (c) {
+			case 'd':
+			case 'i':
+				if (0 > (long)lnum) {
+					lnum = -(long)lnum;
+					tmp = 1;
+				} else
+					tmp = 0;
+				/* FALLTHROUGH */
+			case 'u':
+				do {
+					*--cp = lnum % 10 + '0';
+					lnum /= 10;
+				} while (lnum);
+
+				if (c != 'u') {
+					if (tmp)
+						*--cp = '-';
+					else if (flags & FL_PLUS)
+						*--cp = '+';
+					else if (flags & FL_BLANK)
+						*--cp = ' ';
+				}
+				break;
+
+			case 'o':
+				do {
+					*--cp = (lnum & 0x7) + '0';
+					lnum >>= 3;
+				} while (lnum);
+
+				if ((flags & FL_HASH) && *cp != '0')
+					*--cp = '0';
+				break;
+
+			case 'p':
+			case 'x': {
+				const char *digits = (flags & FL_UPPER) ?
+				    digits_uc : digits_lc;
+				do {
+					*--cp = digits[lnum & 0xf];
+					lnum >>= 4;
+				} while (lnum);
+
+				if (flags & FL_HASH) {
+					*--cp = (flags & FL_UPPER) ? 'X' : 'x';
+					*--cp = '0';
+				}
+			}
+			}
+			len = numbuf + sizeof(numbuf) - (s = cp);
+			if (flags & FL_DOT) {
+				if (precision > len) {
+					field = precision;
+					flags |= FL_ZERO;
+				} else
+					precision = len; /* no loss */
+			}
+			break;
+
+		case 's':
+			if (!(s = va_arg(args, const char *)))
+				s = "(null)";
+			len = utf_mbswidth(s);
+			break;
+
+		case 'c':
+			flags &= ~FL_DOT;
+			numbuf[0] = (char)(va_arg(args, int));
+			s = numbuf;
+			len = 1;
+			break;
+
+		case '%':
+		default:
+			numbuf[0] = c;
+			s = numbuf;
+			len = 1;
+			break;
+		}
+
+		/*
+		 * At this point s should point to a string that is to be
+		 * formatted, and len should be the length of the string.
+		 */
+		if (!(flags & FL_DOT) || len < precision)
+			precision = len;
+		if (field > precision) {
+			field -= precision;
+			if (!(flags & FL_RIGHT)) {
+				field = -field;
+				/* skip past sign or 0x when padding with 0 */
+				if ((flags & FL_ZERO) && (flags & FL_NUMBER)) {
+					if (*s == '+' || *s == '-' ||
+					    *s == ' ') {
+						shf_putc(*s, shf);
+						s++;
+						precision--;
+						nwritten++;
+					} else if (*s == '0') {
+						shf_putc(*s, shf);
+						s++;
+						nwritten++;
+						if (--precision > 0 &&
+						    (*s | 0x20) == 'x') {
+							shf_putc(*s, shf);
+							s++;
+							precision--;
+							nwritten++;
+						}
+					}
+					c = '0';
+				} else
+					c = flags & FL_ZERO ? '0' : ' ';
+				if (field < 0) {
+					nwritten += -field;
+					for ( ; field < 0 ; field++)
+						shf_putc(c, shf);
+				}
+			} else
+				c = ' ';
+		} else
+			field = 0;
+
+		if (precision > 0) {
+			const char *q;
+
+			nwritten += precision;
+			q = utf_skipcols(s, precision);
+			do {
+				shf_putc(*s, shf);
+			} while (++s < q);
+		}
+		if (field > 0) {
+			nwritten += field;
+			for ( ; field > 0 ; --field)
+				shf_putc(c, shf);
+		}
+	}
+
+	return (shf_error(shf) ? EOF : nwritten);
+}
+
+#ifdef MKSH_SMALL
+int
+shf_getc(struct shf *shf)
+{
+	return ((shf)->rnleft > 0 ? (shf)->rnleft--, *(shf)->rp++ :
+	    shf_getchar(shf));
+}
+
+int
+shf_putc(int c, struct shf *shf)
+{
+	return ((shf)->wnleft == 0 ? shf_putchar((c), (shf)) :
+	    ((shf)->wnleft--, *(shf)->wp++ = (c)));
+}
+#endif