vendor/csup/20060302

1 files changed, 1080 insertions, 0 deletions

diff --git a/contrib/csup/stream.c b/contrib/csup/stream.c
new file mode 100644
index 0000000000000..34aa71e3273fe
--- /dev/null
+++ b/contrib/csup/stream.c
@@ -0,0 +1,1080 @@
+/*-
+ * Copyright (c) 2003-2006, Maxime Henrion <mux@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <assert.h>
+#include <zlib.h>
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "misc.h"
+#include "stream.h"
+
+/*
+ * Simple stream API to make my life easier.  If the fgetln() and
+ * funopen() functions were standard and if funopen() wasn't using
+ * wrong types for the function pointers, I could have just used
+ * stdio, but life sucks.
+ *
+ * For now, streams are always block-buffered.
+ */
+
+/*
+ * Try to quiet warnings as much as possible with GCC while staying
+ * compatible with other compilers.
+ */
+#ifndef __unused
+#if defined(__GNUC__) && (__GNUC__ > 2 || __GNUC__ == 2 && __GNUC_MINOR__ >= 7)
+#define	__unused	__attribute__((__unused__))
+#else
+#define	__unused
+#endif
+#endif
+
+/*
+ * Flags passed to the flush methods.
+ *
+ * STREAM_FLUSH_CLOSING is passed during the last flush call before
+ * closing a stream.  This allows the zlib filter to emit the EOF
+ * marker as appropriate.  In all other cases, STREAM_FLUSH_NORMAL
+ * should be passed.
+ *
+ * These flags are completely unused in the default flush method,
+ * but they are very important for the flush method of the zlib
+ * filter.
+ */
+typedef enum {
+	STREAM_FLUSH_NORMAL,
+	STREAM_FLUSH_CLOSING
+} stream_flush_t;
+
+/*
+ * This is because buf_new() will always allocate size + 1 bytes,
+ * so our buffer sizes will still be power of 2 values.
+ */
+#define	STREAM_BUFSIZ	1023
+
+struct buf {
+	char *buf;
+	size_t size;
+	size_t in;
+	size_t off;
+};
+
+struct stream {
+	void *cookie;
+	int fd;
+	struct buf *rdbuf;
+	struct buf *wrbuf;
+	stream_readfn_t *readfn;
+	stream_writefn_t *writefn;
+	stream_closefn_t *closefn;
+	int eof;
+	struct stream_filter *filter;
+	void *fdata;
+};
+
+typedef int	stream_filter_initfn_t(struct stream *, void *);
+typedef void	stream_filter_finifn_t(struct stream *);
+typedef int	stream_filter_flushfn_t(struct stream *, struct buf *,
+		    stream_flush_t);
+typedef ssize_t	stream_filter_fillfn_t(struct stream *, struct buf *);
+
+struct stream_filter {
+	stream_filter_t id;
+	stream_filter_initfn_t *initfn;
+	stream_filter_finifn_t *finifn;
+	stream_filter_fillfn_t *fillfn;
+	stream_filter_flushfn_t *flushfn;
+};
+
+/* Low-level buffer API. */
+#define	buf_avail(buf)		((buf)->size - (buf)->off - (buf)->in)
+#define	buf_count(buf)		((buf)->in)
+#define	buf_size(buf)		((buf)->size)
+
+static struct buf	*buf_new(size_t);
+static void		 buf_more(struct buf *, size_t);
+static void		 buf_less(struct buf *, size_t);
+static void		 buf_free(struct buf *);
+static void		 buf_grow(struct buf *, size_t);
+
+/* Internal stream functions. */
+static ssize_t		 stream_fill(struct stream *);
+static ssize_t		 stream_fill_default(struct stream *, struct buf *);
+static int		 stream_flush_int(struct stream *, stream_flush_t);
+static int		 stream_flush_default(struct stream *, struct buf *,
+			     stream_flush_t);
+
+/* Filters specific functions. */
+static struct stream_filter *stream_filter_lookup(stream_filter_t);
+static int		 stream_filter_init(struct stream *, void *);
+static void		 stream_filter_fini(struct stream *);
+
+/* The zlib stream filter declarations. */
+#define	ZFILTER_EOF	1				/* Got Z_STREAM_END. */
+
+struct zfilter {
+	int flags;
+	struct buf *rdbuf;
+	struct buf *wrbuf;
+	z_stream *rdstate;
+	z_stream *wrstate;
+};
+
+static int		 zfilter_init(struct stream *, void *);
+static void		 zfilter_fini(struct stream *);
+static ssize_t		 zfilter_fill(struct stream *, struct buf *);
+static int		 zfilter_flush(struct stream *, struct buf *,
+			     stream_flush_t);
+
+/* The MD5 stream filter. */
+struct md5filter {
+	MD5_CTX ctx;
+	char *md5;
+};
+
+static int		 md5filter_init(struct stream *, void *);
+static void		 md5filter_fini(struct stream *);
+static ssize_t		 md5filter_fill(struct stream *, struct buf *);
+static int		 md5filter_flush(struct stream *, struct buf *,
+			     stream_flush_t);
+
+/* The available stream filters. */
+struct stream_filter stream_filters[] = {
+	{
+		STREAM_FILTER_NULL,
+		NULL,
+		NULL,
+		stream_fill_default,
+		stream_flush_default
+	},
+	{
+	       	STREAM_FILTER_ZLIB,
+		zfilter_init,
+		zfilter_fini,
+		zfilter_fill,
+		zfilter_flush
+	},
+	{
+		STREAM_FILTER_MD5,
+		md5filter_init,
+		md5filter_fini,
+		md5filter_fill,
+		md5filter_flush
+	}
+};
+
+
+/* Create a new buffer. */
+static struct buf *
+buf_new(size_t size)
+{
+	struct buf *buf;
+
+	buf = xmalloc(sizeof(struct buf));
+	/*
+	 * We keep one spare byte so that stream_getln() can put a '\0'
+	 * there in case the stream doesn't have an ending newline.
+	 */
+	buf->buf = xmalloc(size + 1);
+	buf->size = size;
+	buf->in = 0;
+	buf->off = 0;
+	return (buf);
+}
+
+/*
+ * Grow the size of the buffer.  If "need" is 0, bump its size to the
+ * next power of 2 value.  Otherwise, bump it to the next power of 2
+ * value bigger than "need".
+ */
+static void
+buf_grow(struct buf *buf, size_t need)
+{
+
+	if (need == 0)
+		buf->size = buf->size * 2 + 1; /* Account for the spare byte. */
+	else {
+		assert(need > buf->size);
+		while (buf->size < need)
+			buf->size = buf->size * 2 + 1;
+	}
+	buf->buf = xrealloc(buf->buf, buf->size + 1);
+}
+
+/* Make more room in the buffer if needed. */
+static void
+buf_prewrite(struct buf *buf)
+{
+
+	if (buf_count(buf) == buf_size(buf))
+		buf_grow(buf, 0);
+	if (buf_count(buf) > 0 && buf_avail(buf) == 0) {
+		memmove(buf->buf, buf->buf + buf->off, buf_count(buf));
+		buf->off = 0;
+	}
+}
+
+/* Account for "n" bytes being added in the buffer. */
+static void
+buf_more(struct buf *buf, size_t n)
+{
+
+	assert(n <= buf_avail(buf));
+	buf->in += n;
+}
+
+/* Account for "n" bytes having been read in the buffer. */
+static void
+buf_less(struct buf *buf, size_t n)
+{
+
+	assert(n <= buf_count(buf));
+	buf->in -= n;
+	if (buf->in == 0)
+		buf->off = 0;
+	else
+		buf->off += n;
+}
+
+/* Free a buffer. */
+static void
+buf_free(struct buf *buf)
+{
+
+	free(buf->buf);
+	free(buf);
+}
+
+static struct stream *
+stream_new(stream_readfn_t *readfn, stream_writefn_t *writefn,
+    stream_closefn_t *closefn)
+{
+	struct stream *stream;
+
+	stream = xmalloc(sizeof(struct stream));
+	if (readfn == NULL && writefn == NULL) {
+		errno = EINVAL;
+		return (NULL);
+	}
+	if (readfn != NULL)
+		stream->rdbuf = buf_new(STREAM_BUFSIZ);
+	else
+		stream->rdbuf = NULL;
+	if (writefn != NULL)
+		stream->wrbuf = buf_new(STREAM_BUFSIZ);
+	else
+		stream->wrbuf = NULL;
+	stream->cookie = NULL;
+	stream->fd = -1;
+	stream->readfn = readfn;
+	stream->writefn = writefn;
+	stream->closefn = closefn;
+	stream->filter = stream_filter_lookup(STREAM_FILTER_NULL);
+	stream->fdata = NULL;
+	stream->eof = 0;
+	return (stream);
+}
+
+/* Create a new stream associated with a void *. */
+struct stream *
+stream_open(void *cookie, stream_readfn_t *readfn, stream_writefn_t *writefn,
+    stream_closefn_t *closefn)
+{
+	struct stream *stream;
+
+	stream = stream_new(readfn, writefn, closefn);
+	stream->cookie = cookie;
+	return (stream);
+}
+
+/* Associate a file descriptor with a stream. */
+struct stream *
+stream_open_fd(int fd, stream_readfn_t *readfn, stream_writefn_t *writefn,
+    stream_closefn_t *closefn)
+{
+	struct stream *stream;
+
+	stream = stream_new(readfn, writefn, closefn);
+	stream->cookie = &stream->fd;
+	stream->fd = fd;
+	return (stream);
+}
+
+/* Like open() but returns a stream. */
+struct stream *
+stream_open_file(const char *path, int flags, ...)
+{
+	struct stream *stream;
+	stream_readfn_t *readfn;
+	stream_writefn_t *writefn;
+	va_list ap;
+	mode_t mode;
+	int fd;
+
+	va_start(ap, flags);
+	if (flags & O_CREAT) {
+		/*
+		 * GCC says I should not be using mode_t here since it's
+		 * promoted to an int when passed through `...'.
+		 */
+		mode = va_arg(ap, int);
+		fd = open(path, flags, mode);
+	} else
+		fd = open(path, flags);
+	va_end(ap);
+	if (fd == -1)
+		return (NULL);
+
+	flags &= O_ACCMODE;
+	if (flags == O_RDONLY) {
+		readfn = stream_read_fd;
+		writefn = NULL;
+	} else if (flags == O_WRONLY) {
+		readfn = NULL;
+		writefn = stream_write_fd;
+	} else if (flags == O_RDWR) {
+		assert(flags == O_RDWR);
+		readfn = stream_read_fd;
+		writefn = stream_write_fd;
+	} else {
+		errno = EINVAL;
+		close(fd);
+		return (NULL);
+	}
+
+	stream = stream_open_fd(fd, readfn, writefn, stream_close_fd);
+	if (stream == NULL)
+		close(fd);
+	return (stream);
+}
+
+/* Return the file descriptor associated with this stream, or -1. */
+int
+stream_fileno(struct stream *stream)
+{
+
+	return (stream->fd);
+}
+
+/* Convenience read function for file descriptors. */
+ssize_t
+stream_read_fd(void *cookie, void *buf, size_t size)
+{
+	ssize_t nbytes;
+	int fd;
+
+	fd = *(int *)cookie;
+	nbytes = read(fd, buf, size);
+	return (nbytes);
+}
+
+/* Convenience write function for file descriptors. */
+ssize_t
+stream_write_fd(void *cookie, const void *buf, size_t size)
+{
+	ssize_t nbytes;
+	int fd;
+
+	fd = *(int *)cookie;
+	nbytes = write(fd, buf, size);
+	return (nbytes);
+}
+
+/* Convenience close function for file descriptors. */
+int
+stream_close_fd(void *cookie)
+{
+	int fd, ret;
+
+	fd = *(int *)cookie;
+	ret = close(fd);
+	return (ret);
+}
+
+/* Read some bytes from the stream. */
+ssize_t
+stream_read(struct stream *stream, void *buf, size_t size)
+{
+	struct buf *rdbuf;
+	ssize_t ret;
+	size_t n;
+
+	rdbuf = stream->rdbuf;
+	if (buf_count(rdbuf) == 0) {
+		ret = stream_fill(stream);
+		if (ret <= 0)
+			return (-1);
+	}
+	n = min(size, buf_count(rdbuf));
+	memcpy(buf, rdbuf->buf + rdbuf->off, n);
+	buf_less(rdbuf, n);
+	return (n);
+}
+
+/*
+ * Read a line from the stream and return a pointer to it.
+ *
+ * If "len" is non-NULL, the length of the string will be put into it.
+ * The pointer is only valid until the next stream API call.  The line
+ * can be modified by the caller, provided he doesn't write before or
+ * after it.
+ *
+ * This is somewhat similar to the BSD fgetln() function, except that
+ * "len" can be NULL here.  In that case the string is terminated by
+ * overwriting the '\n' character with a NUL character.  If it's the
+ * last line in the stream and it has no ending newline, we can still
+ * add '\0' after it, because we keep one spare byte in the buffers.
+ *
+ * However, be warned that one can't handle binary lines properly
+ * without knowing the size of the string since those can contain
+ * NUL characters.
+ */
+char *
+stream_getln(struct stream *stream, size_t *len)
+{
+	struct buf *buf;
+	char *cp, *line;
+	ssize_t n;
+	size_t done, size;
+
+	buf = stream->rdbuf;
+	if (buf_count(buf) == 0) {
+		n = stream_fill(stream);
+		if (n <= 0)
+			return (NULL);
+	}
+	cp = memchr(buf->buf + buf->off, '\n', buf_count(buf));
+	for (done = buf_count(buf); cp == NULL; done += n) {
+		n = stream_fill(stream);
+		if (n < 0)
+			return (NULL);
+		if (n == 0)
+			/* Last line of the stream. */
+			cp = buf->buf + buf->off + buf->in - 1;
+		else
+			cp = memchr(buf->buf + buf->off + done, '\n',
+			    buf_count(buf) - done);
+	}
+	line = buf->buf + buf->off;
+	assert(cp >= line);
+	size = cp - line + 1;
+	buf_less(buf, size);
+	if (len != NULL) {
+		*len = size;
+	} else {
+		/* Terminate the string when len == NULL. */
+		if (line[size - 1] == '\n')
+			line[size - 1] = '\0';
+		else
+			line[size] = '\0';
+	}
+	return (line);
+}
+
+/* Write some bytes to a stream. */
+ssize_t
+stream_write(struct stream *stream, const void *src, size_t nbytes)
+{
+	struct buf *buf;
+	int error;
+
+	buf = stream->wrbuf;
+	if (nbytes > buf_size(buf))
+		buf_grow(buf, nbytes);
+	if (nbytes > buf_avail(buf)) {
+		error = stream_flush_int(stream, STREAM_FLUSH_NORMAL);
+		if (error)
+			return (-1);
+	}
+	memcpy(buf->buf + buf->off + buf->in, src, nbytes);
+	buf_more(buf, nbytes);
+	return (nbytes);
+}
+
+/* Formatted output to a stream. */
+int
+stream_printf(struct stream *stream, const char *fmt, ...)
+{
+	struct buf *buf;
+	va_list ap;
+	int error, ret;
+
+	buf = stream->wrbuf;
+again:
+	va_start(ap, fmt);
+	ret = vsnprintf(buf->buf + buf->off + buf->in, buf_avail(buf), fmt, ap);
+	va_end(ap);
+	if (ret < 0)
+		return (ret);
+	if ((unsigned)ret >= buf_avail(buf)) {
+		if ((unsigned)ret >= buf_size(buf))
+			buf_grow(buf, ret + 1);
+		if ((unsigned)ret >= buf_avail(buf)) {
+			error = stream_flush_int(stream, STREAM_FLUSH_NORMAL);
+			if (error)
+				return (-1);
+		}
+		goto again;
+	}
+	buf_more(buf, ret);
+	return (ret);
+}
+
+/* Flush the entire write buffer of the stream. */
+int
+stream_flush(struct stream *stream)
+{
+	int error;
+
+	error = stream_flush_int(stream, STREAM_FLUSH_NORMAL);
+	return (error);
+}
+
+/* Internal flush API. */
+static int
+stream_flush_int(struct stream *stream, stream_flush_t how)
+{
+	struct buf *buf;
+	int error;
+
+	buf = stream->wrbuf;
+	error = (*stream->filter->flushfn)(stream, buf, how);
+	assert(buf_count(buf) == 0);
+	return (error);
+}
+
+/* The default flush method. */
+static int
+stream_flush_default(struct stream *stream, struct buf *buf,
+    stream_flush_t __unused how)
+{
+	ssize_t n;
+
+	while (buf_count(buf) > 0) {
+		do {
+			n = (*stream->writefn)(stream->cookie,
+			    buf->buf + buf->off, buf_count(buf));
+		} while (n == -1 && errno == EINTR);
+		if (n <= 0)
+			return (-1);
+		buf_less(buf, n);
+	}
+	return (0);
+}
+
+/* Flush the write buffer and call fsync() on the file descriptor. */
+int
+stream_sync(struct stream *stream)
+{
+	int error;
+
+	if (stream->fd == -1) {
+		errno = EINVAL;
+		return (-1);
+	}
+	error = stream_flush_int(stream, STREAM_FLUSH_NORMAL);
+	if (error)
+		return (-1);
+	error = fsync(stream->fd);
+	return (error);
+}
+
+/* Like truncate() but on a stream. */
+int
+stream_truncate(struct stream *stream, off_t size)
+{
+	int error;
+
+	if (stream->fd == -1) {
+		errno = EINVAL;
+		return (-1);
+	}
+	error = stream_flush_int(stream, STREAM_FLUSH_NORMAL);
+	if (error)
+		return (-1);
+	error = ftruncate(stream->fd, size);
+	return (error);
+}
+
+/* Like stream_truncate() except the off_t parameter is an offset. */
+int
+stream_truncate_rel(struct stream *stream, off_t off)
+{
+	struct stat sb;
+	int error;
+
+	if (stream->fd == -1) {
+		errno = EINVAL;
+		return (-1);
+	}
+	error = stream_flush_int(stream, STREAM_FLUSH_NORMAL);
+	if (error)
+		return (-1);
+	error = fstat(stream->fd, &sb);
+	if (error)
+		return (-1);
+	error = stream_truncate(stream, sb.st_size + off);
+	return (error);
+}
+
+/* Rewind the stream. */
+int
+stream_rewind(struct stream *stream)
+{
+	int error;
+
+	if (stream->fd == -1) {
+		errno = EINVAL;
+		return (-1);
+	}
+	if (stream->rdbuf != NULL)
+		buf_less(stream->rdbuf, buf_count(stream->rdbuf));
+	if (stream->wrbuf != NULL) {
+		error = stream_flush_int(stream, STREAM_FLUSH_NORMAL);
+		if (error)
+			return (error);
+	}
+	error = lseek(stream->fd, 0, SEEK_SET);
+	return (error);
+}
+
+/* Return EOF status. */
+int
+stream_eof(struct stream *stream)
+{
+
+	return (stream->eof);
+}
+
+/* Close a stream and free any resources held by it. */
+int
+stream_close(struct stream *stream)
+{
+	int error;
+
+	if (stream == NULL)
+		return (0);
+
+	error = 0;
+	if (stream->wrbuf != NULL)
+		error = stream_flush_int(stream, STREAM_FLUSH_CLOSING);
+	stream_filter_fini(stream);
+	if (stream->closefn != NULL)
+		/*
+		 * We might overwrite a previous error from stream_flush(),
+		 * but we have no choice, because wether it had worked or
+		 * not, we need to close the file descriptor.
+		 */
+		error = (*stream->closefn)(stream->cookie);
+	if (stream->rdbuf != NULL)
+		buf_free(stream->rdbuf);
+	if (stream->wrbuf != NULL)
+		buf_free(stream->wrbuf);
+	free(stream);
+	return (error);
+}
+
+/* The default fill method. */
+static ssize_t
+stream_fill_default(struct stream *stream, struct buf *buf)
+{
+	ssize_t n;
+
+	if (stream->eof)
+		return (0);
+	assert(buf_avail(buf) > 0);
+	n = (*stream->readfn)(stream->cookie, buf->buf + buf->off + buf->in,
+	    buf_avail(buf));
+	if (n < 0)
+		return (-1);
+	if (n == 0) {
+		stream->eof = 1;
+		return (0);
+	}
+	buf_more(buf, n);
+	return (n);
+}
+
+/*
+ * Refill the read buffer.  This function is not permitted to return
+ * without having made more bytes available, unless there was an error.
+ * Moreover, stream_fill() returns the number of bytes added.
+ */
+static ssize_t
+stream_fill(struct stream *stream)
+{
+	struct stream_filter *filter;
+	struct buf *buf;
+#ifndef NDEBUG
+	size_t oldcount;
+#endif
+	ssize_t n;
+
+	filter = stream->filter;
+	buf = stream->rdbuf;
+	buf_prewrite(buf);
+#ifndef NDEBUG
+	oldcount = buf_count(buf);
+#endif
+	n = (*filter->fillfn)(stream, buf);
+	assert((n > 0 && n == (signed)(buf_count(buf) - oldcount)) ||
+	    (n <= 0 && buf_count(buf) == oldcount));
+	return (n);
+}
+
+/*
+ * Lookup a stream filter.
+ *
+ * We are not supposed to get passed an invalid filter id, since
+ * filter ids are an enum type and we don't have invalid filter
+ * ids in the enum :-).  Thus, we are not checking for out of
+ * bounds access here.  If it happens, it's the caller's fault
+ * anyway.
+ */
+static struct stream_filter *
+stream_filter_lookup(stream_filter_t id)
+{
+	struct stream_filter *filter;
+
+	filter = stream_filters;
+	while (filter->id != id)
+		filter++;
+	return (filter);
+}
+
+static int
+stream_filter_init(struct stream *stream, void *data)
+{
+	struct stream_filter *filter;
+	int error;
+
+	filter = stream->filter;
+	if (filter->initfn == NULL)
+		return (0);
+	error = (*filter->initfn)(stream, data);
+	return (error);
+}
+
+static void
+stream_filter_fini(struct stream *stream)
+{
+	struct stream_filter *filter;
+
+	filter = stream->filter;
+	if (filter->finifn != NULL)
+		(*filter->finifn)(stream);
+}
+
+/*
+ * Start a filter on a stream.
+ */
+int
+stream_filter_start(struct stream *stream, stream_filter_t id, void *data)
+{
+	struct stream_filter *filter;
+	int error;
+
+	filter = stream->filter;
+	if (id == filter->id)
+		return (0);
+	stream_filter_fini(stream);
+	stream->filter = stream_filter_lookup(id);
+	stream->fdata = NULL;
+	error = stream_filter_init(stream, data);
+	return (error);
+}
+
+
+/* Stop a filter, this is equivalent to setting the null filter. */
+void
+stream_filter_stop(struct stream *stream)
+{
+
+	stream_filter_start(stream, STREAM_FILTER_NULL, NULL);
+}
+
+/* The zlib stream filter implementation. */
+
+/* Take no chances with zlib... */
+static void *
+zfilter_alloc(void __unused *opaque, unsigned int items, unsigned int size)
+{
+
+	return (xmalloc(items * size));
+}
+
+static void
+zfilter_free(void __unused *opaque, void *ptr)
+{
+
+	free(ptr);
+}
+
+static int
+zfilter_init(struct stream *stream, void __unused *data)
+{
+	struct zfilter *zf;
+	struct buf *buf;
+	z_stream *state;
+	int rv;
+
+	zf = xmalloc(sizeof(struct zfilter));
+	memset(zf, 0, sizeof(struct zfilter));
+	if (stream->rdbuf != NULL) {
+		state = xmalloc(sizeof(z_stream));
+		state->zalloc = zfilter_alloc;
+		state->zfree = zfilter_free;
+		state->opaque = Z_NULL;
+		rv = inflateInit(state);
+		if (rv != Z_OK)
+			errx(1, "inflateInit: %s", state->msg);
+		buf = buf_new(buf_size(stream->rdbuf));
+		zf->rdbuf = stream->rdbuf;
+		stream->rdbuf = buf;
+		zf->rdstate = state;
+	}
+	if (stream->wrbuf != NULL) {
+		state = xmalloc(sizeof(z_stream));
+		state->zalloc = zfilter_alloc;
+		state->zfree = zfilter_free;
+		state->opaque = Z_NULL;
+		rv = deflateInit(state, Z_DEFAULT_COMPRESSION);
+		if (rv != Z_OK)
+			errx(1, "deflateInit: %s", state->msg);
+		buf = buf_new(buf_size(stream->wrbuf));
+		zf->wrbuf = stream->wrbuf;
+		stream->wrbuf = buf;
+		zf->wrstate = state;
+	}
+	stream->fdata = zf;
+	return (0);
+}
+
+static void
+zfilter_fini(struct stream *stream)
+{
+	struct zfilter *zf;
+	struct buf *zbuf;
+	z_stream *state;
+	ssize_t n;
+
+	zf = stream->fdata;
+	if (zf->rdbuf != NULL) {
+		state = zf->rdstate;
+		zbuf = zf->rdbuf;
+		/*
+		 * Even if it has produced all the bytes, zlib sometimes
+		 * hasn't seen the EOF marker, so we need to call inflate()
+		 * again to make sure we have eaten all the zlib'ed bytes.
+		 */
+		if ((zf->flags & ZFILTER_EOF) == 0) {
+			n = zfilter_fill(stream, stream->rdbuf);
+			assert(n == 0 && zf->flags & ZFILTER_EOF);
+		}
+		inflateEnd(state);
+		free(state);
+		buf_free(stream->rdbuf);
+		stream->rdbuf = zbuf;
+	}
+	if (zf->wrbuf != NULL) {
+		state = zf->wrstate;
+		zbuf = zf->wrbuf;
+		/*
+		 * Compress the remaining bytes in the buffer, if any,
+		 * and emit an EOF marker as appropriate.  We ignore
+		 * the error because we can't do anything about it at
+		 * this point, and it can happen if we're getting
+		 * disconnected.
+		 */
+		(void)zfilter_flush(stream, stream->wrbuf,
+		    STREAM_FLUSH_CLOSING);
+		deflateEnd(state);
+		free(state);
+		buf_free(stream->wrbuf);
+		stream->wrbuf = zbuf;
+	}
+	free(zf);
+}
+
+static int
+zfilter_flush(struct stream *stream, struct buf *buf, stream_flush_t how)
+{
+	struct zfilter *zf;
+	struct buf *zbuf;
+	z_stream *state;
+	size_t lastin, lastout, ate, prod;
+	int done, error, flags, rv;
+
+	zf = stream->fdata;
+	state = zf->wrstate;
+	zbuf = zf->wrbuf;
+
+	if (how == STREAM_FLUSH_NORMAL)
+		flags = Z_SYNC_FLUSH;
+	else
+		flags = Z_FINISH;
+
+	done = 0;
+	rv = Z_OK;
+
+again:
+	/*
+	 * According to zlib.h, we should have at least 6 bytes
+	 * available when using deflate() with Z_SYNC_FLUSH.
+	 */
+	if ((buf_avail(zbuf) < 6 && flags == Z_SYNC_FLUSH) ||
+	    rv == Z_BUF_ERROR || buf_avail(buf) == 0) {
+		error = stream_flush_default(stream, zbuf, how);
+		if (error)
+			return (error);
+	}
+
+	state->next_in = (Bytef *)(buf->buf + buf->off);
+	state->avail_in = buf_count(buf);
+	state->next_out = (Bytef *)(zbuf->buf + zbuf->off + zbuf->in);
+	state->avail_out = buf_avail(zbuf);
+	lastin = state->avail_in;
+	lastout = state->avail_out;
+	rv = deflate(state, flags);
+	if (rv != Z_BUF_ERROR && rv != Z_OK && rv != Z_STREAM_END)
+		errx(1, "deflate: %s", state->msg);
+	ate = lastin - state->avail_in;
+	prod = lastout - state->avail_out;
+	buf_less(buf, ate);
+	buf_more(zbuf, prod);
+	if ((flags == Z_SYNC_FLUSH && buf_count(buf) > 0) ||
+	    (flags == Z_FINISH && rv != Z_STREAM_END) ||
+	    (rv == Z_BUF_ERROR))
+		goto again;
+
+	assert(rv == Z_OK || (rv == Z_STREAM_END && flags == Z_FINISH));
+	error = stream_flush_default(stream, zbuf, how);
+	return (error);
+}
+
+static ssize_t
+zfilter_fill(struct stream *stream, struct buf *buf)
+{
+	struct zfilter *zf;
+	struct buf *zbuf;
+	z_stream *state;
+	size_t lastin, lastout, new;
+	ssize_t n;
+	int rv;
+
+	zf = stream->fdata;
+	state = zf->rdstate;
+	zbuf = zf->rdbuf;
+
+	assert(buf_avail(buf) > 0);
+	if (buf_count(zbuf) == 0) {
+		n = stream_fill_default(stream, zbuf);
+		if (n <= 0)
+			return (n);
+	}
+again:
+	assert(buf_count(zbuf) > 0);
+	state->next_in = (Bytef *)(zbuf->buf + zbuf->off);
+	state->avail_in = buf_count(zbuf);
+	state->next_out = (Bytef *)(buf->buf + buf->off + buf->in);
+	state->avail_out = buf_avail(buf);
+	lastin = state->avail_in;
+	lastout = state->avail_out;
+	rv = inflate(state, Z_SYNC_FLUSH);
+	buf_less(zbuf, lastin - state->avail_in);
+	new = lastout - state->avail_out;
+	if (new == 0 && rv != Z_STREAM_END) {
+		n = stream_fill_default(stream, zbuf);
+		if (n == -1)
+			return (-1);
+		if (n == 0)
+			return (0);
+		goto again;
+	}
+	if (rv != Z_STREAM_END && rv != Z_OK)
+		errx(1, "inflate: %s", state->msg);
+	if (rv == Z_STREAM_END)
+		zf->flags |= ZFILTER_EOF;
+	buf_more(buf, new);
+	return (new);
+}
+
+/* The MD5 stream filter implementation. */
+static int
+md5filter_init(struct stream *stream, void *data)
+{
+	struct md5filter *mf;
+
+	mf = xmalloc(sizeof(struct md5filter));
+	MD5_Init(&mf->ctx);
+	mf->md5 = data;
+	stream->fdata = mf;
+	return (0);
+}
+
+static void
+md5filter_fini(struct stream *stream)
+{
+	struct md5filter *mf;
+
+	mf = stream->fdata;
+	MD5_End(mf->md5, &mf->ctx);
+	free(stream->fdata);
+}
+
+static ssize_t
+md5filter_fill(struct stream *stream, struct buf *buf)
+{
+	ssize_t n;
+
+	assert(buf_avail(buf) > 0);
+	n = stream_fill_default(stream, buf);
+	return (n);
+}
+
+static int
+md5filter_flush(struct stream *stream, struct buf *buf, stream_flush_t how)
+{
+	struct md5filter *mf;
+	int error;
+
+	mf = stream->fdata;
+	MD5_Update(&mf->ctx, buf->buf + buf->off, buf->in);
+	error = stream_flush_default(stream, buf, how);
+	return (error);
+}