Add an implementation based on tedu@'s design of fmemopen(3) and

open_memstream(3) so they can be polished in-tree.

One of the manpages comes from NetBSD with some tweaks.

Prodded by espie@, krw@, guenther@

4 files changed, 655 insertions, 0 deletions

diff --git a/lib/libc/stdio/fmemopen.3 b/lib/libc/stdio/fmemopen.3
new file mode 100644
index 00000000000..2a996d66797
--- /dev/null
+++ b/lib/libc/stdio/fmemopen.3
@@ -0,0 +1,197 @@
+.\"	$OpenBSD: fmemopen.3,v 1.1 2013/01/01 17:41:13 mpi Exp $
+.\"	$NetBSD: fmemopen.3,v 1.5 2010/10/07 00:14:14 enami Exp $
+.\"
+.\" Copyright (c) 2010 The NetBSD Foundation, Inc.
+.\" All rights reserved.
+.\"
+.\" This code is derived from software contributed to The NetBSD Foundation
+.\" by Christos Zoulas.
+.\"
+.\" 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.
+.\" 3. All advertising materials mentioning features or use of this software
+.\"    must display the following acknowledgement:
+.\"        This product includes software developed by the NetBSD
+.\"        Foundation, Inc. and its contributors.
+.\" 4. Neither the name of The NetBSD Foundation nor the names of its
+.\"    contributors may be used to endorse or promote products derived
+.\"    from this software without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
+.\"
+.Dd $Mdocdate: January 1 2013 $
+.Dt FMEMOPEN 3
+.Os
+.Sh NAME
+.Nm fmemopen
+.Nd open a stream that points to the given buffer
+.Sh SYNOPSIS
+.Fd #include <stdio.h>
+.Ft FILE *
+.Fn fmemopen "void *buffer" "size_t size" "const char *mode"
+.Sh DESCRIPTION
+The
+.Fn fmemopen
+function associates a stream with the given
+.Fa buffer
+and
+.Fa size .
+The
+.Fa buffer
+can be either
+.Dv NULL ,
+or must be of the given
+.Fa size .
+If the
+.Fa buffer
+is
+.Dv NULL ,
+a
+.Fa buffer
+of the given
+.Fa size
+will be dynamically allocated using
+.Xr malloc 3
+and released when
+.Xr fclose 3
+is called.
+.Pp
+The
+.Fa mode
+argument has the same meaning as in
+.Xr fopen 3 .
+.Pp
+The stream treats the buffer as it would treat a file tracking the current
+position to perform I/O operations.
+For example, in the beginning the stream points to the beginning of the buffer,
+unless
+.Dv a
+was specified in the
+.Fa mode
+argument, and then it points to the first
+.Dv NUL
+byte.
+If a
+.Dv NULL
+.Fa buffer
+was specified, then the stream will always point at the first byte of the
+.Fa buffer .
+.Pp
+The stream also keeps track of the
+.Fa size
+of the
+.Fa buffer .
+The
+.Fa size
+is initialized depending on the mode:
+.Bl -tag -width r/w+
+.It Dv r/r+
+Set to the
+.Fa size
+argument.
+.It Dv w/w+
+Set to
+.Dv 0 .
+.It Dv a/a+
+Set to the first
+.Dv NUL
+byte, or the
+.Fa size
+argument if one is not found.
+.El
+.Pp
+Read or write operations advance the buffer, but not to exceed the given
+.Fa size
+of the
+.Fa buffer .
+Trying to read beyond the
+.Fa size
+of the
+.Fa buffer
+results in
+.Dv EOF
+returned.
+.Dv NUL
+bytes are read normally.
+Trying to write beyond the
+.Fa size
+of the
+.Fa buffer
+has no effect.
+.Pp
+When a stream open for writing is either flushed or closed, a
+.Dv NUL
+byte is written at the current position or at the end of the current
+.Fa size
+as kept internally.
+.Sh RETURN VALUES
+Upon successful completion,
+.Fn fmemopen
+returns a
+.Dv FILE
+pointer.
+Otherwise,
+.Dv NULL
+is returned and the global variable
+.Va errno
+is set to indicate the error.
+.Sh ERRORS
+.Bl -tag -width Er
+.It Bq Er EINVAL
+The
+.Fa size
+was
+.Dv 0 ;
+or the
+.Fa mode
+argument is invalid;
+or the
+.Fa buffer
+argument is
+.Dv NULL
+and the
+.Fa mode
+argument does not specify a
+.Dv + .
+.El
+.Pp
+The
+.Fn fmemopen
+function
+may also fail and set
+.Va errno
+for any of the errors
+specified for the routine
+.Xr malloc 3 .
+.Sh SEE ALSO
+.Xr fclose 3 ,
+.Xr fflush 3 ,
+.Xr fopen 3 ,
+.Xr funopen 3 ,
+.Xr malloc 3
+.Sh STANDARDS
+The function
+.Fn fmemopen
+conform to
+.St -p1003.1-2008 .
+.Sh HISTORY
+The
+.Fn fmemopen
+function first appeared in
+.Ox 5.3 .
diff --git a/lib/libc/stdio/fmemopen.c b/lib/libc/stdio/fmemopen.c
new file mode 100644
index 00000000000..fd76f625b23
--- /dev/null
+++ b/lib/libc/stdio/fmemopen.c
@@ -0,0 +1,186 @@
+/*	$OpenBSD: fmemopen.c,v 1.1 2013/01/01 17:41:13 mpi Exp $	*/
+/*
+ * Copyright (c) 2011 Martin Pieuchot <mpi@openbsd.org>
+ * Copyright (c) 2009 Ted Unangst
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "local.h"
+
+struct state {
+	char		*string;	/* actual stream */
+	size_t		 pos;		/* current position */
+	size_t		 size;		/* allocated size */
+	size_t		 len;		/* length of the data */
+};
+
+static int
+fmemopen_read(void *v, char *b, int l)
+{
+	struct state	*st = v;
+	int		 i;
+
+	for (i = 0; i < l && i + st->pos < st->len; i++)
+		b[i] = st->string[st->pos + i];
+	st->pos += i;
+
+	return (i);
+}
+
+static int
+fmemopen_write(void *v, const char *b, int l)
+{
+	struct state	*st = v;
+	int		i;
+
+	for (i = 0; i < l && i + st->pos < st->size; i++)
+		st->string[st->pos + i] = b[i];
+	st->pos += i;
+
+	if (st->pos >= st->len) {
+		st->len = st->pos;
+
+		if (st->len == st->size)
+			st->string[st->len - 1] = '\0';
+		else
+			st->string[st->len] = '\0';
+	}
+
+	return (i);
+}
+
+static fpos_t
+fmemopen_seek(void *v, fpos_t pos, int whence)
+{
+	struct state	*st = v;
+
+	switch (whence) {
+	case SEEK_SET:
+		break;
+	case SEEK_CUR:
+		pos += st->pos;
+		break;
+	case SEEK_END:
+		/*
+		 * XXX The standard is not clear about where to seek
+		 * from the end of the data or the end of the buffer.
+		 */
+		pos += st->len;
+		break;
+	default:
+		errno = EINVAL;
+		return (-1);
+	}
+
+	if (pos < 0 || pos > st->size)
+		return (-1);
+
+	st->pos = pos;
+
+	return (pos);
+}
+
+static int
+fmemopen_close(void *v)
+{
+	free(v);
+
+	return (0);
+}
+
+static int
+fmemopen_close_free(void *v)
+{
+	struct state	*st = v;
+
+	free(st->string);
+	free(st);
+
+	return (0);
+}
+
+FILE *
+fmemopen(void *buf, size_t size, const char *mode)
+{
+	struct state	*st;
+	FILE		*fp;
+	int		 flags, oflags;
+
+	if (size == 0) {
+		errno = EINVAL;
+		return (NULL);
+	}
+
+	if ((flags = __sflags(mode, &oflags)) == 0) {
+		errno = EINVAL;
+		return (NULL);
+	}
+
+	if (buf == NULL && ((oflags & O_RDWR) == 0)) {
+		errno = EINVAL;
+		return (NULL);
+	}
+
+	if ((st = malloc(sizeof(*st))) == NULL)
+		return (NULL);
+
+	if ((fp = __sfp()) == NULL) {
+		free(st);
+		return (NULL);
+	}
+
+	st->pos = 0;
+	st->len = 0;
+	st->size = size;
+
+	if (buf == NULL) {
+		if ((st->string = malloc(size)) == NULL) {
+			free(st);
+			fp->_flags = 0;
+			return (NULL);
+		}
+		*st->string = '\0';
+	} else {
+		st->string = (char *)buf;
+
+		if ((oflags & O_WRONLY) == 0)
+			st->len = size;
+
+		if (oflags & O_TRUNC)
+			*st->string = '\0';
+
+		if (oflags & O_APPEND) {
+			char	*p;
+
+			if ((p = memchr(st->string, '\0', size)) != NULL)
+				st->pos = st->len = (p - st->string);
+			else
+				st->pos = st->len = size;
+		}
+	}
+
+	fp->_flags = (short)flags;
+	fp->_file = -1;
+	fp->_cookie = (void *)st;
+	fp->_read = (flags & __SWR) ? NULL : fmemopen_read;
+	fp->_write = (flags & __SRD) ? NULL : fmemopen_write;
+	fp->_seek = fmemopen_seek;
+	fp->_close = (buf == NULL) ? fmemopen_close_free : fmemopen_close;
+
+	return (fp);
+}
diff --git a/lib/libc/stdio/open_memstream.3 b/lib/libc/stdio/open_memstream.3
new file mode 100644
index 00000000000..f081fd8849b
--- /dev/null
+++ b/lib/libc/stdio/open_memstream.3
@@ -0,0 +1,106 @@
+.\"	$OpenBSD: open_memstream.3,v 1.1 2013/01/01 17:41:13 mpi Exp $
+.\"
+.\" Copyright (c) 2011 Martin Pieuchot <mpi@openbsd.org> 
+.\"
+.\" Permission to use, copy, modify, and distribute this software for any
+.\" purpose with or without fee is hereby granted, provided that the above
+.\" copyright notice and this permission notice appear in all copies.
+.\"
+.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+.\"
+.Dd $Mdocdate: January 1 2013 $
+.Dt OPEN_MEMSTREAM 3
+.Os
+.Sh NAME
+.Nm open_memstream ,
+.Nm open_wmemstream
+.Nd open a memory buffer stream
+.Sh SYNOPSIS
+.Fd #include <stdio.h>
+.Ft FILE *
+.Fn open_memstream "char **pbuf" "size_t *psize"
+.Fd #include <wchar.h>
+.Ft FILE *
+.Fn open_wmemstream "wchar_t **pbuf" "size_t *psize"
+.Sh DESCRIPTION
+The
+.Fn open_memstream
+and
+.Fn open_wmemstream
+functions create a seekable byte-oriented, or respectively wide-oriented,
+stream for writing.
+A dynamically allocated buffer, using
+.Xr malloc 3 ,
+is then wrapped to the pointer referenced by
+.Fa pbuf
+and grows automatically as required.
+.Pp
+When the stream is either closed or flushed, the address of the buffer is
+stored in the pointer referenced by
+.Fa pbuf .
+At the same time the smaller of the current position and the buffer length is
+written in the variable pointed to by
+.Fa psize .
+This value represents the number of bytes, or respectively wide characters,
+contained in the buffer not including the terminating null character.
+.Pp
+The buffer memory should be release after the stream is closed.
+.Sh RETURN VALUES
+Upon successful completion,
+.Fn open_memstream
+and
+.Fn open_wmemstream
+return a
+.Dv FILE
+pointer.
+Otherwise,
+.Dv NULL
+is returned and the global variable
+.Va errno
+is set to indicate the error.
+.Sh ERRORS
+.Bl -tag -width Er
+.It Bq Er EINVAL
+The
+.Fa pbuf
+or the
+.Fa psize
+argument is
+.Dv NULL .
+.El
+.Pp
+The
+.Fn open_memstream
+and
+.Fn open_wmemstream
+functions
+may also fail and set
+.Va errno
+for any of the errors
+specified for the routine
+.Xr malloc 3 .
+.Sh SEE ALSO
+.Xr fmemopen 3 ,
+.Xr funopen 3 ,
+.Xr fopen 3 ,
+.Xr malloc 3
+.Sh STANDARDS
+The functions
+.Fn open_memstream
+and
+.Fn open_wmemstream ,
+conform to
+.St -p1003.1-2008 .
+.Sh HISTORY
+The
+.Fn open_memstream
+and
+.Fn open_wmemstream
+functions first appeared in
+.Ox 5.3 .
diff --git a/lib/libc/stdio/open_memstream.c b/lib/libc/stdio/open_memstream.c
new file mode 100644
index 00000000000..48ae2900f6d
--- /dev/null
+++ b/lib/libc/stdio/open_memstream.c
@@ -0,0 +1,166 @@
+/*	$OpenBSD: open_memstream.c,v 1.1 2013/01/01 17:41:13 mpi Exp $	*/
+/*
+ * Copyright (c) 2011 Martin Pieuchot <mpi@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "local.h"
+
+struct state {
+	char		 *string;	/* actual stream */
+	char		**pbuf;		/* point to the stream */
+	size_t		 *psize;	/* point to min(pos, len) */
+	size_t		  pos;		/* current position */
+	size_t		  size;		/* allocated size */
+	size_t		  len;		/* length of the data */
+};
+
+static int
+memstream_write(void *v, const char *b, int l)
+{
+	struct state	*st = v;
+	int		 i;
+	char		*p;
+
+	if (st->pos + l >= st->size) {
+		/* 1.6 is (very) close to the golden ratio. */
+		size_t	sz = st->size * 8 / 5;
+
+		if (sz < st->pos + l + 1)
+			sz = st->pos + l + 1;
+		p = realloc(st->string, sz);
+		if (!p)
+			return (-1);
+		bzero(p + st->size, sz - st->size);
+		*st->pbuf = st->string = p;
+		st->size = sz;
+	}
+
+	for (i = 0; i < l; i++)
+		st->string[st->pos + i] = b[i];
+	st->pos += i;
+
+	if (st->pos > st->len) {
+		st->len = st->pos;
+		st->string[st->len] = '\0';
+	}
+
+	*st->psize = st->pos;
+
+	return (i);
+}
+
+static fpos_t
+memstream_seek(void *v, fpos_t pos, int w)
+{
+	struct state	*st = v;
+	char		*p;
+
+	switch (w) {
+	case SEEK_SET:
+		break;
+	case SEEK_CUR:
+		pos += st->pos;
+		break;
+	case SEEK_END:
+		pos += st->len;
+		break;
+	default:
+		errno = EINVAL;
+		return (-1);
+	}
+
+	if (pos < 0)
+		return (-1);
+
+	st->pos = pos;
+
+	if (st->pos < st->len)
+		*st->psize = st->pos;
+	else
+		*st->psize = st->len;
+
+	return (pos);
+}
+
+static int
+memstream_close(void *v)
+{
+	struct state	*st = v;
+	char		*p;
+#define MIN(x, y) (((x) < (y)) ? (x) : (y))
+
+	*st->psize = MIN(st->pos, st->len);
+	*st->pbuf = st->string;
+
+	free(st);
+
+	return (0);
+#undef MIN
+}
+
+FILE *
+open_memstream(char **pbuf, size_t *psize)
+{
+	struct state	*st;
+	FILE		*fp;
+
+	if (pbuf == NULL || psize == NULL) {
+		errno = EINVAL;
+		return (NULL);
+	}
+
+	if ((st = malloc(sizeof(*st))) == NULL)
+		return (NULL);
+
+	if ((fp = __sfp()) == NULL) {
+		free(st);
+		return (NULL);
+	}
+
+	if (*psize < 128)
+		st->size = 128;
+	else
+		st->size = *psize;
+
+	if ((st->string = calloc(1, st->size)) == NULL) {
+		free(st);
+		fp->_flags = 0;
+		return (NULL);
+	}
+
+	*st->string = '\0';
+	st->pos = 0;
+	st->len = 0;
+	st->pbuf = pbuf;
+	st->psize = psize;
+
+	*pbuf = st->string;
+	*psize = st->len;
+
+	fp->_flags = __SWR;
+	fp->_file = -1;
+	fp->_cookie = st;
+	fp->_read = NULL;
+	fp->_write = memstream_write;
+	fp->_seek = memstream_seek;
+	fp->_close = memstream_close;
+
+	return (fp);
+}