Add an implementation of the gnu-ish asprintf() and vasprintf(). They are

not based on gpl'ed code, just prototype and usage.  I'm not 100% certain
they behave the same while the system is in trouble (eg: malloc() failing)
but in those circumstances all bets would be off anyway.

These routines work like sprintf() and vsprintf(), except that instead of
using a fixed buffer, they allocate memory and return it to the user
and it's the user's responsibility to free() it.  They have allocate as
much memory as they need (and can get), so the size of strings it can deal
with is limited only by the amount of memory it can malloc() on your
behalf.

There are a few gpl'ed programs starting to use this interface, and it's
becoming more common with the scares about security risks with sprintf().
I dont like the look of the code that the various programs (including
cvs, gdb, libg++, etc) provide if configure can't find it on the system.

It should be possible to modify the stdio core code to provide this
interface more efficiently, I was more worried about having something
that worked and was secure.  :-)  (I noticed that there was once intended
to be a smprintf() routine when our stdio was written for 4.4BSD, but it
looks pretty stillborn, and it's intended interface is not clear).  Since
Linux and gnu libc have this interface, it seemed silly to bring yet
another one onto the scene.

5 files changed, 221 insertions, 38 deletions

diff --git a/include/stdio.h b/include/stdio.h
index e930010..9c4c37e 100644
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -283,6 +283,7 @@ __END_DECLS
  */
 #if !defined (_ANSI_SOURCE) && !defined(_POSIX_SOURCE)
 __BEGIN_DECLS
+int	 asprintf __P((char **, const char *, ...));
 char	*fgetln __P((FILE *, size_t *));
 int	 fpurge __P((FILE *));
 int	 getw __P((FILE *));
@@ -293,6 +294,7 @@ void	 setbuffer __P((FILE *, char *, int));
 int	 setlinebuf __P((FILE *));
 char	*tempnam __P((const char *, const char *));
 int	 snprintf __P((char *, size_t, const char *, ...));
+int	 vasprintf __P((char **, const char *, _BSD_VA_LIST_));
 int	 vsnprintf __P((char *, size_t, const char *, _BSD_VA_LIST_));
 int	 vscanf __P((const char *, _BSD_VA_LIST_));
 int	 vsscanf __P((const char *, const char *, _BSD_VA_LIST_));
diff --git a/lib/libc/stdio/Makefile.inc b/lib/libc/stdio/Makefile.inc
index 5ca5016..b9c02a4 100644
--- a/lib/libc/stdio/Makefile.inc
+++ b/lib/libc/stdio/Makefile.inc
@@ -3,16 +3,16 @@
 # stdio sources
 .PATH: ${.CURDIR}/stdio
 
-SRCS+=	clrerr.c fclose.c fdopen.c feof.c ferror.c fflush.c fgetc.c \
-	fgetln.c fgetpos.c fgets.c fileno.c findfp.c flags.c fopen.c \
+SRCS+=	asprintf.c clrerr.c fclose.c fdopen.c feof.c ferror.c fflush.c \
+	fgetc.c fgetln.c fgetpos.c fgets.c fileno.c findfp.c flags.c fopen.c \
 	fprintf.c fpurge.c fputc.c fputs.c fread.c freopen.c fscanf.c \
 	fseek.c fsetpos.c ftell.c funopen.c fvwrite.c fwalk.c fwrite.c \
 	getc.c getchar.c gets.c getw.c makebuf.c mktemp.c perror.c \
 	printf.c putc.c putchar.c puts.c putw.c refill.c remove.c rewind.c \
 	rget.c scanf.c setbuf.c setbuffer.c setvbuf.c snprintf.c sprintf.c \
-	sscanf.c stdio.c tempnam.c tmpfile.c tmpnam.c ungetc.c vfprintf.c \
-	vfscanf.c vprintf.c vscanf.c vsnprintf.c vsprintf.c vsscanf.c \
-	wbuf.c wsetup.c
+	sscanf.c stdio.c tempnam.c tmpfile.c tmpnam.c ungetc.c vasprintf.c \
+	vfprintf.c vfscanf.c vprintf.c vscanf.c vsnprintf.c vsprintf.c \
+	vsscanf.c wbuf.c wsetup.c
 
 MAN3+=	stdio/fclose.3 stdio/ferror.3 stdio/fflush.3 stdio/fgetln.3 \
 	stdio/fgets.3 stdio/fopen.3 stdio/fputs.3 stdio/fread.3 stdio/fseek.3 \
diff --git a/lib/libc/stdio/asprintf.c b/lib/libc/stdio/asprintf.c
new file mode 100644
index 0000000..9b4d05b
--- /dev/null
+++ b/lib/libc/stdio/asprintf.c
@@ -0,0 +1,59 @@
+/*-
+ * Copyright (c) 1996  Peter Wemm <peter@freebsd.org>
+ *
+ * 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.
+ */
+
+#if defined(LIBC_RCS) && !defined(lint)
+static char rcsid[] = "$Id$";
+#endif /* LIBC_RCS and not lint */
+
+#include <stdio.h>
+#if __STDC__
+#include <stdarg.h>
+#else
+#include <varargs.h>
+#endif
+
+#if __STDC__
+int
+asprintf(char **str, char const *fmt, ...)
+#else
+int
+asprintf(str, fmt, va_alist)
+	char **str;
+	char *fmt;
+	va_dcl
+#endif
+{
+	int ret;
+	va_list ap;
+
+#if __STDC__
+	va_start(ap, fmt);
+#else
+	va_start(ap);
+#endif
+	ret = vasprintf(str, fmt, ap);
+	va_end(ap);
+	return (ret);
+}
diff --git a/lib/libc/stdio/printf.3 b/lib/libc/stdio/printf.3
index 4238a90..e675b3e 100644
--- a/lib/libc/stdio/printf.3
+++ b/lib/libc/stdio/printf.3
@@ -43,10 +43,12 @@
 .Nm fprintf ,
 .Nm sprintf ,
 .Nm snprintf ,
+.Nm asprintf ,
 .Nm vprintf ,
 .Nm vfprintf,
 .Nm vsprintf ,
-.Nm vsnprintf
+.Nm vsnprintf ,
+.Nm vasprintf
 .Nd formatted output conversion
 .Sh SYNOPSIS
 .Fd #include <stdio.h>
@@ -58,8 +60,8 @@
 .Fn sprintf "char *str" "const char *format" ...
 .Ft int
 .Fn snprintf "char *str" "size_t size" "const char *format" ...
-.\" .Ft int
-.\" .Fn smprintf "const char *format" ...
+.Ft int
+.Fn asprintf "char **ret" "const char *format" ...
 .Fd #include <stdarg.h>
 .Ft int
 .Fn vprintf "const char *format" "va_list ap"
@@ -69,8 +71,8 @@
 .Fn vsprintf "char *str" "char *format" "va_list ap"
 .Ft int
 .Fn vsnprintf "char *str" "size_t size" "const char *format" "va_list ap"
-.\" .Ft int
-.\" .Fn vsmprintf "const char *format" "va_list ap"
+.Ft int
+.Fn vasprintf "char **ret" "const char *format" "va_list ap"
 .Sh DESCRIPTION
 The
 .Fn printf
@@ -94,45 +96,47 @@ write output to the given output
 and
 .Fn vsnprintf
 write to the character string
-.Fa str .
-.\" .IR str ;
-.\" and
-.\" .I smprintf
-.\" and
-.\" .I vsmprintf
-.\" dynamically allocate a new string with
-.\" .IR malloc .
+.Fa str ;
+and
+.Fn asprintf
+and
+.Fn vasprintf
+dynamically allocate a new string with
+.Xr malloc 3
+/
+.Xr realloc 3 .
+.Pp
 These functions write the output under the control of a
 .Fa format
 string that specifies how subsequent arguments
 (or arguments accessed via the variable-length argument facilities of
 .Xr stdarg 3 )
 are converted for output.
-.\" Except for
-.\" .I smprintf
-.\" and
-.\" .IR vsmprintf ,
-.\" all of these functions return
+.Pp
 These functions return
 the number of characters printed
 (not including the trailing
 .Ql \e0
 used to end output to strings).
-.\" .I Smprintf
-.\" and
-.\" .I vsmprintf
-.\" return a pointer to a string of an appropriate length;
-.\" this pointer should be passed to
-.\" .I free
-.\" to release the associated storage
-.\" when it is no longer needed.
-.\" If sufficient space is not avaliable,
-.\" .I smprintf
-.\" and
-.\" .I vsmprintf
-.\" will return
-.\" .SM
-.\" .BR
+.Pp
+.Fn Asprintf
+and
+.Fn vasprintf
+return a pointer to a buffer sufficiently large to hold the
+string in the
+.Fa ret
+argument;
+This pointer should be passed to
+.Xr free 3
+to release the allocated storage when it is no longer needed.
+If sufficient space cannot be allocated, 
+.Fn asprintf
+and
+.Fn vasprintf
+will return -1 and set
+.Fa ret
+to be a NULL pointer.
+.Pp
 .Fn Snprintf
 and
 .Fn vsnprintf
@@ -147,6 +151,7 @@ if the return value is greater than or equal to the
 .Fa size
 argument, the string was too short
 and some of the printed characters were discarded.
+.Pp
 .Fn Sprintf
 and
 .Fn vsprintf
@@ -600,6 +605,15 @@ The functions
 and
 .Fn vsnprintf
 are new to this release.
+.Pp
+The functions
+.Fn asprintf
+and
+.Fn vasprintf
+first appeared in the GNU C library.  This implementation is thought
+to be compatable but is not derived from the GNU code.  This implementation
+was written by Peter Wemm <peter@FreeBSD.org> and first appeared in
+FreeBSD-2.2.
 .Sh BUGS
 The conversion formats
 .Cm \&%D ,
diff --git a/lib/libc/stdio/vasprintf.c b/lib/libc/stdio/vasprintf.c
new file mode 100644
index 0000000..bec579a
--- /dev/null
+++ b/lib/libc/stdio/vasprintf.c
@@ -0,0 +1,108 @@
+/*-
+ * Copyright (c) 1996  Peter Wemm <peter@freebsd.org>
+ *
+ * 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.
+ */
+
+#if defined(LIBC_RCS) && !defined(lint)
+static char rcsid[] = "$Id$";
+#endif /* LIBC_RCS and not lint */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#if __STDC__
+#include <stdarg.h>
+#else
+#include <varargs.h>
+#endif
+
+#define CHUNK_SPARE 128 /* how much spare to allocate to avoid realloc calls */
+
+struct bufcookie {
+	char	*base;	/* start of buffer */
+	int	size;
+	int	left;
+};
+
+static int
+writehook(cookie, buf, len)
+	void *cookie;
+	char *buf;
+	int   len;
+{
+	struct bufcookie *h = (struct bufcookie *)cookie;
+
+	if (len == 0)
+		return 0;
+
+	if (len > h->left) {
+		/* grow malloc region */
+		h->left = h->left + len + CHUNK_SPARE;
+		h->size = h->size + len + CHUNK_SPARE;
+		h->base = realloc(h->base, h->size);
+		if (h->base == NULL)
+			return (-1);
+	}
+	/* "write" it */
+	(void)memcpy(h->base + h->size - h->left, buf, len);
+	h->left -= len;
+	return (0);
+}
+
+
+int
+vasprintf(str, fmt, ap)
+	char **str;
+	const char *fmt;
+	va_list ap;
+{
+	int ret;
+	FILE *f;
+	struct bufcookie h;
+
+	h.base = malloc(CHUNK_SPARE);
+	if (h.base == NULL)
+		return (-1);
+	h.size = CHUNK_SPARE;
+	h.left = CHUNK_SPARE;
+
+	f = funopen(&h, NULL, writehook, NULL, NULL);
+	if (f == NULL) {
+		free(h.base);
+		return (-1);
+	}
+	ret = vfprintf(f, fmt, ap);
+	fclose(f);
+	if (ret < 0) {
+		free(h.base);
+		return (-1);
+	}
+	if (h.base == NULL)	/* failed to realloc in writehook */
+		return (-1);
+
+	h.base[h.size - h.left] = '\0';
+	*str = realloc(h.base, h.size - h.left + 1);
+	if (*str == NULL)	/* failed to realloc it to actual size */
+		return -1;
+	return (ret);
+}