Add asprintf.c

Forgotten in 5b6d08cd

src/port/asprintf.c

+/* src/port/asprintf.c */
+
+/* $NetBSD: asprintf.c,v 1.3 2012/07/02 16:02:53 joerg Exp $ */
+
+/*-
+ * Copyright (c) 2007 Joerg Sonnenberger <joerg@NetBSD.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 COPYRIGHT HOLDERS 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
+ * COPYRIGHT HOLDERS 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.
+ */
+
+#include "c.h"
+
+#define HAVE_VA_COPY 1
+
+int
+asprintf(char **ret, const char *fmt, ...)
+{
+	va_list ap;
+	int retval;
+
+	va_start(ap, fmt);
+	retval = vasprintf(ret, fmt, ap);
+	va_end(ap);
+
+	return retval;
+}
+
+int
+vasprintf(char **ret, const char *fmt, va_list ap)
+{
+	char *buf, *new_buf;
+	size_t len;
+	int retval;
+	va_list ap2;
+
+	len = 128;
+	buf = malloc(len);
+	if (buf == NULL) {
+		*ret = NULL;
+		return -1;
+	}
+
+#if defined(HAVE_VA_COPY)
+	va_copy(ap2, ap);
+#define	my_va_end(ap2)	va_end(ap2)
+#elif defined(HAVE___BUILTIN_VA_COPY)
+	__builtin_va_copy(ap2, ap);
+#define	my_va_end(ap2)	__builtin_va_end(ap2)
+#else
+	ap2 = ap;
+#define	my_va_end(ap2)	do {} while (0)
+#endif
+	retval = vsnprintf(buf, len, fmt, ap);
+	if (retval < 0) {
+		free(buf);
+		*ret = NULL;
+		va_end(ap2);
+		return -1;
+	}
+
+	if (retval < len) {
+		new_buf = realloc(buf, retval + 1);
+		if (new_buf == NULL)
+			*ret = buf;
+		else
+			*ret = new_buf;
+		my_va_end(ap2);
+		return retval;
+	}
+
+	len = (size_t)retval + 1;
+	free(buf);
+	buf = malloc(len);
+	if (buf == NULL) {
+		*ret = NULL;
+		my_va_end(ap2);
+		return -1;
+	}
+	retval = vsnprintf(buf, len, fmt, ap2);
+	my_va_end(ap2);
+	if (retval != len - 1) {
+		free(buf);
+		*ret = NULL;
+		return -1;
+	}
+	*ret = buf;
+	return retval;
+}