1 files changed, 75 insertions, 0 deletions
diff --git a/lib/libsys/getpagesizes.c b/lib/libsys/getpagesizes.c
new file mode 100644
index 000000000000..7f481f84177a
--- /dev/null
+++ b/lib/libsys/getpagesizes.c
@@ -0,0 +1,75 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2009 Alan L. Cox <alc@cs.rice.edu>
+ * 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.
+ */
+
+#include <sys/param.h>
+#include <sys/auxv.h>
+#include <sys/errno.h>
+
+#include "libc_private.h"
+
+/*
+ * Retrieves page size information from the system.  Specifically, returns the
+ * number of distinct page sizes that are supported by the system, if
+ * "pagesize" is NULL and "nelem" is 0.  Otherwise, assigns up to "nelem" of
+ * the system-supported page sizes to consecutive elements of the array
+ * referenced by "pagesize", and returns the number of such page sizes that it
+ * assigned to the array.  These page sizes are expressed in bytes.
+ *
+ * The implementation of this function does not directly or indirectly call
+ * malloc(3) or any other dynamic memory allocator that may itself call this
+ * function.
+ */
+int
+getpagesizes(size_t pagesize[], int nelem)
+{
+	static u_long ps[MAXPAGESIZES];
+	static int nops;
+	int i;
+
+	if (nelem < 0 || (nelem > 0 && pagesize == NULL)) {
+		errno = EINVAL;
+		return (-1);
+	}
+	/* Cache the result */
+	if (nops == 0) {
+		if (_elf_aux_info(AT_PAGESIZES, ps, sizeof(ps)) != 0)
+			ps[0] = PAGE_SIZE;
+		/* Count the number of page sizes that are supported. */
+		nops = nitems(ps);
+		while (nops > 0 && ps[nops - 1] == 0)
+			nops--;
+	}
+	if (pagesize == NULL)
+		return (nops);
+	/* Return up to "nelem" page sizes from the cached result. */
+	if (nelem > nops)
+		nelem = nops;
+	for (i = 0; i < nelem; i++)
+		pagesize[i] = ps[i];
+	return (nelem);
+}