libc/misc/getloadavg: Add getloadavg support to uClibc-ng

This borrows getloadavg.c from musl.
getloadavg pops up often. Recently llvm and rust are dependent on it.
glibc and musl have it and no-one actually checks if it's available in your libc.
It's just become way easier to add it in uclibc-ng rather than patch everything else.

Signed-off-by: Lance Fredrickson <lancethepants@gmail.com>

1 files changed, 39 insertions, 0 deletions

diff --git a/libc/misc/getloadavg/getloadavg.c b/libc/misc/getloadavg/getloadavg.c
new file mode 100644
index 000000000..2aee565c0
--- /dev/null
+++ b/libc/misc/getloadavg/getloadavg.c
@@ -0,0 +1,39 @@
+/*
+ * Copyright © 2005-2020 Rich Felker, et al.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Imported from musl C library
+ */
+
+#define _GNU_SOURCE
+#include <stdlib.h>
+#include <sys/sysinfo.h>
+
+int getloadavg(double *a, int n)
+{
+	struct sysinfo si;
+	if (n <= 0) return n ? -1 : 0;
+	sysinfo(&si);
+	if (n > 3) n = 3;
+	for (int i=0; i<n; i++)
+		a[i] = 1.0/(1<<SI_LOAD_SHIFT) * si.loads[i];
+	return n;
+}