Initial s390-tools-2.0.0 import

This commit is based on the s390-tools-1.39.0 version.

Changes on top of s390-tools-1.39.0:

 - Add MIT license to all source files
 - Add LICENSE file
 - Transform REAMDE to README.md (markdown)
 - Add AUTHORS.md file
 - Add CONTRIBUTING.md file
 - Move changelog from README to CHANGELOG.md file

Reviewed-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>

zdev/src/findmnt.c

@@ -0,0 +1,76 @@
+/*
+ * zdev - Modify and display the persistent configuration of devices
+ *
+ * Copyright IBM Corp. 2016, 2017
+ *
+ * s390-tools is free software; you can redistribute it and/or modify
+ * it under the terms of the MIT license. See LICENSE for details.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "devnode.h"
+#include "findmnt.h"
+#include "misc.h"
+
+#define FINDMNT_CMDLINE	"findmnt -n -T %s -o SOURCE 2>/dev/null"
+
+static struct devnode *devnode_from_line(const char *line)
+{
+	char *copy, *end;
+	struct devnode *devnode;
+
+	copy = misc_strdup(line);
+
+	/* Could be /dev/sda[/subvolname] */
+	end = strchr(copy, '[');
+	if (end)
+		*end = 0;
+
+	devnode = devnode_from_node(copy, err_ignore);
+
+	free(copy);
+
+	return devnode;
+}
+
+/* Return a newly allocated ptrlist containing all devnodes that provide
+ * the file system on which @path is located. Return %NULL if no devnodes
+ * were found. We need this in addition to lsblk output because lsblk doesn't
+ * work with btrfs subvolumes. */
+struct util_list *findmnt_get_devnodes_by_path(const char *path)
+{
+	struct util_list *devnodes;
+	char *quoted_path, *cmd, *output, *next, *curr;
+	struct devnode *devnode;
+
+	devnodes = ptrlist_new();
+	quoted_path = quote_str(path, 1);
+	cmd = misc_asprintf(FINDMNT_CMDLINE, quoted_path);
+
+	output = misc_read_cmd_output(cmd, 0, err_ignore);
+	if (!output)
+		goto out;
+
+	/* Iterate over each line. */
+	next = output;
+	while ((curr = strsep(&next, "\n"))) {
+		devnode = devnode_from_line(curr);
+		if (devnode)
+			ptrlist_add(devnodes, devnode);
+	}
+
+out:
+	free(output);
+	free(cmd);
+	free(quoted_path);
+
+	/* Make empty list detection easier for calling function. */
+	if (util_list_is_empty(devnodes)) {
+		ptrlist_free(devnodes, 1);
+		devnodes = NULL;
+	}
+
+	return devnodes;
+}