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>

libdasd/Makefile

@@ -0,0 +1,14 @@
+include ../common.mak
+
+lib = libdasd.a
+
+all: $(lib)
+
+objects = dasd_sys.o
+
+$(lib): $(objects) Makefile
+
+install: all
+
+clean:
+	rm -f *.o $(lib)

libdasd/dasd_sys.c

@@ -0,0 +1,143 @@
+/*
+ * dasd - Library for DASD related functions
+ *
+ * DASD related helper functions for accessing device information via sysfs
+ *
+ * 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 <errno.h>
+#include <stdlib.h>
+
+#include "lib/dasd_sys.h"
+
+/**
+ * Get raw-track access mode status
+ *
+ * The "devnode" parameter can be any valid relative or absolute path to
+ * a DASD device node, for example:
+ *
+ * - /dev/dasda
+ * - /dev/disk/by-path/ccw-0.0.bf20
+ *
+ * @param[in]	devnode		Device node of interest
+ *
+ * @retval	1		Raw-track access mode is enabled
+ * @retval	0		Raw-track access mode is disabled or
+ *				cannot be determined
+ */
+int dasd_sys_raw_track_access(char *devnode)
+{
+	char busid[9];
+	char path[47];
+	FILE *fp;
+	int rc;
+
+	if (u2s_getbusid(devnode, busid))
+		return 0;
+
+	sprintf(path, "/sys/bus/ccw/devices/%s/raw_track_access", busid);
+
+	fp = fopen(path, "r");
+	if (!fp)
+		return 0;
+
+	rc = fgetc(fp) - '0';
+	fclose(fp);
+
+	return (rc == 1) ? 1 : 0;
+}
+
+
+int dasd_get_pm_from_chpid(char *busid, unsigned int chpid, int *mask)
+{
+	unsigned int val;
+	char path[40];
+	int count, i;
+	FILE *fp;
+
+	sprintf(path, "/sys/bus/ccw/devices/%s/../chpids", busid);
+	*mask = 0;
+	fp = fopen(path, "r");
+	if (!fp)
+		return ENODEV;
+
+	for (i = 0; i < 8; i++) {
+		count = fscanf(fp, " %x", &val);
+		if (count != 1) {
+			fclose(fp);
+			return EIO;
+		}
+		if (val == chpid)
+			*mask = 0x80 >> i;
+	}
+	fclose(fp);
+
+	return 0;
+}
+
+/**
+ * reset chpid
+ *
+ * The "devnode" parameter can be any valid relative or absolute path to
+ * a DASD device node, for example:
+ *
+ * - /dev/dasda
+ * - /dev/disk/by-path/ccw-0.0.bf20
+ *
+ * @param[in]	devnode		Device node of interest
+ * @param[in]	chpid		The chpid to reset
+ *                              If NULL all chpids will be reset
+ *
+ * @return     0 on success, otherwise one of the following error codes:
+ *   - EINVAL  No valid chpid specified.
+ *   - ENODEV  Could not open device.
+ *   - ENOENT  Specified chpid not found.
+ *   - EIO     Other I/O error
+ *
+ */
+int dasd_reset_chpid(char *devnode, char *chpid_char)
+{
+	unsigned int chpid;
+	char path[41];
+	char busid[9];
+	int  mask, rc;
+	char *endptr;
+	FILE *fp;
+
+	if (u2s_getbusid(devnode, busid))
+		return ENODEV;
+
+	if (!chpid_char) {
+		sprintf(path, "/sys/bus/ccw/devices/%s/path_reset", busid);
+		fp = fopen(path, "w");
+		if (!fp)
+			return ENODEV;
+		fprintf(fp, "%s", "all\n");
+		fclose(fp);
+		return 0;
+	}
+
+	errno = 0;
+	chpid = strtoul(chpid_char, &endptr, 16);
+	if (errno || (endptr && (*endptr != '\0')))
+		return EINVAL;
+
+	rc = dasd_get_pm_from_chpid(busid, chpid, &mask);
+	if (rc)
+		return rc;
+	if (!mask)
+		return ENOENT;
+
+	sprintf(path, "/sys/bus/ccw/devices/%s/path_reset", busid);
+	fp = fopen(path, "w");
+	if (!fp)
+		return ENODEV;
+	fprintf(fp, "%02x", mask);
+	fclose(fp);
+
+	return 0;
+}