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>

cpuplugd/cpu.c

@@ -0,0 +1,227 @@
+/*
+ * cpuplugd - Linux for System z Hotplug Daemon
+ *
+ * CPU hotplug functions
+ *
+ * Copyright IBM Corp. 2007, 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 <limits.h>
+#include "cpuplugd.h"
+
+
+/*
+ * Return overall number of available cpus. This does not necessarily
+ * mean that those are currently online
+ */
+int get_numcpus()
+{
+	int i;
+	char path[PATH_MAX];
+	int number = 0;
+
+	for (i = 0; ; i++) {
+		/* check whether file exists and is readable */
+		sprintf(path, "/sys/devices/system/cpu/cpu%d/online", i);
+		if (access(path, R_OK) == 0)
+			number++;
+		else
+			break;
+	}
+	return number;
+}
+
+/*
+ * Return number of online cpus
+ */
+int get_num_online_cpus()
+{
+	FILE *filp;
+	int i;
+	char path[PATH_MAX];
+	int status = 0;
+	int value_of_onlinefile, rc;
+
+	for (i = 0; i <= get_numcpus(); i++) {
+		/* check wether file exists and is readable */
+		sprintf(path, "/sys/devices/system/cpu/cpu%d/online", i);
+		if (access(path, R_OK) != 0)
+			continue;
+		filp = fopen(path, "r");
+		if (!filp)
+			cpuplugd_exit("Cannot open cpu online file: "
+				      "%s\n", strerror(errno));
+		else {
+			rc = fscanf(filp, "%d", &value_of_onlinefile);
+			if (rc != 1)
+				cpuplugd_exit("Cannot read cpu online file: "
+					      "%s\n", strerror(errno));
+			if (value_of_onlinefile == 1)
+				status++;
+		}
+		fclose(filp);
+	}
+	return status;
+}
+
+/*
+ * Enable a certain cpu
+ */
+int hotplug(int cpuid)
+{
+	FILE *filp;
+	char path[PATH_MAX];
+	int status, rc;
+
+	sprintf(path, "/sys/devices/system/cpu/cpu%d/online", cpuid);
+	if (access(path, W_OK) == 0) {
+		filp = fopen(path, "w");
+		if (!filp)
+			cpuplugd_exit("Cannot open cpu online file: %s\n",
+				      strerror(errno));
+		fprintf(filp, "1");
+		fclose(filp);
+		/*
+		 * check if the attempt to enable the cpus really worked
+		 */
+		filp = fopen(path, "r");
+		rc = fscanf(filp, "%d", &status);
+		if (rc != 1)
+			cpuplugd_exit("Cannot open cpu online file: %s\n",
+				      strerror(errno));
+		fclose(filp);
+		if (status == 1) {
+			cpuplugd_debug("cpu with id %d enabled\n", cpuid);
+			return 1;
+		} else {
+			cpuplugd_debug("failed to enable cpu with id %d\n",
+				      cpuid);
+			return -1;
+		}
+	} else {
+		cpuplugd_error("hotplugging cpu with id %d failed\n", cpuid);
+		return -1;
+	}
+	return -1;
+}
+
+/*
+ * Disable a certain cpu
+ */
+int hotunplug(int cpuid)
+{
+	FILE *filp;
+	int state, rc;
+	int retval = -1;
+	char path[PATH_MAX];
+
+	state = -1;
+	sprintf(path, "/sys/devices/system/cpu/cpu%d/online", cpuid);
+	if (access(path, W_OK) == 0) {
+		filp = fopen(path, "w");
+		fprintf(filp, "0");
+		fclose(filp);
+		/*
+		 * Check if the attempt to enable the cpus really worked
+		 */
+		filp = fopen(path, "r");
+		rc = fscanf(filp, "%d", &state);
+		if (rc != 1)
+			cpuplugd_error("Failed to disable cpu with id %d\n",
+				       cpuid);
+		fclose(filp);
+		if (state == 0)
+			return 1;
+	} else {
+		cpuplugd_error("unplugging cpu with id %d failed\n", cpuid);
+	}
+	return retval;
+}
+
+/*
+ * Check if a certain cpu is currently online
+ */
+int is_online(int cpuid)
+{
+	FILE *filp;
+	int state;
+	int retval, rc;
+	char path[PATH_MAX];
+
+	retval = -1;
+	sprintf(path, "/sys/devices/system/cpu/cpu%d/online", cpuid);
+	if (access(path, R_OK) == 0) {
+		filp = fopen(path, "r");
+		rc = fscanf(filp, "%d", &state);
+		if (rc == 1) {
+			if (state == 1)
+				retval = 1;
+			if (state == 0)
+				retval = 0;
+			fclose(filp);
+		}
+	}
+	return retval;
+}
+
+/*
+ * Cleanup method. If the daemon is stopped, we (re)activate all cpus
+ */
+void reactivate_cpus()
+{
+	/*
+	 * Only enable the number of cpus which where
+	 * available at daemon startup time
+	 */
+	int cpuid, nc;
+
+	cpuid = 0;
+	/* suppress verbose messages on exit */
+	debug = 0;
+       /*
+	* We check for num_cpu_start != 0 because we might want to
+	* clean up, before we queried for the number on cpus at
+	* startup
+	*/
+	if (num_cpu_start == 0)
+		return;
+	while (get_num_online_cpus() != num_cpu_start && cpuid < get_numcpus()) {
+		nc = get_num_online_cpus();
+		if (nc == num_cpu_start)
+			return;
+		if (nc > num_cpu_start && is_online(cpuid) == 1)
+			hotunplug(cpuid);
+		if (nc < num_cpu_start && is_online(cpuid) == 0)
+			hotplug(cpuid);
+		cpuid++;
+	}
+}
+
+/*
+ * In kernels > 2.6.24 cpus can be deconfigured. The following functions is used
+ * to check if a certain cpus is in a deconfigured state.
+ */
+int cpu_is_configured(int cpuid)
+{
+	FILE *filp;
+	int retval, state, rc;
+	char path[4096];
+
+	retval = -1;
+	sprintf(path, "/sys/devices/system/cpu/cpu%d/configure", cpuid);
+	if (access(path, R_OK) == 0) {
+		filp = fopen(path, "r");
+		rc = fscanf(filp, "%d", &state);
+		if (rc == 1) {
+			if (state == 1)
+				retval = 1;
+			if (state == 0)
+				retval = 0;
+			fclose(filp);
+		}
+	}
+	return retval;
+}