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>

libutil/util_path.c

@@ -0,0 +1,196 @@
+/*
+ * util - Utility function library
+ *
+ * Work with paths
+ *
+ * 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 <err.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "lib/util_base.h"
+#include "lib/util_libc.h"
+#include "lib/util_path.h"
+#include "lib/util_prg.h"
+#include "lib/util_proc.h"
+
+/*
+ * Verify that directory exists
+ */
+static void verify_dir(const char *dir)
+{
+	struct stat sb;
+	int rc;
+
+	rc = stat(dir, &sb);
+	if (rc < 0)
+		err(EXIT_FAILURE, "Could not access directory: %s", dir);
+	if (!S_ISDIR(sb.st_mode))
+		errx(EXIT_FAILURE, "Is not a directory: %s", dir);
+}
+
+/*
+ * Return sysfs mount point
+ */
+static char *sys_mount_point(void)
+{
+	struct util_proc_mnt_entry mnt_entry;
+	static char *mount_point;
+	char *dir;
+
+	if (mount_point)
+		return mount_point;
+	/* Check the environment variable */
+	dir = getenv("SYSFS_ROOT");
+	if (dir) {
+		mount_point = util_strdup(dir);
+	} else {
+		if (util_proc_mnt_get_entry("/proc/mounts", "sysfs",
+					    &mnt_entry))
+			errx(EXIT_FAILURE, "No mount point found for sysfs");
+		mount_point = util_strdup(mnt_entry.file);
+		util_proc_mnt_free_entry(&mnt_entry);
+	}
+	verify_dir(mount_point);
+	return mount_point;
+}
+
+/**
+ * Construct a sysfs path
+ *
+ * The arguments of the function are used to specify a subdirectory under
+ * sysfs root.
+ *
+ * @param[in] fmt  Format string for path
+ * @param[in] ...  Variable arguments for format string
+ *
+ * @returns        Allocated path
+ */
+char *util_path_sysfs(const char *fmt, ...)
+{
+	char *path, *fmt_tot;
+	va_list ap;
+
+	util_asprintf(&fmt_tot, "%s/%s", sys_mount_point(), fmt);
+	 /* Format and return full sysfs path */
+	va_start(ap, fmt);
+	util_vasprintf(&path, fmt_tot, ap);
+	va_end(ap);
+	free(fmt_tot);
+
+	return path;
+}
+
+/**
+ * Test if path exists and is readable
+ *
+ * This function has the same semantics as "-r path" in bash.
+ *
+ * @param[in] fmt   Format string for path to test
+ * @param[in] ...   Variable arguments for format string
+ *
+ * @returns   true  Path exists and is readable
+ *            false Otherwise
+ */
+bool util_path_is_readable(const char *fmt, ...)
+{
+	va_list ap;
+	char *path;
+	bool rc;
+
+	UTIL_VASPRINTF(&path, fmt, ap);
+	rc = access(path, R_OK) == 0 ? true : false;
+	free(path);
+
+	return rc;
+}
+
+/**
+ * Test if path exists and is writable
+ *
+ * This function has the same semantics as "-w path" in bash.
+ *
+ * @param[in] fmt   Format string for path to test
+ * @param[in] ...   Variable arguments for format string
+ *
+ * @returns   true  Path exists and is writable
+ *            false Otherwise
+ */
+bool util_path_is_writable(const char *fmt, ...)
+{
+	va_list ap;
+	char *path;
+	bool rc;
+
+	UTIL_VASPRINTF(&path, fmt, ap);
+	rc = access(path, W_OK) == 0 ? true : false;
+	free(path);
+
+	return rc;
+}
+
+/**
+ * Test if path exists and is a regular file
+ *
+ * This function has the same semantics as "-f path" in bash.
+ *
+ * @param[in] fmt   Format string for path to test
+ * @param[in] ...   Variable arguments for format string
+ *
+ * @returns   true  Path exists and is a regular file
+ *            false Otherwise
+ */
+bool util_path_is_reg_file(const char *fmt, ...)
+{
+	struct stat sb;
+	va_list ap;
+	char *path;
+	bool rc;
+
+	UTIL_VASPRINTF(&path, fmt, ap);
+	if (stat(path, &sb)) {
+		rc = false;
+		goto free_str;
+	}
+	rc = (sb.st_mode & S_IFREG) ? true : false;
+free_str:
+	free(path);
+	return rc;
+}
+
+/**
+ * Test if path exists and is a directory
+ *
+ * This function has the same semantics as "-d path" in bash.
+ *
+ * @param[in] fmt   Format string for path to test
+ * @param[in] ...   Variable arguments for format string
+ *
+ * @returns   true  Path exists and is a directory
+ *            false Otherwise
+ */
+bool util_path_is_dir(const char *fmt, ...)
+{
+	struct stat sb;
+	va_list ap;
+	char *path;
+	bool rc;
+
+	UTIL_VASPRINTF(&path, fmt, ap);
+	if (stat(path, &sb)) {
+		rc = false;
+		goto free_str;
+	}
+	rc = (sb.st_mode & S_IFDIR) ? true : false;
+free_str:
+	free(path);
+	return rc;
+}