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>

dump2tar/include/buffer.h

@@ -0,0 +1,50 @@
+/*
+ * dump2tar - tool to dump files and command output into a tar archive
+ *
+ * Data buffering functions
+ *
+ * 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.
+ */
+
+#ifndef BUFFER_H
+#define BUFFER_H
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+/* Buffers for building tar file entries */
+struct buffer {
+	size_t total;	/* Total number of bytes in buffer */
+	size_t off;	/* Current offset to next free byte in memory buffer */
+	size_t size;	/* Memory buffer size */
+	char *addr;	/* Memory buffer address */
+	bool fd_open;	/* Has fd been openend yet? */
+	FILE *file;	/* FILE * of file containing previous buffer data */
+	int fd;		/* Handle of file containing previous buffer data */
+};
+
+void buffer_init(struct buffer *buffer, size_t size);
+struct buffer *buffer_alloc(size_t size);
+void buffer_reset(struct buffer *buffer);
+void buffer_close(struct buffer *buffer);
+void buffer_free(struct buffer *buffer, bool dyn);
+int buffer_open(struct buffer *buffer);
+int buffer_flush(struct buffer *buffer);
+ssize_t buffer_make_room(struct buffer *buffer, size_t size, bool usefile,
+			 size_t max_buffer_size);
+int buffer_truncate(struct buffer *buffer, size_t len);
+
+ssize_t buffer_read_fd(struct buffer *buffer, int fd, size_t chunk,
+		       bool usefile, size_t max_buffer_size);
+int buffer_add_data(struct buffer *buffer, char *addr, size_t len,
+		    bool usefile, size_t max_buffer_size);
+
+typedef int (*buffer_cb_t)(void *data, void *addr, size_t len);
+int buffer_iterate(struct buffer *buffer, buffer_cb_t cb, void *data);
+void buffer_print(struct buffer *buffer);
+
+#endif /* BUFFER_H */