Put ssh back into the repository

Change-Id: I23324372188fa6ed3f93a32b84365f5df6367590
diff --git a/xmalloc.c b/xmalloc.c
new file mode 100644
index 0000000..9985b4c
--- /dev/null
+++ b/xmalloc.c
@@ -0,0 +1,110 @@
+/* $OpenBSD: xmalloc.c,v 1.27 2006/08/03 03:34:42 deraadt Exp $ */
+/*
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ *                    All rights reserved
+ * Versions of malloc and friends that check their results, and never return
+ * failure (they call fatal if they encounter an error).
+ *
+ * As far as I am concerned, the code I have written for this software
+ * can be used freely for any purpose.  Any derived versions of this
+ * software must be clearly marked as such, and if the derived work is
+ * incompatible with the protocol description in the RFC file, it must be
+ * called by a name other than "ssh" or "Secure Shell".
+ */
+
+#include "includes.h"
+
+#include <sys/param.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "xmalloc.h"
+#include "log.h"
+
+void *
+xmalloc(size_t size)
+{
+	void *ptr;
+
+	if (size == 0)
+		fatal("xmalloc: zero size");
+	ptr = malloc(size);
+	if (ptr == NULL)
+		fatal("xmalloc: out of memory (allocating %lu bytes)", (u_long) size);
+	return ptr;
+}
+
+void *
+xcalloc(size_t nmemb, size_t size)
+{
+	void *ptr;
+
+	if (size == 0 || nmemb == 0)
+		fatal("xcalloc: zero size");
+	if (SIZE_T_MAX / nmemb < size)
+		fatal("xcalloc: nmemb * size > SIZE_T_MAX");
+	ptr = calloc(nmemb, size);
+	if (ptr == NULL)
+		fatal("xcalloc: out of memory (allocating %lu bytes)",
+		    (u_long)(size * nmemb));
+	return ptr;
+}
+
+void *
+xrealloc(void *ptr, size_t nmemb, size_t size)
+{
+	void *new_ptr;
+	size_t new_size = nmemb * size;
+
+	if (new_size == 0)
+		fatal("xrealloc: zero size");
+	if (SIZE_T_MAX / nmemb < size)
+		fatal("xrealloc: nmemb * size > SIZE_T_MAX");
+	if (ptr == NULL)
+		new_ptr = malloc(new_size);
+	else
+		new_ptr = realloc(ptr, new_size);
+	if (new_ptr == NULL)
+		fatal("xrealloc: out of memory (new_size %lu bytes)",
+		    (u_long) new_size);
+	return new_ptr;
+}
+
+void
+xfree(void *ptr)
+{
+	if (ptr == NULL)
+		fatal("xfree: NULL pointer given as argument");
+	free(ptr);
+}
+
+char *
+xstrdup(const char *str)
+{
+	size_t len;
+	char *cp;
+
+	len = strlen(str) + 1;
+	cp = xmalloc(len);
+	strlcpy(cp, str, len);
+	return cp;
+}
+
+int
+xasprintf(char **ret, const char *fmt, ...)
+{
+	va_list ap;
+	int i;
+
+	va_start(ap, fmt);
+	i = vasprintf(ret, fmt, ap);
+	va_end(ap);
+
+	if (i < 0 || *ret == NULL)
+		fatal("xasprintf: could not allocate memory");
+
+	return (i);
+}