Add hostname

hostname.c

@@ -0,0 +1,39 @@
+/* This file is part of ToaruOS and is released under the terms
+ * of the NCSA / University of Illinois License - see LICENSE.md
+ * Copyright (C) 2013-2014 Kevin Lange
+ */
+/* vim: tabstop=4 shiftwidth=4 noexpandtab
+ *
+ * hostname
+ *
+ * Prints or sets the system hostname.
+ */
+#include <stdio.h>
+#include <syscall.h>
+
+#define ROOT_UID 0
+
+int main(int argc, char * argv[]) {
+	if ((argc > 1 && argv[1][0] == '-') || (argc < 2)) {
+		char tmp[256];
+		syscall_gethostname(tmp);
+		printf("%s\n", tmp);
+		return 0;
+	} else {
+		if (syscall_getuid() != ROOT_UID) {
+			fprintf(stderr,"Must be root to set hostname.\n");
+			return 1;
+		} else {
+			syscall_sethostname(argv[1]);
+			FILE * file = fopen("/etc/hostname", "w");
+			if (!file) {
+				return 1;
+			} else {
+				fprintf(file, "%s\n", argv[1]);
+				fclose(file);
+				return 0;
+			}
+		}
+	}
+	return 0;
+}