1 files changed, 57 insertions, 0 deletions
diff --git a/usr/kinit/getarg.c b/usr/kinit/getarg.c
new file mode 100644
index 0000000..fcce247
--- /dev/null
+++ b/usr/kinit/getarg.c
@@ -0,0 +1,57 @@
+#include <string.h>
+#include "kinit.h"
+
+/*
+ * Routines that hunt for a specific argument.  Please note that
+ * they actually search the array backwards.  That is because on the
+ * kernel command lines, it's legal to override an earlier argument
+ * with a later argument.
+ */
+
+/*
+ * Was this boolean argument passed?  If so return the index in the
+ * argv array for it.  For conflicting boolean options, use the
+ * one with the higher index.  The only case when the return value
+ * can be equal, is when they're both zero; so equality can be used
+ * as the default option choice.
+ *
+ * In other words, if two options "a" and "b" are opposites, and "a"
+ * is the default, this can be coded as:
+ *
+ * if (get_flag(argc,argv,"a") >= get_flag(argc,argv,"b"))
+ * 	do_a_stuff();
+ * else
+ *	do_b_stuff();
+ */
+int get_flag(int argc, char *argv[], const char *name)
+{
+	int i;
+
+	for (i = argc-1; i > 0; i--) {
+		if (!strcmp(argv[i], name))
+			return i;
+	}
+	return 0;
+}
+
+/*
+ * Was this textual parameter (foo=option) passed?
+ *
+ * This returns the latest instance of such an option in the argv array.
+ */
+char *get_arg(int argc, char *argv[], const char *name)
+{
+	int len = strlen(name);
+	char *ret = NULL;
+	int i;
+
+	for (i = argc-1; i > 0; i--) {
+		if (argv[i] && strncmp(argv[i], name, len) == 0 &&
+		    (argv[i][len] != '\0')) {
+			ret = argv[i] + len;
+			break;
+		}
+	}
+
+	return ret;
+}