Subject: Again module with parameters

Author: psachin

module_param2/Makefile

@@ -0,0 +1,21 @@
+# Makefile for module_param.c
+# Makefile adopted from free-electrons slides on Kernel development
+ifneq ($(KERNELRELEASE),)
+obj-m := module-param.o
+else
+KDIR=/usr/src/linux-headers-$(shell uname -r)
+
+all: modules
+
+modules:
+	$(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules
+modules_install:
+	$(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules_install
+kernel_clean:
+	$(MAKE) -C $(KDIR) SUBDIRS=$(PWD) clean # from lkmpg
+clean: kernel_clean
+	rm -rvf *~
+
+endif
+
+

module_param2/module-param.c

@@ -0,0 +1,55 @@
+/* hello_param.c*/
+/* Usage:
+   sudo insmod module_param.ko
+
+   OR
+
+   sudo rmmod module_param.ko
+ */
+
+#include<linux/init.h>		/* to initiate a module */
+#include<linux/module.h>	/* to recognise this module as a mmodule */
+
+static char *whom = "Hello";
+module_param(whom, charp, 0);
+MODULE_PARM_DESC(whom, "Whom to greet?");
+
+static int howmany = 3;
+module_param(howmany, int, 0);
+MODULE_PARM_DESC(howmany, "How many subjects?");
+
+static int marks[3] = {18, 67, 90};
+module_param_array(marks, int, &howmany, 0);
+MODULE_PARM_DESC(marks, "Marks obtained");
+
+static int __init hello_param_init(void) {
+    /* entry point of the module */
+    /* to register functionalities and to allocate resources */
+    int i;
+    printk(KERN_INFO "%s world", whom);
+    for (i = 0; i < howmany; i++) {
+	pr_alert("Subject-%d: %d\n", i, marks[i]);
+    }
+
+    return 0;
+}
+
+static void __exit hello_param_exit(void) {
+    /* exit point of the module */
+    /* to unregister functionalities and to deallocate resources */
+    pr_alert(KERN_ALERT "GoodBye, cruel %s\n", whom);
+}
+
+module_init(hello_param_init);	/* whenever the module loads, just to
+				   this line and start hello_init
+				   function first */
+module_exit(hello_param_exit);	/* when the module is removed,
+				   initiate the function
+				   hello_exit. And deallocate any
+				   resources this module uses */
+
+/* additional module info. Can be displayed when calling 'modinfo hello3.ko' */
+MODULE_LICENSE("GPL");		/* license */
+MODULE_AUTHOR("Tas Devil");	/* who wrote it */
+MODULE_DESCRIPTION("hello3: Kernel module demo"); /* purpose of module */
+MODULE_VERSION("0.9");