Lesson 5: Added sysfs and procfs modules

05-Interfaces/Makefile

@@ -0,0 +1,11 @@
+#
+# Homework 5: Building module_procfs and module_sysfs
+#
+
+obj-m :=module_procfs.o module_sysfs.o
+
+all:
+	make -C $(BUILD_KERNEL) M=$(PWD) modules
+
+clean:
+	make -C $(BUILD_KERNEL) M=$(PWD) clean

05-Interfaces/module_procfs.c

@@ -0,0 +1,145 @@
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/proc_fs.h>
+#include <linux/uaccess.h>
+#include <linux/ctype.h>
+
+
+#define DIR_NAME	"my_procfs_dir"
+#define ENT1_NAME	"uppercase"
+#define ENT2_NAME	"statistics"
+
+static char msg[PAGE_SIZE];
+static ssize_t msg_size;
+static char stat_msg[PAGE_SIZE];
+static size_t stat_msg_size;
+static int call_read;
+static int call_write;
+static int total_char;
+
+static ssize_t mywrite(struct file *file, const char __user *pbuf, size_t count, loff_t *ppos)
+{
+	ssize_t not_copied;
+	int i;
+
+	call_write++;
+
+	pr_info("mymodule: mywrite: count=%d\n", count);
+
+	not_copied = copy_from_user(msg, pbuf, count);
+
+	msg_size = count - not_copied;
+
+	for (i = 0; i < msg_size; i++) {
+		total_char++;
+		msg[i] = toupper(msg[i]);
+	}
+
+	pr_info("mymodule: mywrite: msg_size=%d\n", msg_size);
+	return msg_size;
+}
+
+static ssize_t myread(struct file *file, char __user *pbuf, size_t count, loff_t *ppos)
+{
+	ssize_t num, not_copied;
+
+	call_read++;
+
+	pr_info("mymodule: myread: count=%d\n", count);
+
+	num = min_t(ssize_t, msg_size, count);
+
+	if (num) {
+		not_copied = copy_to_user(pbuf, msg, num);
+		num -= not_copied;
+	}
+
+	msg_size = 0; /* Indicate EOF on next read */
+
+	pr_info("mymodule: myread: return=%d\n", num);
+	return num;
+}
+
+static ssize_t stat_read(struct file *file, char __user *pbuf, size_t count, loff_t *ppos)
+{
+	pr_info("Call Statistics:\ncalled Read %d - called Write"
+		" %d Total characters %d\n", call_read, call_write, total_char);
+
+	stat_msg_size = sprintf(stat_msg, "Call Statistics:\n called Read %d"
+	" - called Write %d Total characters %d\n", call_read, call_write, total_char);
+
+	if (count < stat_msg_size)
+		return -EINVAL;
+	if (*ppos != 0)
+		return 0;
+	if (copy_to_user(pbuf, stat_msg, stat_msg_size))
+		return -EINVAL;
+
+	*ppos = stat_msg_size;
+
+	pr_info("mymodule: myread: return=%d\n", stat_msg_size);
+	return stat_msg_size;
+}
+
+
+static const struct file_operations rw_ops = {
+	.owner = THIS_MODULE,
+	.read = myread,
+	.write = mywrite,
+};
+
+static const struct file_operations r_ops = {
+	.owner = THIS_MODULE,
+	.read = stat_read,
+};
+
+
+static struct proc_dir_entry *dir;
+static struct proc_dir_entry *ent1, *ent2;
+
+
+static int mymodule_init(void)
+{
+	dir = proc_mkdir(DIR_NAME, NULL);
+	if (dir == NULL) {
+		pr_err("mymodule: error creating: proc/my_procfs_dir\n");
+		return -ENOMEM;
+	}
+
+	ent1 = proc_create(ENT1_NAME, 0666, dir, &rw_ops);
+	if (ent1 == NULL) {
+		pr_err("mymodule: error creating: proc/my_procfs_dir/uppercase\n");
+		remove_proc_entry(DIR_NAME, NULL);
+		return -ENOMEM;
+	}
+
+	ent2 = proc_create(ENT2_NAME, 0444, dir, &r_ops);
+	if (ent2 == NULL) {
+		pr_err("mymodule: error creating: /proc/my_procfs_dir/statistics\n");
+		remove_proc_entry(ENT1_NAME, dir);
+		remove_proc_entry(DIR_NAME, NULL);
+		return -ENOMEM;
+	}
+
+	pr_info("mymodule: module loaded\nCreate:\n"
+		"/proc/my_procfs_dir/uppercase\n /proc/my_procfs_dir/statistics\n");
+	return 0;
+}
+
+static void mymodule_exit(void)
+{
+	proc_remove(dir);
+
+	pr_info("mymodule: module exited\nRemove:\n"
+		"/proc/my_procfs_dir/uppercase\n/proc/my_procfs_dir/statistics\n");
+}
+
+module_init(mymodule_init);
+module_exit(mymodule_exit);
+
+MODULE_AUTHOR("Dmitriy Ganshin");
+MODULE_DESCRIPTION("Simple Kernel module example procfs: write, read, statistics");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("0.1");

05-Interfaces/module_sysfs.c

@@ -0,0 +1,104 @@
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <linux/ctype.h>
+
+static int call_read;
+static int call_write;
+static int total_char;
+static char str[PAGE_SIZE];
+
+static ssize_t rw_show(struct class *class, struct class_attribute *attr, char *buf)
+{
+	call_read++;
+
+	pr_info("mymodule: rw_show: string: %s\n", str);
+	sprintf(buf, "Output lowercase string:\n%s\n", str);
+	return strlen(buf);
+}
+
+static ssize_t rw_store(struct class *class, struct class_attribute *attr, const char *buf, size_t count)
+{
+	int i;
+	int temp;
+
+	call_write++;
+
+	strcpy(str, buf);
+	temp = strlen(str);
+
+	pr_info("mymodule: rw_store: string: %s\n", str);
+
+	for (i = 0; i < temp; i++) {
+		total_char++;
+		str[i] = tolower(str[i]);
+	}
+	return count;
+}
+
+static ssize_t statistics_show(struct class *class, struct class_attribute *attr, char *buf)
+{
+	pr_info("Statistics:\ncall Read %d call Write %d Total characters %d\n",
+					call_read, call_write, total_char);
+	sprintf(buf, "Statistics:\ncall Read %d call Write %d Total characters %d\n",
+					call_read, call_write, total_char);
+
+	return strlen(buf);
+}
+
+
+CLASS_ATTR_RW(rw);
+CLASS_ATTR_RO(statistics);
+
+static struct class *attr_class;
+
+
+static int mymodule_init(void)
+{
+	int ret;
+
+	attr_class = class_create(THIS_MODULE, "lowercase");
+	if (attr_class == NULL) {
+		pr_err("mymodule: error creating sysfs class\n");
+		return -ENOMEM;
+	}
+
+	ret = class_create_file(attr_class, &class_attr_rw);
+	if (ret) {
+		pr_err("mymodule: error creating sysfs class attribute\n");
+		class_destroy(attr_class);
+		return ret;
+	}
+
+		ret = class_create_file(attr_class, &class_attr_statistics);
+	if (ret) {
+		pr_err("mymodule: error creating sysfs class attribute\n");
+		class_destroy(attr_class);
+		return ret;
+	}
+
+	pr_info("mymodule: module loaded\nCreate:\n/sys/class/lowercase/rw\n"
+					"/sys/class/lowercase/statistics\n");
+	return 0;
+}
+
+static void mymodule_exit(void)
+{
+	class_remove_file(attr_class, &class_attr_statistics);
+	class_remove_file(attr_class, &class_attr_rw);
+	class_destroy(attr_class);
+
+	pr_info("mymodule: module exited\nRemove:\n/sys/class/lowercase/rw\n"
+					"/sys/class/lowercase/statistics\n");
+}
+
+module_init(mymodule_init);
+module_exit(mymodule_exit);
+
+MODULE_AUTHOR("Dmitriy Ganshin");
+MODULE_DESCRIPTION("Simple Kernel module sysfs  (write, read, statistics");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("0.1");