kernel:module: add radix-tree example

kernel/modules/radix-tree/Makefile

@@ -0,0 +1,11 @@
+obj-m := radix_tree.o
+ccflags-y := -std=gnu99 -Wno-declaration-after-statement -O3
+cwd := $(shell pwd)
+
+kdir := /lib/modules/$(shell uname -r)/build
+
+all:
+	make -C ${kdir} M=${cwd} modules
+
+clean:
+	make -C ${kdir} M=${cwd} clean

kernel/modules/radix-tree/radix_tree.c

@@ -0,0 +1,131 @@
+/**
+ * Copyright (C) 2021 jouyouyun <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * radix_tree.c -- kernel radix-tree example
+ *
+ * Written on 星期一,  4 一月 2021.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/radix-tree.h>
+
+#define FLAG_R 1 << 0
+#define FLAG_W 1 << 1
+#define FLAG_D 1 << 2
+
+struct file_node {
+  unsigned long id;
+  unsigned int flag;
+  char *file;
+};
+
+#define MOD_NAME "radix_tree"
+#define DEFAULT_FLAG (FLAG_R | FLAG_W)
+
+static char *_files[] = {
+	"/opt/dlp/data/wps/file1.doc",
+	"/opt/dlp/data/wpa/config.ini",
+	NULL,
+};
+
+static unsigned long id_list[2] = {0};
+
+RADIX_TREE(_root, 0);
+
+static struct file_node *make_file_node(const char *file, const int flag)
+{
+	static size_t node_len = sizeof(struct file_node);
+	int len = strlen(file);
+	struct file_node *node = kzalloc(node_len, GFP_KERNEL);
+
+        if (unlikely(node == NULL))
+		return NULL;
+
+        node->file = kzalloc(len+1, GFP_KERNEL);
+        if (unlikely(node->file == NULL))
+		goto free;
+
+        node->id = (unsigned long)node;
+	node->flag = flag;
+	memcpy(node->file, file, len);
+
+	return node;
+free:
+	kfree(node);
+	return NULL;
+}
+
+static void free_file_node(struct file_node *node)
+{
+	kfree(node->file);
+	kfree(node);
+}
+
+static void lookup_file_node(unsigned long id)
+{
+	struct file_node *node = NULL;
+
+	node = (struct file_node *)radix_tree_lookup(&_root, id);
+	if (unlikely(node == NULL)) {
+		printk("[%s] failed to lookup node: 0x%lx", MOD_NAME, id);
+		return;
+	}
+
+	printk("[%s] node value: id(0x%lx), flag(%u), file(%s)", MOD_NAME, node->id,
+	       node->flag, node->file);
+}
+
+int __init mod_init(void) {
+	int i = 0;
+
+	printk("[%s] init", MOD_NAME);
+	while (_files[i] != NULL) {
+		struct file_node *node = make_file_node(_files[i], DEFAULT_FLAG);
+		if (unlikely(node == NULL)) {
+			printk("[%s] failed to make file_node for '%s'", MOD_NAME, _files[i]);
+			i++;
+			continue;
+		}
+
+		printk("[%s] insert node: 0x%lx", MOD_NAME, node->id);
+		radix_tree_insert(&_root, node->id, (void *)node);
+		id_list[i] = node->id;
+		i++;
+	}
+
+	lookup_file_node(id_list[1]);
+	lookup_file_node(12334);
+	return 0;
+}
+
+void __exit mod_exit(void)
+{
+	void **node_ptr = NULL;
+        struct radix_tree_iter iter;
+
+        printk("[%s] exit", MOD_NAME);
+        radix_tree_for_each_slot(node_ptr, &_root, &iter, 0) {
+		struct file_node *node = (struct file_node*)(*node_ptr);
+                printk("[%s] iter node value: id(0x%lx), flag(%u), file(%s)", MOD_NAME, node->id,
+                       node->flag, node->file);
+                radix_tree_delete(&_root, node->id);
+                free_file_node(node);
+                node = NULL;
+        }
+
+	printk("[%s] empty: %d", MOD_NAME, radix_tree_empty(&_root));
+}
+
+module_init(mod_init);
+module_exit(mod_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("jouyouyun");
+MODULE_DESCRIPTION("a kernel radix-tree example");

kernel/modules/template/Makefile

@@ -0,0 +1,11 @@
+obj-m := template.o
+ccflags-y := -std=gnu99 -Wno-declaration-after-statement -O3
+cwd := $(shell pwd)
+
+kdir := /lib/modules/$(shell uname -r)/build
+
+all:
+	make -C ${kdir} M=${cwd} modules
+
+clean:
+	make -C ${kdir} M=${cwd} clean

kernel/modules/template/template.c

@@ -0,0 +1,36 @@
+/**
+ * Copyright (C) 2021 jouyouyun <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * template.c -- template
+ *
+ * Written on 星期一,  4 一月 2021.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+
+#define MOD_NAME "template"
+
+int __init mod_init(void)
+{
+	printk("[%s] init", MOD_NAME);
+	return 0;
+}
+
+void __exit mod_exit(void)
+{
+	printk("[%s] exit", MOD_NAME);
+}
+
+module_init(mod_init);
+module_exit(mod_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("jouyouyun");
+MODULE_DESCRIPTION("template");

misc/struct_pointer.c

@@ -0,0 +1,73 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define FLAG_R 1 << 0
+#define FLAG_W 1 << 1
+#define FLAG_D 1 << 2
+
+struct foo1 {
+	unsigned long id;
+	unsigned int flag;
+	char *value;
+};
+
+static char *files[] = {
+	"/opt/dlp/data/app1/file1",
+	"/opt/dlp/data/app2/file1",
+	NULL,
+};
+
+#define DEFAULT_FLAG (FLAG_R|FLAG_W|FLAG_D)
+
+static struct foo1 *make_foo1(const char *filename, unsigned int flag)
+{
+	struct foo1 *ret = NULL;
+	int len = strlen(filename);
+
+	ret = calloc(1, sizeof(struct foo1));
+	if (!ret)
+		return NULL;
+
+	ret->value = calloc(len+1, sizeof(char));
+	if (!ret->value)
+		goto free;
+
+	ret->id = (unsigned long)ret;
+	memcpy(ret->value, filename, len);
+	ret->flag = flag;
+
+	return ret;
+free:
+	free(ret);
+	return NULL;
+}
+
+static void free_foo1(struct foo1 *node)
+{
+	free(node->value);
+	free(node);
+	node = NULL;
+}
+
+int main()
+{
+	int i = 0;
+
+	while (files[i] != NULL) {
+		struct foo1 *node = make_foo1(files[i], DEFAULT_FLAG);
+		if (!node) {
+			printf("failed to make node for '%s'\n", files[i]);
+			i++;
+			continue;
+		}
+
+		printf("node addr: %p\n", node);
+		printf("node value: 0x%lx, %u, %s\n", node->id, node->flag, node->value);
+		free_foo1(node);
+		printf("node free success\n");
+		i++;
+	}
+
+	return 0;
+}