faulty.c
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上传日期:2010-01-21
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文件大小:3k
- /*
- * faulty.c -- a module which generates an oops when read
- *
- * Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet
- * Copyright (C) 2001 O'Reilly & Associates
- *
- * The source code in this file can be freely used, adapted,
- * and redistributed in source or binary form, so long as an
- * acknowledgment appears in derived source files. The citation
- * should list that the code comes from the book "Linux Device
- * Drivers" by Alessandro Rubini and Jonathan Corbet, published
- * by O'Reilly & Associates. No warranty is attached;
- * we cannot take responsibility for errors or fitness for use.
- *
- * $Id: faulty.c,v 1.15 2001/07/18 22:28:16 rubini Exp $
- */
- #ifndef __KERNEL__
- # define __KERNEL__
- #endif
- #ifndef MODULE
- # define MODULE
- #endif
- #include <linux/config.h>
- #include <linux/module.h>
- #include <linux/kernel.h> /* printk() */
- #include <linux/sched.h> /* printk() */
- #include <linux/fs.h> /* everything... */
- #include <linux/types.h> /* size_t */
- #include "sysdep.h" /* linux 2.0, 2.2, 2.4 compatibility macros */
- int faulty_major=0;
- char faulty_buf[1024];
- ssize_t faulty_read (struct file *filp, char *buf, size_t count, loff_t *pos)
- {
- int ret, ret2;
- char stack_buf[4];
- printk(KERN_DEBUG "read: buf %p, count %lin", buf, (long)count);
- /* the next line oopses with 2.0, but not with 2.2 and later */
- ret = copy_to_user(buf, faulty_buf, count);
- if (!ret) return count; /* we survived */
- printk(KERN_DEBUG "didn't fail: retryn");
- /* For 2.2 and 2.4, let's try a buffer overflow */
- sprintf(stack_buf, "1234567n");
- if (count > 8) count = 8; /* copy 8 bytes to the user */
- ret2 = copy_to_user(buf, stack_buf, count);
- if (!ret2) return count;
- return ret2;
- }
- ssize_t faulty_write (struct file *filp, const char *buf, size_t count,
- loff_t *pos)
- {
- /* make a simple fault by dereferencing a NULL pointer */
- *(int *)0 = 0;
- return 0;
- }
- #ifdef LINUX_20 /* wrappers for 2.0 */
- int faulty_read_20 (struct inode *ino, struct file *f, char *buf, int count)
- {
- return (int)faulty_read(f, buf, count, &f->f_pos);
- }
- int faulty_write_20 (struct inode *ino, struct file *f, const char *b, int c)
- {
- return (int)faulty_write(f, b, c, &f->f_pos);
- }
- #define faulty_read faulty_read_20
- #define faulty_write faulty_write_20
- #endif /* LINUX_20 */
- struct file_operations faulty_fops = {
- read: faulty_read,
- write: faulty_write,
- };
- int faulty_init(void)
- {
- int result;
- /*
- * Register your major, and accept a dynamic number
- */
- SET_MODULE_OWNER(&faulty_fops);
- result = register_chrdev(faulty_major, "faulty", &faulty_fops);
- if (result < 0) return result;
- if (faulty_major == 0) faulty_major = result; /* dynamic */
- return 0;
- }
- void faulty_cleanup(void)
- {
- unregister_chrdev(faulty_major, "faulty");
- }
- module_init(faulty_init);
- module_exit(faulty_cleanup);