1#include <linux/module.h>
  2
  3#include "notifier-error-inject.h"
  4
  5static int debugfs_errno_set(void *data, u64 val)
  6{
  7	*(int *)data = clamp_t(int, val, -MAX_ERRNO, 0);
  8	return 0;
  9}
 10
 11static int debugfs_errno_get(void *data, u64 *val)
 12{
 13	*val = *(int *)data;
 14	return 0;
 15}
 16
 17DEFINE_SIMPLE_ATTRIBUTE(fops_errno, debugfs_errno_get, debugfs_errno_set,
 18			"%lld\n");
 19
 20static struct dentry *debugfs_create_errno(const char *name, umode_t mode,
 21				struct dentry *parent, int *value)
 22{
 23	return debugfs_create_file(name, mode, parent, value, &fops_errno);
 24}
 25
 26static int notifier_err_inject_callback(struct notifier_block *nb,
 27				unsigned long val, void *p)
 28{
 29	int err = 0;
 30	struct notifier_err_inject *err_inject =
 31		container_of(nb, struct notifier_err_inject, nb);
 32	struct notifier_err_inject_action *action;
 33
 34	for (action = err_inject->actions; action->name; action++) {
 35		if (action->val == val) {
 36			err = action->error;
 37			break;
 38		}
 39	}
 40	if (err)
 41		pr_info("Injecting error (%d) to %s\n", err, action->name);
 42
 43	return notifier_from_errno(err);
 44}
 45
 46struct dentry *notifier_err_inject_dir;
 47EXPORT_SYMBOL_GPL(notifier_err_inject_dir);
 48
 49struct dentry *notifier_err_inject_init(const char *name, struct dentry *parent,
 50			struct notifier_err_inject *err_inject, int priority)
 51{
 52	struct notifier_err_inject_action *action;
 53	umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
 54	struct dentry *dir;
 55	struct dentry *actions_dir;
 56
 57	err_inject->nb.notifier_call = notifier_err_inject_callback;
 58	err_inject->nb.priority = priority;
 59
 60	dir = debugfs_create_dir(name, parent);
 61	if (!dir)
 62		return ERR_PTR(-ENOMEM);
 63
 64	actions_dir = debugfs_create_dir("actions", dir);
 65	if (!actions_dir)
 66		goto fail;
 67
 68	for (action = err_inject->actions; action->name; action++) {
 69		struct dentry *action_dir;
 70
 71		action_dir = debugfs_create_dir(action->name, actions_dir);
 72		if (!action_dir)
 73			goto fail;
 74
 75		/*
 76		 * Create debugfs r/w file containing action->error. If
 77		 * notifier call chain is called with action->val, it will
 78		 * fail with the error code
 79		 */
 80		if (!debugfs_create_errno("error", mode, action_dir,
 81					&action->error))
 82			goto fail;
 83	}
 84	return dir;
 85fail:
 86	debugfs_remove_recursive(dir);
 87	return ERR_PTR(-ENOMEM);
 88}
 89EXPORT_SYMBOL_GPL(notifier_err_inject_init);
 90
 91static int __init err_inject_init(void)
 92{
 93	notifier_err_inject_dir =
 94		debugfs_create_dir("notifier-error-inject", NULL);
 95
 96	if (!notifier_err_inject_dir)
 97		return -ENOMEM;
 98
 99	return 0;
100}
101
102static void __exit err_inject_exit(void)
103{
104	debugfs_remove_recursive(notifier_err_inject_dir);
105}
106
107module_init(err_inject_init);
108module_exit(err_inject_exit);
109
110MODULE_DESCRIPTION("Notifier error injection module");
111MODULE_LICENSE("GPL");
112MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");

 1// SPDX-License-Identifier: GPL-2.0-only
 2#include <linux/module.h>
 3
 4#include "notifier-error-inject.h"
 5
 6static int debugfs_errno_set(void *data, u64 val)
 7{
 8	*(int *)data = clamp_t(int, val, -MAX_ERRNO, 0);
 9	return 0;
10}
11
12static int debugfs_errno_get(void *data, u64 *val)
13{
14	*val = *(int *)data;
15	return 0;
16}
17
18DEFINE_SIMPLE_ATTRIBUTE_SIGNED(fops_errno, debugfs_errno_get, debugfs_errno_set,
19			"%lld\n");
20
21static struct dentry *debugfs_create_errno(const char *name, umode_t mode,
22				struct dentry *parent, int *value)
23{
24	return debugfs_create_file(name, mode, parent, value, &fops_errno);
25}
26
27static int notifier_err_inject_callback(struct notifier_block *nb,
28				unsigned long val, void *p)
29{
30	int err = 0;
31	struct notifier_err_inject *err_inject =
32		container_of(nb, struct notifier_err_inject, nb);
33	struct notifier_err_inject_action *action;
34
35	for (action = err_inject->actions; action->name; action++) {
36		if (action->val == val) {
37			err = action->error;
38			break;
39		}
40	}
41	if (err)
42		pr_info("Injecting error (%d) to %s\n", err, action->name);
43
44	return notifier_from_errno(err);
45}
46
47struct dentry *notifier_err_inject_dir;
48EXPORT_SYMBOL_GPL(notifier_err_inject_dir);
49
50struct dentry *notifier_err_inject_init(const char *name, struct dentry *parent,
51			struct notifier_err_inject *err_inject, int priority)
52{
53	struct notifier_err_inject_action *action;
54	umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
55	struct dentry *dir;
56	struct dentry *actions_dir;
57
58	err_inject->nb.notifier_call = notifier_err_inject_callback;
59	err_inject->nb.priority = priority;
60
61	dir = debugfs_create_dir(name, parent);
 
 
62
63	actions_dir = debugfs_create_dir("actions", dir);
 
 
64
65	for (action = err_inject->actions; action->name; action++) {
66		struct dentry *action_dir;
67
68		action_dir = debugfs_create_dir(action->name, actions_dir);
 
 
69
70		/*
71		 * Create debugfs r/w file containing action->error. If
72		 * notifier call chain is called with action->val, it will
73		 * fail with the error code
74		 */
75		debugfs_create_errno("error", mode, action_dir, &action->error);
 
 
76	}
77	return dir;
 
 
 
78}
79EXPORT_SYMBOL_GPL(notifier_err_inject_init);
80
81static int __init err_inject_init(void)
82{
83	notifier_err_inject_dir =
84		debugfs_create_dir("notifier-error-inject", NULL);
 
 
 
85
86	return 0;
87}
88
89static void __exit err_inject_exit(void)
90{
91	debugfs_remove_recursive(notifier_err_inject_dir);
92}
93
94module_init(err_inject_init);
95module_exit(err_inject_exit);
96
97MODULE_DESCRIPTION("Notifier error injection module");
98MODULE_LICENSE("GPL");
99MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");