summaryrefslogtreecommitdiff
path: root/lib/notifier-error-inject.c
blob: eb4a04afea80a6a2e3d3954cf1b9f00a45faf4a9 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
#include <linux/module.h>

#include "notifier-error-inject.h"

static int debugfs_errno_set(void *data, u64 val)
{
	*(int *)data = clamp_t(int, val, -MAX_ERRNO, 0);
	return 0;
}

static int debugfs_errno_get(void *data, u64 *val)
{
	*val = *(int *)data;
	return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(fops_errno, debugfs_errno_get, debugfs_errno_set,
			"%lld\n");

static struct dentry *debugfs_create_errno(const char *name, umode_t mode,
				struct dentry *parent, int *value)
{
	return debugfs_create_file(name, mode, parent, value, &fops_errno);
}

static int notifier_err_inject_callback(struct notifier_block *nb,
				unsigned long val, void *p)
{
	int err = 0;
	struct notifier_err_inject *err_inject =
		container_of(nb, struct notifier_err_inject, nb);
	struct notifier_err_inject_action *action;

	for (action = err_inject->actions; action->name; action++) {
		if (action->val == val) {
			err = action->error;
			break;
		}
	}
	if (err)
		pr_info("Injecting error (%d) to %s\n", err, action->name);

	return notifier_from_errno(err);
}

struct dentry *notifier_err_inject_dir;
EXPORT_SYMBOL_GPL(notifier_err_inject_dir);

struct dentry *notifier_err_inject_init(const char *name, struct dentry *parent,
			struct notifier_err_inject *err_inject, int priority)
{
	struct notifier_err_inject_action *action;
	umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
	struct dentry *dir;
	struct dentry *actions_dir;

	err_inject->nb.notifier_call = notifier_err_inject_callback;
	err_inject->nb.priority = priority;

	dir = debugfs_create_dir(name, parent);
	if (!dir)
		return ERR_PTR(-ENOMEM);

	actions_dir = debugfs_create_dir("actions", dir);
	if (!actions_dir)
		goto fail;

	for (action = err_inject->actions; action->name; action++) {
		struct dentry *action_dir;

		action_dir = debugfs_create_dir(action->name, actions_dir);
		if (!action_dir)
			goto fail;

		/*
		 * Create debugfs r/w file containing action->error. If
		 * notifier call chain is called with action->val, it will
		 * fail with the error code
		 */
		if (!debugfs_create_errno("error", mode, action_dir,
					&action->error))
			goto fail;
	}
	return dir;
fail:
	debugfs_remove_recursive(dir);
	return ERR_PTR(-ENOMEM);
}
EXPORT_SYMBOL_GPL(notifier_err_inject_init);

static int __init err_inject_init(void)
{
	notifier_err_inject_dir =
		debugfs_create_dir("notifier-error-inject", NULL);

	if (!notifier_err_inject_dir)
		return -ENOMEM;

	return 0;
}

static void __exit err_inject_exit(void)
{
	debugfs_remove_recursive(notifier_err_inject_dir);
}

module_init(err_inject_init);
module_exit(err_inject_exit);

MODULE_DESCRIPTION("Notifier error injection module");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");