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>");
113