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, data: value, fops: &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(name: "actions", parent: dir);
64
65 for (action = err_inject->actions; action->name; action++) {
66 struct dentry *action_dir;
67
68 action_dir = debugfs_create_dir(name: action->name, parent: 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(name: "error", mode, parent: action_dir, value: &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(name: "notifier-error-inject", NULL);
85
86 return 0;
87}
88
89static void __exit err_inject_exit(void)
90{
91 debugfs_remove_recursive(dentry: 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>");
100

source code of linux/lib/notifier-error-inject.c