Root/lib/notifier-error-inject.c

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

Archive Download this file



interactive