| 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 2 | #include <linux/module.h> |
| 3 | |
| 4 | #include "notifier-error-inject.h" |
| 5 | |
| 6 | static int debugfs_errno_set(void *data, u64 val) |
| 7 | { |
| 8 | *(int *)data = clamp_t(int, val, -MAX_ERRNO, 0); |
| 9 | return 0; |
| 10 | } |
| 11 | |
| 12 | static int debugfs_errno_get(void *data, u64 *val) |
| 13 | { |
| 14 | *val = *(int *)data; |
| 15 | return 0; |
| 16 | } |
| 17 | |
| 18 | DEFINE_SIMPLE_ATTRIBUTE_SIGNED(fops_errno, debugfs_errno_get, debugfs_errno_set, |
| 19 | "%lld\n"); |
| 20 | |
| 21 | static 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 | |
| 27 | static 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 | |
| 47 | struct dentry *notifier_err_inject_dir; |
| 48 | EXPORT_SYMBOL_GPL(notifier_err_inject_dir); |
| 49 | |
| 50 | struct 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 | } |
| 79 | EXPORT_SYMBOL_GPL(notifier_err_inject_init); |
| 80 | |
| 81 | static 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 | |
| 89 | static void __exit err_inject_exit(void) |
| 90 | { |
| 91 | debugfs_remove_recursive(notifier_err_inject_dir); |
| 92 | } |
| 93 | |
| 94 | module_init(err_inject_init); |
| 95 | module_exit(err_inject_exit); |
| 96 | |
| 97 | MODULE_DESCRIPTION("Notifier error injection module"); |
| 98 | MODULE_LICENSE("GPL"); |
| 99 | MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>"); |