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(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 if (!dir) 63 return ERR_PTR(-ENOMEM); 64 65 actions_dir = debugfs_create_dir("actions", dir); 66 if (!actions_dir) 67 goto fail; 68 69 for (action = err_inject->actions; action->name; action++) { 70 struct dentry *action_dir; 71 72 action_dir = debugfs_create_dir(action->name, actions_dir); 73 if (!action_dir) 74 goto fail; 75 76 /* 77 * Create debugfs r/w file containing action->error. If 78 * notifier call chain is called with action->val, it will 79 * fail with the error code 80 */ 81 if (!debugfs_create_errno("error", mode, action_dir, 82 &action->error)) 83 goto fail; 84 } 85 return dir; 86 fail: 87 debugfs_remove_recursive(dir); 88 return ERR_PTR(-ENOMEM); 89 } 90 EXPORT_SYMBOL_GPL(notifier_err_inject_init); 91 92 static int __init err_inject_init(void) 93 { 94 notifier_err_inject_dir = 95 debugfs_create_dir("notifier-error-inject", NULL); 96 97 if (!notifier_err_inject_dir) 98 return -ENOMEM; 99 100 return 0; 101 } 102 103 static void __exit err_inject_exit(void) 104 { 105 debugfs_remove_recursive(notifier_err_inject_dir); 106 } 107 108 module_init(err_inject_init); 109 module_exit(err_inject_exit); 110 111 MODULE_DESCRIPTION("Notifier error injection module"); 112 MODULE_LICENSE("GPL"); 113 MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>"); 114