1 #include <linux/module.h> 2 3 #include "notifier-error-inject.h" 4 5 static int debugfs_errno_set(void *data, u64 val) 6 { 7 *(int *)data = clamp_t(int, val, -MAX_ERRNO, 0); 8 return 0; 9 } 10 11 static int debugfs_errno_get(void *data, u64 *val) 12 { 13 *val = *(int *)data; 14 return 0; 15 } 16 17 DEFINE_SIMPLE_ATTRIBUTE(fops_errno, debugfs_errno_get, debugfs_errno_set, 18 "%lld\n"); 19 20 static 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 26 static 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 46 struct dentry *notifier_err_inject_dir; 47 EXPORT_SYMBOL_GPL(notifier_err_inject_dir); 48 49 struct 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; 85 fail: 86 debugfs_remove_recursive(dir); 87 return ERR_PTR(-ENOMEM); 88 } 89 EXPORT_SYMBOL_GPL(notifier_err_inject_init); 90 91 static 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 } 101 102 static void __exit err_inject_exit(void) 103 { 104 debugfs_remove_recursive(notifier_err_inject_dir); 105 } 106 107 module_init(err_inject_init); 108 module_exit(err_inject_exit); 109 110 MODULE_DESCRIPTION("Notifier error injection module"); 111 MODULE_LICENSE("GPL"); 112 MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>"); 113