[PATCH] fault-injection: Use bool-true-false throughout
[linux-3.10.git] / lib / fault-inject.c
1 #include <linux/kernel.h>
2 #include <linux/init.h>
3 #include <linux/random.h>
4 #include <linux/stat.h>
5 #include <linux/types.h>
6 #include <linux/fs.h>
7 #include <linux/module.h>
8 #include <linux/interrupt.h>
9 #include <linux/unwind.h>
10 #include <linux/stacktrace.h>
11 #include <linux/kallsyms.h>
12 #include <linux/fault-inject.h>
13
14 /*
15  * setup_fault_attr() is a helper function for various __setup handlers, so it
16  * returns 0 on error, because that is what __setup handlers do.
17  */
18 int __init setup_fault_attr(struct fault_attr *attr, char *str)
19 {
20         unsigned long probability;
21         unsigned long interval;
22         int times;
23         int space;
24
25         /* "<interval>,<probability>,<space>,<times>" */
26         if (sscanf(str, "%lu,%lu,%d,%d",
27                         &interval, &probability, &space, &times) < 4) {
28                 printk(KERN_WARNING
29                         "FAULT_INJECTION: failed to parse arguments\n");
30                 return 0;
31         }
32
33         attr->probability = probability;
34         attr->interval = interval;
35         atomic_set(&attr->times, times);
36         atomic_set(&attr->space, space);
37
38         return 1;
39 }
40
41 static void fail_dump(struct fault_attr *attr)
42 {
43         if (attr->verbose > 0)
44                 printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure\n");
45         if (attr->verbose > 1)
46                 dump_stack();
47 }
48
49 #define atomic_dec_not_zero(v)          atomic_add_unless((v), -1, 0)
50
51 static bool fail_task(struct fault_attr *attr, struct task_struct *task)
52 {
53         return !in_interrupt() && task->make_it_fail;
54 }
55
56 #ifdef CONFIG_STACK_UNWIND
57
58 static asmlinkage int fail_stacktrace_callback(struct unwind_frame_info *info,
59                                                 void *arg)
60 {
61         int depth;
62         struct fault_attr *attr = arg;
63         bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
64
65         for (depth = 0; depth < attr->stacktrace_depth
66                         && unwind(info) == 0 && UNW_PC(info); depth++) {
67                 if (arch_unw_user_mode(info))
68                         break;
69                 if (attr->reject_start <= UNW_PC(info) &&
70                                UNW_PC(info) < attr->reject_end)
71                         return false;
72                 if (attr->require_start <= UNW_PC(info) &&
73                                UNW_PC(info) < attr->require_end)
74                         found = true;
75         }
76         return found;
77 }
78
79 static bool fail_stacktrace(struct fault_attr *attr)
80 {
81         struct unwind_frame_info info;
82
83         return unwind_init_running(&info, fail_stacktrace_callback, attr);
84 }
85
86 #elif defined(CONFIG_STACKTRACE)
87
88 static bool fail_stacktrace(struct fault_attr *attr)
89 {
90         struct stack_trace trace;
91         int depth = attr->stacktrace_depth;
92         unsigned long entries[MAX_STACK_TRACE_DEPTH];
93         int n;
94         bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
95
96         if (depth == 0)
97                 return found;
98
99         trace.nr_entries = 0;
100         trace.entries = entries;
101         trace.max_entries = (depth < MAX_STACK_TRACE_DEPTH) ?
102                                 depth : MAX_STACK_TRACE_DEPTH;
103         trace.skip = 1;
104         trace.all_contexts = 0;
105
106         save_stack_trace(&trace, NULL);
107         for (n = 0; n < trace.nr_entries; n++) {
108                 if (attr->reject_start <= entries[n] &&
109                                entries[n] < attr->reject_end)
110                         return false;
111                 if (attr->require_start <= entries[n] &&
112                                entries[n] < attr->require_end)
113                         found = true;
114         }
115         return found;
116 }
117
118 #else
119
120 static inline bool fail_stacktrace(struct fault_attr *attr)
121 {
122         static bool firsttime = true;
123
124         if (firsttime) {
125                 printk(KERN_WARNING
126                 "This architecture does not implement save_stack_trace()\n");
127                 firsttime = false;
128         }
129         return false;
130 }
131
132 #endif
133
134 /*
135  * This code is stolen from failmalloc-1.0
136  * http://www.nongnu.org/failmalloc/
137  */
138
139 bool should_fail(struct fault_attr *attr, ssize_t size)
140 {
141         if (attr->task_filter && !fail_task(attr, current))
142                 return false;
143
144         if (!fail_stacktrace(attr))
145                 return false;
146
147         if (atomic_read(&attr->times) == 0)
148                 return false;
149
150         if (atomic_read(&attr->space) > size) {
151                 atomic_sub(size, &attr->space);
152                 return false;
153         }
154
155         if (attr->interval > 1) {
156                 attr->count++;
157                 if (attr->count % attr->interval)
158                         return false;
159         }
160
161         if (attr->probability > random32() % 100)
162                 goto fail;
163
164         return false;
165
166 fail:
167         fail_dump(attr);
168
169         if (atomic_read(&attr->times) != -1)
170                 atomic_dec_not_zero(&attr->times);
171
172         return true;
173 }
174
175 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
176
177 static void debugfs_ul_set(void *data, u64 val)
178 {
179         *(unsigned long *)data = val;
180 }
181
182 static u64 debugfs_ul_get(void *data)
183 {
184         return *(unsigned long *)data;
185 }
186
187 DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
188
189 static struct dentry *debugfs_create_ul(const char *name, mode_t mode,
190                                 struct dentry *parent, unsigned long *value)
191 {
192         return debugfs_create_file(name, mode, parent, value, &fops_ul);
193 }
194
195 static void debugfs_atomic_t_set(void *data, u64 val)
196 {
197         atomic_set((atomic_t *)data, val);
198 }
199
200 static u64 debugfs_atomic_t_get(void *data)
201 {
202         return atomic_read((atomic_t *)data);
203 }
204
205 DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
206                         debugfs_atomic_t_set, "%lld\n");
207
208 static struct dentry *debugfs_create_atomic_t(const char *name, mode_t mode,
209                                 struct dentry *parent, atomic_t *value)
210 {
211         return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
212 }
213
214 void cleanup_fault_attr_dentries(struct fault_attr *attr)
215 {
216         debugfs_remove(attr->dentries.probability_file);
217         attr->dentries.probability_file = NULL;
218
219         debugfs_remove(attr->dentries.interval_file);
220         attr->dentries.interval_file = NULL;
221
222         debugfs_remove(attr->dentries.times_file);
223         attr->dentries.times_file = NULL;
224
225         debugfs_remove(attr->dentries.space_file);
226         attr->dentries.space_file = NULL;
227
228         debugfs_remove(attr->dentries.verbose_file);
229         attr->dentries.verbose_file = NULL;
230
231         debugfs_remove(attr->dentries.task_filter_file);
232         attr->dentries.task_filter_file = NULL;
233
234         debugfs_remove(attr->dentries.stacktrace_depth_file);
235         attr->dentries.stacktrace_depth_file = NULL;
236
237         debugfs_remove(attr->dentries.require_start_file);
238         attr->dentries.require_start_file = NULL;
239
240         debugfs_remove(attr->dentries.require_end_file);
241         attr->dentries.require_end_file = NULL;
242
243         debugfs_remove(attr->dentries.reject_start_file);
244         attr->dentries.reject_start_file = NULL;
245
246         debugfs_remove(attr->dentries.reject_end_file);
247         attr->dentries.reject_end_file = NULL;
248
249         if (attr->dentries.dir)
250                 WARN_ON(!simple_empty(attr->dentries.dir));
251
252         debugfs_remove(attr->dentries.dir);
253         attr->dentries.dir = NULL;
254 }
255
256 int init_fault_attr_dentries(struct fault_attr *attr, const char *name)
257 {
258         mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
259         struct dentry *dir;
260
261         memset(&attr->dentries, 0, sizeof(attr->dentries));
262
263         dir = debugfs_create_dir(name, NULL);
264         if (!dir)
265                 goto fail;
266         attr->dentries.dir = dir;
267
268         attr->dentries.probability_file =
269                 debugfs_create_ul("probability", mode, dir, &attr->probability);
270
271         attr->dentries.interval_file =
272                 debugfs_create_ul("interval", mode, dir, &attr->interval);
273
274         attr->dentries.times_file =
275                 debugfs_create_atomic_t("times", mode, dir, &attr->times);
276
277         attr->dentries.space_file =
278                 debugfs_create_atomic_t("space", mode, dir, &attr->space);
279
280         attr->dentries.verbose_file =
281                 debugfs_create_ul("verbose", mode, dir, &attr->verbose);
282
283         attr->dentries.task_filter_file = debugfs_create_bool("task-filter",
284                                                 mode, dir, &attr->task_filter);
285
286         attr->dentries.stacktrace_depth_file =
287                 debugfs_create_ul("stacktrace-depth", mode, dir,
288                                   &attr->stacktrace_depth);
289
290         attr->dentries.require_start_file =
291                 debugfs_create_ul("require-start", mode, dir, &attr->require_start);
292
293         attr->dentries.require_end_file =
294                 debugfs_create_ul("require-end", mode, dir, &attr->require_end);
295
296         attr->dentries.reject_start_file =
297                 debugfs_create_ul("reject-start", mode, dir, &attr->reject_start);
298
299         attr->dentries.reject_end_file =
300                 debugfs_create_ul("reject-end", mode, dir, &attr->reject_end);
301
302
303         if (!attr->dentries.probability_file || !attr->dentries.interval_file
304             || !attr->dentries.times_file || !attr->dentries.space_file
305             || !attr->dentries.verbose_file || !attr->dentries.task_filter_file
306             || !attr->dentries.stacktrace_depth_file
307             || !attr->dentries.require_start_file
308             || !attr->dentries.require_end_file
309             || !attr->dentries.reject_start_file
310             || !attr->dentries.reject_end_file
311             )
312                 goto fail;
313
314         return 0;
315 fail:
316         cleanup_fault_attr_dentries(attr);
317         return -ENOMEM;
318 }
319
320 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */