Print this page
12257 resync smatch to 0.6.1-rc1-il-4
| Split |
Close |
| Expand all |
| Collapse all |
--- old/usr/src/tools/smatch/src/smatch_mtag.c
+++ new/usr/src/tools/smatch/src/smatch_mtag.c
1 1 /*
2 2 * Copyright (C) 2017 Oracle. All rights reserved.
3 3 *
4 4 * This program is free software; you can redistribute it and/or
5 5 * modify it under the terms of the GNU General Public License
6 6 * as published by the Free Software Foundation; either version 2
7 7 * of the License, or (at your option) any later version.
8 8 *
9 9 * This program is distributed in the hope that it will be useful,
10 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 12 * GNU General Public License for more details.
13 13 *
14 14 * You should have received a copy of the GNU General Public License
15 15 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
16 16 */
17 17
18 18 /*
19 19 * One problem that I have is that it's really hard to track how pointers are
20 20 * passed around. For example, it would be nice to know that the probe() and
21 21 * remove() functions get the same pci_dev pointer. It would be good to know
22 22 * what pointers we're passing to the open() and close() functions. But that
23 23 * information gets lost in a call tree full of function pointer calls.
24 24 *
25 25 * I think the first step is to start naming specific pointers. So when a
26 26 * pointer is allocated, then it gets a tag. So calls to kmalloc() generate a
27 27 * tag. But we might not use that, because there might be a better name like
28 28 * framebuffer_alloc(). The framebuffer_alloc() is interesting because there is
29 29 * one per driver and it's passed around to all the file operations.
30 30 *
31 31 * Perhaps we could make a list of functions like framebuffer_alloc() which take
32 32 * a size and say that those are the interesting alloc functions.
33 33 *
34 34 * Another place where we would maybe name the pointer is when they are passed
35 35 * to the probe(). Because that's an important pointer, since there is one
36 36 * per driver (sort of).
37 37 *
38 38 * My vision is that you could take a pointer and trace it back to a global. So
39 39 * I'm going to track that pointer_tag - 28 bytes takes you to another pointer
40 40 * tag. You could follow that one back and so on. Also when we pass a pointer
41 41 * to a function that would be recorded as sort of a link or path or something.
42 42 *
|
↓ open down ↓ |
42 lines elided |
↑ open up ↑ |
43 43 */
44 44
45 45 #include "smatch.h"
46 46 #include "smatch_slist.h"
47 47 #include "smatch_extra.h"
48 48
49 49 #include <openssl/md5.h>
50 50
51 51 static int my_id;
52 52
53 -static mtag_t str_to_tag(const char *str)
53 +mtag_t str_to_mtag(const char *str)
54 54 {
55 55 unsigned char c[MD5_DIGEST_LENGTH];
56 56 unsigned long long *tag = (unsigned long long *)&c;
57 57 MD5_CTX mdContext;
58 58 int len;
59 59
60 60 len = strlen(str);
61 61 MD5_Init(&mdContext);
62 62 MD5_Update(&mdContext, str, len);
63 63 MD5_Final(c, &mdContext);
64 64
65 65 *tag &= ~MTAG_ALIAS_BIT;
66 66 *tag &= ~MTAG_OFFSET_MASK;
67 67
68 68 return *tag;
69 69 }
70 70
71 71 const struct {
72 72 const char *name;
73 73 int size_arg;
74 74 } allocator_info[] = {
75 75 { "kmalloc", 0 },
76 76 { "kzalloc", 0 },
77 77 { "devm_kmalloc", 1},
78 78 { "devm_kzalloc", 1},
79 79 };
80 80
81 81 static bool is_mtag_call(struct expression *expr)
82 82 {
83 83 struct expression *arg;
84 84 int i;
85 85 sval_t sval;
86 86
87 87 if (expr->type != EXPR_CALL ||
88 88 expr->fn->type != EXPR_SYMBOL ||
89 89 !expr->fn->symbol)
90 90 return false;
91 91
92 92 for (i = 0; i < ARRAY_SIZE(allocator_info); i++) {
93 93 if (strcmp(expr->fn->symbol->ident->name, allocator_info[i].name) == 0)
94 94 break;
95 95 }
96 96 if (i == ARRAY_SIZE(allocator_info))
97 97 return false;
98 98
99 99 arg = get_argument_from_call_expr(expr->args, allocator_info[i].size_arg);
100 100 if (!get_implied_value(arg, &sval))
101 101 return false;
102 102
103 103 return true;
104 104 }
105 105
106 106 struct smatch_state *swap_mtag_return(struct expression *expr, struct smatch_state *state)
107 107 {
108 108 struct expression *left, *right;
109 109 char *left_name, *right_name;
110 110 struct symbol *left_sym;
111 111 struct range_list *rl;
112 112 char buf[256];
113 113 mtag_t tag;
114 114 sval_t tag_sval;
115 115
116 116 if (!expr || expr->type != EXPR_ASSIGNMENT || expr->op != '=')
117 117 return state;
118 118
119 119 if (!estate_rl(state) || strcmp(state->name, "0,4096-ptr_max") != 0)
120 120 return state;
121 121
122 122 left = strip_expr(expr->left);
123 123 right = strip_expr(expr->right);
124 124
|
↓ open down ↓ |
61 lines elided |
↑ open up ↑ |
125 125 if (!is_mtag_call(right))
126 126 return state;
127 127
128 128 left_name = expr_to_str_sym(left, &left_sym);
129 129 if (!left_name || !left_sym)
130 130 return state;
131 131 right_name = expr_to_str(right);
132 132
133 133 snprintf(buf, sizeof(buf), "%s %s %s %s", get_filename(), get_function(),
134 134 left_name, right_name);
135 - tag = str_to_tag(buf);
135 + tag = str_to_mtag(buf);
136 136 tag_sval.type = estate_type(state);
137 137 tag_sval.uvalue = tag;
138 138
139 139 rl = rl_filter(estate_rl(state), valid_ptr_rl);
140 140 rl = clone_rl(rl);
141 141 add_range(&rl, tag_sval, tag_sval);
142 142
143 143 sql_insert_mtag_about(tag, left_name, buf);
144 144
145 145 free_string(left_name);
146 146 free_string(right_name);
147 147
148 148 return alloc_estate_rl(rl);
|
↓ open down ↓ |
3 lines elided |
↑ open up ↑ |
149 149 }
150 150
151 151 int get_string_mtag(struct expression *expr, mtag_t *tag)
152 152 {
153 153 mtag_t xor;
154 154
155 155 if (expr->type != EXPR_STRING || !expr->string)
156 156 return 0;
157 157
158 158 /* I was worried about collisions so I added a xor */
159 - xor = str_to_tag("__smatch string");
160 - *tag = str_to_tag(expr->string->data);
159 + xor = str_to_mtag("__smatch string");
160 + *tag = str_to_mtag(expr->string->data);
161 161 *tag = *tag ^ xor;
162 162
163 163 return 1;
164 164 }
165 165
166 166 int get_toplevel_mtag(struct symbol *sym, mtag_t *tag)
167 167 {
168 168 char buf[256];
169 169
170 170 if (!sym)
171 171 return 0;
172 172
173 173 if (!sym->ident ||
174 174 !(sym->ctype.modifiers & MOD_TOPLEVEL))
175 175 return 0;
176 176
177 177 snprintf(buf, sizeof(buf), "%s %s",
178 178 (sym->ctype.modifiers & MOD_STATIC) ? get_filename() : "extern",
179 179 sym->ident->name);
180 - *tag = str_to_tag(buf);
180 + *tag = str_to_mtag(buf);
181 181 return 1;
182 182 }
183 183
184 184 bool get_symbol_mtag(struct symbol *sym, mtag_t *tag)
185 185 {
186 186 char buf[256];
187 187
188 188 if (!sym || !sym->ident)
189 189 return false;
190 190
191 191 if (get_toplevel_mtag(sym, tag))
192 192 return true;
193 193
194 194 if (get_param_num_from_sym(sym) >= 0)
195 195 return false;
196 196
197 197 snprintf(buf, sizeof(buf), "%s %s %s",
198 198 get_filename(), get_function(), sym->ident->name);
199 - *tag = str_to_tag(buf);
199 + *tag = str_to_mtag(buf);
200 200 return true;
201 201 }
202 202
203 203 static void global_variable(struct symbol *sym)
204 204 {
205 205 mtag_t tag;
206 206
207 207 if (!get_toplevel_mtag(sym, &tag))
208 208 return;
209 209
210 210 sql_insert_mtag_about(tag,
211 211 sym->ident->name,
212 212 (sym->ctype.modifiers & MOD_STATIC) ? get_filename() : "extern");
213 213 }
214 214
215 215 static int get_array_mtag_offset(struct expression *expr, mtag_t *tag, int *offset)
216 216 {
217 217 struct expression *array, *offset_expr;
218 218 struct symbol *type;
219 219 sval_t sval;
220 220 int start_offset;
221 221
222 222 if (!is_array(expr))
223 223 return 0;
224 224
225 225 array = get_array_base(expr);
226 226 if (!array)
227 227 return 0;
228 228 type = get_type(array);
229 229 if (!type || type->type != SYM_ARRAY)
230 230 return 0;
231 231 type = get_real_base_type(type);
232 232 if (!type_bytes(type))
233 233 return 0;
234 234
235 235 if (!expr_to_mtag_offset(array, tag, &start_offset))
236 236 return 0;
237 237
238 238 offset_expr = get_array_offset(expr);
239 239 if (!get_value(offset_expr, &sval))
240 240 return 0;
241 241 *offset = start_offset + sval.value * type_bytes(type);
242 242
243 243 return 1;
244 244 }
245 245
246 246 struct range_list *swap_mtag_seed(struct expression *expr, struct range_list *rl)
247 247 {
248 248 char buf[256];
249 249 char *name;
250 250 sval_t sval;
|
↓ open down ↓ |
41 lines elided |
↑ open up ↑ |
251 251 mtag_t tag;
252 252
253 253 if (!rl_to_sval(rl, &sval))
254 254 return rl;
255 255 if (sval.type->type != SYM_PTR || sval.uvalue != MTAG_SEED)
256 256 return rl;
257 257
258 258 name = expr_to_str(expr);
259 259 snprintf(buf, sizeof(buf), "%s %s %s", get_filename(), get_function(), name);
260 260 free_string(name);
261 - tag = str_to_tag(buf);
261 + tag = str_to_mtag(buf);
262 262 sval.value = tag;
263 263 return alloc_rl(sval, sval);
264 264 }
265 265
266 266 int create_mtag_alias(mtag_t tag, struct expression *expr, mtag_t *new)
267 267 {
268 268 char buf[256];
269 269 int lines_from_start;
270 270 char *str;
271 271
272 272 /*
273 273 * We need the alias to be unique. It's not totally required that it
274 274 * be the same from one DB build to then next, but it makes debugging
275 275 * a bit simpler.
276 276 *
|
↓ open down ↓ |
5 lines elided |
↑ open up ↑ |
277 277 */
278 278
279 279 if (!cur_func_sym)
280 280 return 0;
281 281
282 282 lines_from_start = expr->pos.line - cur_func_sym->pos.line;
283 283 str = expr_to_str(expr);
284 284 snprintf(buf, sizeof(buf), "%lld %d %s", tag, lines_from_start, str);
285 285 free_string(str);
286 286
287 - *new = str_to_tag(buf);
287 + *new = str_to_mtag(buf);
288 288 sql_insert_mtag_alias(tag, *new);
289 289
290 290 return 1;
291 291 }
292 292
293 293 static int get_implied_mtag_offset(struct expression *expr, mtag_t *tag, int *offset)
294 294 {
295 295 struct smatch_state *state;
296 296 struct symbol *type;
297 297 sval_t sval;
298 298
299 299 type = get_type(expr);
300 300 if (!type_is_ptr(type))
301 301 return 0;
302 302 state = get_extra_state(expr);
303 303 if (!state || !estate_get_single_value(state, &sval) || sval.value == 0)
304 304 return 0;
305 305
306 306 *tag = sval.uvalue & ~MTAG_OFFSET_MASK;
307 307 *offset = sval.uvalue & MTAG_OFFSET_MASK;
308 308 return 1;
309 309 }
310 310
311 311 /*
312 312 * The point of this function is to give you the mtag and the offset so
313 313 * you can look up the data in the DB. It takes an expression.
314 314 *
315 315 * So say you give it "foo->bar". Then it would give you the offset of "bar"
316 316 * and the implied value of "foo". Or if you lookup "*foo" then the offset is
317 317 * zero and we look up the implied value of "foo. But if the expression is
318 318 * foo, then if "foo" is a global variable, then we get the mtag and the offset
319 319 * is zero. If "foo" is a local variable, then there is nothing to look up in
320 320 * the mtag_data table because that's handled by smatch_extra.c to this returns
321 321 * false.
322 322 *
323 323 */
324 324 int expr_to_mtag_offset(struct expression *expr, mtag_t *tag, int *offset)
325 325 {
326 326 *tag = 0;
327 327 *offset = 0;
328 328
329 329 if (bits_in_pointer != 64)
330 330 return 0;
331 331
332 332 expr = strip_expr(expr);
333 333 if (!expr)
334 334 return 0;
335 335
336 336 if (is_array(expr))
337 337 return get_array_mtag_offset(expr, tag, offset);
338 338
339 339 if (expr->type == EXPR_PREOP && expr->op == '*') {
340 340 expr = strip_expr(expr->unop);
341 341 return get_implied_mtag_offset(expr, tag, offset);
342 342 } else if (expr->type == EXPR_DEREF) {
343 343 int tmp, tmp_offset = 0;
344 344
345 345 while (expr->type == EXPR_DEREF) {
346 346 tmp = get_member_offset_from_deref(expr);
347 347 if (tmp < 0)
348 348 return 0;
349 349 tmp_offset += tmp;
350 350 expr = strip_expr(expr->deref);
351 351 }
352 352 *offset = tmp_offset;
353 353 if (expr->type == EXPR_PREOP && expr->op == '*') {
354 354 expr = strip_expr(expr->unop);
355 355
356 356 if (get_implied_mtag_offset(expr, tag, &tmp_offset)) {
357 357 // FIXME: look it up recursively?
358 358 if (tmp_offset)
359 359 return 0;
360 360 return 1;
361 361 }
362 362 return 0;
363 363 } else if (expr->type == EXPR_SYMBOL) {
364 364 return get_symbol_mtag(expr->symbol, tag);
365 365 }
366 366 return 0;
367 367 } else if (expr->type == EXPR_SYMBOL) {
368 368 return get_symbol_mtag(expr->symbol, tag);
369 369 }
370 370 return 0;
371 371 }
372 372
373 373 /*
374 374 * This function takes an address and returns an sval. Let's take some
375 375 * example things you might pass to it:
376 376 * foo->bar:
377 377 * If we were only called from smatch_math, we wouldn't need to bother with
378 378 * this because it's already been looked up in smatch_extra.c but this is
379 379 * also called from other places so we have to check smatch_extra.c.
380 380 * &foo
381 381 * If "foo" is global return the mtag for "foo".
382 382 * &foo.bar
383 383 * If "foo" is global return the mtag for "foo" + the offset of ".bar".
384 384 * It also handles string literals.
385 385 *
386 386 */
387 387 int get_mtag_sval(struct expression *expr, sval_t *sval)
388 388 {
389 389 struct symbol *type;
390 390 mtag_t tag;
391 391 int offset = 0;
392 392
393 393 if (bits_in_pointer != 64)
394 394 return 0;
395 395
396 396 expr = strip_expr(expr);
397 397
398 398 type = get_type(expr);
399 399 if (!type_is_ptr(type))
400 400 return 0;
401 401 /*
402 402 * There are several options:
403 403 *
404 404 * If the expr is a string literal, that's an address/mtag.
405 405 * SYM_ARRAY and SYM_FN are mtags. There are "&foo" type addresses.
406 406 * And there are saved pointers "p = &foo;"
407 407 *
408 408 */
409 409
410 410 if (expr->type == EXPR_STRING && get_string_mtag(expr, &tag))
411 411 goto found;
412 412
413 413 if (expr->type == EXPR_SYMBOL &&
414 414 (type->type == SYM_ARRAY || type->type == SYM_FN) &&
415 415 get_toplevel_mtag(expr->symbol, &tag))
416 416 goto found;
417 417
418 418 if (expr->type == EXPR_PREOP && expr->op == '&') {
419 419 expr = strip_expr(expr->unop);
420 420 if (expr_to_mtag_offset(expr, &tag, &offset))
421 421 goto found;
422 422 return 0;
423 423 }
424 424
425 425 if (get_implied_mtag_offset(expr, &tag, &offset))
426 426 goto found;
427 427
428 428 return 0;
429 429 found:
430 430 if (offset >= MTAG_OFFSET_MASK)
431 431 return 0;
432 432
433 433 sval->type = type;
434 434 sval->uvalue = tag | offset;
435 435
436 436 return 1;
437 437 }
438 438
439 439 void register_mtag(int id)
440 440 {
441 441 my_id = id;
442 442
443 443
444 444 /*
445 445 * The mtag stuff only works on 64 systems because we store the
446 446 * information in the pointer itself.
447 447 * bit 63 : set for alias mtags
448 448 * bit 62-12: mtag hash
449 449 * bit 11-0 : offset
450 450 *
451 451 */
452 452
453 453 add_hook(&global_variable, BASE_HOOK);
454 454 }
|
↓ open down ↓ |
157 lines elided |
↑ open up ↑ |
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX