2 * Copyright (C) 2014 Oracle.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version 2
7 * of the License, or (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
19 * This file started out by saying that if you have:
21 * struct foo one, two;
25 * That's equivalent to saying:
30 * Turning an assignment like that into a bunch of small fake assignments is
33 * The call to memcpy(&one, &two, sizeof(foo)); is the same as "one = two;" so
34 * we can re-use the code. And we may as well use it for memset() too.
35 * Assigning pointers is almost the same:
44 * The problem is that you can go a bit crazy with pointers to pointers.
46 * p1->x->y->z->one->two->three = p2->x->y->z->one->two->three;
48 * I don't have a proper solution for this problem right now. I just copy one
49 * level and don't nest. It should handle limitted nesting but intelligently.
51 * The other thing is that you end up with a lot of garbage assignments where
52 * we record "x could be anything. x->y could be anything. x->y->z->a->b->c
53 * could *also* be anything!". There should be a better way to filter this
54 * useless information.
60 #include "smatch_slist.h"
61 #include "smatch_extra.h"
69 static struct symbol
*get_struct_type(struct expression
*expr
)
73 type
= get_type(expr
);
76 if (type
->type
== SYM_PTR
)
77 type
= get_real_base_type(type
);
78 if (type
&& type
->type
== SYM_STRUCT
)
83 static struct expression
*get_right_base_expr(struct symbol
*left_type
, struct expression
*right
)
85 struct symbol
*struct_type
;
90 struct_type
= get_struct_type(right
);
93 if (struct_type
!= left_type
)
96 if (right
->type
== EXPR_PREOP
&& right
->op
== '&')
97 right
= strip_expr(right
->unop
);
99 if (right
->type
== EXPR_CALL
)
102 if (is_pointer(right
))
103 right
= deref_expression(right
);
108 static struct expression
*remove_addr(struct expression
*expr
)
112 expr
= strip_expr(expr
);
116 if (expr
->type
== EXPR_PREOP
&& expr
->op
== '&')
117 return strip_expr(expr
->unop
);
118 type
= get_type(expr
);
119 if (!type
|| type
->type
!= SYM_PTR
)
122 return deref_expression(expr
);
125 static struct expression
*faked_expression
;
126 struct expression
*get_faked_expression(void)
128 if (!__in_fake_assign
)
130 return faked_expression
;
133 static void split_fake_expr(struct expression
*expr
)
140 static void set_inner_struct_members(int mode
, struct expression
*faked
, struct expression
*left
, struct expression
*right
, struct symbol
*member
)
142 struct expression
*left_member
;
143 struct expression
*right_member
= NULL
; /* silence GCC */
144 struct expression
*assign
;
145 struct symbol
*base
= get_real_base_type(member
);
149 left
= member_expression(left
, '.', member
->ident
);
150 if (mode
!= COPY_MEMSET
&& right
)
151 right
= member_expression(right
, '.', member
->ident
);
154 FOR_EACH_PTR(base
->symbol_list
, tmp
) {
157 type
= get_real_base_type(tmp
);
161 if (type
->type
== SYM_ARRAY
)
163 if (type
->type
== SYM_UNION
|| type
->type
== SYM_STRUCT
) {
164 set_inner_struct_members(mode
, faked
, left
, right
, tmp
);
170 left_member
= member_expression(left
, '.', tmp
->ident
);
176 right_member
= member_expression(right
, '.', tmp
->ident
);
178 right_member
= unknown_value_expression(left_member
);
181 right_member
= right
;
185 assign
= assign_expression(left_member
, right_member
);
186 split_fake_expr(assign
);
187 } END_FOR_EACH_PTR(tmp
);
190 static void __struct_members_copy(int mode
, struct expression
*faked
,
191 struct expression
*left
,
192 struct expression
*right
)
194 struct symbol
*struct_type
, *tmp
, *type
;
195 struct expression
*left_member
;
196 struct expression
*right_member
;
197 struct expression
*assign
;
201 if (__in_fake_assign
)
203 faked_expression
= faked
;
205 left
= strip_expr(left
);
206 right
= strip_expr(right
);
208 struct_type
= get_struct_type(left
);
211 * This is not a struct assignment obviously. But this is where
212 * memcpy() is handled so it feels like a good place to add this
216 type
= get_type(left
);
217 if (!type
|| type
->type
!= SYM_BASETYPE
)
220 right
= strip_expr(right
);
221 if (right
&& right
->type
== EXPR_PREOP
&& right
->op
== '&')
222 right
= remove_addr(right
);
224 right
= unknown_value_expression(left
);
225 assign
= assign_expression(left
, right
);
226 split_fake_expr(assign
);
230 if (is_pointer(left
)) {
231 left
= deref_expression(left
);
234 if (mode
!= COPY_MEMSET
)
235 right
= get_right_base_expr(struct_type
, right
);
237 FOR_EACH_PTR(struct_type
->symbol_list
, tmp
) {
238 type
= get_real_base_type(tmp
);
241 if (type
->type
== SYM_ARRAY
)
244 if (type
->type
== SYM_UNION
|| type
->type
== SYM_STRUCT
) {
245 set_inner_struct_members(mode
, faked
, left
, right
, tmp
);
252 left_member
= member_expression(left
, op
, tmp
->ident
);
259 right_member
= member_expression(right
, op
, tmp
->ident
);
261 right_member
= unknown_value_expression(left_member
);
264 right_member
= right
;
268 sm_msg("internal. No right member");
271 assign
= assign_expression(left_member
, right_member
);
272 split_fake_expr(assign
);
273 } END_FOR_EACH_PTR(tmp
);
276 faked_expression
= NULL
;
279 static int returns_zeroed_mem(struct expression
*expr
)
283 if (expr
->type
!= EXPR_CALL
|| expr
->fn
->type
!= EXPR_SYMBOL
)
285 fn
= expr_to_var(expr
->fn
);
288 if (strcmp(fn
, "kcalloc") == 0)
290 if (option_project
== PROJ_KERNEL
&& strstr(fn
, "zalloc"))
295 static int copy_containter_states(struct expression
*left
, struct expression
*right
, int offset
)
297 char *left_name
= NULL
, *right_name
= NULL
;
298 struct symbol
*left_sym
, *right_sym
;
299 struct sm_state
*sm
, *new_sm
;
305 right_name
= expr_to_var_sym(right
, &right_sym
);
306 if (!right_name
|| !right_sym
)
308 left_name
= expr_to_var_sym(left
, &left_sym
);
309 if (!left_name
|| !left_sym
)
312 len
= snprintf(buf
, sizeof(buf
), "%s(-%d)", right_name
, offset
);
313 if (len
>= sizeof(buf
))
316 FOR_EACH_SM(__get_cur_stree(), sm
) {
317 if (sm
->sym
!= right_sym
)
319 if (strncmp(sm
->name
, buf
, len
) != 0)
321 snprintf(new_name
, sizeof(new_name
), "%s%s", left_name
, sm
->name
+ len
);
322 new_sm
= clone_sm(sm
);
323 new_sm
->name
= alloc_sname(new_name
);
324 new_sm
->sym
= left_sym
;
327 } END_FOR_EACH_SM(sm
);
329 free_string(left_name
);
330 free_string(right_name
);
334 static int handle_param_offsets(struct expression
*expr
)
336 struct expression
*right
;
339 right
= strip_expr(expr
->right
);
341 if (right
->type
!= EXPR_BINOP
|| right
->op
!= '-')
344 if (!get_value(right
->right
, &sval
))
347 right
= get_assigned_expr(right
->left
);
350 return copy_containter_states(expr
->left
, right
, sval
.value
);
353 static void returns_container_of(struct expression
*expr
, int param
, char *key
, char *value
)
355 struct expression
*call
, *arg
;
358 if (expr
->type
!= EXPR_ASSIGNMENT
|| expr
->op
!= '=')
360 call
= strip_expr(expr
->right
);
361 if (call
->type
!= EXPR_CALL
)
366 offset
= atoi(value
);
368 arg
= get_argument_from_call_expr(call
->args
, param
);
372 copy_containter_states(expr
->left
, arg
, -offset
);
375 void __fake_struct_member_assignments(struct expression
*expr
)
377 struct symbol
*struct_type
;
378 struct symbol
*left_type
;
383 if (is_zero(expr
->right
))
386 left_type
= get_type(expr
->left
);
388 left_type
->type
!= SYM_PTR
&&
389 left_type
->type
!= SYM_STRUCT
&&
390 left_type
!= &ulong_ctype
)
393 struct_type
= get_struct_type(expr
->left
);
397 if (handle_param_offsets(expr
))
400 if (returns_zeroed_mem(expr
->right
))
401 __struct_members_copy(COPY_MEMSET
, expr
, expr
->left
, zero_expr());
403 __struct_members_copy(COPY_NORMAL
, expr
, expr
->left
, expr
->right
);
406 static void match_memset(const char *fn
, struct expression
*expr
, void *_size_arg
)
408 struct expression
*buf
;
409 struct expression
*val
;
411 buf
= get_argument_from_call_expr(expr
->args
, 0);
412 val
= get_argument_from_call_expr(expr
->args
, 1);
414 buf
= strip_expr(buf
);
415 __struct_members_copy(COPY_MEMSET
, expr
, remove_addr(buf
), val
);
418 static void match_memcpy(const char *fn
, struct expression
*expr
, void *_arg
)
420 struct expression
*dest
;
421 struct expression
*src
;
423 dest
= get_argument_from_call_expr(expr
->args
, 0);
424 src
= get_argument_from_call_expr(expr
->args
, 1);
426 __struct_members_copy(COPY_MEMCPY
, expr
, remove_addr(dest
), remove_addr(src
));
429 static void match_memcpy_unknown(const char *fn
, struct expression
*expr
, void *_arg
)
431 struct expression
*dest
;
433 dest
= get_argument_from_call_expr(expr
->args
, 0);
434 __struct_members_copy(COPY_MEMCPY
, expr
, remove_addr(dest
), NULL
);
437 static void match_sscanf(const char *fn
, struct expression
*expr
, void *unused
)
439 struct expression
*arg
;
443 FOR_EACH_PTR(expr
->args
, arg
) {
446 __struct_members_copy(COPY_MEMCPY
, expr
, remove_addr(arg
), NULL
);
447 } END_FOR_EACH_PTR(arg
);
450 static void unop_expr(struct expression
*expr
)
452 if (expr
->op
!= SPECIAL_INCREMENT
&&
453 expr
->op
!= SPECIAL_DECREMENT
)
456 if (!is_pointer(expr
))
458 __struct_members_copy(COPY_MEMCPY
, expr
, expr
->unop
, NULL
);
461 static void register_clears_param(void)
465 const char *function
;
468 if (option_project
== PROJ_NONE
)
471 snprintf(name
, 256, "%s.clears_argument", option_project_str
);
473 token
= get_tokens_file(name
);
476 if (token_type(token
) != TOKEN_STREAMBEGIN
)
479 while (token_type(token
) != TOKEN_STREAMEND
) {
480 if (token_type(token
) != TOKEN_IDENT
)
482 function
= show_ident(token
->ident
);
484 if (token_type(token
) != TOKEN_NUMBER
)
486 param
= atoi(token
->number
);
487 add_function_hook(function
, &match_memcpy_unknown
, INT_PTR(param
));
493 static void db_param_cleared(struct expression
*expr
, int param
, char *key
, char *value
)
495 struct expression
*arg
;
497 while (expr
->type
== EXPR_ASSIGNMENT
)
498 expr
= strip_expr(expr
->right
);
499 if (expr
->type
!= EXPR_CALL
)
503 * FIXME: __struct_members_copy() requires an expression but
504 * get_variable_from_key() returns a name/sym pair so that doesn't
507 if (strcmp(key
, "$") != 0)
510 arg
= get_argument_from_call_expr(expr
->args
, param
);
514 if (strcmp(value
, "0") == 0)
515 __struct_members_copy(COPY_MEMSET
, expr
, remove_addr(arg
), zero_expr());
517 __struct_members_copy(COPY_MEMCPY
, expr
, remove_addr(arg
), NULL
);
520 void register_struct_assignment(int id
)
522 add_function_hook("memset", &match_memset
, NULL
);
523 add_function_hook("__memset", &match_memset
, NULL
);
525 add_function_hook("memcpy", &match_memcpy
, INT_PTR(0));
526 add_function_hook("memmove", &match_memcpy
, INT_PTR(0));
527 add_function_hook("__memcpy", &match_memcpy
, INT_PTR(0));
528 add_function_hook("__memmove", &match_memcpy
, INT_PTR(0));
530 add_function_hook("sscanf", &match_sscanf
, NULL
);
532 add_hook(&unop_expr
, OP_HOOK
);
533 register_clears_param();
534 select_return_states_hook(PARAM_CLEARED
, &db_param_cleared
);
536 select_return_states_hook(CONTAINER
, &returns_container_of
);