smatch_db.c

   1 /*
   2  * smatch/smatch_db.c
   3  *
   4  * Copyright (C) 2010 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 #include <string.h>
  11 #include <errno.h>
  12 #include <sqlite3.h>
  13 #include "smatch.h"
  14 #include "smatch_slist.h"
  15 #include "smatch_extra.h"
  16
  17 static sqlite3 *db;
  18
  19 struct def_callback {
  20         int hook_type;
  21         void (*callback)(const char *name, struct symbol *sym, char *key, char *value);
  22 };
  23 ALLOCATOR(def_callback, "definition db hook callbacks");
  24 DECLARE_PTR_LIST(callback_list, struct def_callback);
  25 static struct callback_list *callbacks;
  26
  27 struct member_info_callback {
  28         int owner;
  29         void (*callback)(char *fn, int param, char *printed_name, struct smatch_state *state);
  30 };
  31 ALLOCATOR(member_info_callback, "caller_info callbacks");
  32 DECLARE_PTR_LIST(member_info_cb_list, struct member_info_callback);
  33 static struct member_info_cb_list *member_callbacks;
  34
  35 void sql_exec(int (*callback)(void*, int, char**, char**), const char *sql)
  36 {
  37         char *err = NULL;
  38         int rc;
  39
  40         if (option_no_db || !db)
  41                 return;
  42
  43         rc = sqlite3_exec(db, sql, callback, 0, &err);
  44         if (rc != SQLITE_OK) {
  45                 fprintf(stderr, "SQL error #2: %s\n", err);
  46                 exit(1);
  47         }
  48 }
  49
  50 void add_definition_db_callback(void (*callback)(const char *name, struct symbol *sym, char *key, char *value), int type)
  51 {
  52         struct def_callback *def_callback = __alloc_def_callback(0);
  53
  54         def_callback->hook_type = type;
  55         def_callback->callback = callback;
  56         add_ptr_list(&callbacks, def_callback);
  57 }
  58
  59 void add_member_info_callback(int owner, void (*callback)(char *fn, int param, char *printed_name, struct smatch_state *state))
  60 {
  61         struct member_info_callback *member_callback = __alloc_member_info_callback(0);
  62
  63         member_callback->owner = owner;
  64         member_callback->callback = callback;
  65         add_ptr_list(&member_callbacks, member_callback);
  66 }
  67
  68 static void match_call_hack(struct expression *expr)
  69 {
  70         char *name;
  71
  72         /*
  73          * we just want to record something in the database so that if we have
  74          * two calls like:  frob(4); frob(some_unkown); then on the recieving
  75          * side we know that sometimes frob is called with unknown parameters.
  76          */
  77
  78         name = get_fnptr_name(expr->fn);
  79         if (!name)
  80                 return;
  81         if (ptr_list_empty(expr->args))
  82                 return;
  83         sm_msg("info: passes param_value '%s' -1 '$$' min-max", name);
  84         free_string(name);
  85 }
  86
  87 static void print_struct_members(char *fn, struct expression *expr, int param, struct state_list *slist,
  88         void (*callback)(char *fn, int param, char *printed_name, struct smatch_state *state))
  89 {
  90         struct sm_state *sm;
  91         char *name;
  92         struct symbol *sym;
  93         int len;
  94         char printed_name[256];
  95
  96         name = get_variable_from_expr(expr, &sym);
  97         if (!name || !sym)
  98                 goto free;
  99
 100         len = strlen(name);
 101         FOR_EACH_PTR(slist, sm) {
 102                 if (sm->sym != sym)
 103                         continue;
 104                 if (strncmp(name, sm->name, len) || sm->name[len] == '\0')
 105                         continue;
 106                 snprintf(printed_name, sizeof(printed_name), "$$%s", sm->name + len);
 107                 callback(fn, param, printed_name, sm->state);
 108         } END_FOR_EACH_PTR(sm);
 109 free:
 110         free_string(name);
 111 }
 112
 113 static void match_call_info(struct expression *expr)
 114 {
 115         struct member_info_callback *cb;
 116         struct expression *arg;
 117         struct state_list *slist;
 118         char *name;
 119         int i;
 120
 121         name = get_fnptr_name(expr->fn);
 122         if (!name)
 123                 return;
 124
 125         FOR_EACH_PTR(member_callbacks, cb) {
 126                 slist = get_all_states(cb->owner);
 127                 i = 0;
 128                 FOR_EACH_PTR(expr->args, arg) {
 129                         print_struct_members(name, arg, i, slist, cb->callback);
 130                         i++;
 131                 } END_FOR_EACH_PTR(arg);
 132         } END_FOR_EACH_PTR(cb);
 133
 134         free_string(name);
 135         free_slist(&slist);
 136 }
 137
 138 static unsigned long call_count;
 139 static int db_count_callback(void *unused, int argc, char **argv, char **azColName)
 140 {
 141         call_count += strtoul(argv[0], NULL, 10);
 142         return 0;
 143 }
 144
 145 static int get_param(int param, char **name, struct symbol **sym)
 146 {
 147         struct symbol *arg;
 148         int i;
 149
 150         i = 0;
 151         FOR_EACH_PTR(cur_func_sym->ctype.base_type->arguments, arg) {
 152                 /*
 153                  * this is a temporary hack to work around a bug (I think in sparse?)
 154                  * 2.6.37-rc1:fs/reiserfs/journal.o
 155                  * If there is a function definition without parameter name found
 156                  * after a function implementation then it causes a crash.
 157                  * int foo() {}
 158                  * int bar(char *);
 159                  */
 160                 if (arg->ident->name < (char *)100)
 161                         continue;
 162                 if (i == param && arg->ident->name) {
 163                         *name = arg->ident->name;
 164                         *sym = arg;
 165                         return TRUE;
 166                 }
 167                 i++;
 168         } END_FOR_EACH_PTR(arg);
 169
 170         return FALSE;
 171 }
 172
 173 static struct state_list *final_states;
 174 static int prev_func_id = -1;
 175 static int db_callback(void *unused, int argc, char **argv, char **azColName)
 176 {
 177         int func_id;
 178         long type;
 179         long param;
 180         char *name;
 181         struct symbol *sym;
 182         struct def_callback *def_callback;
 183
 184         if (argc != 5)
 185                 return 0;
 186
 187         func_id = atoi(argv[0]);
 188         errno = 0;
 189         type = strtol(argv[1], NULL, 10);
 190         param = strtol(argv[2], NULL, 10);
 191         if (errno)
 192                 return 0;
 193
 194         if (prev_func_id == -1)
 195                 prev_func_id = func_id;
 196         if (func_id != prev_func_id) {
 197                 merge_slist(&final_states, __pop_fake_cur_slist());
 198                 __push_fake_cur_slist();
 199                 prev_func_id = func_id;
 200         }
 201
 202         if (param == -1 || !get_param(param, &name, &sym))
 203                 return 0;
 204
 205         FOR_EACH_PTR(callbacks, def_callback) {
 206                 if (def_callback->hook_type == type)
 207                         def_callback->callback(name, sym, argv[3], argv[4]);
 208         } END_FOR_EACH_PTR(def_callback);
 209
 210         return 0;
 211 }
 212
 213 static void get_direct_callers(struct symbol *sym)
 214 {
 215         char sql_filter[1024];
 216
 217         if (sym->ctype.modifiers & MOD_STATIC) {
 218                 snprintf(sql_filter, 1024,
 219                          "file = '%s' and function = '%s' order by function_id;",
 220                          get_filename(), sym->ident->name);
 221         } else {
 222                 snprintf(sql_filter, 1024,
 223                          "function = '%s' order by function_id;",
 224                          sym->ident->name);
 225         }
 226
 227         run_sql(db_count_callback, "select count(*) from caller_info where %s",
 228                  sql_filter);
 229         if (call_count == 0 || call_count > 100)
 230                 return;
 231
 232         run_sql(db_callback, "select function_id, type, parameter, key, value from caller_info"
 233                 " where %s", sql_filter);
 234 }
 235
 236 static char *ptr_name;
 237 static int get_ptr_name(void *unused, int argc, char **argv, char **azColName)
 238 {
 239         if (!ptr_name)
 240                 ptr_name = alloc_string(argv[0]);
 241         return 0;
 242 }
 243
 244 static void get_function_pointer_callers(struct symbol *sym)
 245 {
 246         ptr_name = NULL;
 247         run_sql(get_ptr_name, "select ptr from function_ptr where function = '%s'",
 248                 sym->ident->name);
 249         if (!ptr_name)
 250                 return;
 251
 252         run_sql(db_count_callback, "select count(*) from caller_info where function = '%s'",
 253                  ptr_name);
 254         if (call_count == 0 || call_count > 100)
 255                 return;
 256
 257         run_sql(db_callback, "select function_id, type, parameter, key, value from caller_info"
 258                 " where function = '%s' order by function_id", ptr_name);
 259 }
 260
 261 static void match_data_from_db(struct symbol *sym)
 262 {
 263         struct sm_state *sm;
 264
 265         if (!sym || !sym->ident || !sym->ident->name)
 266                 return;
 267
 268         __push_fake_cur_slist();
 269         prev_func_id = -1;
 270
 271         call_count = 0;
 272         get_direct_callers(sym);
 273         get_function_pointer_callers(sym);
 274
 275         merge_slist(&final_states, __pop_fake_cur_slist());
 276
 277         if (call_count > 100) {
 278                 free_slist(&final_states);
 279                 return;
 280         }
 281         FOR_EACH_PTR(final_states, sm) {
 282                 __set_sm(sm);
 283         } END_FOR_EACH_PTR(sm);
 284
 285         free_slist(&final_states);
 286 }
 287
 288 static void match_function_assign(struct expression *expr)
 289 {
 290         struct expression *right = expr->right;
 291         struct symbol *sym;
 292         char *fn_name;
 293         char *ptr_name;
 294
 295         if (right->type == EXPR_PREOP && right->op == '&')
 296                 right = right->unop;
 297         if (right->type != EXPR_SYMBOL)
 298                 return;
 299         sym = get_type(right);
 300         if (!sym || sym->type != SYM_FN)
 301                 return;
 302
 303         fn_name = get_variable_from_expr(right, NULL);
 304         ptr_name = get_fnptr_name(expr->left);
 305         if (!fn_name || !ptr_name)
 306                 goto free;
 307
 308         sm_msg("info: sets_fn_ptr '%s' '%s'", ptr_name, fn_name);
 309
 310 free:
 311         free_string(fn_name);
 312         free_string(ptr_name);
 313 }
 314
 315 static void global_variable(struct symbol *sym)
 316 {
 317         struct symbol *struct_type;
 318         struct symbol *base_type;
 319         struct expression *expr;
 320
 321         if (!sym->ident)
 322                 return;
 323         if (!sym->initializer || sym->initializer->type != EXPR_INITIALIZER)
 324                 return;
 325         struct_type = get_base_type(sym);
 326         if (!struct_type || struct_type->type != SYM_STRUCT ||
 327             !struct_type->ident)
 328                 return;
 329
 330         FOR_EACH_PTR(sym->initializer->expr_list, expr) {
 331                 if (expr->type != EXPR_IDENTIFIER)
 332                         continue;
 333                 if (!expr->expr_ident)
 334                         continue;
 335                 if (!expr->ident_expression || !expr->ident_expression->symbol_name)
 336                         continue;
 337                 base_type = get_type(expr->ident_expression);
 338                 if (!base_type || base_type->type != SYM_FN)
 339                         continue;
 340                 sm_msg("info: sets_fn_ptr '(struct %s)->%s' '%s'", struct_type->ident->name,
 341                        expr->expr_ident->name,
 342                        expr->ident_expression->symbol_name->name);
 343         } END_FOR_EACH_PTR(expr);
 344 }
 345
 346 void open_smatch_db(void)
 347 {
 348 #ifdef SQLITE_OPEN_READONLY
 349         int rc;
 350
 351         if (option_no_db)
 352                 return;
 353
 354         rc = sqlite3_open_v2("smatch_db.sqlite", &db, SQLITE_OPEN_READONLY, NULL);
 355         if (rc != SQLITE_OK) {
 356                 option_no_db = 1;
 357                 return;
 358         }
 359         return;
 360 #else
 361         option_no_db = 1;
 362         return;
 363 #endif
 364 }
 365
 366 void register_definition_db_callbacks(int id)
 367 {
 368         if (option_info) {
 369                 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
 370                 add_hook(&match_call_hack, FUNCTION_CALL_HOOK);
 371                 add_hook(&match_function_assign, ASSIGNMENT_HOOK);
 372                 add_hook(&global_variable, BASE_HOOK);
 373                 add_hook(&global_variable, DECLARATION_HOOK);
 374         }
 375
 376         if (option_no_db)
 377                 return;
 378
 379         add_hook(&match_data_from_db, FUNC_DEF_HOOK);
 380 }