/* * Cppcheck - A tool for static C/C++ code analysis * Copyright (C) 2007-2015 Daniel Marjamäki and Cppcheck team. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . */ #include "checkmemoryleak.h" #include "symboldatabase.h" #include "mathlib.h" #include "tokenize.h" #include #include #include #include //--------------------------------------------------------------------------- // Register this check class (by creating a static instance of it) namespace { CheckMemoryLeakInFunction instance1; CheckMemoryLeakInClass instance2; CheckMemoryLeakStructMember instance3; CheckMemoryLeakNoVar instance4; } /** * Count function parameters * \param tok Function name token before the '(' */ static unsigned int countParameters(const Token *tok) { tok = tok->tokAt(2); if (tok->str() == ")") return 0; unsigned int numpar = 1; while (nullptr != (tok = tok->nextArgument())) numpar++; return numpar; } /** List of functions that can be ignored when searching for memory leaks. * These functions don't take the address of the given pointer * This list needs to be alphabetically sorted so we can run bsearch on it. * This list contains function names with const parameters e.g.: atof(const char *) * Reference: http://www.aquaphoenix.com/ref/gnu_c_library/libc_492.html#SEC492 */ static const char * const call_func_white_list[] = { "_open", "_wopen", "access", "adjtime", "asctime", "asctime_r", "asprintf", "assert" , "atof", "atoi", "atol", "chdir", "chmod", "chown" , "clearerr", "creat", "ctime", "ctime_r", "execl", "execle" , "execlp", "execv", "execve", "fchmod", "fclose", "fcntl" , "fdatasync", "feof", "ferror", "fflush", "fgetc", "fgetpos", "fgets" , "flock", "fmemopen", "fnmatch", "fopen", "fopencookie", "for", "fprintf", "fputc", "fputs", "fread", "free" , "freopen", "fscanf", "fseek", "fseeko", "fsetpos", "fstat", "fsync", "ftell", "ftello" , "ftruncate", "fwrite", "getc", "getenv","getgrnam", "gethostbyaddr", "gethostbyname", "getnetbyname" , "getopt", "getopt_long", "getprotobyname", "getpwnam", "gets", "getservbyname", "getservbyport" , "glob", "gmtime", "gmtime_r", "if", "index", "inet_addr", "inet_aton", "inet_network", "initgroups", "ioctl" , "link", "localtime", "localtime_r" , "lockf", "lseek", "lstat", "mblen", "mbstowcs", "mbtowc", "memchr", "memcmp", "memcpy", "memmove", "memset" , "mkdir", "mkfifo", "mknod", "mkstemp" , "obstack_printf", "obstack_vprintf", "open", "opendir", "parse_printf_format", "pathconf" , "perror", "popen" ,"posix_fadvise", "posix_fallocate", "pread" , "printf", "psignal", "puts", "pwrite", "qsort", "read", "readahead", "readdir", "readdir_r" , "readlink", "readv" , "realloc", "regcomp", "remove", "rename", "return", "rewind", "rewinddir", "rindex" , "rmdir" ,"scandir", "scanf", "seekdir" , "setbuf", "setbuffer", "sethostname", "setlinebuf", "setlocale" ,"setvbuf", "sizeof" ,"snprintf", "sprintf", "sscanf" , "stat", "stpcpy", "strcasecmp", "strcat", "strchr", "strcmp", "strcoll" , "strcpy", "strcspn", "strdup", "stricmp", "strlen", "strncasecmp", "strncat", "strncmp" , "strncpy", "strpbrk","strrchr", "strspn", "strstr", "strtod", "strtok", "strtol", "strtoul", "strxfrm", "switch" , "symlink", "sync_file_range", "system", "telldir", "tempnam", "time", "typeid", "unlink" , "utime", "utimes", "vasprintf", "vfprintf", "vfscanf", "vprintf" , "vscanf", "vsnprintf", "vsprintf", "vsscanf", "while", "wordexp","write", "writev" }; //--------------------------------------------------------------------------- bool CheckMemoryLeak::isclass(const Token *tok, unsigned int varid) const { if (tok->isStandardType()) return false; const Variable * var = tokenizer->getSymbolDatabase()->getVariableFromVarId(varid); // return false if the type is a simple record type without side effects // a type that has no side effects (no constructors and no members with constructors) /** @todo false negative: check base class for side effects */ /** @todo false negative: check constructors for side effects */ if (var && var->typeScope() && var->typeScope()->numConstructors == 0 && (var->typeScope()->varlist.empty() || var->type()->needInitialization == Type::True) && var->type()->derivedFrom.empty()) return false; return true; } //--------------------------------------------------------------------------- CheckMemoryLeak::AllocType CheckMemoryLeak::getAllocationType(const Token *tok2, unsigned int varid, std::list *callstack) const { // What we may have... // * var = (char *)malloc(10); // * var = new char[10]; // * var = strdup("hello"); // * var = strndup("hello", 3); if (tok2 && tok2->str() == "(") { tok2 = tok2->link(); tok2 = tok2 ? tok2->next() : nullptr; } if (! tok2) return No; if (tok2->str() == "::") tok2 = tok2->next(); if (! tok2->isName()) return No; if (!Token::Match(tok2, "%type%|%name% ::|. %type%")) { // Does tok2 point on "malloc", "strdup" or "kmalloc".. static const char * const mallocfunc[] = { "malloc", "calloc", "strdup", "strndup", "kmalloc", "kzalloc", "kcalloc" }; for (unsigned int i = 0; i < sizeof(mallocfunc)/sizeof(*mallocfunc); i++) { if (tok2->str() == mallocfunc[i]) return Malloc; } // Using realloc.. if (varid && Token::Match(tok2, "realloc ( %any% ,") && tok2->tokAt(2)->varId() != varid) return Malloc; if (Token::Match(tok2, "new struct| %type% [;()]") || Token::Match(tok2, "new ( std :: nothrow ) struct| %type% [;()]") || Token::Match(tok2, "new ( nothrow ) struct| %type% [;()]")) return New; if (Token::Match(tok2, "new struct| %type% *| [") || Token::Match(tok2, "new ( std :: nothrow ) struct| %type% *| [") || Token::Match(tok2, "new ( nothrow ) struct| %type% *| [")) return NewArray; if (Token::Match(tok2, "fopen|tmpfile|g_fopen (")) return File; if (settings1->standards.posix) { if (Token::Match(tok2, "open|openat|creat|mkstemp|mkostemp|socket (")) { // simple sanity check of function parameters.. // TODO: Make such check for all these functions unsigned int num = countParameters(tok2); if (tok2->str() == "open" && num != 2 && num != 3) return No; // is there a user function with this name? if (tok2->function()) return No; return Fd; } if (Token::simpleMatch(tok2, "popen (")) return Pipe; } // Does tok2 point on "g_malloc", "g_strdup", .. const int alloctype = settings1->library.alloc(tok2); if (alloctype > 0) { if (alloctype == settings1->library.dealloc("free")) return Malloc; if (alloctype == settings1->library.dealloc("fclose")) return File; return Library::ismemory(alloctype) ? OtherMem : OtherRes; } } while (Token::Match(tok2,"%type%|%name% ::|. %type%")) tok2 = tok2->tokAt(2); // User function const Function* func = tok2->function(); if (func == nullptr) return No; // Prevent recursion if (callstack && std::find(callstack->begin(), callstack->end(), func) != callstack->end()) return No; std::list cs; if (!callstack) callstack = &cs; callstack->push_back(func); return functionReturnType(func, callstack); } CheckMemoryLeak::AllocType CheckMemoryLeak::getReallocationType(const Token *tok2, unsigned int varid) { // What we may have... // * var = (char *)realloc(..; if (tok2 && tok2->str() == "(") { tok2 = tok2->link(); tok2 = tok2 ? tok2->next() : nullptr; } if (! tok2) return No; if (varid > 0 && ! Token::Match(tok2, "%name% ( %varid% [,)]", varid)) return No; if (tok2->str() == "realloc") return Malloc; // GTK memory reallocation.. //if (Token::Match(tok2, "g_realloc|g_try_realloc|g_renew|g_try_renew")) return No; } CheckMemoryLeak::AllocType CheckMemoryLeak::getDeallocationType(const Token *tok, unsigned int varid) const { if (tokenizer->isCPP()) { if (Token::Match(tok, "delete %varid% ;", varid)) return New; if (Token::Match(tok, "delete [ ] %varid% ;", varid)) return NewArray; if (Token::Match(tok, "delete ( %varid% ) ;", varid)) return New; if (Token::Match(tok, "delete [ ] ( %varid% ) ;", varid)) return NewArray; } if (tok && tok->str() == "::") tok = tok->next(); if (Token::Match(tok, "free|kfree ( %varid% ) [;:]", varid) || Token::Match(tok, "free|kfree ( %varid% -", varid) || Token::Match(tok, "realloc ( %varid% , 0 ) ;", varid)) return Malloc; if (Token::Match(tok, "fclose ( %varid% )", varid) || Token::simpleMatch(tok, "fcloseall ( )")) return File; if (settings1->standards.posix) { if (Token::Match(tok, "close ( %varid% )", varid)) return Fd; if (Token::Match(tok, "pclose ( %varid% )", varid)) return Pipe; } // Does tok2 point on "g_free", etc .. if (Token::Match(tok, "%type% ( %varid% )", varid)) { const int dealloctype = settings1->library.dealloc(tok); if (dealloctype > 0) return Library::ismemory(dealloctype) ? OtherMem : OtherRes; } return No; } CheckMemoryLeak::AllocType CheckMemoryLeak::getDeallocationType(const Token *tok, const std::string &varname) const { if (tokenizer->isCPP()) { if (Token::Match(tok, std::string("delete " + varname + " [,;]").c_str())) return New; if (Token::Match(tok, std::string("delete [ ] " + varname + " [,;]").c_str())) return NewArray; if (Token::Match(tok, std::string("delete ( " + varname + " ) [,;]").c_str())) return New; if (Token::Match(tok, std::string("delete [ ] ( " + varname + " ) [,;]").c_str())) return NewArray; } if (Token::simpleMatch(tok, std::string("free ( " + varname + " ) ;").c_str()) || Token::simpleMatch(tok, std::string("kfree ( " + varname + " ) ;").c_str()) || Token::simpleMatch(tok, std::string("realloc ( " + varname + " , 0 ) ;").c_str())) return Malloc; if (Token::simpleMatch(tok, std::string("fclose ( " + varname + " )").c_str()) || Token::simpleMatch(tok, "fcloseall ( )")) return File; if (Token::simpleMatch(tok, std::string("close ( " + varname + " )").c_str())) return Fd; if (Token::simpleMatch(tok, std::string("pclose ( " + varname + " )").c_str())) return Pipe; if (Token::Match(tok, ("%type% ( " + varname + " )").c_str())) { int type = settings1->library.dealloc(tok); if (type > 0) return Library::ismemory(type) ? OtherMem : OtherRes; } return No; } //-------------------------------------------------------------------------- //-------------------------------------------------------------------------- void CheckMemoryLeak::memoryLeak(const Token *tok, const std::string &varname, AllocType alloctype) { if (alloctype == CheckMemoryLeak::File || alloctype == CheckMemoryLeak::Pipe || alloctype == CheckMemoryLeak::Fd || alloctype == CheckMemoryLeak::OtherRes) resourceLeakError(tok, varname); else memleakError(tok, varname); } //--------------------------------------------------------------------------- void CheckMemoryLeak::reportErr(const Token *tok, Severity::SeverityType severity, const std::string &id, const std::string &msg) const { std::list callstack; if (tok) callstack.push_back(tok); reportErr(callstack, severity, id, msg); } void CheckMemoryLeak::reportErr(const std::list &callstack, Severity::SeverityType severity, const std::string &id, const std::string &msg) const { const ErrorLogger::ErrorMessage errmsg(callstack, tokenizer?&tokenizer->list:0, severity, id, msg, false); if (errorLogger) errorLogger->reportErr(errmsg); else Check::reportError(errmsg); } void CheckMemoryLeak::memleakError(const Token *tok, const std::string &varname) const { reportErr(tok, Severity::error, "memleak", "Memory leak: " + varname); } void CheckMemoryLeak::memleakUponReallocFailureError(const Token *tok, const std::string &varname) const { reportErr(tok, Severity::error, "memleakOnRealloc", "Common realloc mistake: \'" + varname + "\' nulled but not freed upon failure"); } void CheckMemoryLeak::resourceLeakError(const Token *tok, const std::string &varname) const { std::string errmsg("Resource leak"); if (!varname.empty()) errmsg += ": " + varname; reportErr(tok, Severity::error, "resourceLeak", errmsg); } void CheckMemoryLeak::deallocDeallocError(const Token *tok, const std::string &varname) const { reportErr(tok, Severity::error, "deallocDealloc", "Deallocating a deallocated pointer: " + varname); } void CheckMemoryLeak::deallocuseError(const Token *tok, const std::string &varname) const { reportErr(tok, Severity::error, "deallocuse", "Dereferencing '" + varname + "' after it is deallocated / released"); } void CheckMemoryLeak::mismatchSizeError(const Token *tok, const std::string &sz) const { reportErr(tok, Severity::error, "mismatchSize", "The allocated size " + sz + " is not a multiple of the underlying type's size."); } void CheckMemoryLeak::mismatchAllocDealloc(const std::list &callstack, const std::string &varname) const { reportErr(callstack, Severity::error, "mismatchAllocDealloc", "Mismatching allocation and deallocation: " + varname); } CheckMemoryLeak::AllocType CheckMemoryLeak::functionReturnType(const Function* func, std::list *callstack) const { if (!func || !func->hasBody()) return No; // Get return pointer.. unsigned int varid = 0; unsigned int indentlevel = 0; for (const Token *tok2 = func->functionScope->classStart; tok2 != func->functionScope->classEnd; tok2 = tok2->next()) { if (tok2->str() == "{") ++indentlevel; else if (tok2->str() == "}") { if (indentlevel <= 1) return No; --indentlevel; } if (Token::Match(tok2, "return %name% ;")) { if (indentlevel != 1) return No; varid = tok2->next()->varId(); break; } else if (tok2->str() == "return") { AllocType allocType = getAllocationType(tok2->next(), 0, callstack); if (allocType != No) return allocType; } } // Not returning pointer value.. if (varid == 0) return No; // If variable is not local then alloctype shall be "No" // Todo: there can be false negatives about mismatching allocation/deallocation. // => Generate "alloc ; use ;" if variable is not local? const Variable *var = tokenizer->getSymbolDatabase()->getVariableFromVarId(varid); if (!var || !var->isLocal() || var->isStatic()) return No; // Check if return pointer is allocated.. AllocType allocType = No; for (const Token* tok = func->functionScope->classStart; tok != func->functionScope->classEnd; tok = tok->next()) { if (Token::Match(tok, "%varid% =", varid)) { allocType = getAllocationType(tok->tokAt(2), varid, callstack); } if (Token::Match(tok, "= %varid% ;", varid)) { return No; } if (Token::Match(tok, "static %type% * %varid% [;{}=]", varid)) { return No; } if (Token::Match(tok, "[(,] %varid% [,)]", varid)) { return No; } if (Token::Match(tok, "[(,] & %varid% [.,)]", varid)) { return No; } if (allocType == No && tok->str() == "return") return No; } return allocType; } const char *CheckMemoryLeak::functionArgAlloc(const Function *func, unsigned int targetpar, AllocType &allocType) const { allocType = No; if (!func || !func->functionScope) return ""; if (!Token::simpleMatch(func->retDef, "void")) return ""; std::list::const_iterator arg = func->argumentList.begin(); for (; arg != func->argumentList.end(); ++arg) { if (arg->index() == targetpar-1) break; } if (arg == func->argumentList.end()) return ""; // Is ** if (!arg->isPointer()) return ""; const Token* tok = arg->typeEndToken(); tok = tok->previous(); if (tok->str() != "*") return ""; // Check if pointer is allocated. int realloc = 0; for (tok = func->functionScope->classStart; tok && tok != func->functionScope->classEnd; tok = tok->next()) { if (tok->varId() == arg->declarationId()) { if (Token::Match(tok->tokAt(-3), "free ( * %name% )")) { realloc = 1; allocType = No; } else if (Token::Match(tok->previous(), "* %name% =")) { allocType = getAllocationType(tok->tokAt(2), arg->declarationId()); if (allocType == No) { allocType = getReallocationType(tok->tokAt(2), arg->declarationId()); } if (allocType != No) { if (realloc) return "realloc"; return "alloc"; } } else { // unhandled variable usage: bailout return ""; } } } return ""; } bool CheckMemoryLeakInFunction::notvar(const Token *tok, unsigned int varid, bool endpar) { const std::string end(endpar ? " &&|)" : " [;)&|]"); return bool(Token::Match(tok, ("! %varid%" + end).c_str(), varid) || Token::Match(tok, ("! ( %varid% )" + end).c_str(), varid)); } bool CheckMemoryLeakInFunction::test_white_list(const std::string &funcname, const Settings *settings, bool cpp) { return (std::binary_search(call_func_white_list, call_func_white_list+sizeof(call_func_white_list) / sizeof(call_func_white_list[0]), funcname) || (settings->library.leakignore.find(funcname) != settings->library.leakignore.end()) || (cpp && funcname == "delete")); } const char * CheckMemoryLeakInFunction::call_func(const Token *tok, std::list callstack, const unsigned int varid, AllocType &alloctype, AllocType &dealloctype, bool &allocpar, unsigned int sz) { if (test_white_list(tok->str(), _settings, tokenizer->isCPP())) { if (tok->str() == "asprintf" || tok->str() == "delete" || tok->str() == "fclose" || tok->str() == "for" || tok->str() == "free" || tok->str() == "if" || tok->str() == "realloc" || tok->str() == "return" || tok->str() == "switch" || tok->str() == "while" || tok->str() == "sizeof") { return 0; } // is the varid a parameter? for (const Token *tok2 = tok->tokAt(2); tok2 != tok->linkAt(1); tok2 = tok2->next()) { if (tok2->str() == "(") { tok2 = tok2->nextArgument(); if (!tok2) break; } if (tok2->varId() == varid) { if (tok->strAt(-1) == ".") return "use"; else if (tok2->strAt(1) == "=") return "assign"; else if (tok->str()=="printf") return "use"; // <- it is not certain printf dereference the pointer TODO: check the format string else return "use_"; } } return 0; } if (_settings->library.isnoreturn(tok) && tok->strAt(-1) != "=") return "exit"; if (varid > 0 && (getReallocationType(tok, varid) != No || getDeallocationType(tok, varid) != No)) return 0; if (callstack.size() > 2) return "dealloc_"; const std::string& funcname(tok->str()); for (std::list::const_iterator it = callstack.begin(); it != callstack.end(); ++it) { if ((*it) && (*it)->str() == funcname) return "recursive"; } callstack.push_back(tok); // lock/unlock.. if (varid == 0) { const Function* func = tok->function(); if (!func || !func->hasBody()) return 0; Token *ftok = getcode(func->functionScope->classStart->next(), callstack, 0, alloctype, dealloctype, false, 1); simplifycode(ftok); const char *ret = nullptr; if (Token::simpleMatch(ftok, "; alloc ; }")) ret = "alloc"; else if (Token::simpleMatch(ftok, "; dealloc ; }")) ret = "dealloc"; TokenList::deleteTokens(ftok); return ret; } // how many parameters is there in the function call? const unsigned int numpar = countParameters(tok); if (numpar == 0) { // Taking return value => it is not a noreturn function if (tok->strAt(-1) == "=") return nullptr; // Function is not noreturn if (tok->function() && tok->function()->functionScope) { std::string temp; if (!_settings->library.isScopeNoReturn(tok->function()->functionScope->classEnd, &temp) && temp.empty()) return nullptr; } else if (_settings->library.isnotnoreturn(tok)) return nullptr; return "callfunc"; } unsigned int par = 0; const bool dot(tok->previous()->str() == "."); const bool eq(tok->previous()->str() == "="); const Token *functok = tok; tok = Token::findsimplematch(tok, "("); if (tok) tok = tok->next(); for (; tok; tok = tok->nextArgument()) { ++par; if (Token::Match(tok, "%varid% [,()]", varid)) { if (dot) return "use"; const Function* function = functok->function(); if (!function) return "use"; // how many parameters does the function want? if (numpar != function->argCount()) // TODO: Handle default parameters return "recursive"; if (!function->functionScope) return "use"; const Variable* param = function->getArgumentVar(par-1); if (!param || !param->nameToken()) return "use"; Token *func = getcode(function->functionScope->classStart->next(), callstack, param->declarationId(), alloctype, dealloctype, false, sz); //simplifycode(func); const Token *func_ = func; while (func_ && func_->str() == ";") func_ = func_->next(); const char *ret = nullptr; /** @todo handle "goto" */ if (Token::findsimplematch(func_, "dealloc")) ret = "dealloc"; else if (Token::findsimplematch(func_, "use")) ret = "use"; else if (Token::findsimplematch(func_, "&use")) ret = "&use"; TokenList::deleteTokens(func); return ret; } if (Token::Match(tok, "& %varid% [,()]", varid)) { const Function *func = functok->function(); if (func == 0) continue; AllocType a; const char *ret = functionArgAlloc(func, par, a); if (a != No) { if (alloctype == No) alloctype = a; else if (alloctype != a) alloctype = Many; allocpar = true; return ret; } } if (Token::Match(tok, "%varid% . %name% [,)]", varid)) return "use"; } return (eq || _settings->experimental) ? 0 : "callfunc"; } static void addtoken(Token **rettail, const Token *tok, const std::string &str) { (*rettail)->insertToken(str); (*rettail) = (*rettail)->next(); (*rettail)->linenr(tok->linenr()); (*rettail)->fileIndex(tok->fileIndex()); } Token *CheckMemoryLeakInFunction::getcode(const Token *tok, std::list callstack, const unsigned int varid, CheckMemoryLeak::AllocType &alloctype, CheckMemoryLeak::AllocType &dealloctype, bool classmember, unsigned int sz) { // variables whose value depends on if(!var). If one of these variables // is used in a if-condition then generate "ifv" instead of "if". std::set extravar; // The first token should be ";" Token* rethead = new Token(0); rethead->str(";"); rethead->linenr(tok->linenr()); rethead->fileIndex(tok->fileIndex()); Token* rettail = rethead; int indentlevel = 0; int parlevel = 0; for (; tok; tok = tok->next()) { if (tok->str() == "{") { addtoken(&rettail, tok, "{"); ++indentlevel; } else if (tok->str() == "}") { addtoken(&rettail, tok, "}"); if (indentlevel <= 0) break; --indentlevel; } else if (tok->str() == "(") ++parlevel; else if (tok->str() == ")") --parlevel; if (parlevel == 0 && tok->str() == ";") addtoken(&rettail, tok, ";"); // Start of new statement.. check if the statement has anything interesting if (varid > 0 && parlevel == 0 && Token::Match(tok, "[;{}]")) { if (Token::Match(tok->next(), "[{};]")) continue; // function calls are interesting.. const Token *tok2 = tok; while (Token::Match(tok2->next(), "%name% .")) tok2 = tok2->tokAt(2); if (Token::Match(tok2->next(), "%name% (")) ; else if (Token::Match(tok->next(), "continue|break|return|throw|goto|do|else")) ; else { const Token *skipToToken = nullptr; // scan statement for interesting keywords / varid for (tok2 = tok->next(); tok2; tok2 = tok2->next()) { if (tok2->str() == ";") { // nothing interesting found => skip this statement skipToToken = tok2->previous(); break; } if (tok2->varId() == varid || tok2->str() == ":" || tok2->str() == "{" || tok2->str() == "}") { break; } } if (skipToToken) { tok = skipToToken; continue; } } } if (varid == 0) { if (!callstack.empty() && Token::Match(tok, "[;{}] __cppcheck_lock|__cppcheck_unlock ( ) ;")) { // Type of leak = Resource leak alloctype = dealloctype = CheckMemoryLeak::File; if (tok->next()->str() == "__cppcheck_lock") { addtoken(&rettail, tok, "alloc"); } else { addtoken(&rettail, tok, "dealloc"); } tok = tok->tokAt(3); continue; } if (Token::simpleMatch(tok, "if (")) { addtoken(&rettail, tok, "if"); tok = tok->next()->link(); continue; } } else { if (Token::Match(tok, "%varid% = close ( %varid% )", varid)) { addtoken(&rettail, tok, "dealloc"); addtoken(&rettail, tok, ";"); addtoken(&rettail, tok, "assign"); addtoken(&rettail, tok, ";"); tok = tok->tokAt(5); continue; } // var = strcpy|.. ( var , if (Token::Match(tok, "[;{}] %varid% = memcpy|memmove|memset|strcpy|strncpy|strcat|strncat ( %varid% ,", varid)) { tok = tok->linkAt(4); continue; } if (Token::Match(tok->previous(), "[(;{}] %varid% =", varid) || Token::Match(tok, "asprintf|vasprintf ( & %varid% ,", varid)) { CheckMemoryLeak::AllocType alloc; if (Token::Match(tok, "asprintf|vasprintf (")) { // todo: check how the return value is used. if (!Token::Match(tok->previous(), "[;{}]")) { TokenList::deleteTokens(rethead); return 0; } alloc = Malloc; tok = tok->next()->link(); } else { alloc = getAllocationType(tok->tokAt(2), varid); } //bool realloc = false; if (sz > 1 && Token::Match(tok->tokAt(2), "malloc ( %num% )") && (MathLib::toLongNumber(tok->strAt(4)) % long(sz)) != 0) { mismatchSizeError(tok->tokAt(4), tok->strAt(4)); } if (alloc == CheckMemoryLeak::No) { alloc = getReallocationType(tok->tokAt(2), varid); if (alloc != CheckMemoryLeak::No) { addtoken(&rettail, tok, "realloc"); addtoken(&rettail, tok, ";"); //TODO: this assignment is redundant, should be fixed //realloc = true; tok = tok->tokAt(2); if (Token::Match(tok, "%name% (")) tok = tok->next()->link(); continue; } } // don't check classes.. if (alloc == CheckMemoryLeak::New) { if (Token::Match(tok->tokAt(2), "new struct| %type% [(;]")) { const int offset = tok->strAt(3) == "struct" ? 1 : 0; if (isclass(tok->tokAt(3 + offset), varid)) { alloc = No; } } else if (Token::Match(tok->tokAt(2), "new ( nothrow ) struct| %type%")) { const int offset = tok->strAt(6) == "struct" ? 1 : 0; if (isclass(tok->tokAt(6 + offset), varid)) { alloc = No; } } else if (Token::Match(tok->tokAt(2), "new ( std :: nothrow ) struct| %type%")) { const int offset = tok->strAt(8) == "struct" ? 1 : 0; if (isclass(tok->tokAt(8 + offset), varid)) { alloc = No; } } if (alloc == No && alloctype == No) alloctype = CheckMemoryLeak::New; } if (alloc != No) { //if (! realloc) addtoken(&rettail, tok, "alloc"); if (alloctype != No && alloctype != alloc) alloc = Many; if (alloc != Many && dealloctype != No && dealloctype != Many && dealloctype != alloc) { callstack.push_back(tok); mismatchAllocDealloc(callstack, Token::findmatch(_tokenizer->tokens(), "%varid%", varid)->str()); callstack.pop_back(); } alloctype = alloc; if (Token::Match(tok, "%name% = %type% (")) { tok = tok->linkAt(3); continue; } } // assignment.. else { // is the pointer in rhs? bool rhs = false; bool trailingSemicolon = false; bool used = false; for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next()) { if (tok2->str() == ";") { trailingSemicolon = true; if (rhs) tok = tok2; break; } if (!used && !rhs) { if (Token::Match(tok2, "[=+(,] %varid%", varid)) { if (Token::Match(tok2, "[(,]")) { used = true; addtoken(&rettail, tok, "use"); addtoken(&rettail, tok, ";"); } rhs = true; } } } if (!used) { if (!rhs) addtoken(&rettail, tok, "assign"); else { addtoken(&rettail, tok, "use_"); if (trailingSemicolon) addtoken(&rettail, tok, ";"); } } continue; } } if (Token::Match(tok->previous(), "%op%|;|{|}|) ::| %name%") || (Token::Match(tok->previous(), "( ::| %name%") && (!rettail || rettail->str() != "loop"))) { if (Token::Match(tok, "%varid% ?", varid)) tok = tok->tokAt(2); AllocType dealloc = getDeallocationType(tok, varid); if (dealloc != No && tok->str() == "fcloseall" && alloctype != dealloc) //TODO: this assignment is redundant, should be fixed /*dealloc = No*/; else if (dealloc != No) { addtoken(&rettail, tok, "dealloc"); if (dealloctype != No && dealloctype != dealloc) dealloc = Many; if (dealloc != Many && alloctype != No && alloctype != Many && alloctype != dealloc) { callstack.push_back(tok); mismatchAllocDealloc(callstack, Token::findmatch(_tokenizer->tokens(), "%varid%", varid)->str()); callstack.pop_back(); } dealloctype = dealloc; if (tok->strAt(2) == "(") tok = tok->linkAt(2); continue; } } // if else switch if (Token::simpleMatch(tok, "if (")) { if (alloctype == Fd) { if (Token::Match(tok, "if ( 0|-1 <=|< %varid% )", varid) || Token::Match(tok, "if ( %varid% >|>= 0|-1 )", varid) || Token::Match(tok, "if ( %varid% != -1 )", varid) || Token::Match(tok, "if ( -1 != %varid% )", varid)) { addtoken(&rettail, tok, "if(var)"); tok = tok->next()->link(); continue; } else if (Token::Match(tok, "if ( %varid% == -1 )", varid) || Token::Match(tok, "if ( -1 == %varid% )", varid) || Token::Match(tok, "if ( %varid% < 0 )", varid) || Token::Match(tok, "if ( 0 > %varid% )", varid)) { addtoken(&rettail, tok, "if(!var)"); tok = tok->next()->link(); continue; } } if (Token::Match(tok, "if ( %varid% )", varid)) { addtoken(&rettail, tok, "if(var)"); // Make sure the "use" will not be added tok = tok->next()->link(); continue; } else if (Token::simpleMatch(tok, "if (") && notvar(tok->tokAt(2), varid, true)) { addtoken(&rettail, tok, "if(!var)"); // parse the if-body. // if a variable is assigned then add variable to "extravar". for (const Token *tok2 = tok->next()->link()->tokAt(2); tok2; tok2 = tok2->next()) { if (tok2->str() == "{") tok2 = tok2->link(); else if (tok2->str() == "}") break; else if (Token::Match(tok2, "%var% =")) extravar.insert(tok2->varId()); } tok = tok->next()->link(); continue; } else { // Check if the condition depends on var or extravar somehow.. bool dep = false; const Token* const end = tok->linkAt(1); for (const Token *tok2 = tok->next(); tok2 != end; tok2 = tok2->next()) { if (Token::Match(tok2, "close|pclose|fclose|closedir ( %varid% )", varid)) { addtoken(&rettail, tok, "dealloc"); addtoken(&rettail, tok, ";"); dep = true; break; } else if (alloctype == Fd && Token::Match(tok2, "%varid% !=|>=", varid)) { dep = true; } else if (Token::Match(tok2, "! %varid%", varid)) { dep = true; } else if (Token::Match(tok2, "%name% (") && !test_white_list(tok2->str(), _settings, tokenizer->isCPP())) { bool use = false; for (const Token *tok3 = tok2->tokAt(2); tok3; tok3 = tok3->nextArgument()) { if (Token::Match(tok3->previous(), "(|, &| %varid% ,|)", varid)) { use = true; break; } } if (use) { addtoken(&rettail, tok, "use"); addtoken(&rettail, tok, ";"); dep = false; break; } } else if (tok2->varId() && extravar.find(tok2->varId()) != extravar.end()) { dep = true; } else if (tok2->varId() == varid && (tok2->next()->isConstOp() || tok2->previous()->isConstOp())) dep = true; } if (Token::Match(tok, "if ( ! %varid% &&", varid)) { addtoken(&rettail, tok, "if(!var)"); } else if (tok->next() && tok->next()->link() && Token::Match(tok->next()->link()->tokAt(-3), "&& ! %varid%", varid)) { addtoken(&rettail, tok, "if(!var)"); } else { addtoken(&rettail, tok, (dep ? "ifv" : "if")); } tok = tok->next()->link(); continue; } } } if ((tok->str() == "else") || (tok->str() == "switch")) { addtoken(&rettail, tok, tok->str()); if (Token::simpleMatch(tok, "switch (")) tok = tok->next()->link(); continue; } if ((tok->str() == "case")) { addtoken(&rettail, tok, "case"); addtoken(&rettail, tok, ";"); if (Token::Match(tok, "case %any% :")) tok = tok->tokAt(2); continue; } if ((tok->str() == "default")) { addtoken(&rettail, tok, "default"); addtoken(&rettail, tok, ";"); continue; } // Loops.. else if ((tok->str() == "for") || (tok->str() == "while")) { const Token* const end = tok->linkAt(1); if (Token::simpleMatch(tok, "while ( true )") || Token::simpleMatch(tok, "for ( ; ; )")) { addtoken(&rettail, tok, "while1"); tok = end; continue; } else if (varid && getDeallocationType(tok->tokAt(2), varid) != No) { addtoken(&rettail, tok, "dealloc"); addtoken(&rettail, tok, ";"); } else if (alloctype == Fd && varid) { if (Token::Match(tok, "while ( 0 <= %varid% )", varid) || Token::Match(tok, "while ( %varid% >= 0 )", varid) || Token::Match(tok, "while ( %varid% != -1 )", varid) || Token::Match(tok, "while ( -1 != %varid% )", varid)) { addtoken(&rettail, tok, "while(var)"); tok = end; continue; } else if (Token::Match(tok, "while ( %varid% == -1 )", varid) || Token::Match(tok, "while ( -1 == %varid% )", varid) || Token::Match(tok, "while ( %varid% < 0 )", varid) || Token::Match(tok, "while ( 0 > %varid% )", varid)) { addtoken(&rettail, tok, "while(!var)"); tok = end; continue; } } else if (varid && Token::Match(tok, "while ( %varid% )", varid)) { addtoken(&rettail, tok, "while(var)"); tok = end; continue; } else if (varid && Token::simpleMatch(tok, "while (") && notvar(tok->tokAt(2), varid, true)) { addtoken(&rettail, tok, "while(!var)"); tok = end; continue; } addtoken(&rettail, tok, "loop"); if (varid > 0) { for (const Token *tok2 = tok->tokAt(2); tok2 && tok2 != end; tok2 = tok2->next()) { if (notvar(tok2, varid)) { addtoken(&rettail, tok2, "!var"); break; } } } continue; } if ((tok->str() == "do")) { addtoken(&rettail, tok, "do"); continue; } // continue / break.. else if (tok->str() == "continue") { addtoken(&rettail, tok, "continue"); } else if (tok->str() == "break") { addtoken(&rettail, tok, "break"); } else if (tok->str() == "goto") { addtoken(&rettail, tok, "goto"); } // Return.. else if (tok->str() == "return") { addtoken(&rettail, tok, "return"); if (varid == 0) { addtoken(&rettail, tok, ";"); while (tok && tok->str() != ";") tok = tok->next(); if (!tok) break; continue; } // Returning a auto_ptr of this allocated variable.. if (Token::simpleMatch(tok->next(), "std :: auto_ptr <")) { const Token *tok2 = tok->linkAt(4); if (Token::Match(tok2, "> ( %varid% )", varid)) { addtoken(&rettail, tok, "use"); tok = tok2->tokAt(3); } } else if (varid && Token::Match(tok, "return strcpy|strncpy|memcpy ( %varid%", varid)) { addtoken(&rettail, tok, "use"); tok = tok->tokAt(2); } else { bool use = false; std::stack f; for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next()) { if (tok2->str() == ";") { tok = tok2; break; } if (tok2->str() == "(") f.push(tok2->previous()); else if (!f.empty() && tok2->str() == ")") f.pop(); if (tok2->varId() == varid) { // Read data.. if (!Token::Match(tok2->previous(), "&|(") && tok2->strAt(1) == "[") { } else if (f.empty() || !test_white_list(f.top()->str(), _settings, tokenizer->isCPP()) || getDeallocationType(f.top(),varid)) { use = true; } } } if (use) addtoken(&rettail, tok, "use"); addtoken(&rettail, tok, ";"); } } // throw.. else if (Token::Match(tok, "try|throw|catch")) { addtoken(&rettail, tok, tok->str()); if (tok->strAt(1) == "(") tok = tok->next()->link(); } // Assignment.. if (varid) { if (Token::simpleMatch(tok, "= {")) { const Token* const end2 = tok->linkAt(1); bool use = false; for (const Token *tok2 = tok; tok2 != end2; tok2 = tok2->next()) { if (tok2->varId() == varid) { use = true; break; } } if (use) { addtoken(&rettail, tok, "use"); addtoken(&rettail, tok, ";"); tok = tok->next()->link(); continue; } } if (Token::Match(tok, "& %name% = %varid% ;", varid)) { while (rethead->next()) rethead->deleteNext(); return rethead; } if (Token::Match(tok, "[)=] %varid% [+;)]", varid) || (Token::Match(tok, "%name% + %varid%", varid) && tok->strAt(3) != "[" && tok->strAt(3) != ".") || Token::Match(tok, "<< %varid% ;", varid) || Token::Match(tok, "= strcpy|strcat|memmove|memcpy ( %varid% ,", varid) || Token::Match(tok, "[;{}] %name% [ %varid% ]", varid)) { addtoken(&rettail, tok, "use"); } else if (Token::Match(tok->previous(), ";|{|}|=|(|,|%cop% %varid% [", varid) || Token::Match(tok->previous(), ";|{|}|=|(|,|%cop% %varid% .", varid)) { // warning is written for "dealloc ; use_ ;". // but this use doesn't affect the leak-checking addtoken(&rettail, tok, "use_"); } } // Investigate function calls.. if (Token::Match(tok, "%name% (")) { // A function call should normally be followed by ";" if (Token::simpleMatch(tok->next()->link(), ") {")) { if (!Token::Match(tok, "if|for|while|switch")) { addtoken(&rettail, tok, "exit"); addtoken(&rettail, tok, ";"); tok = tok->next()->link(); continue; } } // Calling setjmp / longjmp => bail out else if (Token::Match(tok, "setjmp|longjmp")) { while (rethead->next()) rethead->deleteNext(); return rethead; } // Inside class function.. if the var is passed as a parameter then // just add a "::use" // The "::use" means that a member function was probably called but it wasn't analysed further else if (classmember) { if (_settings->library.isnoreturn(tok)) addtoken(&rettail, tok, "exit"); else if (!test_white_list(tok->str(), _settings, tokenizer->isCPP())) { const Token* const end2 = tok->linkAt(1); for (const Token *tok2 = tok->tokAt(2); tok2 != end2; tok2 = tok2->next()) { if (tok2->varId() == varid) { addtoken(&rettail, tok, "::use"); break; } } } } else { if (varid > 0 && Token::Match(tok, "%name% ( close|fclose|pclose ( %varid% ) ) ;", varid)) { addtoken(&rettail, tok, "dealloc"); tok = tok->next()->link(); continue; } bool allocpar = false; const char *str = call_func(tok, callstack, varid, alloctype, dealloctype, allocpar, sz); if (str) { if (allocpar) { addtoken(&rettail, tok, str); tok = tok->next()->link(); } else if (varid == 0 || str != std::string("alloc")) { addtoken(&rettail, tok, str); } else if (Token::Match(tok->tokAt(-2), "%varid% =", varid)) { addtoken(&rettail, tok, str); } } else if (varid > 0 && getReallocationType(tok, varid) != No && tok->tokAt(2)->varId() == varid) { addtoken(&rettail, tok, "if"); addtoken(&rettail, tok, "{"); addtoken(&rettail, tok, "dealloc"); addtoken(&rettail, tok, ";"); addtoken(&rettail, tok, "}"); tok = tok->next()->link(); continue; } } } // Callback.. if (Token::Match(tok, "( *| %name%") && Token::simpleMatch(tok->link(),") (")) { const Token *tok2 = tok->next(); if (tok2->str() == "*") tok2 = tok2->next(); tok2 = tok2->next(); while (Token::Match(tok2, ". %name%")) tok2 = tok2->tokAt(2); if (Token::simpleMatch(tok2, ") (")) { for (; tok2; tok2 = tok2->next()) { if (Token::Match(tok2, "[;{]")) break; else if (tok2->varId() == varid) { addtoken(&rettail, tok, "use"); break; } } } } // Linux lists.. if (varid > 0 && Token::Match(tok, "[=(,] & (| %varid% [.[,)]", varid)) { // Is variable passed to a "leak-ignore" function? bool leakignore = false; if (Token::Match(tok, "[(,]")) { const Token *parent = tok; while (parent && parent->str() != "(") parent = parent->astParent(); if (parent && parent->astOperand1() && parent->astOperand1()->isName()) { const std::string &functionName = parent->astOperand1()->str(); if (_settings->library.leakignore.find(functionName) != _settings->library.leakignore.end()) leakignore = true; } } // Not passed to "leak-ignore" function, add "&use". if (!leakignore) addtoken(&rettail, tok, "&use"); } } for (Token *tok1 = rethead; tok1; tok1 = tok1->next()) { if (Token::simpleMatch(tok1, "callfunc alloc ;")) { tok1->deleteThis(); tok1->insertToken("use"); tok1->insertToken(";"); } } return rethead; } void CheckMemoryLeakInFunction::simplifycode(Token *tok) const { { // Replace "throw" that is not in a try block with "return" int indentlevel = 0; int trylevel = -1; for (Token *tok2 = tok; tok2; tok2 = tok2->next()) { if (tok2->str() == "{") ++indentlevel; else if (tok2->str() == "}") { --indentlevel; if (indentlevel <= trylevel) trylevel = -1; } else if (trylevel == -1 && tok2->str() == "try") trylevel = indentlevel; else if (trylevel == -1 && tok2->str() == "throw") tok2->str("return"); } } // Insert extra ";" for (Token *tok2 = tok; tok2; tok2 = tok2->next()) { if (!tok2->previous() || Token::Match(tok2->previous(), "[;{}]")) { if (Token::Match(tok2, "assign|callfunc|use assign|callfunc|use|}")) { tok2->insertToken(";"); } } } // remove redundant braces.. for (Token *start = tok; start; start = start->next()) { if (Token::simpleMatch(start, "; {")) { // the "link" doesn't work here. Find the end brace.. unsigned int indent = 0; for (Token *end = start; end; end = end->next()) { if (end->str() == "{") ++indent; else if (end->str() == "}") { if (indent <= 1) { // If the start/end braces are redundant, delete them if (indent == 1 && Token::Match(end->previous(), "[;{}] } %any%")) { start->deleteNext(); end->deleteThis(); } break; } --indent; } } } } // reduce the code.. // it will be reduced in N passes. When a pass completes without any // simplifications the loop is done. bool done = false; while (! done) { //tok->printOut("simplifycode loop.."); done = true; // reduce callfunc for (Token *tok2 = tok; tok2; tok2 = tok2->next()) { if (tok2->str() == "callfunc") { if (!Token::Match(tok2->previous(), "[;{}] callfunc ; }")) tok2->deleteThis(); } } // If the code starts with "if return ;" then remove it if (Token::Match(tok, ";| if return ;")) { tok->deleteNext(); tok->deleteThis(); if (tok->str() == "return") tok->deleteThis(); if (tok->strAt(1) == "else") tok->deleteNext(); } // simplify "while1" contents.. for (Token *tok2 = tok; tok2; tok2 = tok2->next()) { if (Token::simpleMatch(tok2, "while1 {")) { unsigned int innerIndentlevel = 0; for (Token *tok3 = tok2->tokAt(2); tok3; tok3 = tok3->next()) { if (tok3->str() == "{") ++innerIndentlevel; else if (tok3->str() == "}") { if (innerIndentlevel == 0) break; --innerIndentlevel; } while (innerIndentlevel == 0 && Token::Match(tok3, "[{};] if|ifv|else { continue ; }")) { tok3->deleteNext(5); if (tok3->strAt(1) == "else") tok3->deleteNext(); } } if (Token::simpleMatch(tok2, "while1 { if { dealloc ; return ; } }")) { tok2->str(";"); tok2->deleteNext(3); tok2->tokAt(4)->deleteNext(2); } } } // Main inner simplification loop for (Token *tok2 = tok; tok2; tok2 = tok2 ? tok2->next() : nullptr) { // Delete extra ";" while (Token::Match(tok2, "[;{}] ;")) { tok2->deleteNext(); done = false; } // Replace "{ }" with ";" if (Token::simpleMatch(tok2->next(), "{ }")) { tok2->deleteNext(2); tok2->insertToken(";"); done = false; } // Delete braces around a single instruction.. if (Token::Match(tok2->next(), "{ %name% ; }")) { tok2->deleteNext(); tok2->tokAt(2)->deleteNext(); done = false; } if (Token::Match(tok2->next(), "{ %name% %name% ; }")) { tok2->deleteNext(); tok2->tokAt(3)->deleteNext(); done = false; } // Reduce "if if|callfunc" => "if" else if (Token::Match(tok2, "if if|callfunc")) { tok2->deleteNext(); done = false; } // outer/inner if blocks. Remove outer condition.. else if (Token::Match(tok2->next(), "if|if(var) { if return use ; }")) { tok2->deleteNext(2); tok2->tokAt(4)->deleteNext(); done = false; } else if (tok2->next() && tok2->next()->str() == "if") { // Delete empty if that is not followed by an else if (Token::Match(tok2->next(), "if ; !!else")) { tok2->deleteNext(); done = false; } // Reduce "if X ; else X ;" => "X ;" else if (Token::Match(tok2->next(), "if %name% ; else %name% ;") && tok2->strAt(2) == tok2->strAt(5)) { tok2->deleteNext(4); done = false; } // Reduce "if continue ; if continue ;" => "if continue ;" else if (Token::simpleMatch(tok2->next(), "if continue ; if continue ;")) { tok2->deleteNext(3); done = false; } // Reduce "if return ; alloc ;" => "alloc ;" else if (Token::Match(tok2, "[;{}] if return ; alloc|return ;")) { tok2->deleteNext(3); done = false; } // "[;{}] if alloc ; else return ;" => "[;{}] alloc ;" else if (Token::Match(tok2, "[;{}] if alloc ; else return ;")) { // Remove "if" tok2->deleteNext(); // Remove "; else return" tok2->next()->deleteNext(3); done = false; } // Reduce "if ; else %name% ;" => "if %name% ;" else if (Token::Match(tok2->next(), "if ; else %name% ;")) { tok2->next()->deleteNext(2); done = false; } // Reduce "if ; else" => "if" else if (Token::simpleMatch(tok2->next(), "if ; else")) { tok2->next()->deleteNext(2); done = false; } // Reduce "if return ; else|if return|continue ;" => "if return ;" else if (Token::Match(tok2->next(), "if return ; else|if return|continue|break ;")) { tok2->tokAt(3)->deleteNext(3); done = false; } // Reduce "if continue|break ; else|if return ;" => "if return ;" else if (Token::Match(tok2->next(), "if continue|break ; if|else return ;")) { tok2->next()->deleteNext(3); done = false; } // Remove "else" after "if continue|break|return" else if (Token::Match(tok2->next(), "if continue|break|return ; else")) { tok2->tokAt(3)->deleteNext(); done = false; } // Delete "if { dealloc|assign|use ; return ; }" else if (Token::Match(tok2, "[;{}] if { dealloc|assign|use ; return ; }") && !Token::findmatch(tok, "if {| alloc ;")) { tok2->deleteNext(7); if (tok2->strAt(1) == "else") tok2->deleteNext(); done = false; } // Remove "if { dealloc ; callfunc ; } !!else|return" else if (Token::Match(tok2->next(), "if { dealloc|assign ; callfunc ; }") && !Token::Match(tok2->tokAt(8), "else|return")) { tok2->deleteNext(7); done = false; } continue; } // Reduce "alloc while(!var) alloc ;" => "alloc ;" if (Token::Match(tok2, "[;{}] alloc ; while(!var) alloc ;")) { tok2->deleteNext(3); done = false; } // Reduce "ifv return;" => "if return use;" if (Token::simpleMatch(tok2, "ifv return ;")) { tok2->str("if"); tok2->next()->insertToken("use"); done = false; } // Reduce "if(var) dealloc ;" and "if(var) use ;" that is not followed by an else.. if (Token::Match(tok2, "[;{}] if(var) assign|dealloc|use ; !!else")) { tok2->deleteNext(); done = false; } // Reduce "; if(!var) alloc ; !!else" => "; dealloc ; alloc ;" if (Token::Match(tok2, "; if(!var) alloc ; !!else")) { // Remove the "if(!var)" tok2->deleteNext(); // Insert "dealloc ;" before the "alloc ;" tok2->insertToken(";"); tok2->insertToken("dealloc"); done = false; } // Reduce "if(!var) exit ;" => ";" if (Token::simpleMatch(tok2, "; if(!var) exit ;")) { tok2->deleteNext(2); done = false; } // Reduce "if* ;".. if (Token::Match(tok2->next(), "if(var)|if(!var)|ifv ;")) { // Followed by else.. if (tok2->strAt(3) == "else") { tok2 = tok2->next(); if (tok2->str() == "if(var)") tok2->str("if(!var)"); else if (tok2->str() == "if(!var)") tok2->str("if(var)"); // remove the "; else" tok2->deleteNext(2); } else { // remove the "if*" tok2->deleteNext(); } done = false; } // Reduce "else ;" => ";" if (Token::simpleMatch(tok2->next(), "else ;")) { tok2->deleteNext(); done = false; } // Reduce "while1 continue| ;" => "use ;" if (Token::Match(tok2, "while1 if| continue| ;")) { tok2->str("use"); while (tok2->strAt(1) != ";") tok2->deleteNext(); done = false; } // Reduce "while1 if break ;" => ";" if (Token::simpleMatch(tok2, "while1 if break ;")) { tok2->str(";"); tok2->deleteNext(2); done = false; } // Delete if block: "alloc; if return use ;" if (Token::Match(tok2, "alloc ; if return use ; !!else")) { tok2->deleteNext(4); done = false; } // Reduce "alloc|dealloc|use|callfunc ; exit ;" => "; exit ;" if (Token::Match(tok2, "[;{}] alloc|dealloc|use|callfunc ; exit ;")) { tok2->deleteNext(); done = false; } // Reduce "alloc|dealloc|use ; if(var) exit ;" if (Token::Match(tok2, "alloc|dealloc|use ; if(var) exit ;")) { tok2->deleteThis(); done = false; } // Remove "if exit ;" if (Token::simpleMatch(tok2, "if exit ;")) { tok2->deleteNext(); tok2->deleteThis(); done = false; } // Remove the "if break|continue ;" that follows "dealloc ; alloc ;" if (! _settings->experimental && Token::Match(tok2, "dealloc ; alloc ; if break|continue ;")) { tok2->tokAt(3)->deleteNext(2); done = false; } // if break ; break ; => break ; if (Token::Match(tok2->previous(), "[;{}] if break ; break ;")) { tok2->deleteNext(3); done = false; } // Reduce "do { dealloc ; alloc ; } while(var) ;" => ";" if (Token::simpleMatch(tok2->next(), "do { dealloc ; alloc ; } while(var) ;")) { tok2->deleteNext(8); done = false; } // Reduce "do { alloc ; } " => "alloc ;" /** @todo If the loop "do { alloc ; }" can be executed twice, reduce it to "loop alloc ;" */ if (Token::simpleMatch(tok2->next(), "do { alloc ; }")) { tok2->deleteNext(2); tok2->tokAt(2)->deleteNext(); done = false; } // Reduce "loop break ; => ";" if (Token::Match(tok2->next(), "loop break|continue ;")) { tok2->deleteNext(2); done = false; } // Reduce "loop|do ;" => ";" if (Token::Match(tok2, "loop|do ;")) { tok2->deleteThis(); done = false; } // Reduce "loop if break|continue ; !!else" => ";" if (Token::Match(tok2->next(), "loop if break|continue ; !!else")) { tok2->deleteNext(3); done = false; } // Reduce "loop { if break|continue ; !!else" => "loop {" if (Token::Match(tok2, "loop { if break|continue ; !!else")) { tok2->next()->deleteNext(3); done = false; } // Replace "do ; loop ;" with ";" if (Token::simpleMatch(tok2, "; loop ;")) { tok2->deleteNext(2); done = false; } // Replace "loop loop .." with "loop .." if (Token::simpleMatch(tok2, "loop loop")) { tok2->deleteThis(); done = false; } // Replace "loop if return ;" with "if return ;" if (Token::simpleMatch(tok2->next(), "loop if return")) { tok2->deleteNext(); done = false; } // Reduce "loop|while1 { dealloc ; alloc ; }" if (Token::Match(tok2, "loop|while1 { dealloc ; alloc ; }")) { // delete "{" tok2->deleteNext(); // delete "loop|while1" tok2->deleteThis(); // delete "}" tok2->tokAt(3)->deleteNext(); done = false; } // loop { use ; callfunc ; } => use ; // assume that the "callfunc" is not noreturn if (Token::simpleMatch(tok2, "loop { use ; callfunc ; }")) { tok2->deleteNext(6); tok2->str("use"); tok2->insertToken(";"); done = false; } // Delete if block in "alloc ; if(!var) return ;" if (Token::simpleMatch(tok2, "alloc ; if(!var) return ;")) { tok2->deleteNext(3); done = false; } // Reduce "[;{}] return use ; %name%" => "[;{}] return use ;" if (Token::Match(tok2, "[;{}] return use ; %name%")) { tok2->tokAt(3)->deleteNext(); done = false; } // Reduce "if(var) return use ;" => "return use ;" if (Token::Match(tok2->next(), "if(var) return use ; !!else")) { tok2->deleteNext(); done = false; } // malloc - realloc => alloc ; dealloc ; alloc ; // Reduce "[;{}] alloc ; dealloc ; alloc ;" => "[;{}] alloc ;" if (Token::Match(tok2, "[;{}] alloc ; dealloc ; alloc ;")) { tok2->deleteNext(4); done = false; } // use; dealloc; => dealloc; if (Token::Match(tok2, "[;{}] use ; dealloc ;")) { tok2->deleteNext(2); done = false; } // use use => use while (Token::simpleMatch(tok2, "use use")) { tok2->deleteNext(); done = false; } // use use_ => use if (Token::simpleMatch(tok2, "use use_")) { tok2->deleteNext(); done = false; } // use_ use => use if (Token::simpleMatch(tok2, "use_ use")) { tok2->deleteThis(); done = false; } // use & use => use while (Token::simpleMatch(tok2, "use & use")) { tok2->deleteNext(2); done = false; } // & use use => use while (Token::simpleMatch(tok2, "& use use")) { tok2->deleteThis(); tok2->deleteThis(); done = false; } // use; if| use; => use; while (Token::Match(tok2, "[;{}] use ; if| use ;")) { Token *t = tok2->tokAt(2); t->deleteNext(2+(t->str()=="if" ? 1 : 0)); done = false; } // Delete first part in "use ; return use ;" if (Token::Match(tok2, "[;{}] use ; return use ;")) { tok2->deleteNext(2); done = false; } // try/catch if (Token::simpleMatch(tok2, "try ; catch exit ;")) { tok2->deleteNext(3); tok2->deleteThis(); done = false; } // Delete second case in "case ; case ;" while (Token::simpleMatch(tok2, "case ; case ;")) { tok2->deleteNext(2); done = false; } // Replace switch with if (if not complicated) if (Token::simpleMatch(tok2, "switch {")) { // Right now, I just handle if there are a few case and perhaps a default. bool valid = false; bool incase = false; for (const Token * _tok = tok2->tokAt(2); _tok; _tok = _tok->next()) { if (_tok->str() == "{") break; else if (_tok->str() == "}") { valid = true; break; } else if (_tok->str() == "switch") break; else if (_tok->str() == "loop") break; else if (incase && _tok->str() == "case") break; else if (Token::Match(_tok, "return !!;")) break; if (Token::Match(_tok, "if return|break use| ;")) _tok = _tok->tokAt(2); incase = incase || (_tok->str() == "case"); incase = incase && (_tok->str() != "break" && _tok->str() != "return"); } if (!incase && valid) { done = false; tok2->str(";"); tok2->deleteNext(); tok2 = tok2->next(); bool first = true; while (Token::Match(tok2, "case|default")) { const bool def(tok2->str() == "default"); tok2->str(first ? "if" : "}"); if (first) { first = false; tok2->insertToken("{"); } else { // Insert "else [if] { tok2->insertToken("{"); if (! def) tok2->insertToken("if"); tok2->insertToken("else"); tok2 = tok2->next(); } while (tok2) { if (tok2->str() == "}") break; if (Token::Match(tok2, "break|return ;")) break; if (Token::Match(tok2, "if return|break use| ;")) tok2 = tok2->tokAt(2); else tok2 = tok2->next(); } if (Token::simpleMatch(tok2, "break ;")) { tok2->str(";"); tok2 = tok2->tokAt(2); } else if (tok2 && tok2->str() == "return") { tok2 = tok2->tokAt(2); } } } } } // If "--all" is given, remove all "callfunc".. if (done && _settings->experimental) { for (Token *tok2 = tok; tok2; tok2 = tok2->next()) { if (tok2->str() == "callfunc") { tok2->deleteThis(); done = false; } } } } } const Token *CheckMemoryLeakInFunction::findleak(const Token *tokens) { const Token *result; if ((result = Token::findsimplematch(tokens, "loop alloc ;")) != nullptr) { return result; } if (Token::Match(tokens, "alloc ; if|if(var)|ifv break|continue|return ;")) { return tokens->tokAt(3); } if ((result = Token::findmatch(tokens, "alloc ; if|if(var)|ifv return ;")) != nullptr) { return result->tokAt(3); } if ((result = Token::findmatch(tokens, "alloc ; alloc|assign|return callfunc| ;")) != nullptr) { return result->tokAt(2); } if ((result = Token::findsimplematch(tokens, "; alloc ; if assign ;")) != nullptr) { return result->tokAt(4); } if (((result = Token::findsimplematch(tokens, "; alloc ; if dealloc ; }")) != nullptr) && !result->tokAt(7)) { return result->tokAt(6); } if ((result = Token::findsimplematch(tokens, "alloc ; }")) != nullptr) { if (result->tokAt(3) == nullptr) return result->tokAt(2); } // No deallocation / usage => report leak at the last token if (!Token::findmatch(tokens, "dealloc|use")) { const Token *last = tokens; while (last->next()) last = last->next(); // not a leak if exit is called before the end of the function if (!Token::Match(last->tokAt(-2), "exit|callfunc ; }")) return last; } return nullptr; } // Check for memory leaks for a function variable. void CheckMemoryLeakInFunction::checkScope(const Token *Tok1, const std::string &varname, unsigned int varid, bool classmember, unsigned int sz) { std::list callstack; AllocType alloctype = No; AllocType dealloctype = No; const Token *result; Token *tok = getcode(Tok1, callstack, varid, alloctype, dealloctype, classmember, sz); //tok->printOut((std::string("Checkmemoryleak: getcode result for: ") + varname).c_str()); const bool use_addr = bool(Token::findsimplematch(tok, "&use") != nullptr); // Simplify the code and check if freed memory is used.. for (Token *tok2 = tok; tok2; tok2 = tok2->next()) { while (Token::Match(tok2, "[;{}] ;")) tok2->deleteNext(); } if ((result = Token::findmatch(tok, "[;{}] dealloc ; use_ ;")) != nullptr) { deallocuseError(result->tokAt(3), varname); } // Replace "&use" with "use". Replace "use_" with ";" for (Token *tok2 = tok; tok2; tok2 = tok2->next()) { if (tok2->str() == "&use") tok2->str("use"); else if (tok2->str() == "use_") tok2->str(";"); else if (Token::simpleMatch(tok2, "loop use_ {")) tok2->deleteNext(); else if (tok2->str() == "::use") // Some kind of member function usage. Not analyzed very well. tok2->str("use"); else if (tok2->str() == "recursive") tok2->str("use"); else if (tok2->str() == "dealloc_") tok2->str("dealloc"); else if (tok2->str() == "realloc") { tok2->str("dealloc"); tok2->insertToken("alloc"); tok2->insertToken(";"); } } // If the variable is not allocated at all => no memory leak if (Token::findsimplematch(tok, "alloc") == 0) { TokenList::deleteTokens(tok); return; } simplifycode(tok); if (_settings->debug && _settings->_verbose) { tok->printOut(("Checkmemoryleak: simplifycode result for: " + varname).c_str()); } // If the variable is not allocated at all => no memory leak if (Token::findsimplematch(tok, "alloc") == 0) { TokenList::deleteTokens(tok); return; } /** @todo handle "goto" */ if (Token::findsimplematch(tok, "goto")) { TokenList::deleteTokens(tok); return; } if ((result = findleak(tok)) != nullptr) { memoryLeak(result, varname, alloctype); } else if (!use_addr && (result = Token::findsimplematch(tok, "dealloc ; dealloc ;")) != nullptr) { deallocDeallocError(result->tokAt(2), varname); } // detect cases that "simplifycode" don't handle well.. else if (tok && _settings->debugwarnings) { Token *first = tok; while (first && first->str() == ";") first = first->next(); bool noerr = false; noerr = noerr || Token::simpleMatch(first, "alloc ; }"); noerr = noerr || Token::simpleMatch(first, "alloc ; dealloc ; }"); noerr = noerr || Token::simpleMatch(first, "alloc ; return use ; }"); noerr = noerr || Token::simpleMatch(first, "alloc ; use ; }"); noerr = noerr || Token::simpleMatch(first, "alloc ; use ; return ; }"); noerr = noerr || Token::simpleMatch(first, "alloc ; dealloc ; return ; }"); noerr = noerr || Token::simpleMatch(first, "if alloc ; dealloc ; }"); noerr = noerr || Token::simpleMatch(first, "if alloc ; return use ; }"); noerr = noerr || Token::simpleMatch(first, "if alloc ; use ; }"); noerr = noerr || Token::simpleMatch(first, "alloc ; ifv return ; dealloc ; }"); noerr = noerr || Token::simpleMatch(first, "alloc ; if return ; dealloc; }"); // Unhandled case.. if (!noerr) { std::ostringstream errmsg; errmsg << "inconclusive leak of " << varname << ": "; errmsg << tok->stringifyList(false, false, false, false, false, 0, 0); reportError(first, Severity::debug, "debug", errmsg.str()); } } TokenList::deleteTokens(tok); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- // Check for memory leaks due to improper realloc() usage. // Below, "a" may be set to null without being freed if realloc() cannot // allocate the requested memory: // a = malloc(10); a = realloc(a, 100); //--------------------------------------------------------------------------- static bool isNoArgument(const SymbolDatabase* symbolDatabase, unsigned int varid) { const Variable* var = symbolDatabase->getVariableFromVarId(varid); return var && !var->isArgument(); } void CheckMemoryLeakInFunction::checkReallocUsage() { // only check functions const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; // Search for the "var = realloc(var, 100" pattern within this function for (const Token *tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if (tok->varId() > 0 && Token::Match(tok, "%name% = realloc|g_try_realloc ( %name% , %any%") && tok->varId() == tok->tokAt(4)->varId() && isNoArgument(symbolDatabase, tok->varId())) { // Check that another copy of the pointer wasn't saved earlier in the function if (Token::findmatch(scope->classStart, "%name% = %varid% ;", tok, tok->varId()) || Token::findmatch(scope->classStart, "[{};] %varid% = %name% [;=]", tok, tok->varId())) continue; const Token* tokEndRealloc = tok->linkAt(3); // Check that the allocation isn't followed immediately by an 'if (!var) { error(); }' that might handle failure if (Token::Match(tokEndRealloc->next(), "; if ( ! %varid% ) {", tok->varId())) { const Token* tokEndBrace = tokEndRealloc->linkAt(7); if (tokEndBrace && Token::simpleMatch(tokEndBrace->tokAt(-2), ") ;") && Token::Match(tokEndBrace->linkAt(-2)->tokAt(-2), "{|}|; %name% (")) continue; } memleakUponReallocFailureError(tok, tok->str()); } else if (tok->next()->varId() > 0 && (Token::Match(tok, "* %name% = realloc|g_try_realloc ( * %name% , %any%") && tok->next()->varId() == tok->tokAt(6)->varId()) && isNoArgument(symbolDatabase, tok->next()->varId())) { // Check that another copy of the pointer wasn't saved earlier in the function if (Token::findmatch(scope->classStart, "%name% = * %varid% ;", tok, tok->next()->varId()) || Token::findmatch(scope->classStart, "[{};] * %varid% = %name% [;=]", tok, tok->next()->varId())) continue; const Token* tokEndRealloc = tok->linkAt(4); // Check that the allocation isn't followed immediately by an 'if (!var) { error(); }' that might handle failure if (Token::Match(tokEndRealloc->next(), "; if ( ! * %varid% ) {", tok->next()->varId())) { const Token* tokEndBrace = tokEndRealloc->linkAt(8); if (tokEndBrace && Token::simpleMatch(tokEndBrace->tokAt(-2), ") ;") && Token::Match(tokEndBrace->linkAt(-2)->tokAt(-2), "{|}|; %name% (")) continue; } memleakUponReallocFailureError(tok->next(), tok->strAt(1)); } } } } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- // Checks for memory leaks inside function.. //--------------------------------------------------------------------------- static bool isInMemberFunc(const Scope* scope) { while (scope->nestedIn && !scope->functionOf) scope = scope->nestedIn; return (scope->functionOf != 0); } void CheckMemoryLeakInFunction::check() { // Check locking/unlocking of global resources.. const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; checkScope(scope->classStart->next(), "", 0, scope->functionOf != nullptr, 1); } // Check variables.. for (unsigned int i = 1; i < symbolDatabase->getVariableListSize(); i++) { const Variable* var = symbolDatabase->getVariableFromVarId(i); if (!var || (!var->isLocal() && !var->isArgument()) || var->isStatic() || !var->scope()) continue; if (var->isReference()) continue; if (!var->isPointer() && var->typeStartToken()->str() != "int") continue; // check for known class without implementation (forward declaration) if (var->isPointer() && var->type() && !var->typeScope()) continue; unsigned int sz = _tokenizer->sizeOfType(var->typeStartToken()); if (sz < 1) sz = 1; if (var->isArgument()) checkScope(var->scope()->classStart->next(), var->name(), i, isInMemberFunc(var->scope()), sz); else checkScope(var->nameToken(), var->name(), i, isInMemberFunc(var->scope()), sz); } } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- // Checks for memory leaks in classes.. //--------------------------------------------------------------------------- void CheckMemoryLeakInClass::check() { const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); // only check classes and structures const std::size_t classes = symbolDatabase->classAndStructScopes.size(); for (std::size_t i = 0; i < classes; ++i) { const Scope * scope = symbolDatabase->classAndStructScopes[i]; std::list::const_iterator var; for (var = scope->varlist.begin(); var != scope->varlist.end(); ++var) { if (!var->isStatic() && var->isPointer()) { // allocation but no deallocation of private variables in public function.. const Token *tok = var->typeStartToken(); if (tok->isStandardType()) { if (var->isPrivate()) checkPublicFunctions(scope, var->nameToken()); variable(scope, var->nameToken()); } // known class? else if (var->type()) { // not derived? if (var->type()->derivedFrom.empty()) { if (var->isPrivate()) checkPublicFunctions(scope, var->nameToken()); variable(scope, var->nameToken()); } } } } } } void CheckMemoryLeakInClass::variable(const Scope *scope, const Token *tokVarname) { const std::string& varname = tokVarname->str(); const unsigned int varid = tokVarname->varId(); const std::string& classname = scope->className; // Check if member variable has been allocated and deallocated.. CheckMemoryLeak::AllocType Alloc = CheckMemoryLeak::No; CheckMemoryLeak::AllocType Dealloc = CheckMemoryLeak::No; bool allocInConstructor = false; bool deallocInDestructor = false; // Inspect member functions std::list::const_iterator func; for (func = scope->functionList.begin(); func != scope->functionList.end(); ++func) { const bool constructor = func->isConstructor(); const bool destructor = func->isDestructor(); if (!func->hasBody()) { if (destructor) { // implementation for destructor is not seen => assume it deallocates all variables properly deallocInDestructor = true; Dealloc = CheckMemoryLeak::Many; } continue; } bool body = false; const Token *end = func->functionScope->classEnd; for (const Token *tok = func->arg->link(); tok != end; tok = tok->next()) { if (tok == func->functionScope->classStart) body = true; else { if (!body) { if (!Token::Match(tok, ":|, %varid% (", varid)) continue; } // Allocate.. if (!body || Token::Match(tok, "%varid% =", varid)) { // var1 = var2 = ... // bail out if (tok->strAt(-1) == "=") return; // Foo::var1 = .. // bail out when not same class if (tok->strAt(-1) == "::" && tok->strAt(-2) != scope->className) return; AllocType alloc = getAllocationType(tok->tokAt(body ? 2 : 3), 0); if (alloc != CheckMemoryLeak::No) { if (constructor) allocInConstructor = true; if (Alloc != No && Alloc != alloc) alloc = CheckMemoryLeak::Many; std::list callstack; if (alloc != CheckMemoryLeak::Many && Dealloc != CheckMemoryLeak::No && Dealloc != CheckMemoryLeak::Many && Dealloc != alloc) { callstack.push_back(tok); mismatchAllocDealloc(callstack, classname + "::" + varname); } Alloc = alloc; } } if (!body) continue; // Deallocate.. AllocType dealloc = getDeallocationType(tok, varname); if (dealloc == No) { std::string temp = scope->className + " :: " + varname; dealloc = getDeallocationType(tok, temp); } if (dealloc == No) { std::string temp = "this . " + varname; dealloc = getDeallocationType(tok, temp); } // some usage in the destructor => assume it's related // to deallocation if (destructor && tok->str() == varname) dealloc = CheckMemoryLeak::Many; if (dealloc != CheckMemoryLeak::No) { if (destructor) deallocInDestructor = true; // several types of allocation/deallocation? if (Dealloc != CheckMemoryLeak::No && Dealloc != dealloc) dealloc = CheckMemoryLeak::Many; std::list callstack; if (dealloc != CheckMemoryLeak::Many && Alloc != CheckMemoryLeak::No && Alloc != Many && Alloc != dealloc) { callstack.push_back(tok); mismatchAllocDealloc(callstack, classname + "::" + varname); } Dealloc = dealloc; } // Function call .. possible deallocation else if (Token::Match(tok->previous(), "[{};] %name% (")) { if (!CheckMemoryLeakInFunction::test_white_list(tok->str(), _settings, tokenizer->isCPP())) { return; } } } } } if (allocInConstructor && !deallocInDestructor) { unsafeClassError(tokVarname, classname, classname + "::" + varname /*, Alloc*/); } else if (Alloc != CheckMemoryLeak::No && Dealloc == CheckMemoryLeak::No) { unsafeClassError(tokVarname, classname, classname + "::" + varname /*, Alloc*/); } } void CheckMemoryLeakInClass::unsafeClassError(const Token *tok, const std::string &classname, const std::string &varname) { reportError(tok, Severity::style, "unsafeClassCanLeak", "Class '" + classname + "' is unsafe, '" + varname + "' can leak by wrong usage.\n" "The class '" + classname + "' is unsafe, wrong usage can cause memory/resource leaks for '" + varname + "'. This can for instance be fixed by adding proper cleanup in the destructor."); } void CheckMemoryLeakInClass::checkPublicFunctions(const Scope *scope, const Token *classtok) { // Check that public functions deallocate the pointers that they allocate. // There is no checking how these functions are used and therefore it // isn't established if there is real leaks or not. if (!_settings->isEnabled("warning")) return; const unsigned int varid = classtok->varId(); if (varid == 0) { _tokenizer->getSymbolDatabase()->debugMessage(classtok, "CheckMemoryInClass::checkPublicFunctions found variable \'" + classtok->str() + "\' with varid 0"); return; } // Parse public functions.. // If they allocate member variables, they should also deallocate std::list::const_iterator func; for (func = scope->functionList.begin(); func != scope->functionList.end(); ++func) { if ((func->type == Function::eFunction || func->type == Function::eOperatorEqual) && func->access == Public && func->hasBody()) { const Token *tok2 = func->token; while (tok2->str() != "{") tok2 = tok2->next(); if (Token::Match(tok2, "{|}|; %varid% =", varid)) { const CheckMemoryLeak::AllocType alloc = getAllocationType(tok2->tokAt(3), varid); if (alloc != CheckMemoryLeak::No) publicAllocationError(tok2, tok2->strAt(1)); } else if (Token::Match(tok2, "{|}|; %type% :: %varid% =", varid) && tok2->next()->str() == scope->className) { const CheckMemoryLeak::AllocType alloc = getAllocationType(tok2->tokAt(5), varid); if (alloc != CheckMemoryLeak::No) publicAllocationError(tok2, tok2->strAt(3)); } } } } void CheckMemoryLeakInClass::publicAllocationError(const Token *tok, const std::string &varname) { reportError(tok, Severity::warning, "publicAllocationError", "Possible leak in public function. The pointer '" + varname + "' is not deallocated before it is allocated."); } void CheckMemoryLeakStructMember::check() { const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase(); for (unsigned int i = 1; i < symbolDatabase->getVariableListSize(); i++) { const Variable* var = symbolDatabase->getVariableFromVarId(i); if (!var || !var->isLocal() || var->isStatic()) continue; if (var->typeEndToken()->isStandardType()) continue; checkStructVariable(var); } } bool CheckMemoryLeakStructMember::isMalloc(const Variable *variable) { const unsigned int declarationId(variable->declarationId()); bool alloc = false; for (const Token *tok2 = variable->nameToken(); tok2 && tok2 != variable->scope()->classEnd; tok2 = tok2->next()) { if (Token::Match(tok2, "= %varid% [;=]", declarationId)) { return false; } else if (Token::Match(tok2, "%varid% = malloc|kmalloc (", declarationId)) { alloc = true; } } return alloc; } void CheckMemoryLeakStructMember::checkStructVariable(const Variable * const variable) { // This should be in the CheckMemoryLeak base class static std::set ignoredFunctions; if (ignoredFunctions.empty()) { ignoredFunctions.insert("if"); ignoredFunctions.insert("for"); ignoredFunctions.insert("while"); ignoredFunctions.insert("malloc"); } // Is struct variable a pointer? if (variable->isPointer()) { // Check that variable is allocated with malloc if (!isMalloc(variable)) return; } else if (!_tokenizer->isC()) { // For non-C code a destructor might cleanup members return; } // Check struct.. unsigned int indentlevel2 = 0; for (const Token *tok2 = variable->nameToken(); tok2 != variable->scope()->classEnd; tok2 = tok2->next()) { if (tok2->str() == "{") ++indentlevel2; else if (tok2->str() == "}") { if (indentlevel2 == 0) break; --indentlevel2; } // Unknown usage of struct /** @todo Check how the struct is used. Only bail out if necessary */ else if (Token::Match(tok2, "[(,] %varid% [,)]", variable->declarationId())) break; // Struct member is allocated => check if it is also properly deallocated.. else if (Token::Match(tok2->previous(), "[;{}] %varid% . %var% = malloc|strdup|kmalloc (", variable->declarationId()) || Token::Match(tok2->previous(), "[;{}] %varid% . %var% = new", variable->declarationId()) || Token::Match(tok2->previous(), "[;{}] %varid% . %var% = fopen (", variable->declarationId())) { const unsigned int structid(variable->declarationId()); const unsigned int structmemberid(tok2->tokAt(2)->varId()); // This struct member is allocated.. check that it is deallocated unsigned int indentlevel3 = indentlevel2; for (const Token *tok3 = tok2; tok3; tok3 = tok3->next()) { if (tok3->str() == "{") ++indentlevel3; else if (tok3->str() == "}") { if (indentlevel3 == 0) { memoryLeak(tok3, variable->name() + "." + tok2->strAt(2), Malloc); break; } --indentlevel3; } // Deallocating the struct member.. else if (Token::Match(tok3, "free|kfree ( %var% . %varid% )", structmemberid) || Token::Match(tok3, "delete %var% . %varid%", structmemberid) || Token::Match(tok3, "delete [ ] %var% . %varid%", structmemberid) || Token::Match(tok3, "fclose ( %var% . %varid%", structmemberid)) { // If the deallocation happens at the base level, don't check this member anymore if (indentlevel3 == 0) break; // deallocating and then returning from function in a conditional block => // skip ahead out of the block bool ret = false; while (tok3) { if (tok3->str() == "return") ret = true; else if (tok3->str() == "{" || tok3->str() == "}") break; tok3 = tok3->next(); } if (!ret || !tok3 || tok3->str() != "}") break; --indentlevel3; continue; } // Deallocating the struct.. else if (indentlevel2 == 0 && Token::Match(tok3, "free|kfree ( %varid% )", structid)) { memoryLeak(tok3, variable->name() + "." + tok2->strAt(2), Malloc); break; } // failed allocation => skip code.. else if (Token::Match(tok3, "if ( ! %var% . %varid% )", structmemberid)) { // Goto the ")" tok3 = tok3->next()->link(); // make sure we have ") {".. it should be if (!Token::simpleMatch(tok3, ") {")) break; // Goto the "}" tok3 = tok3->next()->link(); } // succeeded allocation else if (Token::Match(tok3, "if ( %var% . %varid% ) {", structmemberid)) { // goto the ")" tok3 = tok3->next()->link(); // check if the variable is deallocated or returned.. unsigned int indentlevel4 = 0; for (const Token *tok4 = tok3; tok4; tok4 = tok4->next()) { if (tok4->str() == "{") ++indentlevel4; else if (tok4->str() == "}") { --indentlevel4; if (indentlevel4 == 0) break; } else if (Token::Match(tok4, "free|kfree ( %var% . %varid% )", structmemberid)) { break; } } // was there a proper deallocation? if (indentlevel4 > 0) break; } // Returning from function.. else if (tok3->str() == "return") { // Returning from function without deallocating struct member? if (!Token::Match(tok3, "return %varid% ;", structid) && !Token::Match(tok3, "return & %varid% .", structid)) { memoryLeak(tok3, variable->name() + "." + tok2->strAt(2), Malloc); } break; } // struct assignment.. else if (Token::Match(tok3, "= %varid% ;", structid)) { break; } else if (Token::Match(tok3, "= %var% . %varid% ;", structmemberid)) { break; } // goto isn't handled well.. bail out even though there might be leaks else if (tok3->str() == "goto") break; // using struct in a function call.. else if (Token::Match(tok3, "%name% (")) { // Calling non-function / function that doesn't deallocate? if (ignoredFunctions.find(tok3->str()) != ignoredFunctions.end()) continue; // Check if the struct is used.. bool deallocated = false; const Token* const end4 = tok3->linkAt(1); for (const Token *tok4 = tok3; tok4 != end4; tok4 = tok4->next()) { if (Token::Match(tok4, "[(,] &| %varid% [,)]", structid)) { /** @todo check if the function deallocates the memory */ deallocated = true; break; } if (Token::Match(tok4, "[(,] &| %varid% . %name% [,)]", structid)) { /** @todo check if the function deallocates the memory */ deallocated = true; break; } } if (deallocated) break; } } } } } #include "checkuninitvar.h" // CheckUninitVar::analyse void CheckMemoryLeakNoVar::check() { std::set uvarFunctions; { const CheckUninitVar c(_tokenizer, _settings, _errorLogger); c.analyseFunctions(_tokenizer, uvarFunctions); } const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); // only check functions const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; // Checks if a call to an allocation function like malloc() is made and its return value is not assigned. checkForUnusedReturnValue(scope); // Checks to see if a function is called with memory allocated for an argument that // could be leaked if a function called for another argument throws. checkForUnsafeArgAlloc(scope); // goto the "}" that ends the executable scope.. const Token *tok = scope->classEnd; // parse the executable scope until tok is reached... for (const Token *tok2 = tok->link(); tok2 && tok2 != tok; tok2 = tok2->next()) { // allocating memory in parameter for function call.. if (Token::Match(tok2, "[(,] %name% (") && Token::Match(tok2->linkAt(2), ") [,)]")) { const AllocType allocType = getAllocationType(tok2->next(), 0); if (allocType != No) { // locate outer function call.. for (const Token *tok3 = tok2; tok3; tok3 = tok3->previous()) { if (tok3->str() == "(") { // Is it a function call.. if (!Token::Match(tok3->tokAt(-2), "= %name% (")) { const std::string& functionName = tok3->strAt(-1); if ((tokenizer->isCPP() && functionName == "delete") || functionName == "free" || functionName == "fclose" || functionName == "realloc") break; if (CheckMemoryLeakInFunction::test_white_list(functionName, _settings, tokenizer->isCPP())) { functionCallLeak(tok2, tok2->strAt(1), functionName); break; } if (uvarFunctions.find(functionName) != uvarFunctions.end()) { functionCallLeak(tok2, tok2->strAt(1), functionName); break; } } break; } else if (tok3->str() == ")") tok3 = tok3->link(); else if (Token::Match(tok3, "[;{}]")) break; } } } } } } //--------------------------------------------------------------------------- // Checks if a call to an allocation function like malloc() is made and its return value is not assigned. //--------------------------------------------------------------------------- void CheckMemoryLeakNoVar::checkForUnusedReturnValue(const Scope *scope) { for (const Token *tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) { if (Token::Match(tok, "{|}|; %name% (") && tok->strAt(-1) != "=") { tok = tok->next(); const int allocationId = _settings->library.alloc(tok); if (allocationId > 0) returnValueNotUsedError(tok, tok->str()); } } } //--------------------------------------------------------------------------- // Check if an exception could cause a leak in an argument constructed with // shared_ptr/unique_ptr. For example, in the following code, it is possible // that if g() throws an exception, the memory allocated by "new int(42)" // could be leaked. See stackoverflow.com/questions/19034538/ // why-is-there-memory-leak-while-using-shared-ptr-as-a-function-parameter // // void x() { // f(shared_ptr(new int(42)), g()); // } //--------------------------------------------------------------------------- void CheckMemoryLeakNoVar::checkForUnsafeArgAlloc(const Scope *scope) { // This test only applies to C++ source if (!_tokenizer->isCPP() || !_settings->inconclusive || !_settings->isEnabled("warning")) return; for (const Token *tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) { if (Token::Match(tok, "%name% (")) { const Token *endParamToken = tok->next()->link(); std::string pointerType; std::string objectType; std::string functionCalled; // Scan through the arguments to the function call for (const Token *tok2 = tok->tokAt(2); tok2 && tok2 != endParamToken; tok2 = tok2->nextArgument()) { const Function *pFunc = tok2->function(); const bool isNothrow = pFunc && pFunc->isAttributeNothrow(); if (Token::Match(tok2, "shared_ptr|unique_ptr < %name% > ( new %name%")) { pointerType = tok2->str(); objectType = tok2->strAt(6); } else if (!isNothrow) { if (Token::Match(tok2, "%name% (")) functionCalled = tok2->str(); else if (Token::Match(tok2, "%name% < %name% > (")) functionCalled = tok2->str() + "<" + tok2->strAt(2) + ">"; } } if (!pointerType.empty() && !functionCalled.empty()) unsafeArgAllocError(tok, functionCalled, pointerType, objectType); } } } void CheckMemoryLeakNoVar::functionCallLeak(const Token *loc, const std::string &alloc, const std::string &functionCall) { reportError(loc, Severity::error, "leakNoVarFunctionCall", "Allocation with " + alloc + ", " + functionCall + " doesn't release it."); } void CheckMemoryLeakNoVar::returnValueNotUsedError(const Token *tok, const std::string &alloc) { reportError(tok, Severity::error, "leakReturnValNotUsed", "Return value of allocation function " + alloc + " is not used."); } void CheckMemoryLeakNoVar::unsafeArgAllocError(const Token *tok, const std::string &funcName, const std::string &ptrType, const std::string& objType) { const std::string factoryFunc = ptrType == "shared_ptr" ? "make_shared" : "make_unique"; reportError(tok, Severity::warning, "leakUnsafeArgAlloc", "Unsafe allocation. If " + funcName + "() throws, memory could be leaked. Use " + factoryFunc + "<" + objType + ">() instead.", true); // Inconclusive because funcName may never throw }