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cppcheck/test/teststring.cpp

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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2016 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 <http://www.gnu.org/licenses/>.
*/
#include "checkstring.h"
#include "settings.h"
#include "testsuite.h"
#include "tokenize.h"
class TestString : public TestFixture {
public:
TestString() : TestFixture("TestString") {
}
private:
Settings settings;
void run() {
settings.addEnabled("warning");
settings.addEnabled("style");
TEST_CASE(stringLiteralWrite);
TEST_CASE(alwaysTrueFalseStringCompare);
TEST_CASE(suspiciousStringCompare);
TEST_CASE(suspiciousStringCompare_char);
TEST_CASE(strPlusChar1); // "/usr" + '/'
TEST_CASE(strPlusChar2); // "/usr" + ch
TEST_CASE(strPlusChar3); // ok: path + "/sub" + '/'
TEST_CASE(sprintf1); // Dangerous usage of sprintf
TEST_CASE(sprintf2);
TEST_CASE(sprintf3);
TEST_CASE(sprintf4); // struct member
TEST_CASE(incorrectStringCompare);
TEST_CASE(deadStrcmp);
}
void check(const char code[], const char filename[] = "test.cpp") {
// Clear the error buffer..
errout.str("");
// Tokenize..
Tokenizer tokenizer(&settings, this);
std::istringstream istr(code);
tokenizer.tokenize(istr, filename);
// Check char variable usage..
CheckString checkString(&tokenizer, &settings, this);
checkString.runChecks(&tokenizer, &settings, this);
tokenizer.simplifyTokenList2();
checkString.runSimplifiedChecks(&tokenizer, &settings, this);
}
void stringLiteralWrite() {
check("void f() {\n"
" char *abc = \"abc\";\n"
" abc[0] = 'a';\n"
"}");
ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:2]: (error) Modifying string literal \"abc\" directly or indirectly is undefined behaviour.\n", errout.str());
check("void f() {\n"
" char *abc = \"abc\";\n"
" *abc = 'a';\n"
"}");
ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:2]: (error) Modifying string literal \"abc\" directly or indirectly is undefined behaviour.\n", errout.str());
check("void f() {\n"
" QString abc = \"abc\";\n"
" abc[0] = 'a';\n"
"}");
ASSERT_EQUALS("", errout.str());
check("void foo_FP1(char *p) {\n"
" p[1] = 'B';\n"
"}\n"
"void foo_FP2(void) {\n"
" char* s = \"Y\";\n"
" foo_FP1(s);\n"
"}");
ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:5]: (error) Modifying string literal \"Y\" directly or indirectly is undefined behaviour.\n", errout.str());
check("void foo_FP1(char *p) {\n"
" p[1] = 'B';\n"
"}\n"
"void foo_FP2(void) {\n"
" char s[10] = \"Y\";\n"
" foo_FP1(s);\n"
"}");
ASSERT_EQUALS("", errout.str());
}
void alwaysTrueFalseStringCompare() {
check("void f() {\n"
" if (strcmp(\"A\",\"A\")){}\n"
" if (strncmp(\"A\",\"A\",1)){}\n"
" if (strcasecmp(\"A\",\"A\")){}\n"
" if (strncasecmp(\"A\",\"A\",1)){}\n"
" if (memcmp(\"A\",\"A\",1)){}\n"
" if (strverscmp(\"A\",\"A\")){}\n"
" if (bcmp(\"A\",\"A\",1)){}\n"
" if (wcsncasecmp(L\"A\",L\"A\",1)){}\n"
" if (wcsncmp(L\"A\",L\"A\",1)){}\n"
" if (wmemcmp(L\"A\",L\"A\",1)){}\n"
" if (wcscmp(L\"A\",L\"A\")){}\n"
" if (wcscasecmp(L\"A\",L\"A\")){}\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (warning) Unnecessary comparison of static strings.\n"
"[test.cpp:3]: (warning) Unnecessary comparison of static strings.\n"
"[test.cpp:4]: (warning) Unnecessary comparison of static strings.\n"
"[test.cpp:5]: (warning) Unnecessary comparison of static strings.\n"
"[test.cpp:6]: (warning) Unnecessary comparison of static strings.\n"
"[test.cpp:7]: (warning) Unnecessary comparison of static strings.\n"
"[test.cpp:8]: (warning) Unnecessary comparison of static strings.\n"
"[test.cpp:9]: (warning) Unnecessary comparison of static strings.\n"
"[test.cpp:10]: (warning) Unnecessary comparison of static strings.\n"
"[test.cpp:11]: (warning) Unnecessary comparison of static strings.\n"
"[test.cpp:12]: (warning) Unnecessary comparison of static strings.\n"
"[test.cpp:13]: (warning) Unnecessary comparison of static strings.\n", errout.str());
// avoid false positives when the address is modified #6415
check("void f(void *p, int offset) {\n"
" if (!memcmp(p, p + offset, 42)){}\n"
" if (!memcmp(p + offset, p, 42)){}\n"
" if (!memcmp(offset + p, p, 42)){}\n"
" if (!memcmp(p, offset + p, 42)){}\n"
"}");
ASSERT_EQUALS("", errout.str());
// avoid false positives when the address is modified #6415
check("void f(char *c, int offset) {\n"
" if (!memcmp(c, c + offset, 42)){}\n"
" if (!memcmp(c + offset, c, 42)){}\n"
" if (!memcmp(offset + c, c, 42)){}\n"
" if (!memcmp(c, offset + c, 42)){}\n"
"}");
ASSERT_EQUALS("", errout.str());
// avoid false positives when the address is modified #6415
check("void f(std::string s, int offset) {\n"
" if (!memcmp(s.c_str(), s.c_str() + offset, 42)){}\n"
" if (!memcmp(s.c_str() + offset, s.c_str(), 42)){}\n"
" if (!memcmp(offset + s.c_str(), s.c_str(), 42)){}\n"
" if (!memcmp(s.c_str(), offset + s.c_str(), 42)){}\n"
"}");
ASSERT_EQUALS("", errout.str());
check("int main()\n"
"{\n"
" if (strcmp(\"00FF00\", \"00FF00\") == 0)"
" {"
" std::cout << \"Equal\";"
" }"
"}");
ASSERT_EQUALS("[test.cpp:3]: (warning) Unnecessary comparison of static strings.\n", errout.str());
check("void f() {\n"
" if (strcmp($\"00FF00\", \"00FF00\") == 0) {}"
"}");
ASSERT_EQUALS("", errout.str());
check("void f() {\n"
" if ($strcmp(\"00FF00\", \"00FF00\") == 0) {}"
"}");
ASSERT_EQUALS("", errout.str());
check("int main()\n"
"{\n"
" if (stricmp(\"hotdog\",\"HOTdog\") == 0)"
" {"
" std::cout << \"Equal\";"
" }"
"}");
ASSERT_EQUALS("[test.cpp:3]: (warning) Unnecessary comparison of static strings.\n", errout.str());
check("int main()\n"
"{\n"
" if (QString::compare(\"Hamburger\", \"Hotdog\") == 0)"
" {"
" std::cout << \"Equal\";"
" }"
"}");
ASSERT_EQUALS("[test.cpp:3]: (warning) Unnecessary comparison of static strings.\n", errout.str());
check("int main()\n"
"{\n"
" if (QString::compare(argv[2], \"hotdog\") == 0)"
" {"
" std::cout << \"Equal\";"
" }"
"}");
ASSERT_EQUALS("", errout.str());
check("int main()\n"
"{\n"
" if (strncmp(\"hotdog\",\"hotdog\", 6) == 0)"
" {"
" std::cout << \"Equal\";"
" }"
"}");
ASSERT_EQUALS("[test.cpp:3]: (warning) Unnecessary comparison of static strings.\n", errout.str());
check("int foo(const char *buf)\n"
"{\n"
" if (strcmp(buf, buf) == 0)"
" {"
" std::cout << \"Equal\";"
" }"
"}");
ASSERT_EQUALS("[test.cpp:3]: (warning) Comparison of identical string variables.\n", errout.str());
check("int foo(const std::string& buf)\n"
"{\n"
" if (stricmp(buf.c_str(), buf.c_str()) == 0)"
" {"
" std::cout << \"Equal\";"
" }"
"}");
ASSERT_EQUALS("[test.cpp:3]: (warning) Comparison of identical string variables.\n", errout.str());
check("int main() {\n"
" if (\"str\" == \"str\") {\n"
" std::cout << \"Equal\";\n"
" }\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (warning) Unnecessary comparison of static strings.\n", errout.str());
check("int main() {\n"
" if (\"str\" != \"str\") {\n"
" std::cout << \"Equal\";\n"
" }\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (warning) Unnecessary comparison of static strings.\n", errout.str());
check("int main() {\n"
" if (a+\"str\" != \"str\"+b) {\n"
" std::cout << \"Equal\";\n"
" }\n"
"}");
ASSERT_EQUALS("", errout.str());
}
void suspiciousStringCompare() {
check("bool foo(char* c) {\n"
" return c == \"x\";\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (warning) String literal compared with variable 'c'. Did you intend to use strcmp() instead?\n", errout.str());
check("bool foo(const char* c) {\n"
" return \"x\" == c;\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (warning) String literal compared with variable 'c'. Did you intend to use strcmp() instead?\n", errout.str());
check("bool foo(char* c) {\n"
" return foo+\"x\" == c;\n"
"}");
ASSERT_EQUALS("", errout.str());
check("bool foo(char* c) {\n"
" return \"x\" == c+foo;\n"
"}", "test.cpp");
ASSERT_EQUALS("", errout.str());
check("bool foo(char* c) {\n"
" return \"x\" == c+foo;\n"
"}", "test.c");
ASSERT_EQUALS("[test.c:2]: (warning) String literal compared with variable 'c'. Did you intend to use strcmp() instead?\n", errout.str());
check("bool foo(Foo c) {\n"
" return \"x\" == c.foo;\n"
"}", "test.cpp");
ASSERT_EQUALS("", errout.str());
check("bool foo(Foo c) {\n"
" return \"x\" == c.foo;\n"
"}", "test.c");
ASSERT_EQUALS("[test.c:2]: (warning) String literal compared with variable 'c.foo'. Did you intend to use strcmp() instead?\n", errout.str());
check("bool foo(const std::string& c) {\n"
" return \"x\" == c;\n"
"}");
ASSERT_EQUALS("", errout.str());
check("bool foo(const Foo* c) {\n"
" return \"x\" == c->bar();\n" // #4314
"}");
ASSERT_EQUALS("", errout.str());
// Ticket #4257
check("bool foo() {\n"
"MyString *str=Getter();\n"
"return *str==\"bug\"; }\n", "test.c");
ASSERT_EQUALS("[test.c:3]: (warning) String literal compared with variable '*str'. Did you intend to use strcmp() instead?\n", errout.str());
// Ticket #4257
check("bool foo() {\n"
"MyString *str=Getter();\n"
"return *str==\"bug\"; }");
ASSERT_EQUALS("", errout.str());
// Ticket #4257
check("bool foo() {\n"
"MyString **str=OtherGetter();\n"
"return *str==\"bug\"; }");
TODO_ASSERT_EQUALS("[test.cpp:2]: (warning) String literal compared with variable 'c'. Did you intend to use strcmp() instead?\n",
"",
errout.str());
// Ticket #4257
check("bool foo() {\n"
"MyString str=OtherGetter2();\n"
"return &str==\"bug\"; }");
TODO_ASSERT_EQUALS("[test.cpp:2]: (warning) String literal compared with variable 'c'. Did you intend to use strcmp() instead?\n",
"",
errout.str());
// Ticket #5734
check("int foo(char c) {\n"
"return c == '4';}", "test.cpp");
ASSERT_EQUALS("", errout.str());
check("int foo(char c) {\n"
"return c == '4';}", "test.c");
ASSERT_EQUALS("", errout.str());
check("int foo(char c) {\n"
"return c == \"42\"[0];}", "test.cpp");
ASSERT_EQUALS("", errout.str());
check("int foo(char c) {\n"
"return c == \"42\"[0];}", "test.c");
ASSERT_EQUALS("", errout.str());
// 5639 String literal compared with char buffer in a struct
check("struct Example {\n"
" char buffer[200];\n"
"};\n"
"void foo() {\n"
" struct Example example;\n"
" if (example.buffer == \"test\") ;\n"
"}\n", "test.cpp");
ASSERT_EQUALS("[test.cpp:6]: (warning) String literal compared with variable 'example.buffer'. Did you intend to use strcmp() instead?\n", errout.str());
check("struct Example {\n"
" char buffer[200];\n"
"};\n"
"void foo() {\n"
" struct Example example;\n"
" if (example.buffer == \"test\") ;\n"
"}\n", "test.c");
ASSERT_EQUALS("[test.c:6]: (warning) String literal compared with variable 'example.buffer'. Did you intend to use strcmp() instead?\n", errout.str());
}
void suspiciousStringCompare_char() {
check("bool foo(char* c) {\n"
" return c == 'x';\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (warning) Char literal compared with pointer 'c'. Did you intend to dereference it?\n", errout.str());
check("bool foo(char* c) {\n"
" return '\\0' != c;\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (warning) Char literal compared with pointer 'c'. Did you intend to dereference it?\n", errout.str());
check("bool foo(char c) {\n"
" return c == '\\0';\n"
"}");
ASSERT_EQUALS("", errout.str());
check("bool foo(char c) {\n"
" return c == 0;\n"
"}");
ASSERT_EQUALS("", errout.str());
check("bool foo(char* c) {\n"
" return *c == 0;\n"
"}", "test.c");
ASSERT_EQUALS("", errout.str());
check("bool foo(char* c) {\n"
" return *c == 0;\n"
"}");
ASSERT_EQUALS("", errout.str());
check("bool foo(Foo* c) {\n"
" return 0 == c->x;\n"
"}");
ASSERT_EQUALS("", errout.str());
check("void foo(char* c) {\n"
" if(c == '\\0') bar();\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (warning) Char literal compared with pointer 'c'. Did you intend to dereference it?\n", errout.str());
check("void f() {\n"
" struct { struct { char *str; } x; } a;\n"
" return a.x.str == '\\0';"
"}");
ASSERT_EQUALS("[test.cpp:3]: (warning) Char literal compared with pointer 'a.x.str'. Did you intend to dereference it?\n", errout.str());
check("void f() {\n"
" struct { struct { char *str; } x; } a;\n"
" return *a.x.str == '\\0';"
"}");
ASSERT_EQUALS("", errout.str());
}
void sprintf1() {
check("void foo()\n"
"{\n"
" char buf[100];\n"
" sprintf(buf,\"%s\",buf);\n"
"}");
ASSERT_EQUALS("[test.cpp:4]: (error) Undefined behavior: Variable 'buf' is used as parameter and destination in s[n]printf().\n", errout.str());
}
void sprintf2() {
check("void foo()\n"
"{\n"
" char buf[100];\n"
" sprintf(buf,\"%i\",sizeof(buf));\n"
"}");
ASSERT_EQUALS("", errout.str());
}
void sprintf3() {
check("void foo()\n"
"{\n"
" char buf[100];\n"
" sprintf(buf,\"%i\",sizeof(buf));\n"
" if (buf[0]);\n"
"}");
ASSERT_EQUALS("", errout.str());
}
void sprintf4() {
check("struct A\n"
"{\n"
" char filename[128];\n"
"};\n"
"\n"
"void foo()\n"
"{\n"
" const char* filename = \"hello\";\n"
" struct A a;\n"
" snprintf(a.filename, 128, \"%s\", filename);\n"
"}");
ASSERT_EQUALS("", errout.str());
}
void strPlusChar1() {
// Strange looking pointer arithmetic..
check("void foo()\n"
"{\n"
" const char *p = \"/usr\" + '/';\n"
"}");
ASSERT_EQUALS("[test.cpp:3]: (error) Unusual pointer arithmetic. A value of type 'char' is added to a string literal.\n", errout.str());
}
void strPlusChar2() {
// Strange looking pointer arithmetic..
check("void foo()\n"
"{\n"
" char ch = 1;\n"
" const char *p = ch + \"/usr\";\n"
"}");
ASSERT_EQUALS("", errout.str());
// Strange looking pointer arithmetic..
check("void foo()\n"
"{\n"
" int i = 1;\n"
" const char* psz = \"Bla\";\n"
" const std::string str = i + psz;\n"
"}");
ASSERT_EQUALS("", errout.str());
}
void strPlusChar3() {
// Strange looking pointer arithmetic..
check("void foo()\n"
"{\n"
" std::string temp = \"/tmp\";\n"
" std::string path = temp + '/' + \"sub\" + '/';\n"
"}");
ASSERT_EQUALS("", errout.str());
}
void incorrectStringCompare() {
check("int f() {\n"
" return test.substr( 0 , 4 ) == \"Hello\" ? : 0 : 1 ;\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (warning) String literal \"Hello\" doesn't match length argument for substr().\n", errout.str());
check("int f() {\n"
" return test.substr( 0 , 5 ) == \"Hello\" ? : 0 : 1 ;\n"
"}");
ASSERT_EQUALS("", errout.str());
check("int f() {\n"
" return \"Hello\" == test.substr( 0 , 4 ) ? : 0 : 1 ;\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (warning) String literal \"Hello\" doesn't match length argument for substr().\n", errout.str());
check("int f() {\n"
" return \"Hello\" == foo.bar<int>().z[1].substr(i+j*4, 4) ? : 0 : 1 ;\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (warning) String literal \"Hello\" doesn't match length argument for substr().\n", errout.str());
check("int f() {\n"
" return \"Hello\" == test.substr( 0 , 5 ) ? : 0 : 1 ;\n"
"}");
ASSERT_EQUALS("", errout.str());
check("int f() {\n"
" if (\"Hello\") { }\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (warning) Conversion of string literal \"Hello\" to bool always evaluates to true.\n", errout.str());
check("int f() {\n"
" if (\"Hello\" && test) { }\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (warning) Conversion of string literal \"Hello\" to bool always evaluates to true.\n", errout.str());
check("int f() {\n"
" if (test && \"Hello\") { }\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (warning) Conversion of string literal \"Hello\" to bool always evaluates to true.\n", errout.str());
check("int f() {\n"
" while (\"Hello\") { }\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (warning) Conversion of string literal \"Hello\" to bool always evaluates to true.\n", errout.str());
check("int f() {\n"
" assert (test || \"Hello\");\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (warning) Conversion of string literal \"Hello\" to bool always evaluates to true.\n", errout.str());
check("int f() {\n"
" assert (test && \"Hello\");\n"
"}");
ASSERT_EQUALS("", errout.str());
check("int f() {\n"
" assert (\"Hello\" || test);\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (warning) Conversion of string literal \"Hello\" to bool always evaluates to true.\n", errout.str());
check("int f() {\n"
" assert (\"Hello\" && test);\n"
"}");
ASSERT_EQUALS("", errout.str());
check("int f() {\n"
" BOOST_ASSERT (\"Hello\" && test);\n"
"}");
ASSERT_EQUALS("", errout.str());
check("int f() {\n"
" return f2(\"Hello\");\n"
"}");
ASSERT_EQUALS("", errout.str());
}
void deadStrcmp() {
check("void f(const char *str) {\n"
" if (strcmp(str, \"abc\") == 0 || strcmp(str, \"def\")) {}\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (warning) The expression 'strcmp(str,\"def\") != 0' is suspicious. It overlaps 'strcmp(str,\"abc\") == 0'.\n", errout.str());
check("struct X {\n"
" char *str;\n"
"};\n"
"\n"
"void f(const struct X *x) {\n"
" if (strcmp(x->str, \"abc\") == 0 || strcmp(x->str, \"def\")) {}\n"
"}");
ASSERT_EQUALS("[test.cpp:6]: (warning) The expression 'strcmp(x->str,\"def\") != 0' is suspicious. It overlaps 'strcmp(x->str,\"abc\") == 0'.\n", errout.str());
}
};
REGISTER_TEST(TestString)
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