From cc89687e8ca30284b6eea6be098d1ee0120a38e6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <danielm77@spray.se>
Date: Sun, 31 Jul 2011 17:19:23 +0200
Subject: [PATCH] Null pointer: better handling when calling standard functions
 with possible null pointer

---
 lib/checknullpointer.cpp | 15 +++++++++++++++
 test/testnullpointer.cpp |  7 +++++++
 2 files changed, 22 insertions(+)

diff --git a/lib/checknullpointer.cpp b/lib/checknullpointer.cpp
index 05d481523..1ea8ab909 100644
--- a/lib/checknullpointer.cpp
+++ b/lib/checknullpointer.cpp
@@ -715,6 +715,21 @@ void CheckNullPointer::nullPointerByCheckAndDeRef()
                     continue;
                 }
 
+                // function call, check if pointer is dereferenced
+                if (Token::Match(tok2, "%var% ("))
+                {
+                    std::list<const Token *> var;
+                    parseFunctionCall(*tok2, var, 0);
+                    for (std::list<const Token *>::const_iterator it = var.begin(); it != var.end(); ++it)
+                    {
+                        if ((*it)->varId() == varid)
+                        {
+                            nullPointerError(*it, pointerName, linenr);
+                            break;
+                        }
+                    }
+                }
+
                 // calling unknown function (abort/init)..
                 if (Token::simpleMatch(tok2, ") ;") &&
                     (Token::Match(tok2->link()->tokAt(-2), "[;{}] %var% (") ||
diff --git a/test/testnullpointer.cpp b/test/testnullpointer.cpp
index f9f1b9009..93ddcd16c 100644
--- a/test/testnullpointer.cpp
+++ b/test/testnullpointer.cpp
@@ -985,6 +985,13 @@ private:
               "}\n");
         ASSERT_EQUALS("[test.cpp:3]: (error) Possible null pointer dereference: p - otherwise it is redundant to check if p is null at line 2\n", errout.str());
 
+        check("void foo(char *p) {\n"
+              "    if (p) {\n"
+              "    }\n"
+              "    strcpy(p, \"abc\");\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (error) Possible null pointer dereference: p - otherwise it is redundant to check if p is null at line 2\n", errout.str());
+
         check("void foo(abc *p) {\n"
               "    if (!p) {\n"
               "    }\n"