# HG changeset patch
# User Chris Peterson <cpeterson@mozilla.com>
# Date 1531631232 25200
#      Sat Jul 14 22:07:12 2018 -0700
# Node ID 8a9e7ed36126dd6f9454a58b732dcec308805558
# Parent  21408667426c71a87770c4422400b7da004d3f1c
Bug 1475882 - clang-analyzer: Enable clang-analyzer-unix.cstring.NullArg check. r=andi

Check for null pointers being passed as arguments to C string functions. There are no clang-analyzer-unix.cstring.NullArg warnings in mozilla-central!

strlen
strnlen
strcpy
strncpy
strcat
strncat
strcmp
strncmp
strcasecmp
strncasecmp

https://clang-analyzer.llvm.org/available_checks.html

MozReview-Commit-ID: EkfaItfo5cu

diff --git a/tools/clang-tidy/config.yaml b/tools/clang-tidy/config.yaml
--- a/tools/clang-tidy/config.yaml
+++ b/tools/clang-tidy/config.yaml
@@ -31,16 +31,18 @@ clang_checkers:
   - name: clang-analyzer-security.insecureAPI.strcpy
     publish: !!bool no
   - name: clang-analyzer-security.insecureAPI.UncheckedReturn
     publish: !!bool yes
   - name: clang-analyzer-security.insecureAPI.vfork
     publish: !!bool yes
   - name: clang-analyzer-unix.cstring.BadSizeArg
     publish: !!bool yes
+  - name: clang-analyzer-unix.cstring.NullArg
+    publish: !!bool yes
   - name: misc-argument-comment
     publish: !!bool yes
   - name: misc-assert-side-effect
     publish: !!bool yes
   - name: misc-bool-pointer-implicit-conversion
     publish: !!bool yes
   - name: misc-forward-declaration-namespace
     # Name with clang tidy 6.0. We are currently using 5.0
diff --git a/tools/clang-tidy/test/clang-analyzer-unix.cstring.NullArg.cpp b/tools/clang-tidy/test/clang-analyzer-unix.cstring.NullArg.cpp
new file mode 100644
--- /dev/null
+++ b/tools/clang-tidy/test/clang-analyzer-unix.cstring.NullArg.cpp
@@ -0,0 +1,14 @@
+// https://clang-analyzer.llvm.org/available_checks.html
+
+#include "structures.h"
+
+int my_strlen(const char* s)
+{
+  return strlen(s); // warning
+}
+
+int bad_caller()
+{
+  const char* s = nullptr;
+  return my_strlen(s);
+}
diff --git a/tools/clang-tidy/test/clang-analyzer-unix.cstring.NullArg.json b/tools/clang-tidy/test/clang-analyzer-unix.cstring.NullArg.json
new file mode 100644
--- /dev/null
+++ b/tools/clang-tidy/test/clang-analyzer-unix.cstring.NullArg.json
@@ -0,0 +1,1 @@
+"[[\"warning\", \"Null pointer argument in call to string length function\", \"clang-analyzer-unix.cstring.NullArg\"]]"
\ No newline at end of file
diff --git a/tools/clang-tidy/test/structures.h b/tools/clang-tidy/test/structures.h
--- a/tools/clang-tidy/test/structures.h
+++ b/tools/clang-tidy/test/structures.h
@@ -83,9 +83,10 @@ char *mktemp(char *tmpl);
 pid_t vfork(void);
 
 int abort() { return 0; }
 
 #define assert(x)                                                              \
   if (!(x))                                                                    \
   (void)abort()
 
+std::size_t strlen(const char *s);
 char *strncat(char *s1, const char *s2, std::size_t n);