[scudo] Handle mallinfo2

[vitalybuka]

Summary

mallinfo is deprecated by GLIBC

[pcc]

Doesn't this require a wrapper for mallinfo2() as well that returns a struct mallinfo2?

[pcc]

compiler-rt/lib/scudo/standalone/tests/wrappers_c_test.cpp

263

It doesn't look like glibc's headers define a macro named mallinfo2, so this will always be false.

[vitalybuka]

In D113951#3133267, @pcc wrote:

Doesn't this require a wrapper for mallinfo2() as well that returns a struct mallinfo2?

Thanks, it does.

compiler-rt/lib/scudo/standalone/tests/wrappers_c_test.cpp

263

https://github.com/bminor/glibc/blob/cbcd65c8b526555d9b98628338973f91f74002ad/malloc/malloc.h#L99

[vitalybuka]

compiler-rt/lib/scudo/standalone/tests/wrappers_c_test.cpp

263

I mean, you are correct, I need to do something better. Probably check GLIBC version,
It was speculative fix without trying on the bot.

https://lab.llvm.org/staging/#/builders/97/builds/560/steps/37/logs/stdio

[vitalybuka]

handle mallinfo2

[cryptoad]

compiler-rt/lib/scudo/standalone/wrappers_c.inc

61 ↗

(On Diff #387451)

While the test requires the check, is there something that always prevents us from defining mallinfo2? I don't think it would conflict with anything, and it would be there for people to use it if they want.

[vitalybuka]

define always

compiler-rt/lib/scudo/standalone/tests/wrappers_c_test.cpp

 #endif
 
   EXPECT_EQ(valloc(SIZE_MAX), nullptr);
 }
 
 #if !SCUDO_FUCHSIA
 TEST(ScudoWrappersCTest, MallInfo) {
   const size_t BypassQuarantineSize = 1024U;
+  auto MallInfo = []() {
+#ifdef mallinfo2
+    return mallinfo2();
+#else
+    return mallinfo();
+#endif
+  };
 
-  struct mallinfo MI = mallinfo();
+  auto MI = MallInfo();
   size_t Allocated = MI.uordblks;
   void *P = malloc(BypassQuarantineSize);
   EXPECT_NE(P, nullptr);
-  MI = mallinfo();
+  MI = MallInfo();
   EXPECT_GE(static_cast<size_t>(MI.uordblks), Allocated + BypassQuarantineSize);
   EXPECT_GT(static_cast<size_t>(MI.hblkhd), 0U);
   size_t Free = MI.fordblks;
   free(P);
-  MI = mallinfo();
+  MI = MallInfo();
   EXPECT_GE(static_cast<size_t>(MI.fordblks), Free + BypassQuarantineSize);
 }
 #endif
 
 static uintptr_t BoundaryP;
 static size_t Count;
 
 static void callback(uintptr_t Base, size_t Size, void *Arg) {