Add new interceptor for atof(3)

[krytarowski]

Summary

atof - convert ASCII string to double

[vitalybuka]

lib/sanitizer_common/sanitizer_common_interceptors.inc

7256

const char?

7260

atof does not scan full string

test/sanitizer_common/TestCases/NetBSD/atof.cc

7

shouldn't it be a Posix test?

[krytarowski]

lib/sanitizer_common/sanitizer_common_interceptors.inc

7260

Right, I will handle it differently.

test/sanitizer_common/TestCases/NetBSD/atof.cc

7

It's standard C interface, but I defer porting it to other OSes to others.

[krytarowski]

The proper way to handle is to go for wrapping it with strtod(3), however it requires refactoring of existing sanitizers (msan, dfsan...).

I'm about to push upstream all remaining local patches and interrupt my involvement (and The NetBSD Foundation one) due to our resources and switch to other projects.
There is still a lot of work to do, but unless something will change it will wait probably for next GSoC (although I have candidates who would jump aboard).

lib/sanitizer_common/sanitizer_common_interceptors.inc

 #define INIT_NETENT \
   COMMON_INTERCEPT_FUNCTION(getnetent); \
   COMMON_INTERCEPT_FUNCTION(getnetbyname); \
   COMMON_INTERCEPT_FUNCTION(getnetbyaddr)
 #else
 #define INIT_NETENT
 #endif
 
+#if SANITIZER_INTERCEPT_ATOF
+INTERCEPTOR(double, atof, char *nptr) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, atof, nptr);
+  if (nptr)
+    COMMON_INTERCEPTOR_READ_RANGE(ctx, nptr, REAL(strlen)(nptr) + 1);
+  return REAL(atof)(nptr);
+}
+#define INIT_ATOF COMMON_INTERCEPT_FUNCTION(atof)
+#else
+#define INIT_ATOF
+#endif
+
 static void InitializeCommonInterceptors() {
   static u64 metadata_mem[sizeof(MetadataHashMap) / sizeof(u64) + 1];
   interceptor_metadata_map = new((void *)&metadata_mem) MetadataHashMap();
 
   INIT_MMAP;
   INIT_MMAP64;
   INIT_TEXTDOMAIN;
   INIT_STRLEN;
static void InitializeCommonInterceptors() {
   INIT_STRLCPY;
   INIT_DEVNAME;
   INIT_DEVNAME_R;
   INIT_FGETLN;
   INIT_STRMODE;
   INIT_TTYENT;
   INIT_PROTOENT;
   INIT_NETENT;
+  INIT_ATOF;
 
   INIT___PRINTF_CHK;
 }

lib/sanitizer_common/sanitizer_platform_interceptors.h

 
 #define SANITIZER_INTERCEPT_DEVNAME (SI_NETBSD || SI_OPENBSD || SI_FREEBSD)
 #define SANITIZER_INTERCEPT_DEVNAME_R (SI_NETBSD || SI_FREEBSD)
 #define SANITIZER_INTERCEPT_FGETLN (SI_NETBSD || SI_FREEBSD)
 #define SANITIZER_INTERCEPT_STRMODE (SI_NETBSD || SI_FREEBSD)
 #define SANITIZER_INTERCEPT_TTYENT SI_NETBSD
 #define SANITIZER_INTERCEPT_PROTOENT SI_NETBSD
 #define SANITIZER_INTERCEPT_NETENT SI_NETBSD
+#define SANITIZER_INTERCEPT_ATOF SI_NETBSD
 
 #endif  // #ifndef SANITIZER_PLATFORM_INTERCEPTORS_H

test/sanitizer_common/TestCases/NetBSD/atof.cc

+// RUN: %clangxx -O0 -g %s -o %t && %run %t 2>&1 | FileCheck %s
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void) {
+  double d;
+
+  d = atof("3.14");
+  printf("atof() = %.2f\n", d);
+
+  // CHECK: atof() = 3.14
+
+  return 0;
+}