[Sanitizers] intercept hexdump on FreeBSD.

Reviewers: vitalybuka
Reviewed-By: vitalybuka

Differential Revision: https://reviews.llvm.org/D110471

Author: devnexen

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc

@@ -10357,6 +10357,20 @@ INTERCEPTOR(int, __xuname, int size, void *utsname) {
 #define INIT___XUNAME
 #endif
 
+#if SANITIZER_INTERCEPT_HEXDUMP
+INTERCEPTOR(void, hexdump, const void *ptr, int length, const char *header, int flags) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, hexdump, ptr, length, header, flags);
+  COMMON_INTERCEPTOR_READ_RANGE(ctx, ptr, length);
+  COMMON_INTERCEPTOR_READ_RANGE(ctx, header, internal_strlen(header) + 1);
+  REAL(hexdump)(ptr, length, header, flags);
+}
+
+#define INIT_HEXDUMP COMMON_INTERCEPT_FUNCTION(hexdump);
+#else
+#define INIT_HEXDUMP
+#endif
+
 #include "sanitizer_common_interceptors_netbsd_compat.inc"
 
 static void InitializeCommonInterceptors() {
@@ -10675,6 +10689,7 @@ static void InitializeCommonInterceptors() {
   INIT_PROCCTL
   INIT_UNAME;
   INIT___XUNAME;
+  INIT_HEXDUMP;
 
   INIT___PRINTF_CHK;
 }

compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h

@@ -591,6 +591,7 @@
 #define SANITIZER_INTERCEPT___XUNAME SI_FREEBSD
 #define SANITIZER_INTERCEPT_FLOPEN SI_FREEBSD
 #define SANITIZER_INTERCEPT_PROCCTL SI_FREEBSD
+#define SANITIZER_INTERCEPT_HEXDUMP SI_FREEBSD
 
 // This macro gives a way for downstream users to override the above
 // interceptor macros irrespective of the platform they are on. They have

compiler-rt/test/sanitizer_common/TestCases/FreeBSD/hexdump.cc

@@ -0,0 +1,23 @@
+// RUN: %clangxx -O0 -g %s -o %t -lutil && %run %t 2>&1 | FileCheck %s
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <libutil.h>
+
+int main(void) {
+  printf("hexdump");
+  char *line;
+  size_t lineno = 0, len;
+  const char *delim = "\\\\#";
+  FILE *fp = fopen("/etc/fstab", "r");
+  assert(fp);
+  line = fparseln(fp, &len, &lineno, delim, 0);
+  hexdump(line, len, nullptr, 0);
+  free(line);
+  fclose(fp);
+  assert(lineno != 0);
+  assert(len > 0);
+
+  return 0;
+}