[Sanitizers] Fix internal_lseek() to work on FreeBSD

[kutuzov.viktor.84]

Summary

off_t is 64-bit on FreeBSD in both i386 and x86-64 modes.

[emaste]

lib/sanitizer_common/sanitizer_internal_defs.h

87–88

This comment is mildly confusing with the addition of FreeBSD to the #if. FreeBSD is "special" in the same way that Mac and Linux/x86-64 are.

The warning above clearly explains the issue. Probably just remove the "Mac and..." comment as it's redundant with the test.

[kutuzov.viktor.84]

Comment fixed. Thanks Ed.

[samsonov]

LGTM

lib/sanitizer_common/sanitizer_internal_defs.h

 typedef signed   char s8;
 typedef signed   short s16;  // NOLINT
 typedef signed   int s32;
 typedef signed   long long s64;  // NOLINT
 typedef int fd_t;
 
 // WARNING: OFF_T may be different from OS type off_t, depending on the value of
 // _FILE_OFFSET_BITS. This definition of OFF_T matches the ABI of system calls
 // like pread and mmap, as opposed to pread64 and mmap64.
-// Mac and Linux/x86-64 are special.
-#if SANITIZER_MAC || (SANITIZER_LINUX && defined(__x86_64__))
+// FreeBSD, Mac and Linux/x86-64 are special.
+#if SANITIZER_FREEBSD || SANITIZER_MAC || \
+  (SANITIZER_LINUX && defined(__x86_64__))
 typedef u64 OFF_T;
 #else
 typedef uptr OFF_T;
 #endif
 typedef u64  OFF64_T;
 
 #if (SANITIZER_WORDSIZE == 64) || SANITIZER_MAC
 typedef uptr operator_new_size_type;

lib/sanitizer_common/tests/sanitizer_libc_test.cc

TEST(SanitizerCommon, InternalMmapWithOffset) {
   uptr res = OpenFile(tmpfile, true);
   ASSERT_FALSE(internal_iserror(res));
   fd_t fd = res;
 
   uptr page_size = GetPageSizeCached();
   res = internal_ftruncate(fd, page_size * 2);
   ASSERT_FALSE(internal_iserror(res));
 
-  internal_lseek(fd, page_size, SEEK_SET);
-  internal_write(fd, "AB", 2);
+  res = internal_lseek(fd, page_size, SEEK_SET);
+  ASSERT_FALSE(internal_iserror(res));
+
+  res = internal_write(fd, "AB", 2);
+  ASSERT_FALSE(internal_iserror(res));
 
   char *p = (char *)MapWritableFileToMemory(nullptr, page_size, fd, page_size);
   ASSERT_NE(nullptr, p);
 
   ASSERT_EQ('A', p[0]);
   ASSERT_EQ('B', p[1]);
 
   internal_close(fd);
   internal_munmap(p, page_size);
   internal_unlink(tmpfile);
 }
 #endif