We still need the pread/pwrite hack for HP-UX 11.11 at least.

This time around, avoid defining _LARGEFILE64_SOURCE and just declare
pread64/pwrite64 ourselves.

config.h.in

@@ -153,6 +153,14 @@
    don't. */
 #undef HAVE_DECL_PATH_MAX
 
+/* Define to 1 if you have the declaration of `pread64', and to 0 if you
+   don't. */
+#undef HAVE_DECL_PREAD64
+
+/* Define to 1 if you have the declaration of `pwrite64', and to 0 if you
+   don't. */
+#undef HAVE_DECL_PWRITE64
+
 /* Define to 1 if you have the declaration of `QUAD_MAX', and to 0 if you
    don't. */
 #undef HAVE_DECL_QUAD_MAX
@@ -651,6 +659,9 @@
 /* Define to 1 if you have the `pread' function. */
 #undef HAVE_PREAD
 
+/* Define to 1 if you have the `pread64' function. */
+#undef HAVE_PREAD64
+
 /* Define to 1 if you have the `priv_set' function. */
 #undef HAVE_PRIV_SET
 
@@ -678,6 +689,9 @@
 /* Define to 1 if you have the `pwrite' function. */
 #undef HAVE_PWRITE
 
+/* Define to 1 if you have the `pwrite64' function. */
+#undef HAVE_PWRITE64
+
 /* Define to 1 if you have the `pw_dup' function. */
 #undef HAVE_PW_DUP
 

configure

@@ -20904,6 +20904,44 @@ if test "x$ac_cv_func_pread" = xyes
 then :
   printf "%s\n" "#define HAVE_PREAD 1" >>confdefs.h
 
+    # pread/pwrite on 32-bit HP-UX 11.x may not support large files
+    case "$host_os" in
+	hpux*|hiuxmpp*)
+
+  for ac_func in pread64 pwrite64
+do :
+  as_ac_var=`printf "%s\n" "ac_cv_func_$ac_func" | $as_tr_sh`
+ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
+if eval test \"x\$"$as_ac_var"\" = x"yes"
+then :
+  cat >>confdefs.h <<_ACEOF
+#define `printf "%s\n" "HAVE_$ac_func" | $as_tr_cpp` 1
+_ACEOF
+
+		ac_fn_check_decl "$LINENO" "pread64" "ac_cv_have_decl_pread64" "$ac_includes_default" "$ac_c_undeclared_builtin_options" "CFLAGS"
+if test "x$ac_cv_have_decl_pread64" = xyes
+then :
+  ac_have_decl=1
+else $as_nop
+  ac_have_decl=0
+fi
+printf "%s\n" "#define HAVE_DECL_PREAD64 $ac_have_decl" >>confdefs.h
+ac_fn_check_decl "$LINENO" "pwrite64" "ac_cv_have_decl_pwrite64" "$ac_includes_default" "$ac_c_undeclared_builtin_options" "CFLAGS"
+if test "x$ac_cv_have_decl_pwrite64" = xyes
+then :
+  ac_have_decl=1
+else $as_nop
+  ac_have_decl=0
+fi
+printf "%s\n" "#define HAVE_DECL_PWRITE64 $ac_have_decl" >>confdefs.h
+
+
+fi
+
+done
+	    ;;
+    esac
+
 else $as_nop
 
     case " $LIBOBJS " in

configure.ac

@@ -2542,7 +2542,16 @@ dnl Function checks
 dnl
 AC_FUNC_GETGROUPS
 AC_CHECK_FUNCS_ONCE([fexecve fmemopen killpg nl_langinfo faccessat wordexp getauxval fseeko])
-AC_CHECK_FUNCS([pread], [], [
+AC_CHECK_FUNCS([pread], [
+    # pread/pwrite on 32-bit HP-UX 11.x may not support large files
+    case "$host_os" in
+	hpux*|hiuxmpp*)
+	    AC_CHECK_FUNCS([pread64 pwrite64], [
+		AC_CHECK_DECLS([pread64, pwrite64])
+	    ])
+	    ;;
+    esac
+], [
     AC_LIBOBJ(pread)
     SUDO_APPEND_COMPAT_EXP(sudo_pread)
 ])

include/sudo_compat.h

@@ -347,17 +347,23 @@ int getdomainname(char *, size_t);
 #endif
 
 /*
- * HP-UX 11.00 has broken pread/pwrite that can't handle a 64-bit off_t
+ * HP-UX 11.00 has broken pread/pwrite on 32-bit machines when
- * on 32-bit machines.
+ * _FILE_OFFSET_BITS == 64.  Use pread64/pwrite64 instead.
  */
 #if defined(__hpux) && !defined(__LP64__)
 # ifdef HAVE_PREAD64
 #  undef pread
 #  define pread(_a, _b, _c, _d) pread64((_a), (_b), (_c), (_d))
+#  if defined(HAVE_DECL_PREAD64) && !HAVE_DECL_PREAD64
+    ssize_t pread64(int fd, void *buf, size_t nbytes, off64_t offset);
+#  endif
 # endif
 # ifdef HAVE_PWRITE64
 #  undef pwrite
 #  define pwrite(_a, _b, _c, _d) pwrite64((_a), (_b), (_c), (_d))
+#  if defined(HAVE_DECL_PWRITE64) && !HAVE_DECL_PWRITE64
+    ssize_t pwrite64(int fd, const void *buf, size_t nbytes, off64_t offset);
+#  endif
 # endif
 #endif /* __hpux && !__LP64__ */