Imported Upstream version 4.19.0upstream/4.19.0upstream

1 files changed, 132 insertions, 0 deletions

diff --git a/src/gl/m4/year2038.m4 b/src/gl/m4/year2038.m4
new file mode 100644
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+++ b/src/gl/m4/year2038.m4
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+# year2038.m4 serial 8
+dnl Copyright (C) 2017-2022 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Attempt to ensure that 'time_t' can go past the year 2038 and that
+dnl the functions 'time', 'stat', etc. work with post-2038 timestamps.
+
+m4_ifdef([AC_SYS_YEAR2038], [
+  AC_DEFUN([gl_YEAR2038_EARLY])
+  AC_DEFUN([gl_YEAR2038], [AC_SYS_YEAR2038])
+  AC_DEFUN([gl_YEAR2038_BODY], [_AC_SYS_YEAR2038])
+], [
+
+AC_DEFUN([gl_YEAR2038_EARLY],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    mingw*)
+      AC_DEFINE([__MINGW_USE_VC2005_COMPAT], [1],
+        [For 64-bit time_t on 32-bit mingw.])
+      ;;
+  esac
+])
+
+# gl_YEAR2038_TEST_INCLUDES
+# -------------------------
+AC_DEFUN([gl_YEAR2038_TEST_INCLUDES],
+[[
+  #include <time.h>
+  /* Check that time_t can represent 2**32 - 1 correctly.  */
+  #define LARGE_TIME_T \\
+    ((time_t) (((time_t) 1 << 30) - 1 + 3 * ((time_t) 1 << 30)))
+  int verify_time_t_range[(LARGE_TIME_T / 65537 == 65535
+                           && LARGE_TIME_T % 65537 == 0)
+                          ? 1 : -1];
+]])
+
+# gl_YEAR2038_BODY(REQUIRE-YEAR2038-SAFE)
+-----------------------------------------
+AC_DEFUN([gl_YEAR2038_BODY],
+[
+ AC_ARG_ENABLE([year2038],
+   [  --disable-year2038      omit support for timestamps past the year 2038])
+ AS_IF([test "$enable_year2038" != no],
+ [
+  dnl On many systems, time_t is already a 64-bit type.
+  dnl On those systems where time_t is still 32-bit, it requires kernel
+  dnl and libc support to make it 64-bit. For glibc 2.34 and later on Linux,
+  dnl defining _TIME_BITS=64 and _FILE_OFFSET_BITS=64 is needed on x86 and ARM.
+  dnl
+  dnl On native Windows, the system include files define types __time32_t
+  dnl and __time64_t. By default, time_t is an alias of
+  dnl   - __time32_t on 32-bit mingw,
+  dnl   - __time64_t on 64-bit mingw and on MSVC (since MSVC 8).
+  dnl But when compiling with -D__MINGW_USE_VC2005_COMPAT, time_t is an
+  dnl alias of __time64_t.
+  dnl And when compiling with -D_USE_32BIT_TIME_T, time_t is an alias of
+  dnl __time32_t.
+  AC_CACHE_CHECK([for time_t past the year 2038], [gl_cv_type_time_t_y2038],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_SOURCE([gl_YEAR2038_TEST_INCLUDES])],
+       [gl_cv_type_time_t_y2038=yes], [gl_cv_type_time_t_y2038=no])
+    ])
+  if test "$gl_cv_type_time_t_y2038" = no; then
+    AC_CACHE_CHECK([for 64-bit time_t with _TIME_BITS=64],
+      [gl_cv_type_time_t_bits_macro],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_SOURCE([[#define _TIME_BITS 64
+                           #define _FILE_OFFSET_BITS 64
+                           ]gl_YEAR2038_TEST_INCLUDES])],
+         [gl_cv_type_time_t_bits_macro=yes],
+         [gl_cv_type_time_t_bits_macro=no])
+      ])
+    if test "$gl_cv_type_time_t_bits_macro" = yes; then
+      AC_DEFINE([_TIME_BITS], [64],
+        [Number of bits in a timestamp, on hosts where this is settable.])
+      dnl AC_SYS_LARGFILE also defines this; it's OK if we do too.
+      AC_DEFINE([_FILE_OFFSET_BITS], [64],
+        [Number of bits in a file offset, on hosts where this is settable.])
+      gl_cv_type_time_t_y2038=yes
+    fi
+  fi
+  if test $gl_cv_type_time_t_y2038 = no; then
+    AC_COMPILE_IFELSE(
+      [AC_LANG_SOURCE(
+         [[#ifdef _USE_32BIT_TIME_T
+             int ok;
+           #else
+             error fail
+           #endif
+         ]])],
+      [AC_MSG_FAILURE(
+         [The 'time_t' type stops working after January 2038.
+          Remove _USE_32BIT_TIME_T from the compiler flags.])],
+      [# If not cross-compiling and $1 says we should check,
+       # and 'touch' works with a large timestamp, then evidently wider time_t
+       # is desired and supported, so fail and ask the builder to fix the
+       # problem.  Otherwise, just warn the builder.
+       m4_ifval([$1],
+         [if test $cross_compiling = no \
+             && TZ=UTC0 touch -t 210602070628.15 conftest.time 2>/dev/null; then
+            case `TZ=UTC0 LC_ALL=C ls -l conftest.time 2>/dev/null` in
+              *'Feb  7  2106'* | *'Feb  7 17:10'*)
+                AC_MSG_FAILURE(
+                  [The 'time_t' type stops working after January 2038,
+                   and your system appears to support a wider 'time_t'.
+                   Try configuring with 'CC="${CC} -m64"'.
+                   To build with a 32-bit time_t anyway (not recommended),
+                   configure with '--disable-year2038'.]);;
+            esac
+            rm -f conftest.time
+          fi])
+       if test "$gl_warned_about_y2038" != yes; then
+         AC_MSG_WARN(
+           [The 'time_t' type stops working after January 2038,
+            and this package needs a wider 'time_t' type
+            if there is any way to access timestamps after that.
+            Configure with 'CC="${CC} -m64"' perhaps?])
+         gl_warned_about_y2038=yes
+       fi
+      ])
+  fi])
+])
+
+AC_DEFUN([gl_YEAR2038],
+[
+  gl_YEAR2038_BODY([require-year2038-safe])
+])
+
+]) # m4_ifndef AC_SYS_YEAR2038