build: provide a better date format when using SOURCE_DATE_EPOCH

And define the appropriate date at configure time.

diff --git a/configure.ac b/configure.ac
index c18dba936c587b946cba09a3d0e785e658ff095e..47b1ea2193f769e1836cd28087983666ea1cbcb7 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -366,10 +366,8 @@ if test x"$os" = x"Linux"; then
     fi
 fi
 
-# Build date
-if test x"$SOURCE_DATE_EPOCH" != x; then
-   AC_DEFINE_UNQUOTED(BUILD_DATE, "[$SOURCE_DATE_EPOCH]", [Build date and time])
-fi
+AX_BUILD_DATE_EPOCH(BUILD_DATE, "%FT%TZ", [BUILD_DATE="(unknown)"])
+AC_DEFINE_UNQUOTED(BUILD_DATE, "[$BUILD_DATE]", [Build date and time])
 AC_DEFINE_UNQUOTED(LLDP_CC, "[$CC $LLDP_CFLAGS $LLDP_CPPFLAGS $CFLAGS $CPPFLAGS]", [C compiler command])
 AC_DEFINE_UNQUOTED(LLDP_LD, "[$LD $LLDP_LDFLAGS $LLDP_BIN_LDFLAGS $LDFLAGS $LIBS]", [Linker compiler command])
 

diff --git a/m4/ax_build_date_epoch.m4 b/m4/ax_build_date_epoch.m4
new file mode 100644 (file)
index 0000000..2e81b72
--- /dev/null
+++ b/m4/ax_build_date_epoch.m4
@@ -0,0 +1,70 @@
+# ===========================================================================
+#    http://www.gnu.org/software/autoconf-archive/ax_build_date_epoch.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_BUILD_DATE_EPOCH(VARIABLE[, FORMAT[, ACTION-IF-FAIL]])
+#
+# DESCRIPTION
+#
+#   Sets VARIABLE to a string representing the current time.  It is
+#   formatted according to FORMAT if specified, otherwise it is formatted as
+#   the number of seconds (excluding leap seconds) since the UNIX epoch (01
+#   Jan 1970 00:00:00 UTC).
+#
+#   If the SOURCE_DATE_EPOCH environment variable is set, it uses the value
+#   of that variable instead of the current time.  See
+#   https://reproducible-builds.org/specs/source-date-epoch).  If
+#   SOURCE_DATE_EPOCH is set but cannot be properly interpreted as a UNIX
+#   timestamp, then execute ACTION-IF-FAIL if specified, otherwise error.
+#
+#   VARIABLE is AC_SUBST-ed.
+#
+# LICENSE
+#
+#   Copyright (c) 2016 Eric Bavier <bavier@member.fsf.org>
+#
+#   This program is free software: you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation, either version 3 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 1
+
+AC_DEFUN([AX_BUILD_DATE_EPOCH],
+[dnl
+AC_MSG_CHECKING([for build time])
+ax_date_fmt="m4_default($2,%s)"
+AS_IF([test x"$SOURCE_DATE_EPOCH" = x],
+ [$1=`date -u "+$ax_date_fmt"`],
+ [ax_build_date=`date -u -d "@$SOURCE_DATE_EPOCH" "+$ax_date_fmt" 2>/dev/null \
+                 || date -u -r "$SOURCE_DATE_EPOCH" "+$ax_date_fmt" 2>/dev/null`
+  AS_IF([test x"$ax_build_date" = x],
+   [m4_ifval([$3],
+      [$3],
+      [AC_MSG_ERROR([malformed SOURCE_DATE_EPOCH])])],
+   [$1=$ax_build_date])])
+AC_MSG_RESULT([$$1])
+])dnl AX_BUILD_DATE_EPOCH

diff --git a/src/version.c b/src/version.c
index 0c3c5be1008bb5e84a9166921365e4ca7c080e3b..9f835b9e5cde83ddb7b6cffb1cdc9ed75a1fee88 100644 (file)
--- a/src/version.c
+++ b/src/version.c
@@ -22,10 +22,6 @@
 #include <stdio.h>
 #include "compat/compat.h"
 
-#ifndef BUILD_DATE
-# define BUILD_DATE __DATE__ " " __TIME__
-#endif
-
 static void
 version_display_array(FILE *destination, const char *prefix, const char *const *items)
 {