Embed changelog entry date and time instead of build date and time

This makes reproducible builds possible. For non-package builds, simply
use the start of the Unix time. Also make sure that all time values are
in the UTC timezone.

Closes: #762674

2 files changed, 14 insertions, 3 deletions

diff --git a/debian/rules b/debian/rules
index 3ceeb205..20a3fa25 100755
--- a/debian/rules
+++ b/debian/rules
@@ -1,7 +1,13 @@
 #!/usr/bin/make -f
 # Should be include-links, but that somehow fails.
 export DEBVER=$(shell dpkg-parsechangelog | sed -n -e 's/^Version: //p')
-export DEB_CFLAGS_MAINT_APPEND=-Wno-write-strings
+export DATETIME:=$(shell dpkg-parsechangelog | sed -n -e 's/^Date: //p')
+export DATE_CMD:=env TZ=UTC LC_ALL=C.UTF-8 date
+export DATE:=$(shell $(DATE_CMD) --date="$(DATETIME)" "+%b %_d %Y")
+export TIME:=$(shell $(DATE_CMD) --date="$(DATETIME)" "+%H:%M:%S")
+export DEB_CFLAGS_MAINT_APPEND=-Wno-write-strings \
+                               -DDATE=\""$(DATE)"\" \
+                               -DTIME=\""$(TIME)"\"
 export PATH := $(CURDIR)/utils:$(PATH)
 export pyversions := $(CURDIR)/utils/pyversions
 
diff --git a/python/apt_pkgmodule.cc b/python/apt_pkgmodule.cc
index 5f211b3e..ca20ef18 100644
--- a/python/apt_pkgmodule.cc
+++ b/python/apt_pkgmodule.cc
@@ -880,8 +880,13 @@ extern "C" void initapt_pkg()
    // Version..
    PyModule_AddStringConstant(Module,"VERSION",(char *)pkgVersion);
    PyModule_AddStringConstant(Module,"LIB_VERSION",(char *)pkgLibVersion);
-   PyModule_AddStringConstant(Module,"DATE",__DATE__);
-   PyModule_AddStringConstant(Module,"TIME",__TIME__);
+#ifdef DATE
+   PyModule_AddStringConstant(Module,"DATE",DATE);
+   PyModule_AddStringConstant(Module,"TIME",TIME);
+#else
+   PyModule_AddStringConstant(Module,"DATE", "Jan  1 1970");
+   PyModule_AddStringConstant(Module,"TIME", "00:00:00");
+#endif
 
    // My constants
    PyModule_AddIntConstant(Module,"PRI_IMPORTANT",pkgCache::State::Important);