pyrox.dev
1https://gcc.gnu.org/ml/gcc-patches/2015-06/msg02210.html
2
3diff --git a/libcpp/macro.c b/libcpp/macro.c
4index 1e0a0b5..a52e3cb 100644
5--- a/libcpp/macro.c
6+++ b/libcpp/macro.c
7@@ -349,14 +349,38 @@ _cpp_builtin_macro_text (cpp_reader *pfile, cpp_hashnode *node)
8 slow on some systems. */
9 time_t tt;
10 struct tm *tb = NULL;
11+ char *source_date_epoch;
12
13- /* (time_t) -1 is a legitimate value for "number of seconds
14- since the Epoch", so we have to do a little dance to
15- distinguish that from a genuine error. */
16- errno = 0;
17- tt = time(NULL);
18- if (tt != (time_t)-1 || errno == 0)
19- tb = localtime (&tt);
20+ /* Allow the date and time to be set externally by an exported
21+ environment variable to enable reproducible builds. */
22+ source_date_epoch = getenv ("SOURCE_DATE_EPOCH");
23+ if (source_date_epoch)
24+ {
25+ errno = 0;
26+ tt = (time_t) strtol (source_date_epoch, NULL, 10);
27+ if (errno == 0)
28+ {
29+ tb = gmtime (&tt);
30+ if (tb == NULL)
31+ cpp_error (pfile, CPP_DL_ERROR,
32+ "SOURCE_DATE_EPOCH=\"%s\" is not a valid date",
33+ source_date_epoch);
34+ }
35+ else
36+ cpp_error (pfile, CPP_DL_ERROR,
37+ "SOURCE_DATE_EPOCH=\"%s\" is not a valid number",
38+ source_date_epoch);
39+ }
40+ else
41+ {
42+ /* (time_t) -1 is a legitimate value for "number of seconds
43+ since the Epoch", so we have to do a little dance to
44+ distinguish that from a genuine error. */
45+ errno = 0;
46+ tt = time(NULL);
47+ if (tt != (time_t)-1 || errno == 0)
48+ tb = localtime (&tt);
49+ }
50
51 if (tb)
52 {