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authorDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2019-08-02 11:41:36 +0200
committerDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2019-08-02 11:41:36 +0200
commit402fc5a6000bf0ec12f05d4aa2b3e250ec85a60a (patch)
tree7d9a1b7bc77cbd0211e3e4cb31c079778207453a /lib/util
parenteddb62072f4d4d2402d520e5041d9677fa6efdff (diff)
Implement support for SOURCE_DATE_EPOCH environment variable
reproducible-builds.org suggests the use of an environment variable as a source for time stamps: https://reproducible-builds.org/specs/source-date-epoch/ This commit adds support for setting the default mtime from the variable, if it is set and only defaulting to 0 if not. The timestamp given by the command line switch takes precedence. Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Diffstat (limited to 'lib/util')
-rw-r--r--lib/util/source_date_epoch.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/lib/util/source_date_epoch.c b/lib/util/source_date_epoch.c
new file mode 100644
index 0000000..1397e52
--- /dev/null
+++ b/lib/util/source_date_epoch.c
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * source_date_epoch.h
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+#include "util.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <ctype.h>
+
+uint32_t get_source_date_epoch(void)
+{
+ const char *str, *ptr;
+ uint32_t x, tval = 0;
+
+ str = getenv("SOURCE_DATE_EPOCH");
+
+ if (str == NULL || *str == '\0')
+ return 0;
+
+ for (ptr = str; *ptr != '\0'; ++ptr) {
+ if (!isdigit(*ptr))
+ goto fail_nan;
+
+ x = (*ptr) - '0';
+
+ if (tval > (UINT32_MAX - x) / 10)
+ goto fail_ov;
+
+ tval = tval * 10 + x;
+ }
+
+ return tval;
+fail_ov:
+ fprintf(stderr, "WARNING: SOURCE_DATE_EPOCH=%s does not fit into "
+ "32 bit integer\n", str);
+ return 0;
+fail_nan:
+ fprintf(stderr, "WARNING: SOURCE_DATE_EPOCH=%s is not a positive "
+ "number\n", str);
+ return 0;
+}