[PATCH 1/2] mkstandalone: ensure stable timestamps for generated images

[Michael Chang]

This change mirrors a previous fix [1] but is specific to images
generated by grub-mkstandalone.

The former fix (85a7be241) focused on utilizing a stable timestamp
during binary generation in the util/mkimage context. This commit
extends that approach to the images produced by grub-mkstandalone,
ensuring consistency and stability in timestamps across all generated
binaries.

[1] 85a7be241 util/mkimage: Use stable timestamp when generating
binaries.

Signed-off-by: Michael Chang <mchang@suse.com>
Signed-off-by: Bernhard Wiedemann <bwiedemann@suse.com>
---
 util/grub-mkstandalone.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/util/grub-mkstandalone.c b/util/grub-mkstandalone.c
index bdbeea6a6..8e1229925 100644
--- a/util/grub-mkstandalone.c
+++ b/util/grub-mkstandalone.c
@@ -30,6 +30,9 @@
 #pragma GCC diagnostic error "-Wmissing-prototypes"
 #pragma GCC diagnostic error "-Wmissing-declarations"
 
+/* use 2015-01-01T00:00:00+0000 as a stock timestamp */
+#define STABLE_EMBEDDING_TIMESTAMP 1420070400
+
 static char *output_image;
 static char **files;
 static int nfiles;
@@ -184,7 +187,6 @@ add_tar_file (const char *from,
   struct head hd;
   grub_util_fd_t in;
   ssize_t r;
-  grub_uint32_t mtime = 0;
   grub_uint32_t size;
 
   COMPILE_TIME_ASSERT (sizeof (hd) == 512);
@@ -192,8 +194,6 @@ add_tar_file (const char *from,
   if (grub_util_is_special_file (from))
     return;
 
-  mtime = grub_util_get_mtime (from);
-
   optr = tcn = xmalloc (strlen (to) + 1);
   for (iptr = to; *iptr == '/'; iptr++);
   for (; *iptr; iptr++)
@@ -234,7 +234,7 @@ add_tar_file (const char *from,
       memcpy (hd.gid, "0001750", 7);
 
       set_tar_value (hd.size, optr - tcn, 12);
-      set_tar_value (hd.mtime, mtime, 12);
+      set_tar_value (hd.mtime, STABLE_EMBEDDING_TIMESTAMP, 12);
       hd.typeflag = 'L';
       memcpy (hd.magic, MAGIC, sizeof (hd.magic));
       memcpy (hd.uname, "grub", 4);
@@ -264,7 +264,7 @@ add_tar_file (const char *from,
   memcpy (hd.gid, "0001750", 7);
 
   set_tar_value (hd.size, size, 12);
-  set_tar_value (hd.mtime, mtime, 12);
+  set_tar_value (hd.mtime, STABLE_EMBEDDING_TIMESTAMP, 12);
   hd.typeflag = '0';
   memcpy (hd.magic, MAGIC, sizeof (hd.magic));
   memcpy (hd.uname, "grub", 4);
-- 
2.43.0