initramfs: Use KBUILD_BUILD_TIMESTAMP for generated entries

gen_init_cpio gets the current time and uses it for each symlink,
special file, and directory.  Grab the current time once and make it
possible to override it with the KBUILD_BUILD_TIMESTAMP variable for
reproducible builds.

Signed-off-by: Michal Marek <mmarek@suse.cz>

1 files changed, 40 insertions, 13 deletions

diff --git a/usr/gen_init_cpio.c b/usr/gen_init_cpio.c
index 7f06884ecd41..af0f22fb1ef7 100644
--- a/usr/gen_init_cpio.c
+++ b/usr/gen_init_cpio.c
@@ -22,6 +22,7 @@
 
 static unsigned int offset;
 static unsigned int ino = 721;
+static time_t default_mtime;
 
 struct file_handler {
         const char *type;
@@ -102,7 +103,6 @@ static int cpio_mkslink(const char *name, const char *target,
                          unsigned int mode, uid_t uid, gid_t gid)
 {
         char s[256];
-        time_t mtime = time(NULL);
 
         if (name[0] == '/')
                 name++;
@@ -114,7 +114,7 @@ static int cpio_mkslink(const char *name, const char *target,
                 (long) uid,             /* uid */
                 (long) gid,             /* gid */
                 1,                      /* nlink */
-                (long) mtime,           /* mtime */
+                (long) default_mtime,   /* mtime */
                 (unsigned)strlen(target)+1, /* filesize */
                 3,                      /* major */
                 1,                      /* minor */
@@ -152,7 +152,6 @@ static int cpio_mkgeneric(const char *name, unsigned int mode,
                        uid_t uid, gid_t gid)
 {
         char s[256];
-        time_t mtime = time(NULL);
 
         if (name[0] == '/')
                 name++;
@@ -164,7 +163,7 @@ static int cpio_mkgeneric(const char *name, unsigned int mode,
                 (long) uid,             /* uid */
                 (long) gid,             /* gid */
                 2,                      /* nlink */
-                (long) mtime,           /* mtime */
+                (long) default_mtime,   /* mtime */
                 0,                      /* filesize */
                 3,                      /* major */
                 1,                      /* minor */
@@ -242,7 +241,6 @@ static int cpio_mknod(const char *name, unsigned int mode,
                        unsigned int maj, unsigned int min)
 {
         char s[256];
-        time_t mtime = time(NULL);
 
         if (dev_type == 'b')
                 mode |= S_IFBLK;
@@ -259,7 +257,7 @@ static int cpio_mknod(const char *name, unsigned int mode,
                 (long) uid,             /* uid */
                 (long) gid,             /* gid */
                 1,                      /* nlink */
-                (long) mtime,           /* mtime */
+                (long) default_mtime,   /* mtime */
                 0,                      /* filesize */
                 3,                      /* major */
                 1,                      /* minor */
@@ -460,7 +458,7 @@ static int cpio_mkfile_line(const char *line)
 static void usage(const char *prog)
 {
         fprintf(stderr, "Usage:\n"
-                "\t%s <cpio_list>\n"
+                "\t%s [-t <timestamp>] <cpio_list>\n"
                 "\n"
                 "<cpio_list> is a file containing newline separated entries that\n"
                 "describe the files to be included in the initramfs archive:\n"
@@ -491,7 +489,11 @@ static void usage(const char *prog)
                 "nod /dev/console 0600 0 0 c 5 1\n"
                 "dir /root 0700 0 0\n"
                 "dir /sbin 0755 0 0\n"
-                "file /sbin/kinit /usr/src/klibc/kinit/kinit 0755 0 0\n",
+                "file /sbin/kinit /usr/src/klibc/kinit/kinit 0755 0 0\n"
+                "\n"
+                "<timestamp> is time in seconds since Epoch that will be used\n"
+                "as mtime for symlinks, special files and directories. The default\n"
+                "is to use the current time for these entries.\n",
                 prog);
 }
 
@@ -529,17 +531,42 @@ int main (int argc, char *argv[])
         char *args, *type;
         int ec = 0;
         int line_nr = 0;
+        const char *filename;
+
+        default_mtime = time(NULL);
+        while (1) {
+                int opt = getopt(argc, argv, "t:h");
+                char *invalid;
 
-        if (2 != argc) {
+                if (opt == -1)
+                        break;
+                switch (opt) {
+                case 't':
+                        default_mtime = strtol(optarg, &invalid, 10);
+                        if (!*optarg || *invalid) {
+                                fprintf(stderr, "Invalid timestamp: %s\n",
+                                                optarg);
+                                usage(argv[0]);
+                                exit(1);
+                        }
+                        break;
+                case 'h':
+                case '?':
+                        usage(argv[0]);
+                        exit(opt == 'h' ? 0 : 1);
+                }
+        }
+
+        if (argc - optind != 1) {
                 usage(argv[0]);
                 exit(1);
         }
-
-        if (!strcmp(argv[1], "-"))
+        filename = argv[optind];
+        if (!strcmp(filename, "-"))
                 cpio_list = stdin;
-        else if (! (cpio_list = fopen(argv[1], "r"))) {
+        else if (!(cpio_list = fopen(filename, "r"))) {
                 fprintf(stderr, "ERROR: unable to open '%s': %s\n\n",
-                        argv[1], strerror(errno));
+                        filename, strerror(errno));
                 usage(argv[0]);
                 exit(1);
         }