#83 unzip cannot be compiled with -DTIME_T_TYPE_DOUBLE=1 to make it Y2038 compliant on 32bit

[Taketo Kabe]

I tried to make unzip Y2038 compliant by -DTIME_T_TYPE_DOUBLE on 32bit, but the code didi not compile.
Below is the fix.
With this patch, zipfile composed on x86_64 was properly unzipped on 32bit unzip.

From: <kabe@>
Subject: Make it compile with -DTIME_T_TYPE_DOUBLE

diff -up ./process.c.t64 ./process.c
--- ./process.c.t64     2025-08-09 17:43:34.238185944 +0900
+++ ./process.c 2025-08-09 17:45:30.942845653 +0900
@@ -2854,7 +2854,7 @@ unsigned ef_scan_for_izux(ef_buf, ef_len
                                 i_time));
 #ifdef TIME_T_TYPE_DOUBLE
                         if ((ulg)(i_time) & (ulg)(0x80000000L)) {
-                            if (ut_in_archive_sgn == -1)
+                            if (ut_in_archive_sgn == -1) {
                               z_utim->atime =
                                 (time_t)((long)i_time | (~(long)0x7fffffffL));
                             } else if (ut_in_archive_sgn == 1) {
@@ -2884,13 +2884,14 @@ unsigned ef_scan_for_izux(ef_buf, ef_len
                     }
                 }
                 if (flags & EB_UT_FL_CTIME) {
+                    unsigned eb_idx = EB_UT_TIME1;
                     if ((eb_idx+4) <= eb_len) {
                         i_time = (long)makelong((EB_HEADSIZE+eb_idx) + ef_buf);
                         TTrace((stderr,"  UT e.f. creation time = %ld\n",
                                 i_time));
 #ifdef TIME_T_TYPE_DOUBLE
                         if ((ulg)(i_time) & (ulg)(0x80000000L)) {
-                            if (ut_in_archive_sgn == -1)
+                            if (ut_in_archive_sgn == -1) {
                               z_utim->ctime =
                                 (time_t)((long)i_time | (~(long)0x7fffffffL));
                             } else if (ut_in_archive_sgn == 1) {
@@ -3037,7 +3038,7 @@ unsigned ef_scan_for_izux(ef_buf, ef_len
                     TTrace((stderr,"  Unix EF actime = %ld\n", i_time));
 #ifdef TIME_T_TYPE_DOUBLE
                     if ((ulg)(i_time) & (ulg)(0x80000000L)) {
-                        if (ut_in_archive_sgn == -1)
+                        if (ut_in_archive_sgn == -1) {
                             z_utim->atime =
                               (time_t)((long)i_time | (~(long)0x7fffffffL));
                         } else if (ut_in_archive_sgn == 1) {

[Paul Marquess]

Thanks for taking the time to provide a patch for TIME_T_TYPE_DOUBLE.

Confirmed that building the unzip 6.0 source with -DTIME_T_TYPE_DOUBLE does trigger a number of compilation issues.

Although your patch does silence them, I see that the updates to the development source for unzip appear to have a fix for this issue -- it builds with any compilation errors. . With a very superficial look at the sources, I suspect your's my be the correct change. Won't know for sure until I run a few tests.

One thing I notice is that the patch needs fuzz to make it apply. What version of unzip sources did you apply this change to and where did you get it?

$ patch -p1 <../2038.diff 
(Stripping trailing CRs from patch; use --binary to disable.)
patching file process.c
Hunk #1 succeeded at 2798 (offset -56 lines).
Hunk #2 succeeded at 2828 (offset -56 lines).
patch unexpectedly ends in middle of line
Hunk #3 succeeded at 2979 with fuzz 1 (offset -59 lines).

Out of interest, are you encountering an issue that means you need this fix right now?