Fix test_write_filter_gzip on Ubuntu s390x

Ubuntu patches zlib to use DFLTCC hardware DEFLATE acceleration on s390x
on compression levels 1-6, causing levels 1 and 6 to produce output with
the same lengths.  Avoid the resulting test failure by comparing the
output lengths of levels 1 and 9 instead.

Tested on Ubuntu 24.04 on s390x hardware.

Fixes: https://github.com/libarchive/libarchive/issues/1515

diff --git a/libarchive/test/test_write_filter_gzip.c b/libarchive/test/test_write_filter_gzip.c
index a6681d7618b12d8d15c952a916a5723a31bb8568..0d5a91aa38b8c2817101b106500c1162ecfcc821 100644 (file)
--- a/libarchive/test/test_write_filter_gzip.c
+++ b/libarchive/test/test_write_filter_gzip.c
@@ -40,7 +40,7 @@ DEFINE_TEST(test_write_filter_gzip)
        size_t buffsize, datasize;
        unsigned char *rbuff;
        char path[16];
-       size_t used1, used2;
+       size_t used1, used2, used3;
        int i, r, use_prog = 0;
 
        buffsize = 2000000;
@@ -218,7 +218,7 @@ DEFINE_TEST(test_write_filter_gzip)
        assertEqualIntA(a, ARCHIVE_OK,
            archive_write_set_filter_option(a, NULL, "compression-level", "1"));
        assertEqualIntA(a, ARCHIVE_OK,
-           archive_write_open_memory(a, buff, buffsize, &used2));
+           archive_write_open_memory(a, buff, buffsize, &used3));
        for (i = 0; i < 100; i++) {
                snprintf(path, sizeof(path), "file%03d", i);
                assert((ae = archive_entry_new()) != NULL);
@@ -234,10 +234,13 @@ DEFINE_TEST(test_write_filter_gzip)
        assertEqualIntA(a, ARCHIVE_OK, archive_write_close(a));
        assertEqualInt(ARCHIVE_OK, archive_write_free(a));
 
-       /* Level 1 really does result in larger data. */
-       failure("Compression-level=1 wrote %d bytes; default wrote %d bytes",
-           (int)used2, (int)used1);
-       assert(used2 > used1);
+       /* Level 1 really does result in larger data than level 9.
+        * We can't compare levels 1 and 6 because those produce identical
+        * results on Ubuntu s390x, since Ubuntu configures both levels to
+        * use DFLTCC hardware compression. */
+       failure("Compression-level=1 wrote %d bytes; compression-level=9 wrote %d bytes",
+           (int)used3, (int)used2);
+       assert(used3 > used2);
 
        /* Basic gzip header tests */
        rbuff = (unsigned char *)buff;
@@ -255,7 +258,7 @@ DEFINE_TEST(test_write_filter_gzip)
                skipping("gzip reading not fully supported on this platform");
        } else {
                assertEqualIntA(a, ARCHIVE_OK,
-                   archive_read_open_memory(a, buff, used2));
+                   archive_read_open_memory(a, buff, used3));
                for (i = 0; i < 100; i++) {
                        snprintf(path, sizeof(path), "file%03d", i);
                        if (!assertEqualInt(ARCHIVE_OK,