libarchive: open_zipped() does not need to check extensions for e.g. gzip

We only need to check for signature-less extensions,
currently only .lzma. The rest can be happily autodetected.

This fixes "zcat FILE_WITHOUT_GZ_EXT" case, among others.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 11 insertions, 12 deletions

diff --git a/archival/libarchive/open_transformer.c b/archival/libarchive/open_transformer.c
index 4e9826441..1aeba13bc 100644
--- a/archival/libarchive/open_transformer.c
+++ b/archival/libarchive/open_transformer.c
@@ -182,27 +182,26 @@ int FAST_FUNC setup_unzip_on_fd(int fd, int fail_if_not_detected)
 
 int FAST_FUNC open_zipped(const char *fname)
 {
-        char *sfx;
         int fd;
 
         fd = open(fname, O_RDONLY);
         if (fd < 0)
                 return fd;
 
-        sfx = strrchr(fname, '.');
-        if (sfx) {
-                sfx++;
-                if (ENABLE_FEATURE_SEAMLESS_LZMA && strcmp(sfx, "lzma") == 0)
-                        /* .lzma has no header/signature, just trust it */
+        if (ENABLE_FEATURE_SEAMLESS_LZMA) {
+                /* .lzma has no header/signature, can only detect it by extension */
+                char *sfx = strrchr(fname, '.');
+                if (sfx && strcmp(sfx+1, "lzma") == 0) {
                         open_transformer_with_sig(fd, unpack_lzma_stream, "unlzma");
-                else
-                if ((ENABLE_FEATURE_SEAMLESS_GZ && strcmp(sfx, "gz") == 0)
-                 || (ENABLE_FEATURE_SEAMLESS_BZ2 && strcmp(sfx, "bz2") == 0)
-                 || (ENABLE_FEATURE_SEAMLESS_XZ && strcmp(sfx, "xz") == 0)
-                ) {
-                        setup_unzip_on_fd(fd, /*fail_if_not_detected:*/ 1);
+                        return fd;
                 }
         }
+        if ((ENABLE_FEATURE_SEAMLESS_GZ)
+         || (ENABLE_FEATURE_SEAMLESS_BZ2)
+         || (ENABLE_FEATURE_SEAMLESS_XZ)
+        ) {
+                setup_unzip_on_fd(fd, /*fail_if_not_detected:*/ 1);
+        }
 
         return fd;
 }