dpkg-deb: work around bogus error message when working with XZ compressed packages

function                                             old     new   delta
unpack_xz_stream                                    2309    2317      +8
bb_full_fd_action                                    464     472      +8

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

1 files changed, 8 insertions, 5 deletions

diff --git a/libbb/copyfd.c b/libbb/copyfd.c
index ae5c26999..d41fd10f0 100644
--- a/libbb/copyfd.c
+++ b/libbb/copyfd.c
@@ -18,7 +18,7 @@
  * was seen to cause largish delays when user tries to ^C a file copy.
  * Let's use a saner size.
  * Note: needs to be >= max(CONFIG_FEATURE_COPYBUF_KB),
- * or else "copy to eof" code will use neddlesly short reads.
+ * or else "copy to eof" code will use needlesly short reads.
  */
 #define SENDFILE_BIGBUF (16*1024*1024)
 
@@ -60,10 +60,13 @@ static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
                 ssize_t rd;
 
                 if (sendfile_sz) {
-                        rd = sendfile(dst_fd, src_fd, NULL,
-                                size > sendfile_sz ? sendfile_sz : size);
-                        if (rd >= 0)
-                                goto read_ok;
+                        /* dst_fd == -1 is a fake, else... */
+                        if (dst_fd >= 0) {
+                                rd = sendfile(dst_fd, src_fd, NULL,
+                                        size > sendfile_sz ? sendfile_sz : size);
+                                if (rd >= 0)
+                                        goto read_ok;
+                        }
                         sendfile_sz = 0; /* do not try sendfile anymore */
                 }
 #if CONFIG_FEATURE_COPYBUF_KB > 4