wget: correctly handle failure to -c (continue)

function                                             old     new   delta
reset_beg_range_to_zero                                -      52     +52
wget_main                                           2168    2189     +21

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

1 files changed, 16 insertions, 0 deletions

diff --git a/networking/wget.c b/networking/wget.c
index 8520fe2b9..013b87801 100644
--- a/networking/wget.c
+++ b/networking/wget.c
@@ -350,6 +350,14 @@ static char *gethdr(FILE *fp)
         return hdrval;
 }
 
+static void reset_beg_range_to_zero(void)
+{
+        //bb_error_msg("restart failed");
+        G.beg_range = 0;
+        xlseek(G.output_fd, 0, SEEK_SET);
+        ftruncate(G.output_fd, 0);
+}
+
 static FILE* prepare_ftp_session(FILE **dfpp, struct host_info *target, len_and_sockaddr *lsa)
 {
         FILE *sfp;
@@ -421,6 +429,8 @@ static FILE* prepare_ftp_session(FILE **dfpp, struct host_info *target, len_and_
                 sprintf(G.wget_buf, "REST %"OFF_FMT"u", G.beg_range);
                 if (ftpcmd(G.wget_buf, NULL, sfp) == 350)
                         G.content_len -= G.beg_range;
+                else
+                        reset_beg_range_to_zero();
         }
 
         if (ftpcmd("RETR ", target->path, sfp) > 150)
@@ -744,6 +754,12 @@ However, in real world it was observed that some web servers
 (e.g. Boa/0.94.14rc21) simply use code 204 when file size is zero.
 */
                 case 204:
+                        if (G.beg_range != 0) {
+                                /* "Range:..." was not honored by the server.
+                                 * Restart download from the beginning.
+                                 */
+                                reset_beg_range_to_zero();
+                        }
                         break;
                 case 300:  /* redirection */
                 case 301: