Sort info_hashes in a scrape so that the reply forms a valid bencoded dict

1 files changed, 12 insertions, 2 deletions

diff --git a/ot_http.c b/ot_http.c
index 14952b5..2216453 100644
--- a/ot_http.c
+++ b/ot_http.c
@@ -24,6 +24,7 @@
 #include "ot_scan.h"
 #include "ot_event.h"
 #include "ot_fdstate.h"
+#include "ot_vector.h"
 #include "ot_fmt.h"
 #include "ot_stats.h"
 #include "ot_urlencoded.h"
@@ -233,7 +234,6 @@ static ssize_t http_handle_stats(const int64_t sock, struct ot_workstruct *ws, c
                                               {"scrp", TASK_STATS_SCRAPE},
                                               {"udp4", TASK_STATS_UDP},
                                               {"tcp4", TASK_STATS_TCP},
-                                              {"busy", TASK_STATS_BUSY_NETWORKS},
                                               {"torr", TASK_STATS_TORRENTS},
                                               {"fscr", TASK_STATS_FULLSCRAPE},
                                               {"s24s", TASK_STATS_SLASH24S},
@@ -418,13 +418,15 @@ static ssize_t http_handle_fullscrape(const int64_t sock, struct ot_workstruct *
 }
 #endif
 
+static int compare_hash(const void *left, const void *right) { return memcmp(left, right, sizeof(ot_hash)); }
+
 static ssize_t http_handle_scrape(const int64_t sock, struct ot_workstruct *ws, char *read_ptr) {
   static const ot_keywords keywords_scrape[] = {{"info_hash", 1}, {NULL, -3}};
 
   ot_hash *multiscrape_buf = (ot_hash *)ws->request;
   char    *reply           = ws->reply;
   int      scanon          = 1;
-  size_t   numwant         = 0;
+  size_t   i, unique, numwant = 0;
 
   /* This is to hack around stupid clients that send "scrape ?info_hash" */
   if (read_ptr[-1] != '?') {
@@ -461,6 +463,14 @@ static ssize_t http_handle_scrape(const int64_t sock, struct ot_workstruct *ws,
   if (numwant > OT_MAXMULTISCRAPE_COUNT)
     numwant = OT_MAXMULTISCRAPE_COUNT;
 
+  /* A bencoded dictionary has its keys in order and names each one once, so
+     the answer cannot just follow the order the client asked in */
+  qsort(multiscrape_buf, numwant, sizeof(ot_hash), compare_hash);
+  for (i = unique = 1; i < numwant; ++i)
+    if (memcmp(multiscrape_buf[i], multiscrape_buf[unique - 1], sizeof(ot_hash)))
+      memcpy(multiscrape_buf[unique++], multiscrape_buf[i], sizeof(ot_hash));
+  numwant = unique;
+
   /* Enough for http header + whole scrape string */
   return_tcp_scrape_for_torrent((const ot_hash *)multiscrape_buf, numwant, &reply, ws->outbuf + G_OUTBUF_SIZE);
   ws->reply_size = reply - ws->reply;