1 files changed, 23 insertions, 15 deletions

diff --git a/ot_fullscrape.c b/ot_fullscrape.c
index 2ba3b24..8518bd2 100644
--- a/ot_fullscrape.c
+++ b/ot_fullscrape.c
@@ -18,6 +18,7 @@
 #endif
 
 /* Opentracker */
+#include "ot_fmt.h"
 #include "ot_hex.h"
 #include "ot_fullscrape.h"
 #include "ot_iovec.h"
@@ -83,10 +84,15 @@ void fullscrape_deliver( int64_t sock, ot_tasktype tasktype ) {
   mutex_workqueue_pushtask( sock, TASK_FULLSCRAPE | tasktype );
 }
 
-static char * fullscrape_write_one( ot_tasktype mode, char *r, ot_torrent *torrent, ot_hash *hash ) {
-  size_t seed_count = torrent->peer_list6->seed_count + torrent->peer_list4->seed_count;
-  size_t peer_count = torrent->peer_list6->peer_count + torrent->peer_list4->peer_count;
-  size_t down_count = torrent->peer_list6->down_count + torrent->peer_list4->down_count;
+static void fullscrape_write_one( ot_tasktype mode, char **cursor, ot_torrent *torrent, ot_hash *hash ) {
+  /* Callers guarantee this much room: the chunk writer keeps its low
+     watermark that far from the end, the compressors hand over a buffer of
+     exactly that size */
+  char       *r          = *cursor;
+  const char *r_end      = r + OT_SCRAPE_MAXENTRYLEN;
+  size_t      seed_count = torrent->peer_list6->seed_count + torrent->peer_list4->seed_count;
+  size_t      peer_count = torrent->peer_list6->peer_count + torrent->peer_list4->peer_count;
+  size_t      down_count = torrent->peer_list6->down_count + torrent->peer_list4->down_count;
 
   switch (mode & TASK_TASK_MASK) {
   case TASK_FULLSCRAPE:
@@ -98,18 +104,18 @@ static char * fullscrape_write_one( ot_tasktype mode, char *r, ot_torrent *torre
     memcpy(r, hash, sizeof(ot_hash));
     r += sizeof(ot_hash);
     /* push rest of the scrape string */
-    r += sprintf(r, "d8:completei%zde10:downloadedi%zde10:incompletei%zdee", seed_count, down_count, peer_count - seed_count);
+    fmt_append(&r, r_end, "d8:completei%zde10:downloadedi%zde10:incompletei%zdee", seed_count, down_count, peer_count - seed_count);
 
     break;
   case TASK_FULLSCRAPE_TPB_ASCII:
     hex_from_hash(r, *hash);
     r += 2 * sizeof(ot_hash);
-    r += sprintf(r, ":%zd:%zd\n", seed_count, peer_count - seed_count);
+    fmt_append(&r, r_end, ":%zd:%zd\n", seed_count, peer_count - seed_count);
     break;
   case TASK_FULLSCRAPE_TPB_ASCII_PLUS:
     hex_from_hash(r, *hash);
     r += 2 * sizeof(ot_hash);
-    r += sprintf(r, ":%zd:%zd:%zd\n", seed_count, peer_count - seed_count, down_count);
+    fmt_append(&r, r_end, ":%zd:%zd:%zd\n", seed_count, peer_count - seed_count, down_count);
     break;
   case TASK_FULLSCRAPE_TPB_BINARY:
     memcpy(r, *hash, sizeof(ot_hash));
@@ -120,15 +126,15 @@ static char * fullscrape_write_one( ot_tasktype mode, char *r, ot_torrent *torre
     break;
   case TASK_FULLSCRAPE_TPB_URLENCODED:
     r += urlencoded_format(r, *hash, sizeof(ot_hash));
-    r += sprintf(r, ":%zd:%zd\n", seed_count, peer_count - seed_count);
+    fmt_append(&r, r_end, ":%zd:%zd\n", seed_count, peer_count - seed_count);
     break;
   case TASK_FULLSCRAPE_TRACKERSTATE:
     hex_from_hash(r, *hash);
     r += 2 * sizeof(ot_hash);
-    r += sprintf(r, ":%zd:%zd\n", torrent->peer_list6->base, down_count);
+    fmt_append(&r, r_end, ":%zd:%zd\n", torrent->peer_list6->base, down_count);
     break;
   }
-  return r;
+  *cursor = r;
 }
 
 static void fullscrape_make(int taskid, ot_tasktype mode) {
@@ -145,7 +151,7 @@ static void fullscrape_make(int taskid, ot_tasktype mode) {
   re = r + OT_SCRAPE_CHUNK_SIZE - OT_SCRAPE_MAXENTRYLEN;
 
   if ((mode & TASK_TASK_MASK) == TASK_FULLSCRAPE)
-    r += sprintf(r, "d5:filesd");
+    fmt_append(&r, (char *)iovector.iov_base + OT_SCRAPE_CHUNK_SIZE, "d5:filesd");
 
   /* For each bucket... */
   for (bucket = 0; bucket < OT_BUCKET_COUNT; ++bucket) {
@@ -156,7 +162,7 @@ static void fullscrape_make(int taskid, ot_tasktype mode) {
 
     /* For each torrent in this bucket.. */
     for (i = 0; i < torrents_list->size; ++i) {
-      r = fullscrape_write_one(mode, r, torrents + i, &torrents[i].hash);
+      fullscrape_write_one(mode, &r, torrents + i, &torrents[i].hash);
 
       if (r > re) {
         iovector.iov_len = r - (char *)iovector.iov_base;
@@ -187,7 +193,7 @@ static void fullscrape_make(int taskid, ot_tasktype mode) {
   }
 
   if ((mode & TASK_TASK_MASK) == TASK_FULLSCRAPE)
-    r += sprintf(r, "ee");
+    fmt_append(&r, (char *)iovector.iov_base + OT_SCRAPE_CHUNK_SIZE, "ee");
 
   /* Send rest of data */
   iovector.iov_len = r - (char *)iovector.iov_base;
@@ -230,7 +236,8 @@ static void fullscrape_make_gzip(int taskid, ot_tasktype mode) {
     /* For each torrent in this bucket.. */
     for (i = 0; i < torrents_list->size; ++i) {
       char compress_buffer[OT_SCRAPE_MAXENTRYLEN];
-      r             = fullscrape_write_one(mode, compress_buffer, torrents + i, &torrents[i].hash);
+      r             = compress_buffer;
+      fullscrape_write_one(mode, &r, torrents + i, &torrents[i].hash);
       strm.next_in  = (uint8_t *)compress_buffer;
       strm.avail_in = r - compress_buffer;
       zres          = deflate(&strm, Z_NO_FLUSH);
@@ -359,7 +366,8 @@ static void fullscrape_make_zstd(int taskid, ot_tasktype mode) {
     /* For each torrent in this bucket.. */
     for (i = 0; i < torrents_list->size; ++i) {
       char compress_buffer[OT_SCRAPE_MAXENTRYLEN];
-      r             = fullscrape_write_one(mode, compress_buffer, torrents + i, &torrents[i].hash);
+      r             = compress_buffer;
+      fullscrape_write_one(mode, &r, torrents + i, &torrents[i].hash);
       inbuf.src     = compress_buffer;
       inbuf.size    = r - compress_buffer;
       inbuf.pos     = 0;