Completely rewritten fullscrape code. All assumptions on how deflate() works were a little naive. Needs more error checking and testing.

ot_fullscrape.c

@@ -25,10 +25,18 @@
    Full scrapes usually are huge and one does not want to
    allocate more memory. So lets get them in 512k units
 */
-#define OT_SCRAPE_CHUNK_SIZE (512*1024)
+#define OT_SCRAPE_CHUNK_SIZE (1024)
 
 /* "d8:completei%zde10:downloadedi%zde10:incompletei%zdee" */
-#define OT_FULLSCRAPE_MAXENTRYLEN 256
+#define OT_SCRAPE_MAXENTRYLEN 256
+
+#ifdef WANT_COMPRESSION_GZIP
+#define IF_COMPRESSION( TASK ) if( mode & TASK_FLAG_GZIP ) TASK
+#define WANT_COMPRESSION_GZIP_PARAM( param1, param2 ) , param1, param2
+#else
+#define IF_COMPRESSION( TASK )
+#define WANT_COMPRESSION_GZIP_PARAM( param1, param2 )
+#endif
 
 /* Forward declaration */
 static void fullscrape_make( int *iovec_entries, struct iovec **iovector, ot_tasktype mode );
@@ -69,11 +77,38 @@ void fullscrape_deliver( int64 socket, ot_tasktype tasktype ) {
   mutex_workqueue_pushtask( socket, tasktype );
 }
 
+static int fullscrape_increase( int *iovec_entries, struct iovec **iovector,
+                         char **r, char **re  WANT_COMPRESSION_GZIP_PARAM( z_stream *strm, ot_tasktype mode ) ) {
+  /* Allocate a fresh output buffer at the end of our buffers list */
+  if( !( *r = iovec_fix_increase_or_free( iovec_entries, iovector, *r, OT_SCRAPE_CHUNK_SIZE ) ) ) {
+
+    /* Deallocate gzip buffers */
+    IF_COMPRESSION( deflateEnd(strm); )
+
+    /* Release lock on current bucket and return */
+    return -1;
+  }
+
+  /* Adjust new end of output buffer */
+  *re = *r + OT_SCRAPE_CHUNK_SIZE - OT_SCRAPE_MAXENTRYLEN;
+  
+  /* When compressing, we have all the bytes in output buffer */
+  IF_COMPRESSION( { \
+    *re -= OT_SCRAPE_MAXENTRYLEN; \
+    strm->next_out  = (ot_byte*)*r; \
+    strm->avail_out = OT_SCRAPE_CHUNK_SIZE; \
+    deflate( strm, Z_NO_FLUSH ); \
+    *r = (char*)strm->next_out; \
+  } )
+
+  return 0;
+}
+
 static void fullscrape_make( int *iovec_entries, struct iovec **iovector, ot_tasktype mode ) {
-  int   bucket;
+  int      bucket;
-  char *r, *re;
+  char    *r, *re;
 #ifdef WANT_COMPRESSION_GZIP
-  char  compress_buffer[OT_FULLSCRAPE_MAXENTRYLEN];
+  char     compress_buffer[OT_SCRAPE_MAXENTRYLEN];
   z_stream strm;
 #endif
 
@@ -83,28 +118,24 @@ static void fullscrape_make( int *iovec_entries, struct iovec **iovector, ot_tas
   if( !( r = iovec_increase( iovec_entries, iovector, OT_SCRAPE_CHUNK_SIZE ) ) )
     return;
 
-  /* ... and pointer to end of current output buffer.
+  /* re points to low watermark */
-     This works as a low watermark */
+  re = r + OT_SCRAPE_CHUNK_SIZE - OT_SCRAPE_MAXENTRYLEN;
-  re = r + OT_SCRAPE_CHUNK_SIZE;
 
 #ifdef WANT_COMPRESSION_GZIP
   if( mode & TASK_FLAG_GZIP ) {
+    re += OT_SCRAPE_MAXENTRYLEN;
     byte_zero( &strm, sizeof(strm) );
-    strm.next_in = (ot_byte*)r;
+    strm.next_in   = (ot_byte*)compress_buffer;
+    strm.next_out  = (ot_byte*)r;
+    strm.avail_out = OT_SCRAPE_CHUNK_SIZE;
     if( deflateInit2(&strm,9,Z_DEFLATED,31,8,Z_DEFAULT_STRATEGY) != Z_OK )
       fprintf( stderr, "not ok.\n" );
-
-    strm.next_out  = (unsigned char*)r;
-    strm.avail_out = OT_SCRAPE_CHUNK_SIZE;
     r = compress_buffer;
   }
 #endif
 
-  /* Reply dictionary only needed for bencoded fullscrape */
+  if( ( mode & TASK_TASK_MASK ) == TASK_FULLSCRAPE )
-  if( ( mode & TASK_TASK_MASK ) == TASK_FULLSCRAPE ) {
+    r += sprintf( r, "d5:filesd" );
-    memmove( r, "d5:filesd", 9 );
-    r += 9;
-  }
 
   /* For each bucket... */
   for( bucket=0; bucket<OT_BUCKET_COUNT; ++bucket ) {
@@ -121,13 +152,15 @@ static void fullscrape_make( int *iovec_entries, struct iovec **iovector, ot_tas
       switch( mode & TASK_TASK_MASK ) {
       case TASK_FULLSCRAPE:
       default:
+
         /* push hash as bencoded string */
         *r++='2'; *r++='0'; *r++=':';
         memmove( r, hash, 20 ); r+=20;
 
         /* push rest of the scrape string */
         r += sprintf( r, "d8:completei%zde10:downloadedi%zde10:incompletei%zdee", peer_list->seed_count, peer_list->down_count, peer_list->peer_count-peer_list->seed_count );
-        break;
+
+         break;
       case TASK_FULLSCRAPE_TPB_ASCII:
         to_hex( r, *hash ); r+=40;
         r += sprintf( r, ":%zd:%zd\n", peer_list->seed_count, peer_list->peer_count-peer_list->seed_count );
@@ -144,73 +177,41 @@ static void fullscrape_make( int *iovec_entries, struct iovec **iovector, ot_tas
       }
 
 #ifdef WANT_COMPRESSION_GZIP
-      if( mode & TASK_FLAG_GZIP ) {
+     if( mode & TASK_FLAG_GZIP ) {
         strm.next_in  = (ot_byte*)compress_buffer;
         strm.avail_in = r - compress_buffer;
-        if( deflate( &strm, Z_NO_FLUSH ) != Z_OK )
+        deflate( &strm, Z_NO_FLUSH );
-          fprintf( stderr, "Not ok.\n" );
         r = (char*)strm.next_out;
       }
 #endif
 
-      /* If we reached our low watermark in buffer... */
+      /* Check if there still is enough buffer left */
-      if( re - r <= OT_FULLSCRAPE_MAXENTRYLEN ) {
+      while( ( r > re ) && fullscrape_increase( iovec_entries, iovector, &r, &re WANT_COMPRESSION_GZIP_PARAM( &strm, mode ) ) )
-
+        return mutex_bucket_unlock( bucket );
-        /* crop current output buffer to the amount really used */
-        iovec_fixlast( iovec_entries, iovector, OT_SCRAPE_CHUNK_SIZE - ( re - r ) );
-        
-        /* And allocate a fresh output buffer at the end of our buffers list */
-        if( !( r = iovec_increase( iovec_entries, iovector, OT_SCRAPE_CHUNK_SIZE ) ) ) {
-        
-          /* If this fails: free buffers */
-          iovec_free( iovec_entries, iovector );
-
-#ifdef WANT_COMPRESSION_GZIP
-          deflateEnd(&strm);
-#endif
-
-          /* Release lock on current bucket and return */
-          mutex_bucket_unlock( bucket );
-          return;
-        }
-        
-        /* Adjust new end of output buffer */
-        re = r + OT_SCRAPE_CHUNK_SIZE;
 
-#ifdef WANT_COMPRESSION_GZIP
+      IF_COMPRESSION( r = compress_buffer; )
-        if( mode & TASK_FLAG_GZIP ) {
-          strm.next_out  = (ot_byte*)r;
-          strm.avail_out = OT_SCRAPE_CHUNK_SIZE;
-        }
-#endif
-      }
-#ifdef WANT_COMPRESSION_GZIP
-      if( mode & TASK_FLAG_GZIP ) {
-        r = compress_buffer;
-      }
-#endif
     }
-    
+
     /* All torrents done: release lock on currenct bucket */
     mutex_bucket_unlock( bucket );
   }
 
-  /* Close bencoded scrape dictionary if necessary */
+  if( ( mode & TASK_TASK_MASK ) == TASK_FULLSCRAPE )
-  if( ( mode & TASK_TASK_MASK ) == TASK_FULLSCRAPE ) {
+    r += sprintf( r, "ee" );
-    *r++='e'; *r++='e';
-  }
 
 #ifdef WANT_COMPRESSION_GZIP
   if( mode & TASK_FLAG_GZIP ) {
-    strm.next_in  = (ot_byte*) compress_buffer;
+    strm.next_in  = (ot_byte*)compress_buffer;
     strm.avail_in = r - compress_buffer;
-    if( deflate( &strm, Z_FINISH ) != Z_STREAM_END )
+    deflate( &strm, Z_FINISH );
-      fprintf( stderr, "Not ok.\n" );
     r = (char*)strm.next_out;
-	  deflateEnd(&strm);
+
+    while( ( r > re ) && fullscrape_increase( iovec_entries, iovector, &r, &re WANT_COMPRESSION_GZIP_PARAM( &strm, mode ) ) )
+      return mutex_bucket_unlock( bucket );
+    deflateEnd(&strm);
   }
 #endif
 
   /* Release unused memory in current output buffer */
-  iovec_fixlast( iovec_entries, iovector, OT_SCRAPE_CHUNK_SIZE - ( re - r ) );
+  iovec_fixlast( iovec_entries, iovector, r );
 }