New large chunk allocation code

ot_iovec.c

@@ -0,0 +1,60 @@
+/* This software was written by Dirk Engling <erdgeist@erdgeist.org>
+   It is considered beerware. Prost. Skol. Cheers or whatever. */
+
+/* System */
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/uio.h>
+
+/* Libowfat */
+
+/* Opentracker */
+#include "ot_iovec.h"
+
+void *iovec_increase( int *iovec_entries, struct iovec **iovector, size_t new_alloc ) {
+  void *new_ptr = realloc( *iovector, 1 + *iovec_entries * sizeof( struct iovec ) );
+  if( !new_ptr )
+    return NULL;
+  *iovector = new_ptr;
+  new_ptr = mmap( NULL, new_alloc, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0 );
+  if( !new_ptr )
+    return NULL;
+  ((*iovector)[*iovec_entries]).iov_base = new_ptr;
+  ((*iovector)[*iovec_entries]).iov_len  = new_alloc;  
+  ++*iovec_entries;
+  return new_ptr;
+}
+
+void iovec_free( int *iovec_entries, struct iovec **iovector ) {
+  int i;
+  for( i=0; i<*iovec_entries; ++i )
+    munmap( ((*iovector)[i]).iov_base, ((*iovector)[i]).iov_len );
+  *iovec_entries = 0;
+}
+
+void  iovec_fixlast( int *iovec_entries, struct iovec **iovector, size_t new_alloc ) {
+  int page_size = getpagesize();
+  size_t old_alloc, old_pages, new_pages;
+
+  if( !*iovec_entries ) return;
+
+  old_alloc = ((*iovector)[ *iovec_entries - 1 ]).iov_len;
+  old_pages = 1 + old_alloc / page_size;
+  new_pages = 1 + new_alloc / page_size;
+
+  if( old_pages != new_pages ) {
+    munmap( ((char*)((*iovector)[ *iovec_entries - 1 ]).iov_base ) +  new_pages * page_size,
+            old_alloc - new_pages * page_size );
+  }
+  ((*iovector)[*iovec_entries - 1 ]).iov_len = new_alloc;
+}
+
+size_t iovec_length( int *iovec_entries, struct iovec **iovector ) {
+  size_t length = 0;
+  int i;
+  for( i=0; i<*iovec_entries; ++i )
+    length += ((*iovector)[i]).iov_len;
+  return length;
+}

ot_iovec.h

@@ -0,0 +1,14 @@
+/* This software was written by Dirk Engling <erdgeist@erdgeist.org>
+   It is considered beerware. Prost. Skol. Cheers or whatever. */
+
+#ifndef __OT_IOVEC_H__
+#define __OT_IOVEC_H__
+
+#include <sys/uio.h>
+
+void  *iovec_increase( int *iovec_entries, struct iovec **iovector, size_t new_alloc );
+void   iovec_fixlast( int *iovec_entries, struct iovec **iovector, size_t new_alloc );
+void   iovec_free( int *iovec_entries, struct iovec **iovector );
+size_t iovec_length( int *iovec_entries, struct iovec **iovector );
+
+#endif