An open and free bittorrent tracker https://erdgeist.org/gitweb/opentracker
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/* 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, void *last_ptr ) {
int page_size = getpagesize();
size_t old_alloc, new_alloc, old_pages, new_pages;
char * base = (char*)((*iovector)[ *iovec_entries - 1 ]).iov_base;
if( !*iovec_entries ) return;
old_alloc = ((*iovector)[ *iovec_entries - 1 ]).iov_len;
new_alloc = ((char*)last_ptr) - base;
old_pages = 1 + old_alloc / page_size;
new_pages = 1 + new_alloc / page_size;
if( old_pages != new_pages ) {
munmap( base + new_pages * page_size, old_alloc - new_pages * page_size );
}
((*iovector)[*iovec_entries - 1 ]).iov_len = new_alloc;
}
void *iovec_fix_increase_or_free( int *iovec_entries, struct iovec **iovector, void *last_ptr, size_t new_alloc ) {
void *new_ptr;
iovec_fixlast( iovec_entries, iovector, last_ptr );
if( !( new_ptr = iovec_increase( iovec_entries, iovector, new_alloc ) ) )
iovec_free( iovec_entries, iovector );
return new_ptr;
}
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;
}