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