1 /* This software was written by Dirk Engling <erdgeist@erdgeist.org>
2 It is considered beerware. Prost. Skol. Cheers or whatever.
3
4 $id$ */
5
6 /* System */
7 #include <sys/types.h>
8 #include <sys/mman.h>
9 #include <stdlib.h>
10 #include <unistd.h>
11 #include <sys/uio.h>
12
13 /* Libowfat */
14
15 /* Opentracker */
16 #include "ot_iovec.h"
17
iovec_increase(int * iovec_entries,struct iovec ** iovector,size_t new_alloc)18 void *iovec_increase( int *iovec_entries, struct iovec **iovector, size_t new_alloc ) {
19 void *new_ptr = realloc( *iovector, (1 + *iovec_entries ) * sizeof( struct iovec ) );
20 if( !new_ptr )
21 return NULL;
22 *iovector = new_ptr;
23 new_ptr = mmap( NULL, new_alloc, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0 );
24 if( !new_ptr )
25 return NULL;
26 ((*iovector)[*iovec_entries]).iov_base = new_ptr;
27 ((*iovector)[*iovec_entries]).iov_len = new_alloc;
28 ++*iovec_entries;
29 return new_ptr;
30 }
31
iovec_free(int * iovec_entries,struct iovec ** iovector)32 void iovec_free( int *iovec_entries, struct iovec **iovector ) {
33 int i;
34 for( i=0; i<*iovec_entries; ++i )
35 munmap( ((*iovector)[i]).iov_base, ((*iovector)[i]).iov_len );
36 *iovec_entries = 0;
37 }
38
iovec_fixlast(int * iovec_entries,struct iovec ** iovector,void * last_ptr)39 void iovec_fixlast( int *iovec_entries, struct iovec **iovector, void *last_ptr ) {
40 int page_size = getpagesize();
41 size_t old_alloc, new_alloc, old_pages, new_pages;
42 char * base = (char*)((*iovector)[ *iovec_entries - 1 ]).iov_base;
43
44 if( !*iovec_entries ) return;
45
46 old_alloc = ((*iovector)[ *iovec_entries - 1 ]).iov_len;
47 new_alloc = ((char*)last_ptr) - base;
48 old_pages = 1 + old_alloc / page_size;
49 new_pages = 1 + new_alloc / page_size;
50
51 if( old_pages != new_pages )
52 munmap( base + new_pages * page_size, old_alloc - new_pages * page_size );
53 ((*iovector)[*iovec_entries - 1 ]).iov_len = new_alloc;
54 }
55
iovec_fix_increase_or_free(int * iovec_entries,struct iovec ** iovector,void * last_ptr,size_t new_alloc)56 void *iovec_fix_increase_or_free( int *iovec_entries, struct iovec **iovector, void *last_ptr, size_t new_alloc ) {
57 void *new_ptr;
58
59 iovec_fixlast( iovec_entries, iovector, last_ptr );
60
61 if( !( new_ptr = iovec_increase( iovec_entries, iovector, new_alloc ) ) )
62 iovec_free( iovec_entries, iovector );
63
64 return new_ptr;
65 }
66
67
iovec_length(int * iovec_entries,struct iovec ** iovector)68 size_t iovec_length( int *iovec_entries, struct iovec **iovector ) {
69 size_t length = 0;
70 int i;
71 for( i=0; i<*iovec_entries; ++i )
72 length += ((*iovector)[i]).iov_len;
73 return length;
74 }
75
76 const char *g_version_iovec_c = "$Source$: $Revision$\n";
77