1 | /******************************************************************* |
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2 | * File: omMmap.c |
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3 | * Purpose: implementing valloc via mmap |
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4 | * Author: obachman (Olaf Bachmann) |
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5 | * Created: 11/99 |
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6 | * Version: $Id: omMmap.c,v 1.6 2001-04-30 09:02:09 Singular Exp $ |
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7 | *******************************************************************/ |
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8 | #include <unistd.h> |
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9 | #include <fcntl.h> |
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10 | #include <sys/mman.h> |
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11 | |
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12 | #if !defined(MAP_ANONYMOUS) && defined(MAP_ANON) |
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13 | #define MAP_ANONYMOUS MAP_ANON |
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14 | #endif |
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15 | |
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16 | static void* omVallocMmap(size_t size) |
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17 | { |
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18 | void* addr; |
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19 | #ifndef MAP_ANONYMOUS |
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20 | static int fd = -1; |
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21 | #endif |
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22 | |
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23 | #ifdef MAP_ANONYMOUS |
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24 | #ifndef __CYGWIN__ |
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25 | /* under cygwin, MAP_PRIVATE|MAP_ANONYMOUS fails */ |
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26 | addr = mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); |
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27 | #else |
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28 | /* however, the following works */ |
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29 | addr = mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE, -1, 0); |
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30 | #endif |
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31 | #else /* !MAP_ANONYMOUS */ |
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32 | if (fd < 0) |
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33 | { |
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34 | fd = open("/dev/zero", O_RDWR); |
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35 | if (fd < 0) return NULL; |
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36 | } |
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37 | addr = mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); |
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38 | #endif |
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39 | |
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40 | if (addr == (void*) -1) return NULL; |
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41 | return addr; |
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42 | } |
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43 | |
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44 | static int omVfreeMmap(void* addr, size_t size) |
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45 | { |
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46 | return munmap(addr, size); |
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47 | } |
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