sos-code-article10/userland/myprog8.c

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2018-07-13 17:13:10 +02:00
/* Copyright (C) 2005 David Decotigny
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
USA.
*/
#include <libc.h>
#include <stdarg.h>
#include <debug.h>
/**
* @file myprog8.c
* Make sure that shared mappings (here: anonymous shared mapping) are
* really shared between father and child
*/
int main(void)
{
int i;
char *zoup;
int fd;
fd = open("/dev/zero", O_RDWR);
zoup = mmap((void*)4096, 8*1024*1024,
PROT_READ | PROT_WRITE,
MAP_SHARED,
fd, 0x123456789012345ULL);
close(fd);
bochs_printf("mapped @%x\n", (unsigned)zoup);
switch (fork())
{
case 0:
bochs_printf("CHILD 1: %d %d\n", zoup[42], zoup[43]);
for (i = 0 ; i < 1000000 ; i++)
zoup[43] = i / 19;
bochs_printf("CHILD 2: %d %d\n", zoup[42], zoup[43]);
for (i = 0 ; i < 1000000 ; i++)
zoup[43] = i / 19;
bochs_printf("CHILD 3: %d %d\n", zoup[42], zoup[43]);
break;
default:
bochs_printf("FATHER 1: %d %d\n", zoup[42], zoup[43]);
for (i = 0 ; i < 1000000 ; i++)
zoup[42] = i / 17;
bochs_printf("FATHER 2: %d %d\n", zoup[42], zoup[43]);
break;
}
return 0;
}