71 lines
2.0 KiB
C
71 lines
2.0 KiB
C
/* Copyright (C) 2005 David Decotigny
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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USA.
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*/
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#include <crt.h>
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#include <libc.h>
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#include <stdarg.h>
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#include <debug.h>
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/**
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* @file myprog14.c
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*
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* uaccess tests. Demonstrate that a page fault in kernel during
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* userspace access (with uaccess.c functions) is NEVER (or at least
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* should not be) fatal:
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* - licit page faults are resolved as usual (COW, page_in, ...)
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* - illicit page faults are caught and the uaccess functions tolerate
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* and report it
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*
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* We use the temporary syscall 4012 (hexdump) to force the kernel to
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* call user_memcpy and do some page faults.
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*/
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int main(void)
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{
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char * zoup;
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int fd;
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fd = open("/dev/zero", O_RDWR);
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zoup = mmap(0, 8192,
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PROT_READ | PROT_WRITE,
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MAP_SHARED,
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fd, 34);
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close(fd);
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bochs_printf("mapped @%x\n", (unsigned)zoup);
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/* Do some forks to complicate things */
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fork();
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fork();
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/* Force the first page of the mapping to be allocated */
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*zoup = 'a';
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_sos_syscall2(4012, (unsigned)zoup, 16384);
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/*
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* all 3 cases are handled here:
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* - [zoup, zoup + 4kB[: no page fault at all (page already mapped)
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* - [zoup+4kB, zoup + 8kB[: page fault => /dev/zero page_in() called
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* - [zoup+8kB, ...[: page fault => illegal user address =>
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* user_memcpy reports that only 8kB out of the 16kB could be
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* hexdumped
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*/
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return 0;
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}
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