83 lines
2.3 KiB
C
83 lines
2.3 KiB
C
/*
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* Copyright (C) 2015 Michael Brown <mbrown@fensystems.co.uk>.
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*
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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 as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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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., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*
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* You can also choose to distribute this program under the terms of
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* the Unmodified Binary Distribution Licence (as given in the file
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* COPYING.UBDL), provided that you have satisfied its requirements.
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*/
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FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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#include <stdlib.h>
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#include <errno.h>
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#include <ipxe/fault.h>
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/** @file
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*
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* Fault injection
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*
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*/
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/**
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* Inject fault with a specified probability
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*
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* @v rate Reciprocal of fault probability (must be non-zero)
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* @ret rc Return status code
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*/
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int inject_fault_nonzero ( unsigned int rate ) {
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/* Do nothing unless we want to inject a fault now */
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if ( ( random() % rate ) != 0 )
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return 0;
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/* Generate error number here so that faults can be injected
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* into files that don't themselves have error file
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* identifiers (via errfile.h).
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*/
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return -EFAULT;
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}
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/**
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* Corrupt data with a specified probability
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*
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* @v rate Reciprocal of fault probability (must be non-zero)
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* @v data Data
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* @v len Length of data
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* @ret rc Return status code
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*/
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void inject_corruption_nonzero ( unsigned int rate, const void *data,
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size_t len ) {
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uint8_t *writable;
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size_t offset;
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/* Do nothing if we have no data to corrupt */
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if ( ! len )
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return;
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/* Do nothing unless we want to inject a fault now */
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if ( ! inject_fault_nonzero ( rate ) )
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return;
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/* Get a writable pointer to the nominally read-only data */
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writable = ( ( uint8_t * ) data );
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/* Pick a random victim byte and zap it */
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offset = ( random() % len );
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writable[offset] ^= random();
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}
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