iPXE
fault.c
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1 /*
2  * Copyright (C) 2015 Michael Brown <mbrown@fensystems.co.uk>.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License as
6  * published by the Free Software Foundation; either version 2 of the
7  * License, or (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful, but
10  * WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17  * 02110-1301, USA.
18  *
19  * You can also choose to distribute this program under the terms of
20  * the Unmodified Binary Distribution Licence (as given in the file
21  * COPYING.UBDL), provided that you have satisfied its requirements.
22  */
23 
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25 
26 #include <stdlib.h>
27 #include <errno.h>
28 #include <ipxe/fault.h>
29 
30 /** @file
31  *
32  * Fault injection
33  *
34  */
35 
36 /**
37  * Inject fault with a specified probability
38  *
39  * @v rate Reciprocal of fault probability (must be non-zero)
40  * @ret rc Return status code
41  */
42 int inject_fault_nonzero ( unsigned int rate ) {
43 
44  /* Do nothing unless we want to inject a fault now */
45  if ( ( random() % rate ) != 0 )
46  return 0;
47 
48  /* Generate error number here so that faults can be injected
49  * into files that don't themselves have error file
50  * identifiers (via errfile.h).
51  */
52  return -EFAULT;
53 }
54 
55 /**
56  * Corrupt data with a specified probability
57  *
58  * @v rate Reciprocal of fault probability (must be non-zero)
59  * @v data Data
60  * @v len Length of data
61  * @ret rc Return status code
62  */
63 void inject_corruption_nonzero ( unsigned int rate, const void *data,
64  size_t len ) {
65  uint8_t *writable;
66  size_t offset;
67 
68  /* Do nothing if we have no data to corrupt */
69  if ( ! len )
70  return;
71 
72  /* Do nothing unless we want to inject a fault now */
73  if ( ! inject_fault_nonzero ( rate ) )
74  return;
75 
76  /* Get a writable pointer to the nominally read-only data */
77  writable = ( ( uint8_t * ) data );
78 
79  /* Pick a random victim byte and zap it */
80  offset = ( random() % len );
81  writable[offset] ^= random();
82 }
Error codes.
void inject_corruption_nonzero(unsigned int rate, const void *data, size_t len)
Corrupt data with a specified probability.
Definition: fault.c:63
static userptr_t size_t offset
Offset of the first segment within the content.
Definition: deflate.h:259
#define EFAULT
Bad address.
Definition: errno.h:393
long int random(void)
Generate a pseudo-random number between 0 and 2147483647L or 2147483562?
Definition: random.c:30
unsigned char uint8_t
Definition: stdint.h:10
int inject_fault_nonzero(unsigned int rate)
Inject fault with a specified probability.
Definition: fault.c:42
uint32_t len
Length.
Definition: ena.h:14
FILE_LICENCE(GPL2_OR_LATER_OR_UBDL)
Fault injection.
struct arbelprm_port_state_change_st data
Message.
Definition: arbel.h:12