diff options
| -rw-r--r-- | src/core/fault.c | 29 | ||||
| -rw-r--r-- | src/include/ipxe/fault.h | 21 |
2 files changed, 50 insertions, 0 deletions
diff --git a/src/core/fault.c b/src/core/fault.c index 91289fd..63d3cca 100644 --- a/src/core/fault.c +++ b/src/core/fault.c @@ -51,3 +51,32 @@ int inject_fault_nonzero ( unsigned int rate ) { */ return -EFAULT; } + +/** + * Corrupt data with a specified probability + * + * @v rate Reciprocal of fault probability (must be non-zero) + * @v data Data + * @v len Length of data + * @ret rc Return status code + */ +void inject_corruption_nonzero ( unsigned int rate, const void *data, + size_t len ) { + uint8_t *writable; + size_t offset; + + /* Do nothing if we have no data to corrupt */ + if ( ! len ) + return; + + /* Do nothing unless we want to inject a fault now */ + if ( ! inject_fault_nonzero ( rate ) ) + return; + + /* Get a writable pointer to the nominally read-only data */ + writable = ( ( uint8_t * ) data ); + + /* Pick a random victim byte and zap it */ + offset = ( random() % len ); + writable[offset] ^= random(); +} diff --git a/src/include/ipxe/fault.h b/src/include/ipxe/fault.h index 32aa064..356296c 100644 --- a/src/include/ipxe/fault.h +++ b/src/include/ipxe/fault.h @@ -9,9 +9,12 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); +#include <stdint.h> #include <config/fault.h> extern int inject_fault_nonzero ( unsigned int rate ); +extern void inject_corruption_nonzero ( unsigned int rate, const void *data, + size_t len ); /** * Inject fault with a specified probability @@ -29,4 +32,22 @@ inject_fault ( unsigned int rate ) { return inject_fault_nonzero ( rate ); } +/** + * Corrupt data with a specified probability + * + * @v rate Reciprocal of fault probability (zero for no faults) + * @v data Data + * @v len Length of data + * @ret rc Return status code + */ +static inline __attribute__ (( always_inline )) void +inject_corruption ( unsigned int rate, const void *data, size_t len ) { + + /* Force dead code elimination in non-fault-injecting builds */ + if ( rate == 0 ) + return; + + return inject_corruption_nonzero ( rate, data, len ); +} + #endif /* _IPXE_FAULT_H */ |