Compressed Dump

Compressed Dump White Paper, Version 1.3

page 24

be used when the dump devices have com-

pressed memory images. See crashconf(1M).

Other formats, for example tape archival formats, may be added in the future.

Cache

Caching mechanism is implemented to improve the performance while analyzing

PARDIR format crash dumps. This caching mechanism is used to keep the uncom-

pressed pages so that subsequent requests can be satisﬁed from the cache. By

default, this caching mechanism will be disabled. It can be enabled by setting the

environment variable LIBCRASH_ENABLE_CACHE. It will create the cached ﬁles

in the crash dump directory.

RETURN VALUE

Most of the calls in libcrash return an integer status value. A zero return value indi-

cates success. A positive return value indicates some sort of warning, despite which

the requested operation was completed. A negative return value indicates some

sort of error, which prevented completion of the requested operation. The values

returned by the library are:

CR_OK Success.

CRWARN_NOEXPECTED The expected size or checksum of one or more

ﬁles in the crash dump was not recorded, so the

integrity of the dump cannot be veriﬁed. The dump

might be corrupt.

CRWARN_NOACTUAL The checksum of one or more ﬁles in the crash

dump could not be computed, so it could not be

checked against the expected value. The dump

might be corrupt.

CRWARN_SWAPPEDON A raw device containing a portion of the crash

dump has been swapped on, so the dump is prob-

ably corrupt.

CRWARN_MISMATCH The size or checksum of one or more ﬁles in the

crash dump did not match what was expected.

The dump is probably corrupt.

CRERR_NOPAGE A read or write request was issued for a memory

address that does not exist on the target machine.

CRERR_READONLY A write request was issued for a crash dump.

Writes are supported only to running systems

through the /dev/mem driver.