For several people, the limiter causes bigger problems that
it solves, so it is better to have it disabled by default.
Those who want to have a limiter by default need to enable
it via the environment variable XZ_DEFAULTS.
Support for environment variable XZ_DEFAULTS was added. It is
parsed before XZ_OPT and technically identical with it. The
intended uses differ quite a bit though; see the man page.
The memory usage limit can now be set separately for
compression and decompression using --memlimit-compress and
--memlimit-decompress. To set both at once, -M or --memlimit
can be used. --memory was retained as a legacy alias for
--memlimit for backwards compatibility.
The semantics of --info-memory were changed in backwards
incompatible way. Compatibility wasn't meaningful due to
changes in the memory usage limiter functionality.
The memory usage limiter info is no longer shown at the
bottom of xz --long -help.
The memory usage limiter support for removed completely from xzdec.
xz's man page was updated to match the above changes. Various
unrelated fixes were also made to the man page.
Hopefully these help a bit when learning the basics
of liblzma API. I plan to write detailed examples about
both basic and advanced features with lots of comments,
but these two examples are good have right now.
The examples were written by Daniel Mealha Cabrita. Thanks.
When using -O2 with GCC, it liked to swap two comparisons
in one "if" statement. It's otherwise fine except that
the latter part, which is seemingly never executed, got
executed (nothing wrong with that) and then triggered
warning in Valgrind about conditional jump depending on
uninitialized variable. A few people find this annoying
so do things a bit differently to avoid the warning.
message_filters_to_str() converts the filter chain to
a string. message_filters_show() replaces the original
message_filters().
uint32_to_optstr() was also added to show the dictionary
size in nicer format when possible.
Don't use #error to generate compile error, because some
compilers actually don't take it as an error. This fixes
tuklib_physmem on IRIX.
Fix incorrect error check for sysconf() return values.
Add AIX, HP-UX, and Tru64 specific code to detect the
amount RAM.
Add HP-UX specific code to detect the number of CPU cores.
Thanks a lot to Peter O'Gorman for initial patches,
testing, and debugging these fixes.
The extra space for showing both has been taken from the
sizes field. If the sizes grow big, bigger units than MiB
will be used. It makes it slightly difficult to see that
progress is still happening with huge files, but it should
be OK in practice.
Thanks to Trent W. Buck for <http://bugs.debian.org/574583>
and Jonathan Nieder for suggestions how to fix it.
Originally both base-2 and base-10 were supported, but since
there seems to be little need for base-10 in XZ Utils, treat
everything as base-2 and also be more relaxed about the case
of the first letter of the suffix. Now xz will accept e.g.
KiB, Ki, k, K, kB, and KB, and interpret them all as 1024. The
recommended spelling of the suffixes are still KiB, MiB, and GiB.
It still feels a bit wrong to round 1 byte to 1 MiB but
at least it is now done consistently so that the same
byte value is always rounded the same way to MiB.
Previously the default limit was always 40 % of RAM. The
new limit is a little bit more complex:
- If 40 % of RAM is at least 80 MiB, 40 % of RAM is used
as the limit.
- If 80 % of RAM is over 80 MiB, 80 MiB is used as the limit.
- Otherwise 80 % of RAM is used as the limit.
This should make it possible to decompress files created with
"xz -9" on more systems. Swapping is generally more expected
on systems with less RAM, so higher default limit on them
shouldn't cause too bad surprises in terms of heavy swapping.
Instead, the higher default limit should reduce the number of
bad surprises when it used to prevent decompression of files
created with "xz -9". The DoS prevention system shouldn't be
a DoS itself.
Note that even with the new default limit, a system with 64 MiB
RAM cannot decompress files created with "xz -9" without user
overriding the limit. This should be OK, because if xz is going
to need more memory than the system has RAM, it will run very
very slowly and thus it's good that user has to override the limit
in that case.
With bad luck, lzma_code() could return LZMA_BUF_ERROR
when it shouldn't.
This has been here since the early days of liblzma.
It got triggered by the modifications made to the xz
tool in commit 18c10c30d2
but only when decompressing .lzma files. Somehow I managed
to miss testing that with Valgrind earlier.
This fixes <http://bugs.gentoo.org/show_bug.cgi?id=305591>.
Thanks to Rafał Mużyło for helping to debug it on IRC.
lzma_block.version has to be initialized even for
lzma_block_header_decode(). This way a future version
of liblzma won't allocate memory in a way that an old
application doesn't know how to free it.
The subtlety of this change is that all current apps
using lzma_block_header_decode() will keep working for
now, because the only possible version value is zero,
and lzma_block_header_decode() unconditionally sets the
version to zero even now. Unless fixed, these apps will
break in the future if a new version of the Block options
is ever needed.
Lasse Collin
Jonathan Nieder