Sometimes pixz will segfault when using the -x option to extract individual files. The conditions which trigger the crash are such that there is a small chance of a crash for each file extracted using the -x option. The more files one extracts (using -x), the greater the chances of encountering the crash.

A more detailed analysis of the bug and a fix can be found in pull request https://github.com/vasi/pixz/pull/105

In read_thread(), in the "Do we need this block?" block, it failed to advance to the next wanted_t when w->end is exactly equal to uend.

In the particular case I looked at, this resulted in read_thread() erroneously putting two blocks into the queue (pipeline_split(), read.c:570) instead of one.

This resulted in a subsequent crash in tar_read() at read.c:660, where gArWanted was null (when clearly the code does not expect it to be null at that point).

My use case:

I have several hundred large .tar.xz files (created by pixz). Each archive contains over 200k files. I frequently need to extract a lot of files from each archive, but not all files, only a specific subset. So I am making heavy use of the -x option to pixz.

I am trying to decompress a 3.1 TiB .tpxz file that was compressed using 1.0.6 and the error message that I am getting is:

"Error decoding stream footer"

What can/should I do as a workaround for this issue so that I can try and get my data back?

Your help is greatly appreciated.

Thank you.

[root@localhost pixz-master]# ./autogen.sh configure.ac:47: installing './config.guess' configure.ac:47: installing './config.sub' configure.ac:11: installing './install-sh' configure.ac:11: installing './missing' src/Makefile.am: installing './depcomp' parallel-tests: installing './test-driver' [root@localhost pixz-master]# ./config config.guess config.sub configure
[root@localhost pixz-master]# ./configure checking for a BSD-compatible install... /usr/bin/install -c checking whether build environment is sane... yes checking for a thread-safe mkdir -p... /usr/bin/mkdir -p checking for gawk... gawk checking whether make sets $(MAKE)... yes checking whether make supports nested variables... yes checking for style of include used by make... GNU checking for gcc... gcc checking whether the C compiler works... yes checking for C compiler default output file name... a.out checking for suffix of executables... checking whether we are cross compiling... no checking for suffix of object files... o checking whether we are using the GNU C compiler... yes checking whether gcc accepts -g... yes checking for gcc option to accept ISO C89... none needed checking dependency style of gcc... gcc3 checking for gcc option to accept ISO C99... -std=gnu99 checking for gcc -std=gnu99 option to accept ISO Standard C... (cached) -std=gnu99 checking for a2x... no configure: error: AsciiDoc not found, not able to generate the man page. [root@localhost pixz-master]#

Can I help you?

just running pixz on an existing tar file creates a tpxz file, but when I then do an extract with a piped file, I get a warning about seeking, which I presume implied that an index was not created.

E.g.

cd /tmp
curl -OLf https://gitlab.com/api/v4/projects/26210301/packages/generic/glibc/2.27_x86_64/glibc-2.27-chromeos-x86_64.tar.xz
xz -d glibc-2.27-chromeos-x86_64.tar.xz
pixz -9 glibc-2.27-chromeos-x86_64.tar 
curl -Ls file:///tmp/glibc-2.27-chromeos-x86_64.tpxz  |  pixz -x usr/local/lib64/Scrt1.o usr/local/lib64/crti.o usr/local/lib64/crtn.o | tar x
can not seek in input: Illegal seek

(Here I get everything extracted, instead of just the files I want. The goal is to later just extract the files directly piped from a curl download.)