journalctl -r -n flags incorrectly processed

[ceecko]

I'm running version 208 - unfortunately I can't install the latest version but the issues seems to be present in the master as well as of writing.

journalctl --version
systemd 208
+PAM +LIBWRAP +AUDIT +SELINUX +IMA +SYSVINIT +LIBCRYPTSETUP +GCRYPT +ACL +XZ

Consider the following log entries:

2015-01-01 log1
2015-02-02 log2
2015-03-03 log3
2015-04-04 log4

Issuing journalctl -n 2 properly shows this:

2015-03-03 log3
2015-04-04 log4

However issuing journalctl -r -n 2 shows this:

2015-02-02 log2
2015-01-01 log1

This is because in journalctl.c line 2087 skips journal by arg_lines but doesn't take into account arg_reverse. Consequently on line 2153 the journal is read from arg_lines backwards which ultimately skips first arg_lines lines.

The expected output of journalctl -r -n 2 is:

2015-04-04 log4
2015-03-03 log3

[fwjavox]

This still applies to version 239. A workaround is to specify the cursor of the point where you want to start reading.
Edit: I also checked version 241, same behaviour.

[timo-schluessler]

I can confirm this bug in 242.
It is fixed by first checking for arg_reverse and then for arg_lines. The following patch fixes this.

fix-nr-of-lines-when-reversing.diff.gz

[dtardon]

@timo-schluessler Could you submit your patch as a pull request?

[timo-schluessler]

Sorry for my late reply. Please find the pull request at #14552.