Re: git: e9ae9fa93745 - main - syslog(3): unbreak log generation using fabricated PID
Date: Tue, 03 Jan 2023 06:55:11 UTC
Kristof Provost wrote: > On 9 Aug 2022, at 10:30, Eugene Grosbein wrote: >> The branch main has been updated by eugen: >> >> URL: https://cgit.FreeBSD.org/src/commit/?id=e9ae9fa93745669b7dd0341d333257ad6cfe8e37 >> >> commit e9ae9fa93745669b7dd0341d333257ad6cfe8e37 >> Author: Eugene Grosbein <eugen@FreeBSD.org> >> AuthorDate: 2022-08-08 22:21:02 +0000 >> Commit: Eugene Grosbein <eugen@FreeBSD.org> >> CommitDate: 2022-08-08 22:21:02 +0000 >> >> syslog(3): unbreak log generation using fabricated PID >> >> Recover application ability to supply fabricated PID >> embedded into ident that was lost when libc switched >> to generation of RFC 5424 log messages, for example: >> >> logger -t "ident[$$]" -p user.notice "test" >> >> It is essential for long running scripts. >> Also, this change unbreaks matching resulted entries >> by ident in syslog.conf: >> >> !ident >> *.* /var/log/ident.log >> >> Without the fix, the log (and matching) was broken: >> >> Aug 1 07:36:58 hostname ident[123][86483]: test >> >> Now it works as expected and worked before breakage: >> >> Aug 1 07:39:40 hostname ident[123]: test >> >> Differential: https://reviews.freebsd.org/D36005 >> MFC after: 2 weeks >> --- >> lib/libc/gen/syslog.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++--- >> 1 file changed, 51 insertions(+), 3 deletions(-) >> > <snip> > >> - (void)fprintf(fp, "%d ", getpid()); >> + if (LogPid == -1) >> + LogPid = getpid(); > > I believe this introduced unexpected behaviour for syslog(). If we log something prior to fork()ing we’ll keep logging with the old pid. That’s a fairly common pattern for daemonising code, and it’s something openvpn ran into: https://github.com/OpenVPN/openvpn/issues/198 And likely https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=268666.