Re: [Pkg-zfsonlinux-devel] Bug#595790: hostid: useless unless fixed
[Michael Stone]
> Other platforms have deprecated gethostid, that's the best way forward for
> linux, IMO.
Which platforms is this? I find FreeBSD recommend to use sysctl and
KERN_HOSTID to get the hostid integer directly from the kernel instead
of using gethostid(), which isn't really depricating the feature, only
the way to get access to it. A quick search did not show any other
platforms depricating the function and feature, so I am curious to learn
what those are.
> This proposal doesn't fix the problem generally and actually changes
> the semantics of the call. (It was originally expected that the value
> would remain constant independent of a particular OS installation,
> which is not a property of a value stored on disk.)
My proposal is to use the DMI info which should stay the same
independent of OS installation.
> The main users of hostid (that I'm aware of) tended to be commercial
> software vendors locking licenses to systems--and they typically
> didn't use gethostid on linux because it was useless for the
> purpose. So I'm not aware of a userbase for this call on linux, and
> nobody should be using it for new development.
The users I am aware of is zfs-linux and the tools we wrote at work to
detect when a Linux machine was reinstalled or had its hardware changed.
The use case of zfs-linux require the ID to be unique among the machines
sharing a storage solution, and not globally unique.
A search in the source of all Debian packages[1] show this list of 148
packages mentioning the string 'gethostid': actiona alpine amanda
apcupsd aplus-fsf arpwatch ats-lang-anairiats audit bacula bareos
bluefish bsdgames burp busybox casacore cde cdrdao cdrkit
chromium-browser cl-irc clisp cmucl condor coreutils ctwm cython dc3dd
dcmtk deheader deja-dup dicom3tools dietlibc dist dmtcp dx e17
eclipse-titan edk2 emscripten erlang facter fpc frama-c freebsd-utils
freetds fs-uae ga gcc-h8300-hms gdb ghc glibc gnucash gnulib
gnustep-netclasses golang golang-1.6 golang-1.7 golang-golang-x-sys
hercules highlight hugs98 hurd iputils isdnutils ivtools kfreebsd-10
krb5 ksh latrace ldc libcanberra libconvert-binary-c-perl
libdata-uuid-perl libexplain libpam-tacplus libpcap libposix-2008-perl
linux linux-grsec ltrace lua-posix manpages manpages-de manpages-es
manpages-fr manpages-ja manpages-pl metview minc-tools mingw-w64 mono
mono-reference-assemblies musl nam ncbi-tools6 netatalk newlib nim nmap
nordugrid-arc ns2 ntirpc nwchem open-iscsi open-vm-tools openafs openmpi
otp pidgin pidgin-nateon pimd polygraph praat prayer pulseaudio
python-ptrace qemu radare2 rat roaraudio samhain sbcl silo-llnl sipxtapi
slirp smlnj sniffit spl-linux splint strace talksoup.app tau tcpdump
tcpslice tkrat topal trinity tripwire uclibc uclmmbase uhd uw-imap vde2
xfsdump yap zephyr zfs-fuse zfsutils.
I do not know what they use gethostid() for. :)
[1] curl -s https://codesearch.debian.net/results/2308ff3051ed55cc/packages.json | jq -r '.Packages[]'
--
Happy hacking
Petter Reinholdtsen
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