[lsb-discuss] gLSB: sysinit: clearify algorithm for determining status of programs
tobias.burnus at physik.fu-berlin.de
Wed Sep 3 13:35:58 PDT 2003
the gLSB 1.3 initfunctions.sgml contains:
"If an entry is found in /var/run/basename.pid, then that value is
returned. Compliant implementations of the LSB may attempt other
mechanisms for determining the pid(s), although this is not required
(and not recommended, since a user can trick startup scripts by creating
processes that appear to be system programs in the process list thus
creating a potential security exposure)."
This explicily allows this: first checking for the pidfile and then,
if it doesn't exist, checking the /proc system (using e.g. pidof).
There are two possible reasons for the case that there is no pidfile
present: (a) the program doesn't use pidfiles (implicitly assumed above)
or (b) it is not running.
This makes trouble when a daemon is started twice with different
pid and coniguration files. My all ready cited example,
/usr/sbin/sshd -f /etc/ssh/sshd_config2 -p 123 (/var/run/zedv-sshd.pid),
shows that pidof $BIN == pidof /usr/sbin/sshd has no chance to
discriminate those two. Considering that one can pass a basename instead of
a pathname to pidofproc and killproc, things are even worse.
I therefore would like to prohibit the checking of other pids but those
given in the pidfile. My main problem is that at least three distributions
use the pidof fallback: RedHat, SuSE and Debian. Thus I'm a bit reluctant to
simply disallow this.
Therefore I would really appreciate to get some feedback from the
The current spec (gLSB 1.9-CVS) is now:
"Compliant implementations may (but should not) use other mechanisms
besides those based on pidfiles."
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