[ClusterLabs] Antw: Coming in Pacemaker 2.0.0: Reliable exit codes

[Ken Gaillot]

On Thu, 2018-01-11 at 08:59 +0100, Ulrich Windl wrote:
> Hi!
> 
> Will those exit code be compatible with <sysexits.h>, i.e. will it be
> a superset or a subset of it? If not, it would be the right time.

Yes! It will be a superset. From the new source code:

/*
 * Exit statuses
 *
 * We want well-specified (i.e. OS-invariant) exit status codes for our
daemons
 * and applications so they can be relied on by callers. (Function
return codes
 * and errno's do not make good exit statuses.)
 *
 * The only hard rule is that exit statuses must be between 0 and 255;
all else
 * is convention. Universally, 0 is success, and 1 is generic error
(excluding
 * OSes we don't support -- for example, OpenVMS considers 1 success!).
 *
 * For init scripts, the LSB gives meaning to 0-7, and sets aside 150-
199 for
 * application use. OCF adds 8-9 and 189-199.
 *
 * sysexits.h was an attempt to give additional meanings, but never
really
 * caught on. It uses 0 and 64-78.
 *
 * Bash reserves 2 ("incorrect builtin usage") and 126-255 (126 is
"command
 * found but not executable", 127 is "command not found", 128 + n is
 * "interrupted by signal n").
 *
 * tldp.org recommends 64-113 for application use.
 *
 * We try to overlap with the above conventions when practical.
 */

We are using 0-1 as success and generic error, 2-7 overlapping with
LSB+OCF, 64-78 overlapping with sysexits.h, 100-109 (possibly more
later) for custom errors, and 124 overlapping with timeout(1).

> 
> Regards,
> Ulrich
> 
> 
> > > > Ken Gaillot <kgaillot at redhat.com> schrieb am 10.01.2018 um
> > > > 23:22 in Nachricht
> 
> <1515622941.4815.21.camel at redhat.com>:
> > Every time you run a command on the command line or in a script, it
> > returns an exit status. These are most useful in scripts to check
> > for
> > errors.
> > 
> > Currently, Pacemaker daemons and command-line tools return an
> > unreliable mishmash of exit status codes, sometimes including
> > negative
> > numbers (which get bitwise-remapped to the 0-255 range) and/or C
> > library errno codes (which can vary across OSes).
> > 
> > The only thing scripts could rely on was 0 means success and
> > nonzero
> > means error.
> > 
> > Beginning with Pacemaker 2.0.0, everything will return a well-
> > defined
> > set of reliable exit status codes. These codes can be viewed using
> > the
> > existing crm_error tool using the --exit parameter. For example:
> > 
> >     crm_error --exit --list
> > 
> > will list all possible exit statuses, and
> > 
> >     crm_error --exit 124
> > 
> > will show a textual description of what exit status 124 means.
> > 
> > This will mainly be of interest to users who script Pacemaker
> > commands
> > and check the return value. If your scripts rely on the current
> > exit
> > codes, you may need to update your scripts for 2.0.0.
> > -- 
> > Ken Gaillot <kgaillot at redhat.com>
> > 
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> 
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-- 
Ken Gaillot <kgaillot at redhat.com>