shooting oneself in the foot with "ldconfig -v"
noackjr at alumni.rice.edu
Wed Oct 10 21:27:53 PDT 2007
On Wed, October 10, 2007 18:34, Erik Trulsson wrote:
> On Wed, Oct 10, 2007 at 05:41:29PM -0400, Jonathan Noack wrote:
>> Hey folks,
>> I'm running 6.2-p8 and was trying to clean up my "portsclean -L" output
>> today. It was reporting tons of duplicate libraries in /usr/X11R6 and
>> /usr/local even though X11R6 is an alias to /usr/local. I tracked the
>> problem to portclean's use of `ldconfig -elf -r` which was reporting
>> directories and libraries in /usr/X11R6. I read the ldconfig manpage in
>> an attempt to understand more and saw this line:
>> -v Switch on verbose mode.
>> I told myself, "Self, the '-v' option may allow you to determine what's
>> going on. It can't help knowing more!" Alas, the "-v" option doesn't
>> behave as advertised. Instead it clears the shared library cache
>> (reference: http://www.parsed.org/tip/231/). An empty shared library
>> cache means all dynamically-linked programs fail. This has the
>> side-effect of preventing me from logging into the box to fix it (I
>> off before I figured this out). "Reboot and all will be well," you say?
>> Yes, on boot /etc/rc.d/ldconfig is run and it builds the shared library
>> cache. Unfortunately, the box is 1,000 miles away in my apartment. :(
>> This brings me to the question:
>> Is the "-v" option broken or is the documentation out of date?
> No, the '-v' option behaves as documented and is not broken.
> It is, however, intended to be used in conjunction with some other option.
> You see, running ldconfig(8) without any arguments at all will clear the
> shared library cache. (Actually it will replace the cache with the files
> found in the specified directories, but since none were specified...)
> Adding '-v' will not change what ldconfig does, except possibly letting
> it be a bit more verbose about what happens.
Not according to ldconfig(8); running ldconfig without any arguments
-R Rescan the previously configured directories. This opens the
previous hints file and fetches the directory list from the
header. Any additional pathnames on the command line are also
processed. This is the default action when no parameters are
The previously configured directory list was fully populated, so
effectively there should have been no change as the previously configured
directories were untouched and I specified no additional pathnames.
> ldconfig is behaving as designed and documented, so the bug, such as it
> is in the design of ldconfig that lets you screw up the machine by simply
> running ldconfig without any option.
Are you saying that by specifying "-v" I no longer satisfied the "no
parameters are given" clause and ended up in a default place in the logic?
I could see how an unconditional shared library cache clear coupled with
no additional action (no matching actions to pursue) could get me the
results I got. If so that behavior is really confusing. IMHO a verbose
switch shouldn't change behavior; it should just spam the console a lot.
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