SystemV IPC. Segment info

[Vagner]

Hello!
A few weeks ago, I ran into problem, which related to SystemV IPC.
More than 20 processes attached to a segment shared queue. Process-initiator for
create segment was killed, as process which was accessed to segment
last. Segment didn't free memory, but tagged it as SHMSEG_REMOVED as
the result. This is a reason of memory overflow (memory assotiated as
shm). Moreover, processes, which was attached to this segment did't
get a new data. I have one resolve. I need to restarted all process,
which still attached to segment. But this reason have a problem. We
haven't list of this processes at system. Moreover, struct shmid_ds,
which described segment, haven't this info too.

This patch is a resolve of problem. It: 
- added a linked list of structures shmid_pi in struct shmid_ds. PID
(and last access time) recorded to this struct consistently. Memory
allocates with ident 'shminfo' for this list of struct shmid_pi.
- added syscall shminf for get all elements from list shmid_ds.
- added option [-P] in ipcs(1) for system call shminf.

Thanks.

-- 
Respectfully,
Stanislav Putrya
System administrator
FotoStrana.Ru Ltd.
ICQ IM: 328585847
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email: putrya at playform.ru
email: root.vagner at gmail.com
site: bsdway.ru
site: fotostrana.ru

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