Although it seems that System V IPC is obsolete thing, it's still used by many (enterprise) tools like databases, application servers etc.
The classic tool ipcs(1) provides basic overview, unfortunately the output is very fixed and it's impossible to mix the output columns (for example --pid and --creator cannot be used together etc.). It's also very difficult to extend the current implementation without break backward compatibility.
The solution is a new libsmartcols based tool: lsipc(1). It's like many another util-linux ls-like tools, columns are maintains independently, it's easy to extend, user has absolute control on the output and it provides more output formats (including JSON).
The important and unique is the default (--global) output:
# lsipc
RESOURCE DESCRIPTION LIMIT USED USE%
MSGMNI Number of message queues 32000 0 0.00%
MSGMAX Max size of message (bytes) 8192 0 0.00%
MSGMNB Default max size of queue (bytes) 16384 0 0.00%
SHMMNI Shared memory segments 4096 21 0.51%
SHMALL Shared memory pages 268435456 294049 0.11%
SEMMNS Total number of semaphores 1024000000 0 0.00%
SEMMNI Number of Semaphore IDs 32000 0 0.00%
the information about shared memory is provided with COMMAND column, that makes things more human friendly:
# lsipc --shmem
KEY ID PERMS OWNER SIZE NATTCH STATUS CTIME CPID LPID COMMAND
0x6c6c6536 0 rw------- root 4K 0 Jul16 288 288
0x00000000 327681 rw------- kzak 4M 2 dest Jul16 1487 992 gjs /home/kzak/.local/share/gnome-shell/extensions/
0x00000000 393219 rw------- kzak 512K 2 dest Jul16 1141 2853 /usr/bin/gnome-shell
0x00000000 2064389 rw------- kzak 384K 2 dest Jul17 9443 992 xchat
0x00000000 47611910 rw------- kzak 8M 2 dest 10:07 2853 804 /usr/lib64/firefox/firefox
0x00000000 2228231 rw------- kzak 384K 2 dest Jul17 9443 992 xchat
0x00000000 2195464 rw------- kzak 2M 2 dest Jul17 9443 992 xchat
0x00000000 42303503 rw------- kzak 8M 2 dest Jul22 1340 992 /usr/bin/gnome-software --gapplication-service
0x00000000 42270736 rw------- kzak 4M 2 dest Jul22 1340 992 /usr/bin/gnome-software --gapplication-service
0x00000000 43188243 rw------- kzak 4M 2 dest Jul22 8873 1845 /usr/libexec/gnome-terminal-server
0x00000000 33882133 rw------- kzak 384K 2 dest Jul20 26049 992 /usr/bin/python3 /usr/bin/hp-systray --force-startup
and you can define your own output:
# lsipc --shmem -o KEY,SIZE,PERMS
KEY SIZE PERMS
0x6c6c6536 4K rw-------
0x00000000 4M rw-------
0x00000000 512K rw-------
0x00000000 384K rw-------
0x00000000 8M rw-------
0x00000000 384K rw-------
0x00000000 2M rw-------
0x00000000 8M rw-------
0x00000000 4M rw-------
0x00000000 4M rw-------
0x00000000 384K rw-------
or ask for specific segment:
# lsipc --shmem --id 47611910
Key: 0x00000000
ID: 47611910
Owner: kzak
Permissions: rw-------
Creator UID: 1000
Creator user: kzak
Creator GID: 1000
Creator group: kzak
UID: 1000
User name: kzak
GID: 1000
Group name: kzak
Last change: Thu Jul 23 10:07:46 2015
Segment size: 8M
Attached processes: 2
Status: dest
Attach time: Thu Jul 23 10:07:46 2015
Creator command: /usr/lib64/firefox/firefox
Creator PID: 2853
Last user PID: 804
and it should be easy to export complex info about IPC to the monitoring tool:
# lsipc --json -o resource,limit,used
{
"ipclimits": [
{"resource": "MSGMNI", "limit": "32000", "used": "0"},
{"resource": "MSGMAX", "limit": "8192", "used": "0"},
{"resource": "MSGMNB", "limit": "16384", "used": "0"},
{"resource": "SHMMNI", "limit": "4096", "used": "11"},
{"resource": "SHMALL", "limit": "268435456", "used": "8097"},
{"resource": "SEMMNS", "limit": "1024000000", "used": "0"},
{"resource": "SEMMNI", "limit": "32000", "used": "0"}
]
}
lsipc(1) will be available in util-linux v2.27 (probaly August 2015).
