An introductory line shall be written with the format:
"IPC status from %s as of %s\n", <source>, <date>
where <source> indicates the source used to gather the statistics
and <date> is the information that would be produced by the date
command when invoked in the POSIX locale.
The ipcs utility then shall create up to three reports depending
upon the -q, -m, and -s options. The first report shall indicate
the status of message queues, the second report shall indicate
the status of shared memory segments, and the third report shall
indicate the status of semaphore sets.
If the corresponding facility is not installed or has not been
used since the last reboot, then the report shall be written out
in the format:
"%s facility not in system.\n", <facility>
where <facility> is Message Queue, Shared Memory, or Semaphore,
as appropriate. If the facility has been installed and has been
used since the last reboot, column headings separated by one or
more <space> characters and followed by a <newline> shall be
written as indicated below followed by the facility name written
out using the format:
"%s:\n", <facility>
where <facility> is Message Queues, Shared Memory, or Semaphores,
as appropriate. On the second and third reports the column
headings need not be written if the last column headings written
already provide column headings for all information in that
report.
The column headings provided in the first column below and the
meaning of the information in those columns shall be given in
order below; the letters in parentheses indicate the options that
shall cause the corresponding column to appear; ``all'' means
that the column shall always appear. Each column is separated by
one or more <space> characters. Note that these options only
determine what information is provided for each report; they do
not determine which reports are written.
T (all) Type of facility:
q Message queue.
m Shared memory segment.
s Semaphore.
This field is a single character written using the
format %c.
ID (all) The identifier for the facility entry. This field
shall be written using the format %d.
KEY (all) The key used as an argument to msgget(), semget(), or
shmget() to create the facility entry.
Note: The key of a shared memory segment is changed
to IPC_PRIVATE when the segment has been
removed until all processes attached to the
segment detach it.
This field shall be written using the format 0x%x.
MODE (all) The facility access modes and flags. The mode shall
consist of 11 characters that are interpreted as
follows.
The first character shall be:
S If a process is waiting on a msgsnd()
operation.
- If the above is not true.
The second character shall be:
R If a process is waiting on a msgrcv()
operation.
C or - If the associated shared memory segment is to
be cleared when the first attach operation is
executed.
- If none of the above is true.
The next nine characters shall be interpreted as
three sets of three bits each. The first set refers
to the owner's permissions; the next to permissions
of others in the usergroup of the facility entry; and
the last to all others. Within each set, the first
character indicates permission to read, the second
character indicates permission to write or alter the
facility entry, and the last character is a <hyphen-
minus> ('-').
The permissions shall be indicated as follows:
r If read permission is granted.
w If write permission is granted.
a If alter permission is granted.
- If the indicated permission is not granted.
The first character following the permissions
specifies if there is an alternate or additional
access control method associated with the facility.
If there is no alternate or additional access control
method associated with the facility, a single <space>
shall be written; otherwise, another printable
character is written.
OWNER (all) The user name of the owner of the facility entry. If
the user name of the owner is found in the user
database, at least the first eight column positions
of the name shall be written using the format %s.
Otherwise, the user ID of the owner shall be written
using the format %d.
GROUP (all) The group name of the owner of the facility entry. If
the group name of the owner is found in the group
database, at least the first eight column positions
of the name shall be written using the format %s.
Otherwise, the group ID of the owner shall be written
using the format %d.
The following nine columns shall be only written out for message
queues:
CREATOR (a,c)
The user name of the creator of the facility entry.
If the user name of the creator is found in the user
database, at least the first eight column positions
of the name shall be written using the format %s.
Otherwise, the user ID of the creator shall be
written using the format %d.
CGROUP (a,c)
The group name of the creator of the facility entry.
If the group name of the creator is found in the
group database, at least the first eight column
positions of the name shall be written using the
format %s. Otherwise, the group ID of the creator
shall be written using the format %d.
CBYTES (a,o)
The number of bytes in messages currently outstanding
on the associated message queue. This field shall be
written using the format %d.
QNUM (a,o) The number of messages currently outstanding on the
associated message queue. This field shall be written
using the format %d.
QBYTES (a,b)
The maximum number of bytes allowed in messages
outstanding on the associated message queue. This
field shall be written using the format %d.
LSPID (a,p) The process ID of the last process to send a message
to the associated queue. This field shall be written
using the format:
"%d", <pid>
where <pid> is 0 if no message has been sent to the
corresponding message queue; otherwise, <pid> shall
be the process ID of the last process to send a
message to the queue.
LRPID (a,p) The process ID of the last process to receive a
message from the associated queue. This field shall
be written using the format:
"%d", <pid>
where <pid> is 0 if no message has been received from
the corresponding message queue; otherwise, <pid>
shall be the process ID of the last process to
receive a message from the queue.
STIME (a,t) The time the last message was sent to the associated
queue. If a message has been sent to the
corresponding message queue, the hour, minute, and
second of the last time a message was sent to the
queue shall be written using the format
%d:%2.2d:%2.2d. Otherwise, the format " no-entry"
shall be written.
RTIME (a,t) The time the last message was received from the
associated queue. If a message has been received
from the corresponding message queue, the hour,
minute, and second of the last time a message was
received from the queue shall be written using the
format %d:%2.2d:%2.2d. Otherwise, the format " no-
entry" shall be written.
The following eight columns shall be only written out for shared
memory segments.
CREATOR (a,c)
The user of the creator of the facility entry. If the
user name of the creator is found in the user
database, at least the first eight column positions
of the name shall be written using the format %s.
Otherwise, the user ID of the creator shall be
written using the format %d.
CGROUP (a,c)
The group name of the creator of the facility entry.
If the group name of the creator is found in the
group database, at least the first eight column
positions of the name shall be written using the
format %s. Otherwise, the group ID of the creator
shall be written using the format %d.
NATTCH (a,o)
The number of processes attached to the associated
shared memory segment. This field shall be written
using the format %d.
SEGSZ (a,b) The size of the associated shared memory segment.
This field shall be written using the format %d.
CPID (a,p) The process ID of the creator of the shared memory
entry. This field shall be written using the format
%d.
LPID (a,p) The process ID of the last process to attach or
detach the shared memory segment. This field shall be
written using the format:
"%d", <pid>
where <pid> is 0 if no process has attached the
corresponding shared memory segment; otherwise, <pid>
shall be the process ID of the last process to attach
or detach the segment.
ATIME (a,t) The time the last attach on the associated shared
memory segment was completed. If the corresponding
shared memory segment has ever been attached, the
hour, minute, and second of the last time the segment
was attached shall be written using the format
%d:%2.2d:%2.2d. Otherwise, the format " no-entry"
shall be written.
DTIME (a,t) The time the last detach on the associated shared
memory segment was completed. If the corresponding
shared memory segment has ever been detached, the
hour, minute, and second of the last time the segment
was detached shall be written using the format
%d:%2.2d:%2.2d. Otherwise, the format " no-entry"
shall be written.
The following four columns shall be only written out for
semaphore sets:
CREATOR (a,c)
The user of the creator of the facility entry. If the
user name of the creator is found in the user
database, at least the first eight column positions
of the name shall be written using the format %s.
Otherwise, the user ID of the creator shall be
written using the format %d.
CGROUP (a,c)
The group name of the creator of the facility entry.
If the group name of the creator is found in the
group database, at least the first eight column
positions of the name shall be written using the
format %s. Otherwise, the group ID of the creator
shall be written using the format %d.
NSEMS (a,b) The number of semaphores in the set associated with
the semaphore entry. This field shall be written
using the format %d.
OTIME (a,t) The time the last semaphore operation on the set
associated with the semaphore entry was completed. If
a semaphore operation has ever been performed on the
corresponding semaphore set, the hour, minute, and
second of the last semaphore operation on the
semaphore set shall be written using the format
%d:%2.2d:%2.2d. Otherwise, the format " no-entry"
shall be written.
The following column shall be written for all three reports when
it is requested:
CTIME (a,t) The time the associated entry was created or changed.
The hour, minute, and second of the time when the
associated entry was created shall be written using
the format %d:%2.2d:%2.2d.
