AT&T UNIX™PC Unix System V Users Manual - tenox

INTR0 (2)
time_t shm_dtime;
time_t shm_ctime;
INTR0 (2)
I* last detach time *I
I* last change time *I
I* Times measured in sees since *I
I* 00:00:00 GMT, Jan. 1, 1970 *I
Shm_perm is a ipc_perm structure that specifies the shared
memory operation permission (see below). This structure includes
the following members:
ushort cuid; I* creator user id *I
ushort cgid; I* creator group id *I
ushort uid; I* user id *I
ushort gid; I* group id *I
ushort mode; I* rlw permission *I
Shm_segsz specifies the size of the shared memory segment.
Shm_cpid is the process id of the process that created the shared
memory identifier. Shm_lpid is the process id of the last process
that performed a shmop(2) operation. Shm_nattch is the
number of processes that currently have this segment attached.
Shm_atime is the time of the last shmat operation, shm_dtime
is the time of the last shmdt operation, and shm_ctime is the
time of the last shmctl(2) operation that changed one of the
members of the above structure.
Shared Memory Operation Permissions.
In the shmop(2) and shmctl(2) system call descriptions, the permission
required for an operation is interpreted as follows:
00400 Read by user
00200 Write by user
00060 Read, Write by group
00006 Read, Write by others
Read and Write permissions on a shmid are granted to a process if
one or more of the following are true:
The process's effective user ID is super-user.
The process's effective user ID matches shm_perm.[c] uid
in the data structure associated with shmid and the
appropriate bit of the "user" portion (0600) of
shm_perm.mode is set.
The process's effective user ID does not match
shm_perm.[c]uid and the process's effective group ID
matches shm_perm.[c]gid and the appropriate bit of the
"group" portion (060) of shm_perm.mode is set.
The process's effective user ID does not match
shm_perm.[c]uid and the process's effective group ID
does not match shm_perm.[c]gid and the appropriate
bit of the "other" portion (06) of shm_perm.mode is
set.
Otherwise, the corresponding permissions are denied.
SEE ALSO
intro(3).
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