HP-UX Reference (11i v2 04/09) - 7 Device (Special) Files, 9 General Information, Index (vol 10)

s
glossary(9) glossary(9)
semaphore operation permissions
In the semop (2) and semctl (2) system call descriptions, the permission required for an operation is indi-
cated for each operation. Whether a particular process has these permissions for an object is determined
by the object’s permission mode bits as follows:
00400 Read by user
00200 Alter by user
00060 Read, Alter by group
00006 Read, Alter by others
Read and Alter permissions on a
semid are granted to a process if one or more of the following are true:
• The process’s effective user ID is superuser.
• The process’s effective user ID matches
sem_perm.[c]uid in the data structure associated with
semid and the appropriate bit of the "user" portion (0600) of
sem_perm.mode
is set.
• The process’s effective user ID does not match
sem_perm.[c]uid and the appropriate bit of the
"group" portion (060) of
sem_perm.mode is set.
• The process’s effective user ID does not match
sem_perm.[c]uid and the process’s effective group
ID does not match
sem_perm.[c
]gid and neither of sem_perm.[c]gid is in the process’s group
access list and the appropriate bit of the "other" portion (06) of
sem_perm.mode
is set.
Otherwise, the corresponding permissions are denied.
semid
See semaphore identifier.
session
Each process group is a member of a session. A process is considered to be a member of the session of
which its process group is a member. A newly created process joins the session of its creator. A process
can alter its session membership (see setsid (2)). A session can have multiple process groups (see
setpgid (2)).
session leader
A process that has created a session (see setsid (2)).
session lifetime
The period between when a session is created and the end of the lifetime of all process groups that
remain as members of the session.
set-group-ID bit
A single bit in the mode of every file in the file system. If a file is executed whose set-group-ID bit is
set, the effective group ID of the process which executed the file is set equal to the real group ID of
the owner of the file. See also group.
set-user-ID bit
A single bit in the mode of every file in the file system. If a file is executed whose set-user-ID bit is set,
the effective user ID of the process that executed the file is set equal to the real user ID of the owner
of the file.
shared library
An executable file that can be shared between several different programs. Code from a shared library is
not linked into the program by ld(1), but is instead mapped into the process’s address space at run time
by the dynamic loader. Shared libraries must contain position-independent code, and are created by
ld(1). They typically have the file name suffix
.sl.
shared memory identifier (shmid)
A unique positive integer created by a shmget(2) system call. Each shmid has a segment of memory
(referred to as a shared memory segment) and a data structure associated with it. The data structure is
referred to as
shmid_ds and contains the following members:
struct
ipc_perm shm_perm; /* operation permission struct */
int shm_segsz; /* size of segment */
ushort shm_cpid; /* creator pid */
HP-UX 11i Version 2: September 2004 − 20 − Hewlett-Packard Company Section 9−−21