HP-UX Reference (11i v2 07/12) - 7 Device (Special) Files, 9 General Information, Index (vol 10)

s
glossary(9) glossary(9)
ushort semncnt; /* # awaiting semval > cval */
ushort semzcnt; /* # awaiting semval = 0 */
semval
is a nonnegative integer. sempid is equal to the process ID of the last process that performed a
semaphore operation on this semaphore. semncnt is a count of the number of processes that are
currently suspended awaiting this semaphore’s
semval to become greater than its current value.
semzcnt is a count of the number of processes that are currently suspended awaiting this semaphore’s
semval to become zero.
semaphore operation permissions
In the semop(2) and semctl(2) system call descriptions, the permission required for an operation is indicated
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.
HP-UX 11i Version 2: December 2007 Update − 20 − Hewlett-Packard Company 259