HP-UX Reference (11i v3 07/02) - 7 Device (Special) Files, 9 General Information, Index (vol 10)

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glossary(9) glossary(9)
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 */
size_t shm_segsz; /* size of segment */
pid_t shm_cpid; /* creator pid */
pid_t shm_lpid; /* pid of last operation */
shmatt_t shm_nattch; /* number of current attaches */
time_t shm_atime; /* last attach time */
time_t shm_dtime; /* last detach time */
time_t shm_ctime; /* last change time */
/* Times measured in secs since */
/* 00:00:00 GMT, Jan. 1, 1970 */
Shared memory identifiers can be created using ftok(3C).
shm_perm is a ipc_perm structure that specifies the permission for a shmop(2) or shmctl(2) operation
(see below). This structure includes the following members:
uid_t cuid; /* creator user id */
gid_t cgid; /* creator group id */
uid_t uid; /* user id */
gid_t gid; /* group id */
mode_t mode; /* r/w permission */
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 indi-
cated for each operation. Whether a particular process has the permission to perform a shmop(2) or
shmctl(2) operation on an object is determined by the object’s permission mode bits as follows:
00400 Read by user
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