.\" Copyright (c) 1993 Luigi P. Bai (lpb@softint.com) July 28, 1993
.\" and Copyright 1993 Giorgio Ciucci <giorgio@crcc.it>
.\" and Copyright 2004, 2005 Michael Kerrisk <mtk.manpages@gmail.com>
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.\" Modified 1993-07-28, Rik Faith <faith@cs.unc.edu>
.\" Modified 1993-11-28, Giorgio Ciucci <giorgio@crcc.it>
.\" Modified 1997-01-31, Eric S. Raymond <esr@thyrsus.com>
.\" Modified 2001-02-18, Andries Brouwer <aeb@cwi.nl>
.\" Modified 2002-01-05, 2004-05-27, 2004-06-17,
.\"    Michael Kerrisk <mtk.manpages@gmail.com>
.\" Modified 2004-10-11, aeb
.\" Modified, Nov 2004, Michael Kerrisk <mtk.manpages@gmail.com>
.\"	Language and formatting clean-ups
.\"	Updated shmid_ds structure definitions
.\"	Added information on SHM_DEST and SHM_LOCKED flags
.\"	Noted that CAP_IPC_LOCK is not required for SHM_UNLOCK
.\"		since kernel 2.6.9
.\" Modified, 2004-11-25, mtk, notes on 2.6.9 RLIMIT_MEMLOCK changes
.\" 2005-04-25, mtk -- noted aberrant Linux behavior w.r.t. new
.\"	attaches to a segment that has already been marked for deletion.
.\" 2005-08-02, mtk: Added IPC_INFO, SHM_INFO, SHM_STAT descriptions.
.\"
.\" Japanese Version Copyright (c) 1997 HANATAKA Shinya
.\"         all rights reserved.
.\" Translated 1997-03-01, HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Updated & Modified 2001-06-13, Yuichi SATO <ysato@h4.dion.ne.jp>
.\" Updated & Modified 2005-01-05, Yuichi SATO <ysato444@yahoo.co.jp>
.\" Updated & Modified 2005-09-06, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\" Updated & Modified 2005-10-08, Akihiro MOTOKI
.\" Updated 2006-07-21, Akihiro MOTOKI, LDP v2.36
.\"
.\"WORD:	shared memory		ͭ
.\"WORD:	segment			
.\"WORD:	owner			ͭ
.\"WORD:	group			롼
.\"WORD:	creator			
.\"WORD:	super-user		ѡ桼
.\"WORD:	detach			ʬΥ
.\"WORD:	attach			ղ
.\"WORD:	swap			å
.\"WORD:	identifier		̻
.\"WORD:	member			С
.\"WORD:	feature test macro	ǽޥ
.\"
.TH SHMCTL 2 2008-08-07 "Linux" "Linux Programmer's Manual"
.SH ̾
shmctl \- ͭ (shared memory) 椹
.SH 
.ad l
.B #include <sys/ipc.h>
.br
.B #include <sys/shm.h>
.sp
.BI "int shmctl(int " shmid ", int " cmd ", struct shmid_ds *" buf );
.ad b
.SH 
.BR shmctl ()
ϡ̻Ҥ
.I shmid
ζͭꡦȤФ
.I cmd
ǻؼ̿¹Ԥ롣
.PP
.I buf
ϡ \fIshmid_ds\fP ¤ΤؤΥݥ󥿤Ǥ롣
ι¤Τ \fI<sys/shm.h>\fP ǰʲΤ褦Ƥ
.PP
.in +4n
.nf
struct shmid_ds {
    struct ipc_perm shm_perm;    /* ͭȵ */
    size_t          shm_segsz;   /* ȤΥ (Х) */
    time_t          shm_atime;   /* Ǹղ (attach) λ */
    time_t          shm_dtime;   /* ǸʬΥ (detach) λ */
    time_t          shm_ctime;   /* ǸѹԤ줿 */
    pid_t           shm_cpid;    /*  (creator)  PID */
    pid_t           shm_lpid;    /* Ǹ shmat(2)/shmdt(2)  PID */
    shmatt_t        shm_nattch;  /* ղäƤ */
    ...
};
.fi
.in
.PP
.I ipc_perm
¤Τ \fI<sys/ipc.h>\fP ǰʲΤ褦Ƥ
(Ĵ줿եɤ
.B IPC_SET
ȤäǽǤ):
.PP
.in +4n
.nf
struct ipc_perm {
    key_t          __key;    /* shmget(2) Ϳ륭 */
    uid_t          \fBuid\fP;      /* ͭԤμ¸ UID */
    gid_t          \fBgid\fP;      /* ͭԤμ¸ GID */
    uid_t          cuid;     /* Ԥμ¸ UID */
    gid_t          cgid;     /* Ԥμ¸ GID */
    unsigned short \fBmode\fP;     /* \fB\fP + SHM_DEST 
                                SHM_LOCKED ե饰 */
    unsigned short __seq;    /* ֹ */
};
.fi
.in
.PP
.I cmd
Ȥͭͤϰʲ̤:
.br
.TP 10
.B IPC_STAT
.I shmid
˴ϢŤ줿ͥǡ¤Τξ
\fIbuf\fP ǻؤ줿
.I shmid_ds
¤Τ˥ԡ롣
ƤӽФ϶ͭꡦȤФ
ɤ߹ߵĤʤФʤʤ
.TP
.B IPC_SET
.I buf
ˤäƻؤ
.I shmid_ds
¤ΤΤĤΥСͤ
ζͭꡦȤ˴ϢŤ줿ͥǡ¤Τ˽񤭹ߡ
.I shm_ctime
С⹹롣
ʲΥեɤѹǤ롣
\fIshm_perm.uid\fP, \fIshm_perm.gid\fP,
\fIshm_perm.mode\fP (κDz 9 ӥå)
ƤӽФץμ¸ UID ͭ
.RI ( shm_perm.uid )
ޤϺ
.RI ( shm_perm.cuid )
Ȱפ뤫ƤӽФøʤФʤʤ
.TP
.B IPC_RMID
Ȥ˴ѤߤΥޡդ롣
ȤϡºݤˤϺǸץȤʬΥ (Ϣ
.I shmid_ds
¤Τ
.I shm_nattch
С 0 ˤʤä) ǤΤ˴롣
ƤӽФϽͭԤԤǤ뤫øʤФʤʤ
Ȥ˴Υޡդȡ
Ϣǡ¤Τˤ
.I shm_perm.mode
եɤ (ɸǤϤʤ)
.B SHM_DEST
ե饰ꤵ롣
Υǡ¤Τ
.B IPC_STAT
Ǽ롣
.PP
ƤӽФϺǽŪˤϥȤ˺줺˴\fIʤФʤʤ\fP
ǤʤСե (fault) 줿ڡ
꤫å (swap) ˻Ĥ³롣
.TP 10
.BR IPC_INFO " (Linux ͭ)"
ƥΤǤζͭ¤ȥѥ᡼˴ؤ
.I buf
ؤ¤Τ֤
ι¤Τ
.I shminfo
Ǥ (Τᥭ㥹ȤɬפǤ)
.I shminfo

.B _GNU_SOURCE
ǽޥ줿
.I <sys/shm.h>
ǰʲΤ褦:
.nf
.in +4n

struct  shminfo {
    unsigned long shmmax; /* 祻ȥ */
    unsigned long shmmin; /* Ǿȥ
                              1 */
    unsigned long shmmni; /* 祻ȿ */
    unsigned long shmseg; /* ץղäǤ
                             Ȥκ
                             ͥǤ̤ */
    unsigned long shmall; /* ͭκڡ
                             ƥΤǤ */
};

.in
.fi

.IR shmmni ,
.IR shmmax ,
.I shmall

.I /proc
ˤƱ̾ΥեͳѹǽǤ롣
ܤ
.BR proc (5)
򻲾ȡ
.TP
.BR SHM_INFO " (Linux ͭ)"
꤬ͭ񤷤Ƥ륷ƥ񸻤˴ؤ
Ǽ
.I shm_info
¤Τ֤
ι¤Τϡ
.B _GNU_SOURCE
ǽޥ줿
.I <sys/shm.h>
ǰʲΤ褦:
.nf
.in +4n

struct shm_info {
    int           used_ids; /* ¸ߤ륻ȿ */
    unsigned long shm_tot;  /* ͭΥڡ */
    unsigned long shm_rss;  /* ˤ (åפ
                               ʤ) ͭڡ */
    unsigned long shm_swp;  /* åפƤ붦ͭ
                               ڡ */
    unsigned long swap_attempts;
                            /* Linux 2.4 ʹߤǤ̤ */
    unsigned long swap_successes;
                            /* Linux 2.4 ʹߤǤ̤ */
};
.in
.fi
.TP
.BR SHM_STAT " (Linux ͭ)"
.B IPC_STAT
Ʊ
.I shmid_ds
¤Τ֤
â
.I shmid
ϡȼ̻ҤǤϤʤƥƤζͭ
Ȥ˴ؤ륫ͥؤΥǥå
Ǥ롣
.PP
ƤӽФϡ\fIcmd\fP ˰ʲͤꤹ뤳ȤǡͭꡦȤ
åפ뤳ȤɻߤꡢĤǤ:
.br
.TP 10
.BR SHM_LOCK " (Linux ͭ)"
ͭꡦȤ򥹥åפ뤳Ȥɻߤ롣
åͭˤʤä塢ƤӽФϡ
¸ߤ뤳Ȥ׵ᤵ줿ƤΥڡեȤʤФʤʤ
Ȥåȡ
Ϣǡ¤Τˤ
.I shm_perm.mode
եɤ (ɸŪǤϤʤ)
.B SHM_LOCKED
ե饰ꤵ롣
Υǡ¤Τ
.B IPC_STAT
Ǽ롣
.TP
.BR SHM_UNLOCK " (Linux ͭ)"
ȤΥååסȤ뤳Ȥǽˤ롣
.PP
2.6.10 ΥͥǤϡøץ
.B SHM_LOCK

.B SHM_UNLOCK
Ѥ뤳ȤǤ
2.6.10 ʹߤΥͥǤϡøץǤäƤ⼡ξ
Ѥ뤳ȤǤ롣ξȤϡץμ¸ UID
ΥȤνͭԤ⤷ϺԤ UID Ȱפ
.RB ( SHM_LOCK
ξˤ) åιפ
.B RLIMIT_MEMLOCK
꥽
.RB ( setrlimit (2)
) ϰäƤ뤳ȤǤ롣
.\" There was some weirdness in 2.6.9: SHM_LOCK and SHM_UNLOCK could
.\" be applied to a segment, regardless of ownership of the segment.
.\" This was a botch-up in the move to RLIMIT_MEMLOCK, and was fixed
.\" in 2.6.10.  MTK, May 2005
.SH ֤
.B IPC_INFO

.B SHM_INFO
ϡȡƤζͭꥻȤ˴ؤ
Ƥ륫ͥλ楨ȥΥǥå
֤ͤ
(ξϡƥƤζͭꥻȤ˴ؤ
뤿ˡ
.B SHM_STAT
򷫤֤¹Ԥݤ˻ѤǤ)
.B SHM_STAT
ϡȡ
.I shmid
ǻꤵ줿ǥåĶͭꥻȤμ̻Ҥ֤
¾ϡξ 0 ֤

顼ξ \-1 ֤
.I errno
Ŭڤꤹ롣
.SH 顼
.TP
.B EACCES

\fBIPC_STAT\fP ޤ \fBSHM_STAT\fP ׵ᤵ졢
\fIshm_perm.mode\fP 
.I shmid
ؤɤ߹ߥƤ餺
ĸƤӽФץ
.B CAP_IPC_OWNER
ѥӥƥ (capability) äƤʤ
.TP
.B EFAULT
.I cmd

.B IPC_SET

.B IPC_STAT
ꤵ줿
.I buf
ǻؤƤ륢ɥ쥹˥Ǥʤ
.TP
.B EIDRM
\fIshmid\fP  (remove) 줿̻ (identifier) ؤƤ롣
.TP
.B EINVAL
\fIshmid\fP ͭʼ̻ҤǤʤ
\fIcmd\fP ͭʥޥɤǤʤ
⤷ϡ
.B SHM_STAT
ξˡ
.I shmid
ǻꤵ줿ǥå̤ͤѤΥåȤ򻲾ȤƤ
.TP
.B ENOMEM
(2.6.9 ʹߤΥͥˤ)
.B SHM_LOCK
ꤵ졢
åͽΥȤΥ
(å붦ͭꡦȤιץХȿ) 
ƤӽФץμ¥桼 ID ˤĤƤ¤Ķ
¤
.B RLIMIT_MEMLOCK
եȻ¤
.RB ( setrlimit (2)
򻲾)
.TP
.B EOVERFLOW
\fBIPC_STAT\fP ߤ졢GID  UID ͤ
.I buf
ǻؼ빽¤Τ˳Ǽˤ礭᤮롣
.TP
.B EPERM
\fBIPC_SET\fP  \fBIPC_RMID\fP ߤ졢
ƤӽФץμ¸桼 ID 
.RI ( shm_perm.cuid )
Ǥͭ
.RI ( shm_perm.uid )
Ǥʤץøʤ (Linux Ǥ
.B CAP_SYS_ADMIN
ѥӥƥʤ)

ޤ (2.6.9 Υͥ)
.B SHM_LOCK
ޤ
.B SHM_UNLOCK
ꤵƤ뤬ץøʤ
(Linux Ǥ
.B CAP_IPC_LOCK
ѥӥƥʤ)
(Linux 2.6.9 ʹߤǤϡ
.B RLIMIT_MEMLOCK
 0 ǸƤӽФøʤˤ⡢Υ顼롣)
.SH 
SVr4, POSIX.1-2001.
.\" SVr4 ˤ¾ EINVAL, ENOENT, ENOSPC, ENOMEM,
.\" EEXIST 顼ˤĤƤεҤ롣
.\" SVr4  SVID ˤ EIDRM 顼ˤĤƤεҤϤʤ
.SH 
.BR IPC_INFO ,
.BR SHM_STAT ,
.B SHM_INFO
ϡ
.BR ipcs (8)
ץdzƺѤλ񸻤˴ؤ󶡤뤿
ѤƤ롣衢ѹ줿ꡢ
/proc ե륷ƥΥ󥿥ե˰ư뤫⤷ʤ

Linux Ǥϡ
.I shmctl(IPC_RMID)
ȤäƤǤ˺ޡĤƤ붦ͭꡦȤ
ץղ (attach)
.RB ( shmat (2))
뤳ȤĤƤ롣
εǽ¾ Unix μǤѤǤʤ
ܿθץꥱǤϤ˰¸ʤ褦ˤ٤Ǥ롣

\fI¤ shmid_ds\fP ¿Υեɤϡ
Linux 2.2 Ǥ
.I short
äLinux 2.4 Ǥ
.I long
ˤʤä
ˤϡglibc-2.1.91 ʹߤδĶ
ƥѥ뤹нʬǤ롣
ͥϿθƤӽФȸŤθƤӽФ
.I cmd

.B IPC_64
ե饰Ƕ̤롣
.SH Ϣ
.BR mlock (2),
.BR setrlimit (2),
.BR shmget (2),
.BR shmop (2),
.BR capabilities (7),
.BR shm_overview (7),
.BR svipc (7)