.\" This man page is Copyright (C) 1999 Andi Kleen <ak@muc.de>.
.\" Permission is granted to distribute possibly modified copies
.\" of this page provided the header is included verbatim,
.\" and in case of nontrivial modification author and date
.\" of the modification is added to the header.
.\"
.\" Modified, 2003-12-02, Michael Kerrisk, <mtk-manpages@gmx.net>
.\" Modified, 2003-09-23, Adam Langley
.\" Modified, 2004-05-27, Michael Kerrisk, <mtk-manpages@gmx.net>
.\"	Added SOCK_SEQPACKET
.\"
.\" Japanese Version Copyright (c) 1999 Shouichi Saito and
.\"     NAKANO Takeo all rights reserved.
.\" Translated 1999-12-06, NAKANO Takeo <nakano@apm.seikei.ac.jp>
.\"     based on the work by Shouichi Saito <ss236rx@ymg.urban.ne.jp>
.\" Updated 2003-01-07, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\" Updated 2005-02-21, Akihiro MOTOKI
.\"
.\"WORD		abstract namespace		̾
.\"WORD         anonymous socket		̵̾å
.\"WORD		credential			Ǥ
.\"WORD		ancillary message		å
.\"WORD		file descriptor			եǥץ
.\"
.\" : ݤ Unix  capitalize Ƥȡ
.\"       LDP_man-pages 1.662.01 ˤ unix  Unix ѹꡢ
.\"       տŪɽȻפ롣
.\"
.TH UNIX  7 2004-05-27 "Linux Man Page" "Linux Programmer's Manual" 
.SH ̾
unix, PF_UNIX, AF_UNIX, PF_LOCAL, AF_LOCAL \- 
ץ̿ѤΥå
.SH 
.B #include <sys/socket.h>
.br
.B #include <sys/un.h>

.IB unix_socket " = socket(PF_UNIX, type, 0);"
.br
.IB error " = socketpair(PF_UNIX, type, 0, int *" sv ");"

.SH 
.B PF_UNIX
.RB ( PF_LOCAL

.BR PF_FILE
Ȥ) åȥեߥ꡼ϡƱޥǥץƱΤ
ΨŪ̿뤿Ѥ롣 Unix åȤϡ
.RB ( socketpair (2)
Ǻ) ̾ʤˤǤ뤷åȷΥե
ϢŤ뤳ȤǤ롣
 Linux Ǥϡե륷ƥ˰¸ʤ
̾ (abstract namespace) ⥵ݡȤƤ롣

.\" MOTOKI: 䤹褦 .TP ѹ
ͭʥפϰʲ̤Ǥ:
.TP
.B SOCK_STREAM
ȥ꡼ظΥå
.TP
.B SOCK_DGRAM
å¸ǡظΥå
(ۤȤɤ Unix μǤϡUnix ɥᥤ󡦥ǡࡦåȤ
˿Ǥǡ¤ؤϹԤʤ)
.TP
.B SOCK_SEQPACKET
(ͥ 2.6.4 ʹߤѤǤ) 
å¸줿ǥåϤ³ظå

Unix åȤǤϡǡȤä
եǥץץοǤ (credential) 
뤳ȤǤ롣

.SH ɥ쥹Υեޥå
Unix ɥ쥹ϥե륷ƥǤϥե̾Ȥ졢
֤̾Ǥ¾ȽŤʤʤʸȤƤ롣
.BR socketpair (2)
Ǻ줿åȤ̾ʤ̾ʤåȰʳΥåȤǤϡ
³西åȤΥɥ쥹
.BR connect (2)
ȤäǤ롣
륢ɥ쥹
.BR bind (2)
ȤäǤ롣
륢ɥ쥹ޤäƤʤåȤ³줿硢
ưŪ֤̾¾ȽŤʤʤɥ쥹롣

.RS
.nf
#define UNIX_PATH_MAX	108

.ta 4n 17n 42n
struct sockaddr_un {
	sa_family_t	sun_family;	/* AF_UNIX */
	char	sun_path[UNIX_PATH_MAX];	/* pathname */
};
.fi
.RE 

.B sun_family
ˤɬ
.BR AF_UNIX
äƤ롣
.B sun_path
ˤϡե륷ƥΥå̾ NULL ǽü줿ʸȤ
ǼƤ롣
.B sun_path
Х 0 ǻϤޤ硢
 Unix ץȥ⥸塼ǴƤ
֤̾򻲾Ȥ롣
֤̾ˤ륽åȤΥɥ쥹ϡ
.BR sun_path
λĤΥХȤɽ롣
֤֤̾̾ NULL ǽüƤʤȤա

.SH åȥץ
ŪͳˤꡢΥץ
Ȥ PF_UNIX ͭΥץǤäƤ SOL_SOCKET ǻꤹ롣
åȥեߥ꡼Ȥ SOL_SOCKET ꤹȡ
.BR setsockopt (2)
ǥץǤ
.BR getsockopt (2)
ǼǤ롣
.\" NAKANO added this TP
.TP
.B SO_PASSCRED
ץåȤƿǤǤ褦ˤ롣
Υץ󤬥åȤƤơޤåȤ³Ƥʤȡ
֤̾¾ȽŤʤʤ̾ưŪ롣
֡ͤΥե饰롣

.SH å
ǡˤϡ
.BR sendmsg (2)

.BR recvmsg (2)
Ѥ롣
Ūͳˤꡢʲ˼åη
Ȥ PF_UNIX ͭΤΤǤäƤ SOL_SOCKET ǻꤹ롣
ˤϡ¤
.B cmsghdr

.B cmsg_level
եɤ SOL_SOCKET 򥻥åȤ
.B cmsg_type
եɤ˥פ򥻥åȤ롣
ܺ٤
.BR cmsg (3)
򸫤衣
.\"O
.TP
.B SCM_RIGHTS
¾Υץǥץ󤵤줿եǥץΥåȤ롣
ǡʬ˥եǥץäƤ롣
Ϥ줿եǥץϡ
.BR dup (2)
줿Τ褦˿񤦡
.\"O
.TP
.B SCM_CREDENTIALS
Unix Ǥ롣ǧڤѤ뤳ȤǤ롣
Ǥϡ
.B struct ucred
åȤϤ롣

.RS
.nf
.ta 4n 11n 17n
struct ucred {
	pid_t	pid;	/* process id of the sending process */  
	uid_t	uid;	/* user id of the sending process */ 
	gid_t	gid;	/* group id of the sending process */ 
};
.fi
.RE 
 
¦ꤷǤϡͥ뤬å롣
¸桼 ID  0 Υץˤϡ
ʬȰʳͤꤹ롣
¦ϰʲ 3 ĤꤷʤФʤʤ
1) ʬȤΥץ ID
.RB ( CAP_SYS_ADMIN
¤äƤʤ)
2) ʬȤΥ桼 ID 뤤ϼ¸桼 ID  set user ID
.RB ( CAP_SETUID
¤äƤʤ)
3) ʬȤΥ롼 ID 뤤ϼ¹ԥ롼 ID  set group ID
.RB ( CAP_SETGID
äƤʤ)
.B struct ucred
å뤿ˤϡåȤФ
.B SO_PASSCRED
ץͭˤʤƤϤʤʤ
.SH С
.B SCM_CREDENTIALS
֤̾ϡLinux 2.2 Ƴ줿
ܿɬפʥץǤϻȤ٤ǤϤʤ
(BSD ͳΥƥˤ⿮Ǥ򥵥ݡȤƤΤ뤬
μξܺ٤ϥƥˤäưۤʤ)
.\"O
.SH 
Linux μǤϡե륷ƥ夫鸫륽åȤϡ
餬֤Ƥǥ쥯ȥΥѡߥå˽
åȤνͭԡ롼סѡߥåѹǤ롣
åȤȤȤǥ쥯ȥФ
ץ񤭹ߤȸ (¹) ¤äƤʤС˼Ԥ롣
åȥ֥Ȥ³ˤϡ read/write ¤ɬפǤ롣
ưϡ¿ BSD ͳΥƥȤϰۤʤäƤ
(BSD Ǥ Unix åȤФƤϥѡߥå̵뤹)
ܿɬפʥץǤϡ
ƥ򤳤λͤ˰¸ƤϤʤʤ

ե̾ꤷƥåȤ˥Хɤȡ
ե륷ƥ˥åȤ롣
ɬפʤʤäȤ˸ƤӤ桼ʤФʤʤ
.RB ( unlink (2)
Ѥ)

Unix ̾ȤظĤפŬѤ롣
åȤϤĤǤ unlink 뤳ȤǤǸλȤ
줿Ȥ˥ե륷ƥफ롣

SOCK_STREAM ǥեǥץ修ǤϤˤϡ
Ʊ send/recv_msg ǡʳΥǡ򾯤ʤȤ
1 Х/ɬפ롣

.SH 顼
.TP
.B ENOMEM
꤬­ʤ
.TP
.B ECONNREFUSED
listen ֤ˤʤåȥ֥ȤФ
.BR connect (2)
ƤФ줿⡼ȥåȤ¸ߤƤʤä
ե̾åȤǤϤʤäʤɤΤȤ˵롣
.TP
.B EINVAL
Ϥ褯븶ϡ
Ϥɥ쥹 sun_type եɤ AF_UNIX ꤷʤä
ԤȤФƥåȤξ֤ͭǤϤʤäʤɡ
.TP
.B EOPNOTSUPP
ȥ꡼ظǤʤåȤФƥȥ꡼ƤӽФ줿
ޤӰ賰ǡץѤ褦Ȥ
.TP
.B EPROTONOSUPPORT
Ϥ줿ץȥ뤬 PF_UNIX Ǥʤ
.TP
.B ESOCKTNOSUPPORT
̤ΤΥåȥס
.TP 
.B EPROTOTYPE
⡼ȥåȤȥ륽åȤΥפפƤʤä
(SOCK_DGRAM  SOCK_STREAM)
.TP
.B EADDRINUSE
򤷤åȤѤƤޤϡ
ե륷ƥΥåȥ֥Ȥ¸ߤƤ
.TP
.B EISCONN
³Ƥ륽åȤФ
.BR connect (2)
ƤФ줿ޤϡꤷåȥɥ쥹
³ѤߤΥåȤä
.TP
.B ENOTCONN
å˥åȥɥ쥹ɬפ
ΥåȤ³Ƥʤ
.TP
.B ECONNRESET
⡼ȥåȤͽʤǥ줿
.TP
.B EPIPE
⡼ȥåȤȥ꡼ॽåȾǥ줿
ǽʾ
.B SIGPIPE
Ʊ롣򤱤ˤ
.B MSG_NOSIGNAL
ե饰
.BR sendmsg (2)

.BR recvmsg (2)
Ϥ
.TP
.B EFAULT
桼ꥢɥ쥹
.TP
.B EPERM
Ԥ
.B struct ucred
ʿǤϤ
.PP
¾ˤѤΥåؤǥ顼äꡢ
ե륷ƥ˥åȥ֥ȤȤ
ե륷ƥΥ顼뤳Ȥ롣
줾ξܺ٤Ŭڤ man ڡ򻲾Ȥ뤳ȡ
.SH Ϣ
.BR recvmsg (2),
.BR sendmsg (2),
.BR socket (2),
.BR socketpair (2),
.BR cmsg (3),
.BR capabilities (7),
.BR socket (7)