.\" 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@gmail.com>
.\" Modified, 2003-09-23, Adam Langley
.\" Modified, 2004-05-27, Michael Kerrisk, <mtk.manpages@gmail.com>
.\"	Added SOCK_SEQPACKET
.\" 2008-05-27, mtk, Provide a clear description of the three types of
.\"     address that can appear in the sockaddr_un structure: pathname,
.\"     unnamed, and abstract.
.\"
.\" 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
.\" Updated 2005-12-26, Akihiro MOTOKI
.\" Updated 2008-08-08, Akihiro MOTOKI, LDP v3.05
.\"
.\"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 2008-12-01 "Linux" "Linux Programmer's Manual"
.SH ̾
unix, AF_UNIX, AF_LOCAL \- 
ץ̿ѤΥå
.SH 
.B #include <sys/socket.h>
.br
.B #include <sys/un.h>

.IB unix_socket " = socket(AF_UNIX, type, 0);"
.br
.IB error " = socketpair(AF_UNIX, type, 0, int *" sv ");"
.SH 
.B AF_UNIX
.RB ( AF_LOCAL
Ȥ) åȥեߥ꡼ϡƱޥǥץƱΤ
ΨŪ̿뤿Ѥ롣 
ŪˡUnix åȤϡ̾ʤˤǤ뤷
(åȷǤȰΤĤ) ե륷ƥΥѥ̾
դ뤳ȤǤ롣
 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
(Linux 2.6.4 ʹߤѤǤ)
å¸줿ǥåϤ³ظå

Unix åȤǤϡǡȤä
եǥץץοǤ (credential) 
뤳ȤǤ롣
.SS ɥ쥹Υեޥå
Unix ɥᥤ󥽥åȤΥɥ쥹ϰʲι¤Τɽ롣
.in +4n
.nf

#define UNIX_PATH_MAX    108

struct sockaddr_un {
    sa_family_t sun_family;               /* AF_UNIX */
    char        sun_path[UNIX_PATH_MAX];  /* pathname */
};
.fi
.in
.PP
.I sun_family
ˤɬ
.B AF_UNIX
äƤ롣

ι¤ΤǤ 3 Υɥ쥹̤롣
.IP * 3
.IR "pathname (ѥ̾)" :
.BR bind (2)
ȤäơUnix ɥᥤ󥽥åȤ NULL ü줿ե륷ƥ
ѥ̾˷դ뤳ȤǤ롣
.BR getsockname (2),
.BR getpeername (2),
.BR accept (2)
åȤΥɥ쥹֤ݤˤϡ
Ĺ
.I "sizeof(sa_family_t) + strlen(sun_path) + 1"
Ǥꡢ
.I sun_path
 NULL ü줿ѥ̾Ǽ롣
.IP *
.IR "unnamed (̾ʤ)" :
.BR bind (2)
Ȥäƥѥ̾˷դ뤳ȤǤʤȥ꡼෿ΥåȤ
̾ʤƱͤˡ
.BR socketpair (2)
Ǻ 2 ĤΥåȤ̾ʤ
.BR getsockname (2),
.BR getpeername (2),
.BR accept (2)
̾ʤΥåȤΥɥ쥹֤ݤˤϡ
Ĺ
.I "sizeof(sa_family_t)"
Ǥꡢ
.I sun_path
ϸ٤ǤϤʤ
.\" Ȥˤʤΰ㤤¸ߤ롣
.\" FreeBSD ǤĹ 16 ХȤȤʤꡢHP-UX ǤĹ 0 ХȤȤʤ롣
.IP *
.IR "abstract ()" :
ݥåȥɥ쥹ϡ
.I sun_path[0]
̥Х ('\\0') Ǥ뤳Ȥ̤Ǥ롣
.I sun_path
λĤХȤˤ꥽åȤΡ̾פ
(̾Υ̥ХȤˤ̤ʰ̣Ϥʤ)
̾ϥե륷ƥΥѥ̾Ȥϲδطʤ
֤̾ˤ륽åȤΥɥ쥹ϡ
.I sun_path
λĤΥХȤɽ롣
.BR getsockname (2),
.BR getpeername (2),
.BR accept (2)
ݥåȤΥɥ쥹֤ݤˤϡĹ
.I "sizeof(struct sockaddr_un)"
Ǥꡢ
.I sun_path
֤̾̾Ǽ롣
åȤ֤̾ Linux ˤĥǤꡢܿϤʤ
.SS åȥץ
ŪͳˤꡢΥץ
Ȥ
.B AF_UNIX
ͭΥץǤäƤ
.B SOL_SOCKET
ǻꤹ롣
åȥեߥ꡼Ȥ
.B 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
.SS å API
ǤϡLinux  Unix ɥᥤ󡦥åȤǤΡ
ɥᥤͭξܺٻͤȥå API ǥݡȤƤʤǽ
Ĥ롣

Unix ɥᥤ󡦥åȤǤϡӰ賰ǡ (out-of-band data) 

.RB ( send (2)

.BR recv (2)

.B MSG_OOB
ե饰) ϥݡȤƤʤ

.BR send (2)
.B MSG_MORE
ե饰 Unix ɥᥤ󡦥åȤǤϥݡȤƤʤ

.BR recv (2)

.I flags
Ǥ
.B MSG_TRUNC
λѤ Unix ɥᥤ󡦥åȤǤϥݡȤƤʤ

.B SO_SNDBUF
åȥץ Unix ɥᥤ󡦥åȤǸ̤Ĥ
.B SO_RCVBUF
ϸ̤ʤ
ǡࡦåȤǤϡ
.B SO_SNDBUF
ͤϥǡξ¥Ȥʤ롣
ºݤξͤϡ
.B SO_SNDBUF
ץȤꤵ줿ͤ 2
.RB ( socket (7)
) 饪ХإåɤȤƻѤ 32 ХȤͤȤʤ롣
.SS å
ǡˤϡ
.BR sendmsg (2)

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

.I cmsg_level
եɤ
.B SOL_SOCKET
򥻥åȤ
.I cmsg_type
եɤ˥פ򥻥åȤ롣
ܺ٤
.BR cmsg (3)
򸫤衣
.TP
.B SCM_RIGHTS
¾Υץǥץ󤵤줿եǥץΥåȤ롣
ǡʬ˥եǥץäƤ롣
Ϥ줿եǥץϡ
.BR dup (2)
줿Τ褦˿񤦡
.TP
.B SCM_CREDENTIALS
Unix Ǥ롣ǧڤѤ뤳ȤǤ롣
Ǥϡ
.I struct ucred
åȤϤ롣
ι¤Τ
.I <sys/socket.h>
ǰʲΤ褦Ƥ롣

.in +4n
.nf
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
.in

glibc 2.8 ʹߤǤϡι¤Τ뤿ˤϵǽޥ
.B _GNU_SOURCE
ʤФʤʤ

¦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)
.I struct ucred
å뤿ˤϡåȤФ
.B SO_PASSCRED
ץͭˤʤƤϤʤʤ
.SH 顼
.TP
.B EADDRINUSE
򤷤åȤѤƤޤϡ
ե륷ƥΥåȥ֥Ȥ¸ߤƤ
.TP
.B ECONNREFUSED
listen ֤ˤʤåȥ֥ȤФ
.BR connect (2)
ƤФ줿⡼ȥåȤ¸ߤƤʤä
ե̾åȤǤϤʤäʤɤΤȤ˵롣
.TP
.B ECONNRESET
⡼ȥåȤͽʤǥ줿
.TP
.B EFAULT
桼ꥢɥ쥹
.TP
.B EINVAL
Ϥ褯븶ϡ
Ϥɥ쥹
.I sun_type
եɤ AF_UNIX ꤷʤä
ԤȤФƥåȤξ֤ͭǤϤʤäʤɡ
.TP
.B EISCONN
³Ƥ륽åȤФ
.BR connect (2)
ƤФ줿ޤϡꤷåȥɥ쥹
³ѤߤΥåȤä
.TP
.B ENOMEM
꤬­ʤ
.TP
.B ENOTCONN
å˥åȥɥ쥹ɬפ
ΥåȤ³Ƥʤ
.TP
.B EOPNOTSUPP
ȥ꡼ظǤʤåȤФƥȥ꡼ƤӽФ줿
ޤӰ賰ǡץѤ褦Ȥ
.TP
.B EPERM
Ԥ
.I struct ucred
ʿǤϤ
.TP
.B EPIPE
⡼ȥåȤȥ꡼ॽåȾǥ줿
ǽʾ
.B SIGPIPE
Ʊ롣򤱤ˤ
.B MSG_NOSIGNAL
ե饰
.BR sendmsg (2)

.BR recvmsg (2)
Ϥ
.TP
.B EPROTONOSUPPORT
Ϥ줿ץȥ뤬 AF_UNIX Ǥʤ
.TP
.B EPROTOTYPE
⡼ȥåȤȥ륽åȤΥפפƤʤä
.RB ( SOCK_DGRAM

.BR SOCK_STREAM )
.TP
.B ESOCKTNOSUPPORT
̤ΤΥåȥס
.PP
¾ˤѤΥåؤǥ顼äꡢ
ե륷ƥ˥åȥ֥ȤȤ
ե륷ƥΥ顼뤳Ȥ롣
줾ξܺ٤Ŭڤ man ڡ򻲾Ȥ뤳ȡ
.SH С
.B SCM_CREDENTIALS
֤̾ϡLinux 2.2 Ƴ줿
ܿɬפʥץǤϻȤ٤ǤϤʤ
(BSD ͳΥƥˤ⿮Ǥ򥵥ݡȤƤΤ뤬
μξܺ٤ϥƥˤäưۤʤ)
.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

.B SOCK_STREAM
ǥեǥץ修ǤϤˤϡƱ
.BR sendmsg (2)

.BR recvmsg (2)
ǡʳΥǡ򾯤ʤȤ
1 Х/ɬפ롣

Unix ɥᥤΥȥ꡼ࡦåȤǤϡ
Ӱ賰ǡγǰϥݡȤʤ
.SH 
.BR bind (2)
ȡ
.SH Ϣ
.BR recvmsg (2),
.BR sendmsg (2),
.BR socket (2),
.BR socketpair (2),
.BR cmsg (3),
.BR capabilities (7),
.BR credentials (7),
.BR socket (7)