.\" Copyright (C) 2008 Michael Kerrisk <mtk.manpages@gmail.com>
.\" starting from a version by Davide Libenzi <davidel@xmailserver.org>
.\"
.\" This program is free software; you can redistribute it and/or modify
.\" it under the terms of the GNU General Public License as published by
.\" the Free Software Foundation; either version 2 of the License, or
.\" (at your option) any later version.
.\"
.\" This program is distributed in the hope that it will be useful,
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
.\" GNU General Public License for more details.
.\"
.\" You should have received a copy of the GNU General Public License
.\" along with this program; if not, write to the Free Software
.\" Foundation, Inc., 59 Temple Place, Suite 330, Boston,
.\" MA  02111-1307  USA
.\"
.\" Japanese Version Copyright (c) 2008  Akihiro MOTOKI
.\"         all rights reserved.
.\" Translated 2008-04-06, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>, LDP v2.79
.\" Updated 2008-11-10, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>, LDP v3.13
.\" Updated 2009-02-23, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>, LDP v3.18
.\" 
.TH SIGNALFD 2 2009-01-13 Linux "Linux Programmer's Manual"
.SH ̾
signalfd \- ʥդѤΥեǥץ
.SH 
.B #include <sys/signalfd.h>
.sp
.BI "int signalfd(int " fd ", const sigset_t *" mask ", int " flags );
.SH 
.BR signalfd ()
ϡƤӽФƤΥʥդ뤿˻Ѥե
ǥץ롣
ˡϥʥϥɥ
.BR sigwaitinfo (2)
ѤˡȤʤΤǤꡢΥեǥץ
.BR select (2),
.BR poll (2),
.BR epoll (7)
ǴƻǤȤ롣

.I mask
ˤϡƤӽФΥեǥץͳǼդ
ʥ뽸ꤹ롣ΰǻꤹ륷ʥ뽸Ƥϡ
.BR sigsetops (3)
ƤޥȤäƽ뤳ȤǤ롣
̾եǥץͳǼ륷ʥ뽸ϡ
Υʥ뤬ǥեȤˡ˴𤤤ƽΤɤˡ
.BR sigprocmask (2)
Ȥäƥ֥åƤ٤Ǥ롣
ʥ
.B SIGKILL

.B SIGSTOP
 signalfd եǥץͳǼ뤳ȤϤǤʤ
Υʥ뤬
.I mask
ǻꤵ줿ˤۤä̵뤵롣

.I fd
 \-1 ξ硢
.BR signalfd ()
Ͽեǥץ
.I mask
ǻꤵ줿ʥ뽸򤽤Υեǥץ˴Ϣդ롣
.I fd
 \-1 ʳξ硢
.I fd
ˤͭʴ¸ signalfd եǥץꤷʤФʤ餺
Υǥץ˴ϢդƤ륷ʥ뽸
.I mask
Ȥä֤롣

Linux 2.6.27 ʹߤǤϡ
ʲͤΤĤӥåñ̤ (OR) ǻꤹ뤳Ȥǡ
.BR signalfd ()
ο񤤤ѹ뤳ȤǤ롣
.TP 14
.B SFD_NONBLOCK
륪ץե뵭 (open file description) 
.B O_NONBLOCK
ե륹ơե饰򥻥åȤ롣
Υե饰ȤȤǡ
.B O_NONBLOCK
򥻥åȤ뤿
.BR fcntl (2)
ɲäǸƤӽФɬפʤʤ롣
.TP
.B SFD_CLOEXEC
եǥץФ
close-on-exec
.RB ( FD_CLOEXEC )
ե饰򥻥åȤ롣
Υե饰ΩͳˤĤƤϡ
.BR open (2)

.B O_CLOEXEC
ե饰򻲾ȤΤȡ
.PP
С 2.6.26  Linux Ǥϡ
.I flags
̤ѤǤꡢ0 ꤷʤФʤʤ

.BR signalfd ()
֤եǥץϰʲ򥵥ݡȤƤ롣
.TP
.BR read (2)
.I mask
˻ꤵƤ륷ʥΤİʾ夬ΥץФ
Ԥ (pending) ǤСΥʥξ
.BR read (2)
Ϥ줿ХåեȤäơ
.I signalfd_siginfo
¤Τ˳Ǽ֤롣
.BR read (2)
ϡХåե˳ǼǽϰϤǤǤ¿νԤΥʥ
ĤƤξ֤
ХåեϺǤ
.I "sizeof(struct signalfd_siginfo)"
ХȤ礭ʤФʤʤ
.BR read (2)
֤ͤɤ߽Ф줿ȡΥХȿǤ롣
.IP
.BR read (2)
Ԥ줿̡ʥϾ񤵤졢
ΥʥϤΥץФƤϽԤǤϤʤʤ
(Ĥޤꡢʥϥɥª뤳Ȥʤ
.BR sigwaitinfo (2)
ȤäƼ뤳ȤǤʤʤ)
.IP
.I mask
˻ꤵƤ륷ʥ뤬ΥץФưĤԤǤʤС
.BR read (2)
ϡ
.I mask
ǻꤵ줿ʥΤ줫ĤΥץФȯޤ
 (block) 롢⤷ϥեǥץ (non-blocking)
ꤵƤϥ顼
.B EAGAIN
ǼԤ롣
.TP
.BR poll "(2), " select "(2) (Ʊͤ)"
.I mask
˻ꤵ줿ʥΤİʾ夬ΥץФƽԤǤС
եǥץɤ߽ФǽȤʤ
.RB ( select (2)

.I readfds

.BR poll (2)

.B POLLIN
ե饰)
.IP
signalfd եǥץϡʳΥեǥץ
¿ API Ǥ
.BR pselect (2),
.BR ppoll (2),
.BR epoll (7)
⥵ݡȤƤ롣
.TP
.BR close (2)
եǥץʹߤɬפʤʤäݤˤϡ٤Ǥ롣
Ʊ signalfd ֥Ȥ˴Ϣդ줿եǥץ
ȡΥ֥Ѥλ񸻤ͥˤ롣
.SS signalfd_siginfo ¤
signalfd եǥץ
.BR read (2)
֤
.I signalfd_siginfo
¤ΤΥեޥåȤϰʲ̤Ǥ롣
.in +4n
.nf

struct signalfd_siginfo {
struct signalfd_siginfo {
    uint32_t ssi_signo;   /* ʥֹ */
    int32_t  ssi_errno;   /* 顼ֹ (̤) */
    int32_t  ssi_code;    /* ʥ륳 */
    uint32_t ssi_pid;     /*  PID */
    uint32_t ssi_uid;     /* μ UID */
    int32_t  ssi_fd;      /* եǥץ (SIGIO) */
    uint32_t ssi_tid;     /* ͥ륿 ID (POSIX )
    uint32_t ssi_band;    /* Band ٥ (SIGIO) */
    uint32_t ssi_overrun; /* POSIX ޤΥС */
    uint32_t ssi_trapno;  /* ʥθȤʤäȥåֹ */
.\" ۤȤɤΥƥ ssi_trapno ̤
    int32_t  ssi_status;  /* λơʥ (SIGCHLD) */
    int32_t  ssi_int;     /* sigqueue(2) 줿 */
    uint64_t ssi_ptr;     /* sigqueue(2) 줿ݥ */
    uint64_t ssi_utime;   /* 񤷤桼 CPU  (SIGCHLD) */
    uint64_t ssi_stime;   /* 񤷤ƥ CPU  (SIGCHLD) */
    uint64_t ssi_addr;    /* ʥɥ쥹
                             (ϡɥʥξ) */
    uint8_t  pad[\fIX\fP];      /* pad 礭 128 Х
                             (ΥեɲѤξγ) */
};

.fi
.in
.I signalfd_siginfo
¤Τγƥեɤϡ
.I siginfo_t
¤ΤƱ褦̾ΥեɤƱͤǤ롣
.I siginfo_t
¤ΤˤĤƤ
.BR sigaction (2)
롣
֤줿
.I signalfd_siginfo
¤ΤƤΥեɤ륷ʥФͭʤ櫓ǤϤʤ
ɤΥեɤͭϡ
.I ssi_code
եɤ֤ͤȽꤹ뤳ȤǤ롣
Υեɤ
.I siginfo_t

.I si_code
եɤƱͤǤ롣ܺ٤
.BR sigaction (2)
򻲾ȡ
.SS fork(2) Ǥΰ
.BR fork (2)
Ԥȡҥץ signalfd եǥץΥԡ
Ѿ롣
ҥץǤΥեǥץ
.BR read (2)
ԤȡҥץФ륭塼äƤ륷ʥ˴ؤ
֤롣
.SS execve(2) Ǥΰ
¾ΥեǥץƱͤˡ
signalfd եǥץ
.BR execve (2)
ǥץ󤵤줿ޤޤȤʤ롣âΥեǥץ
close-on-exec Υޡ
.RB ( fcntl (2)
) դƤϥ롣
.BR execve (2)
ɤ߽ФǽȤʤäƤƤΥʥϿư줿ץ
Ǥ³ɤ߽ФǽǤ
(ŪʥʥΰƱǤꡢ
ԤΥ֥å줿ʥ
.BR execve (2)
ǽԤΤޤޤȤʤ)
.SS åɤǤΰ
ޥåɥץˤ signalfd եǥץΰ
ʥɸŪʰƱǤ롣
ȡ륹åɤ signalfd եǥץ
ɤ߽ФԤȡΥåɼȰƤΥʥȥץ (ʤ
åɥ롼) ƤΥʥ뤬ɤ߽Ф롣
(åɤƱץ¾ΥåɰƤΥʥɤ߽ФȤϤǤʤ)
.SH ֤
ȡ
.BR signalfd ()
 signalfd եǥץ֤
֤եǥץϡ
.IR fd
 \-1 ξϿΥեǥץǤꡢ
.I fd
ͭ signalfd եǥץä
.I fd
ȤǤ롣
顼ξ硢\-1 ֤
.I errno
˥顼򼨤ͤꤹ롣
.SH 顼
.TP
.B EBADF
եǥץ
.I fd
ͭʥեǥץǤʤ
.TP
.B EINVAL
.I fd
ͭ signalfd եǥץǤϤʤ
.\" or, the
.\" .I sizemask
.\" argument is not equal to
.\" .IR sizeof(sigset_t) ;
.TP
.B EINVAL
.I flags
̵
Linux 2.6.26 Ǥϡ
.I flags
 0 ʳ͡
.TP
.B EMFILE
ץѤߤΥեǥץοץξ¤
ãƤ
.TP
.B ENFILE
ץѤߤΥեƥΤξ¤ãƤ
.TP
.B ENODEV
(ͥ) ̵̾ inode ǥХޥȤǤʤä
.TP
.B ENOMEM
 signalfd եǥץΤ˽ʬʥ꤬ʤä
.SH С
.BR signalfd ()
ϥͥ 2.6.22 ʹߤ Linux ѲǽǤ롣
ư glibc ¦ΥݡȤϥС 2.8 ʹߤ󶡤Ƥ롣
.\" signalfd() is in glibc 2.7, but reportedly does not build
.BR signalfd4 ()
ƥॳ (ա׻) 
ͥ 2.6.27 ʹߤ Linux ѲǽǤ롣
.SH 
.BR signalfd ()

.BR signalfd4 ()
 Linux ͭǤ롣
.SH 
ºݤ Linux ΥƥॳǤ
.I "size_t sizemask"
ȤɲäɬפǤ롣ΰ
.I mask
Υꤹ롣
glibc 
.BR signalfd ()
åѡؿˤϤΰϴޤޤ줺
åѡؿɬפͤ׻ǸƤӽФƥॳ󶡤롣

ĤΥץʣ signalfd եǥץ뤳ȤǤ롣
ˤꡢۤʤեǥץǰۤʤ륷ʥ뤳Ȥ
Ǥ (εǽ
.BR select (2),
.BR poll (2),
.BR epoll (7)
Ȥäƥեǥץƻ뤹ͭѤ⤷ʤ
ۤʤ륷ʥ뤬夹ȡۤʤեǥץѲǽ
ʤ뤫)
ĤΥʥ뤬İʾΥեǥץ
.I mask
˴ޤޤƤ硢ΥʥȯϤΥʥ
.I mask
˴ޤեǥץΤ줫Ĥɤ߽ФȤǤ롣
.SH ؤˤ Linux Υƥॳ
ؤˤ Linux ƥॳढꡢ
.BR signalfd ()
ȡäȿ
.BR signalfd4 ()
Ǥ롣
.BR signalfd ()

.I flags
Ƥʤ
.BR signalfd4 ()
ǤϾ嵭ͤ
.I flags
Ƥ롣
glibc 2.9 ʹߤǤϡ
.BR signalfd ()
Υåѡؿϡ
.BR signalfd4 ()
ѲǽǤСѤ롣
.SH Х
ͥ 2.6.25 Ǥϡ
.BR sigqueue (2)
ˤ줿ʥȰϤǡǤϡե
.I ssi_ptr

.I ssi_int
ꤵʤ
.\" The fix also was put into 2.6.24.5
.SH 
Υץϡʥ
.B SIGINT

.B SIGQUIT
 signalfd եǥץͳǼ롣
ʥ
.B SIGQUIT
˥ץϽλ롣
ʲ˼륻åˤΥץλȤ򼨤
.in +4n
.nf

.RB "$" " ./signalfd_demo"
.BR "^C" "                   # Control\-C generates SIGINT"
Got SIGINT
.B ^C
Got SIGINT
\fB^\\\fP                    # Control\-\\ generates SIGQUIT
Got SIGQUIT
$
.fi
.in
.SS ץΥ
\&
.nf
#include <sys/signalfd.h>
#include <signal.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>

#define handle_error(msg) \\
    do { perror(msg); exit(EXIT_FAILURE); } while (0)

int
main(int argc, char *argv[])
{
    sigset_t mask;
    int sfd;
    struct signalfd_siginfo fdsi;
    ssize_t s;

    sigemptyset(&mask);
    sigaddset(&mask, SIGINT);
    sigaddset(&mask, SIGQUIT);

    /* Block signals so that they aren\(aqt handled
       according to their default dispositions */

    if (sigprocmask(SIG_BLOCK, &mask, NULL) == \-1)
        handle_error("sigprocmask");

    sfd = signalfd(\-1, &mask, 0);
    if (sfd == \-1)
        handle_error("signalfd");

    for (;;) {
        s = read(sfd, &fdsi, sizeof(struct signalfd_siginfo));
        if (s != sizeof(struct signalfd_siginfo))
            handle_error("read");

        if (fdsi.ssi_signo == SIGINT) {
            printf("Got SIGINT\\n");
        } else if (fdsi.ssi_signo == SIGQUIT) {
            printf("Got SIGQUIT\\n");
            exit(EXIT_SUCCESS);
        } else {
            printf("Read unexpected signal\\n");
        }
    }
}
.fi
.SH Ϣ
.BR eventfd (2),
.BR poll (2),
.BR read (2),
.BR select (2),
.BR sigaction (2),
.BR sigprocmask (2),
.BR sigwaitinfo (2),
.BR timerfd_create (2),
.BR sigsetops (3),
.BR sigwait (3),
.BR epoll (7),
.BR signal (7)