.\" Hey Emacs! This file is -*- nroff -*- source.
.\"
.\" Copyright (c) 1992 Drew Eckhardt (drew@cs.colorado.edu), March 28, 1992
.\"
.\" 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.\" manual page may be incorrect or out-of-date.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 by Michael Haardt <michael@moria.de>
.\" Modified Wed Jul 21 22:47:01 1993 by Rik Faith (faith@cs.unc.edu)
.\" Modified 21 Aug 1994 by Michael Chastain (mec@shell.portal.com):
.\"   Fixed typoes.
.\" Modified Fri Jan 31 16:24:28 1997 by Eric S. Raymond <esr@thyrsus.com>
.\" Modified Fri Nov 12 22:57:27 1999 by Urs Thuermann <urs@isnogud.escape.de>
.\"
.\" Japanese Version Copyright (c) 1996 TABATA Tomohira
.\"         all rights reserved.
.\" Translated Thu Jul  4 22:15:20 JST 1996
.\"         by TABATA Tomohira <loba@k2.t.u-tokyo.ac.jp>
.\" Modified Sun Dec 14 00:30:35 JST 1997
.\"         by HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Modified Fri Aug 17 20:15:01 JST 2001
.\"         by HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\"
.TH EXECVE 2 1997-09-03 "Linux 2.0.30" "Linux Programmer's Manual"
.SH ̾
execve \- ץ¹Ԥ
.SH 
.B #include <unistd.h>
.sp
.BI "int execve(const char *" filename ", char *const " argv
.BI "[], char *const " envp []);
.SH 
\fBexecve()\fP ϡ\fIfilename\fP ˤäƻꤵ줿ץ¹Ԥ롣
\fIfilename\fP ϡХʥ¹Է"\fB#! \fIinterpreter \fR[arg]" 
ȤιԤǻϤޤ륹ץȤǤʤФʤʤ
Ԥξ硢interpreter Ŭڤʼ¹ԥեΥѥ̾ǤʤФʤ餺
켫ȤץȤǤäƤϤʤʤƤ
\fBinterpreter\fR [arg] \fIfilename\fR ηǸƤӽФ롣

\fIargv\fP ϿץϤʸǤ롣
\fIenvp\fP ʸǤꡢŪ \fBkey=value\fR η
ƤꡢץδĶѿȤϤ롣
\fIargv\fP  \fIenvp\fP ξȤ NULL ݥ󥿡ǽäƤ
ɬפ롣ȴĶѿϸƤӽФ줿ץ main ؿ
\fBint main(int argc, char *argv[], char *envp[])\fR
Τ褦뤳Ȥˤäƥǽˤʤ롣

硢\fBexecve()\fP ֤ʤ
ơƤӽФΥץ text, data, bss, åϡɤ߹ޤ
ץˤäƾ񤭤롣
ƤӽФ줿ץϡƤӽФ PID  
exec (close on exec)ꤵƤʤ٤Ƥ
ե롦ǥץѾ롣
ƤӽФץαʥϲ롣ƤӽФΥץ
ꤵ줿ʥͻưϥǥեưᤵ롣
SIGCHLD ʥ뤬 SIG_IGN ꤵƤ SIG_DFL ˥ꥻå
뤫⤷ʤʤ⤷ʤ

⤷Υץब ptrace Ƥȡ\fBexecve()\fP 
ˤΥץ \fBSIGTRAP\fP 롣

⤷ \fIfilename\fP ǻꤵ줿ץե set-uid ӥåȤ
ꤵƤ硢ƤӽФץͭ(effective)桼 ID 
ץեνͭ(owner)ѹ롣Ʊͤ˥ץե
set-gid ӥåȤꤵƤƤӽФץͭ롼 ID
ץեΥ롼(group)ѹ롣

¹ԥե뤬ͭ饤֥Υ֤ޤߥʥߥå
줿 a.out ¹Էä硢¹Ԥγϻ Linux 
ʥߥå󥫡
.BR ld.so (8)
ƤӽФ졢ɬפʶͭ饤֥ɤ߹ǥ󥯤Ԥ

¹ԥե뤬ʥߥå󥯤줿 ELF ¹Էä硢
PT_INTERP Ȥ˻ꤵ줿󥿥ץ꥿ɬפ
ͭ饤֥(shared library)ɤ߹Τ˻Ѥ롣
̾Ѥ륤󥿡ץ꥿ Linux libc version 5 󥯤Хʥ
ξˤ \fI/lib/ld-linux.so.1\fR GNU libc version 2 󥯤
Хʥξˤ \fI/lib/ld-linux.so.2\fR Ѥ롣
.SH ֤
 \fBexecve()\fP ֤ʤ顼ξ \-1 ֤
.I errno
Ŭꤹ롣
.SH 顼
.TP
.B EACCES
ե뤫ץȤΥ󥿥ץ꥿̤ΥեǤʤ
.TP
.B EACCES
ե뤫ץȤޤ ELF 󥿥ץ꥿˼¹Ե(execute permission)
ͿƤʤɬפʶͭ饤֥ޤϥ󥿥ץ꥿Ĥʤ
.TP
.B EPERM
ե롦ƥब
.I noexec 
ǥޥȤƤ롣
.TP
.B EPERM
ե롦ƥब
.I nosuid
ǥޥȤ졢ե SUID 뤤 SGID ӥåȤꤵƤ롣
.TP
.B E2BIG
ꥹȤ礭᤮롣
.TP
.B ENOEXEC
¹ԥե뤬ǤʤǤ뤫㤦ƥ㡼ΤΤ
¾Υեޥåȡ顼ˤ¹ԤǤʤä
.TP
.B EFAULT
.I filename
ǽʥɥ쥹֤γؤƤ롣
.TP
.B ENAMETOOLONG
.I filename
Ĺ᤮롣
.TP
.B ENOENT
ե
.I filename
ץȤ ELF Υ󥿥ץ꥿¸ߤʤ
.TP
.B ENOMEM
ͥ˽ʬʥ꤬ʤ
.TP
.B ENOTDIR
.I filename
䥹ץȤ ELF Υ󥿥ץ꥿ιǤǥ쥯ȥǤʤ
.TP
.B EACCES
.I filename
䥹ץȤ ELF Υ󥿥ץ꥿ιǤ˸(search permission)
ͿƤʤ
.TP
.B ELOOP
.I filename
䥹ץȤ ELF Υ󥿥ץ꥿褹ݤ
ܥå󥯤¿᤮롣
.TP
.B ETXTBSY
¹ԥե񤭹Ѥ˥ץ󤷤Ƥץ롣
.TP
.B EIO
I/O 顼ȯ
.TP
.B ENFILE
ΥƥǥץǤեθ³ãä
.TP
.B EMFILE
ΥץץǤեξ¤ޤǴ˥ץ󤷤Ƥ롣
.TP
.B EINVAL
ELF ¹Էʣ PT_INTERP Ȥ¸ߤ롣
(ʤʣΥ󥿥ץ꥿ꤷ)
.TP
.B EISDIR
ELF 󥿥ץ꥿ǥ쥯ȥä
.TP
.B ELIBBAD
ELF 󥿥ץ꥿ǤեޥåȤǤʤä

.SH 
SVr4, SVID, X/OPEN, BSD 4.3.  POSIX ˤ #! ưˤĤƤεҤ
ʤ¾ϸߴ롣SVr4 ˤ¾ EAGAIN, EINTR, ELIBACC, ENOLINK,
EMULTIHOP ˤĤƤεҤ롣POSIX ˤ ETXTBSY, EPERM, EFAULT,
ELOOP, EIO, ENFILE, EMFILE, EINVAL, EISDIR, ELIBBAD 顼֤ˤĤ
εҤϤʤ

.SH 
SUID ץ SGID ץ \fBptrace()\fP Ǥʤ

Linux ϥץȤ SUID  SGID ӥåȤ̵뤹롣

ե륷ƥ
.I nosuid
ǥޥȤ SUID/SGID ¹ԥեɤͤ˰ϡ
Linux ͥΥСˤäưۤʤ:
СǤϡǤɬפʸ¤äƤơ
μ¹Ԥݤ( EPERM ֤)̤ΤСǤ
SUID/SGID ӥåȤΤߤ̵뤷Ƽ¹Ԥ롣

#! ¹ԷΥ롦ץȤΣܤˤϺ 127 ʸƤ롣

.\" .SH BUGS
.\" Some Linux versions have failed to check permissions on ELF
.\" interpreters.  This is a security hole, because it allows users to
.\" open any file, such as a rewinding tape device, for reading.  Some
.\" Linux versions have also had other security holes in \fBexecve()\fP,
.\" that could be exploited for denial of service by a suitably crafted
.\" ELF binary. There are no known problems with 2.0.34 or 2.2.15.
.SH Ϣ
.BR chmod (2),
.BR fork (2),
.BR execl (3),
.BR environ (5),
.BR ld.so (8).