1.\" Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org> 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" Portions of this text are reprinted and reproduced in electronic form 26.\" from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- 27.\" Portable Operating System Interface (POSIX), The Open Group Base 28.\" Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of 29.\" Electrical and Electronics Engineers, Inc and The Open Group. In the 30.\" event of any discrepancy between this version and the original IEEE and 31.\" The Open Group Standard, the original IEEE and The Open Group Standard is 32.\" the referee document. The original Standard can be obtained online at 33.\" http://www.opengroup.org/unix/online.html. 34.\" 35.\" $FreeBSD$ 36.\" 37.Dd May 9, 2013 38.Dt POSIX_SPAWN_FILE_ACTIONS_ADDOPEN 3 39.Os 40.Sh NAME 41.Nm posix_spawn_file_actions_addopen , 42.Nm posix_spawn_file_actions_adddup2 , 43.Nm posix_spawn_file_actions_addclose 44.Nd "add open, dup2 or close action to spawn file actions object" 45.Sh LIBRARY 46.Lb libc 47.Sh SYNOPSIS 48.In spawn.h 49.Ft int 50.Fn posix_spawn_file_actions_addopen "posix_spawn_file_actions_t * file_actions" "int fildes" "const char *restrict path" "int oflag" "mode_t mode" 51.Ft int 52.Fn posix_spawn_file_actions_adddup2 "posix_spawn_file_actions_t * file_actions" "int fildes" "int newfildes" 53.Ft int 54.Fn posix_spawn_file_actions_addclose "posix_spawn_file_actions_t * file_actions" "int fildes" 55.Sh DESCRIPTION 56These functions add an open, dup2 or close action to a spawn 57file actions object. 58.Pp 59A spawn file actions object is of type 60.Vt posix_spawn_file_actions_t 61(defined in 62.In spawn.h ) 63and is used to specify a series of actions to be performed by a 64.Fn posix_spawn 65or 66.Fn posix_spawnp 67operation in order to arrive at the set of open file descriptors for the 68child process given the set of open file descriptors of the parent. 69.Pp 70A spawn file actions object, when passed to 71.Fn posix_spawn 72or 73.Fn posix_spawnp , 74specify how the set of open file descriptors in the calling 75process is transformed into a set of potentially open file descriptors 76for the spawned process. 77This transformation is as if the specified sequence of actions was 78performed exactly once, in the context of the spawned process (prior to 79execution of the new process image), in the order in which the actions 80were added to the object; additionally, when the new process image is 81executed, any file descriptor (from this new set) which has its 82.Dv FD_CLOEXEC 83flag set is closed (see 84.Fn posix_spawn ) . 85.Pp 86The 87.Fn posix_spawn_file_actions_addopen 88function adds an open action to the object referenced by 89.Fa file_actions 90that causes the file named by 91.Fa path 92to be opened (as if 93.Bd -literal -offset indent 94open(path, oflag, mode) 95.Ed 96.Pp 97had been called, and the returned file descriptor, if not 98.Fa fildes , 99had been changed to 100.Fa fildes ) 101when a new process is spawned using this file actions object. 102If 103.Fa fildes 104was already an open file descriptor, it is closed before the new 105file is opened. 106.Pp 107The string described by 108.Fa path 109is copied by the 110.Fn posix_spawn_file_actions_addopen 111function. 112.Pp 113The 114.Fn posix_spawn_file_actions_adddup2 115function adds a dup2 action to the object referenced by 116.Fa file_actions 117that causes the file descriptor 118.Fa fildes 119to be duplicated as 120.Fa newfildes 121(as if 122.Bd -literal -offset indent 123dup2(fildes, newfildes) 124.Ed 125.Pp 126had been called) when a new process is spawned using this file actions object, 127except that the 128.Dv FD_CLOEXEC 129flag for 130.Fa newfildes 131is cleared even if 132.Fa fildes 133is equal to 134.Fa newfildes . 135The difference from 136.Fn dup2 137is useful for passing a particular file descriptor 138to a particular child process. 139.Pp 140The 141.Fn posix_spawn_file_actions_addclose 142function adds a close action to the object referenced by 143.Fa file_actions 144that causes the file descriptor 145.Fa fildes 146to be closed (as if 147.Bd -literal -offset indent 148close(fildes) 149.Ed 150.Pp 151had been called) when a new process is spawned using this file actions 152object. 153.Sh RETURN VALUES 154Upon successful completion, these functions return zero; 155otherwise, an error number is returned to indicate the error. 156.Sh ERRORS 157These 158functions fail if: 159.Bl -tag -width Er 160.It Bq Er EBADF 161The value specified by 162.Fa fildes 163or 164.Fa newfildes 165is negative. 166.It Bq Er ENOMEM 167Insufficient memory exists to add to the spawn file actions object. 168.El 169.Sh SEE ALSO 170.Xr close 2 , 171.Xr dup2 2 , 172.Xr open 2 , 173.Xr posix_spawn 3 , 174.Xr posix_spawn_file_actions_destroy 3 , 175.Xr posix_spawn_file_actions_init 3 , 176.Xr posix_spawnp 3 177.Sh STANDARDS 178The 179.Fn posix_spawn_file_actions_addopen , 180.Fn posix_spawn_file_actions_adddup2 181and 182.Fn posix_spawn_file_actions_addclose 183functions conform to 184.St -p1003.1-2001 , 185with the exception of the behavior of 186.Fn posix_spawn_file_actions_adddup2 187if 188.Fa fildes 189is equal to 190.Fa newfildes 191(clearing 192.Dv FD_CLOEXEC ) . 193A future update of the Standard is expected to require this behavior. 194.Sh HISTORY 195The 196.Fn posix_spawn_file_actions_addopen , 197.Fn posix_spawn_file_actions_adddup2 198and 199.Fn posix_spawn_file_actions_addclose 200functions first appeared in 201.Fx 8.0 . 202.Sh AUTHORS 203.An \&Ed Schouten Aq Mt ed@FreeBSD.org 204