163 lines
4.4 KiB
Groff
163 lines
4.4 KiB
Groff
.\" $NetBSD: getcwd.3,v 1.11 1999/03/22 19:44:40 garbled Exp $
|
|
.\"
|
|
.\" Copyright (c) 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the University of
|
|
.\" California, Berkeley and its contributors.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)getcwd.3 8.2 (Berkeley) 12/11/93
|
|
.\"
|
|
.Dd December 11, 1993
|
|
.Dt GETCWD 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm getcwd ,
|
|
.Nm getwd
|
|
.Nd get working directory pathname
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.Fd #include <unistd.h>
|
|
.Ft char *
|
|
.Fn getcwd "char *buf" "size_t size"
|
|
.Ft char *
|
|
.Fn getwd "char *buf"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn getcwd
|
|
function copies the absolute pathname of the current working directory
|
|
into the memory referenced by
|
|
.Fa buf
|
|
and returns a pointer to
|
|
.Fa buf .
|
|
The
|
|
.Fa size
|
|
argument is the size, in bytes, of the array referenced by
|
|
.Fa buf .
|
|
.Pp
|
|
If
|
|
.Fa buf
|
|
is
|
|
.Dv NULL ,
|
|
space is allocated as necessary to store the pathname.
|
|
This space may later be
|
|
.Xr free 3 Ns 'd.
|
|
.Pp
|
|
The function
|
|
.Fn getwd
|
|
is a compatibility routine which calls
|
|
.Fn getcwd
|
|
with its
|
|
.Fa buf
|
|
argument and a size of
|
|
.Dv MAXPATHLEN
|
|
(as defined in the include
|
|
file
|
|
.Aq Pa sys/param.h ) .
|
|
Obviously,
|
|
.Fa buf
|
|
should be at least
|
|
.Dv MAXPATHLEN
|
|
bytes in length.
|
|
.Pp
|
|
These routines have traditionally been used by programs to save the
|
|
name of a working directory for the purpose of returning to it.
|
|
A much faster and less error-prone method of accomplishing this is to
|
|
open the current directory
|
|
.Pq Ql \&.
|
|
and use the
|
|
.Xr fchdir 2
|
|
function to return.
|
|
.Sh RETURN VALUES
|
|
Upon successful completion, a pointer to the pathname is returned.
|
|
Otherwise a
|
|
.Dv NULL
|
|
pointer is returned and the global variable
|
|
.Va errno
|
|
is set to indicate the error.
|
|
In addition,
|
|
.Fn getwd
|
|
copies the error message associated with
|
|
.Va errno
|
|
into the memory referenced by
|
|
.Fa buf .
|
|
.Sh ERRORS
|
|
The
|
|
.Fn getcwd
|
|
function
|
|
will fail if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EACCES
|
|
Read or search permission was denied for a component of the pathname.
|
|
.It Bq Er EINVAL
|
|
The
|
|
.Fa size
|
|
argument is zero.
|
|
.It Bq Er ENOENT
|
|
A component of the pathname no longer exists.
|
|
.It Bq Er ENOMEM
|
|
Insufficient memory is available.
|
|
.It Bq Er ERANGE
|
|
The
|
|
.Fa size
|
|
argument is greater than zero but smaller than the length of the pathname
|
|
plus 1.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr chdir 2 ,
|
|
.Xr fchdir 2 ,
|
|
.Xr malloc 3 ,
|
|
.Xr strerror 3
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn getcwd
|
|
function
|
|
conforms to
|
|
.St -p1003.1-90 .
|
|
The ability to specify a
|
|
.Dv NULL
|
|
pointer and have
|
|
.Fn getcwd
|
|
allocate memory as necessary is an extension.
|
|
.Sh HISTORY
|
|
The
|
|
.Fn getwd
|
|
function appeared in
|
|
.Bx 4.0 .
|
|
.Sh SECURITY CONSIDERATIONS
|
|
As
|
|
.Fn getwd
|
|
does not know the length of the supplied buffer, it is possible
|
|
for a long (but valid) path to overflow the buffer and provide
|
|
a means for an attacker to exploit the caller.
|
|
.Fn getcwd
|
|
should be used in place of
|
|
.Fn getwd
|
|
(the latter is only provided for compatibility purposes).
|