151 lines
4.1 KiB
Groff
151 lines
4.1 KiB
Groff
.\" $NetBSD: setmode.3,v 1.21 2009/01/11 02:46:27 christos Exp $
|
|
.\"
|
|
.\" Copyright (c) 1989, 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. 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.
|
|
.\"
|
|
.\" @(#)setmode.3 8.2 (Berkeley) 4/28/95
|
|
.\"
|
|
.Dd January 4, 2009
|
|
.Dt SETMODE 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm getmode ,
|
|
.Nm setmode
|
|
.Nd modify mode bits
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In unistd.h
|
|
.Ft void *
|
|
.Fn setmode "const char *mode_str"
|
|
.Ft mode_t
|
|
.Fn getmode "const void *set" "mode_t mode"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn setmode
|
|
function accepts a string representation of a file mode change,
|
|
compiles it to binary form, and returns an abstract representation
|
|
that may be passed to
|
|
.Fn getmode .
|
|
The string may be an numeric (octal) or symbolic string of the form
|
|
accepted by
|
|
.Xr chmod 1 ,
|
|
and may represent either an exact mode to set or a change to make to
|
|
the existing mode.
|
|
.Pp
|
|
The
|
|
.Fn getmode
|
|
function
|
|
adjusts the file permission bits given by
|
|
.Fa mode
|
|
according to the compiled change representation
|
|
.Fa set ,
|
|
and returns the adjusted mode.
|
|
While only the permission bits are altered, other parts of the file
|
|
mode, particularly the type, may be examined.
|
|
.Pp
|
|
Because some of the possible symbolic values are defined relative to
|
|
the file creation mask,
|
|
.Fn setmode
|
|
may call
|
|
.Xr umask 2 ,
|
|
temporarily changing the mask.
|
|
If this occurs, the file creation mask will be restored before
|
|
.Fn setmode
|
|
returns.
|
|
If the calling program changes the value of its file creation mask
|
|
after calling
|
|
.Fn setmode ,
|
|
.Fn setmode
|
|
must be called again to recompile the mode string if
|
|
.Fn getmode
|
|
is to modify future file modes correctly.
|
|
.Pp
|
|
If the mode passed to
|
|
.Fn setmode
|
|
is invalid,
|
|
.Fn setmode
|
|
returns
|
|
.Dv NULL .
|
|
.Sh EXAMPLES
|
|
The effects of the shell command
|
|
.Ql "chmod a+x myscript.sh"
|
|
can be duplicated as follows:
|
|
.Bd -literal -offset indent
|
|
const char *file = "myscript.sh";
|
|
struct stat st;
|
|
mode_t newmode;
|
|
|
|
stat(file, \*[Am]st);
|
|
newmode = getmode(setmode("a+x"), st.st_mode);
|
|
chmod(file, newmode);
|
|
.Ed
|
|
.Sh ERRORS
|
|
The
|
|
.Fn setmode
|
|
function
|
|
may fail and set
|
|
.Va errno
|
|
for any of the errors specified for the library routines
|
|
.Xr malloc 3
|
|
or
|
|
.Xr strtol 3 .
|
|
In addition,
|
|
.Fn setmode
|
|
will fail and set
|
|
.Va errno
|
|
to:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EINVAL
|
|
The
|
|
.Fa mode
|
|
argument does not represent a valid mode.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr chmod 1 ,
|
|
.Xr stat 2 ,
|
|
.Xr umask 2 ,
|
|
.Xr malloc 3
|
|
.Sh HISTORY
|
|
The
|
|
.Fn getmode
|
|
and
|
|
.Fn setmode
|
|
functions first appeared in
|
|
.Bx 4.4 .
|
|
.Sh BUGS
|
|
Each call to
|
|
.Nm setmode
|
|
allocates a small amount of memory that there is no correct way to
|
|
free.
|
|
.Pp
|
|
The type of
|
|
.Fa set
|
|
should really be some opaque struct type used only by these functions
|
|
rather than
|
|
.Ft void * .
|