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Diffstat (limited to 'lib/libc/sys/access.2')
-rw-r--r-- | lib/libc/sys/access.2 | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/lib/libc/sys/access.2 b/lib/libc/sys/access.2 new file mode 100644 index 0000000..9b1c036 --- /dev/null +++ b/lib/libc/sys/access.2 @@ -0,0 +1,135 @@ +.\" Copyright (c) 1980, 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. +.\" +.\" @(#)access.2 8.2 (Berkeley) 4/1/94 +.\" $FreeBSD$ +.\" +.Dd April 1, 1994 +.Dt ACCESS 2 +.Os BSD 4 +.Sh NAME +.Nm access +.Nd check access permissions of a file or pathname +.Sh SYNOPSIS +.Fd #include <unistd.h> +.Ft int +.Fn access "const char *path" "int mode" +.Sh DESCRIPTION +The +.Fn access +function checks the accessibility of the +file named by +.Fa path +for the access permissions indicated by +.Fa mode . +The value of +.Fa mode +is the bitwise inclusive OR of the access permissions to be +checked +.Pf ( Dv R_OK +for read permission, +.Dv W_OK +for write permission and +.Dv X_OK +for execute/search permission) or the existence test, +.Dv F_OK . +All components of the pathname +.Fa path +are checked for access permissions (including +.Dv F_OK ) . +.Pp +The real user ID is used in place of the effective user ID +and the real group access list +(including the real group ID) are +used in place of the effective ID for verifying permission. +.Pp +Even if a process has appropriate privileges and indicates success for +.Dv X_OK , +the file may not actually have execute permission bits set. +Likewise for +.Dv R_OK +and +.Dv W_OK . +.Sh RETURN VALUES +If +.Fa path +cannot be found or if any of the desired access modes would +not be granted, then a -1 value is returned; otherwise +a 0 value is returned. +.Sh ERRORS +Access to the file is denied if: +.Bl -tag -width Er +.It Bq Er ENOTDIR +A component of the path prefix is not a directory. +.It Bq Er ENAMETOOLONG +A component of a pathname exceeded 255 characters, +or an entire path name exceeded 1023 characters. +.It Bq Er ENOENT +The named file does not exist. +.It Bq Er ELOOP +Too many symbolic links were encountered in translating the pathname. +.It Bq Er EROFS +Write access is requested for a file on a read-only file system. +.It Bq Er ETXTBSY +Write access is requested for a pure procedure (shared text) +file presently being executed. +.It Bq Er EACCES +Permission bits of the file mode do not permit the requested +access, or search permission is denied on a component of the +path prefix. The owner of a file has permission checked with +respect to the ``owner'' read, write, and execute mode bits, +members of the file's group other than the owner have permission +checked with respect to the ``group'' mode bits, and all +others have permissions checked with respect to the ``other'' +mode bits. +.It Bq Er EFAULT +.Fa Path +points outside the process's allocated address space. +.It Bq Er EIO +An I/O error occurred while reading from or writing to the file system. +.El +.Sh SEE ALSO +.Xr chmod 2 , +.Xr stat 2 +.Sh STANDARDS +The +.Fn access +function call is expected to conform to +.St -p1003.1-90 . +.Sh CAVEAT +.Fn Access +is a potential security hole and +should never be used. +.Sh HISTORY +An +.Fn access +function call appeared in +.At v7 . |