1.\" Copyright (c) 1980, 1991, 1993 2.\" The Regents of the University of California. 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.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)access.2 8.2 (Berkeley) 4/1/94 33.\" $FreeBSD$ 34.\" 35.Dd April 1, 1994 36.Dt ACCESS 2 37.Os 38.Sh NAME 39.Nm access 40.Nd check access permissions of a file or pathname 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.Fd #include <unistd.h> 45.Ft int 46.Fn access "const char *path" "int mode" 47.Sh DESCRIPTION 48The 49.Fn access 50function checks the accessibility of the 51file named by 52.Fa path 53for the access permissions indicated by 54.Fa mode . 55The value of 56.Fa mode 57is the bitwise inclusive OR of the access permissions to be 58checked 59.Pf ( Dv R_OK 60for read permission, 61.Dv W_OK 62for write permission and 63.Dv X_OK 64for execute/search permission) or the existence test, 65.Dv F_OK . 66All components of the pathname 67.Fa path 68are checked for access permissions (including 69.Dv F_OK ) . 70.Pp 71The real user ID is used in place of the effective user ID 72and the real group access list 73(including the real group ID) are 74used in place of the effective ID for verifying permission. 75.Pp 76Even if a process has appropriate privileges and indicates success for 77.Dv X_OK , 78the file may not actually have execute permission bits set. 79Likewise for 80.Dv R_OK 81and 82.Dv W_OK . 83.Sh RETURN VALUES 84If 85.Fa path 86cannot be found or if any of the desired access modes would 87not be granted, then a -1 value is returned; otherwise 88a 0 value is returned. 89.Sh ERRORS 90Access to the file is denied if: 91.Bl -tag -width Er 92.It Bq Er ENOTDIR 93A component of the path prefix is not a directory. 94.It Bq Er ENAMETOOLONG 95A component of a pathname exceeded 255 characters, 96or an entire path name exceeded 1023 characters. 97.It Bq Er ENOENT 98The named file does not exist. 99.It Bq Er ELOOP 100Too many symbolic links were encountered in translating the pathname. 101.It Bq Er EROFS 102Write access is requested for a file on a read-only file system. 103.It Bq Er ETXTBSY 104Write access is requested for a pure procedure (shared text) 105file presently being executed. 106.It Bq Er EACCES 107Permission bits of the file mode do not permit the requested 108access, or search permission is denied on a component of the 109path prefix. The owner of a file has permission checked with 110respect to the ``owner'' read, write, and execute mode bits, 111members of the file's group other than the owner have permission 112checked with respect to the ``group'' mode bits, and all 113others have permissions checked with respect to the ``other'' 114mode bits. 115.It Bq Er EFAULT 116.Fa Path 117points outside the process's allocated address space. 118.It Bq Er EIO 119An I/O error occurred while reading from or writing to the file system. 120.El 121.Sh SEE ALSO 122.Xr chmod 2 , 123.Xr stat 2 124.Sh STANDARDS 125The 126.Fn access 127function call is expected to conform to 128.St -p1003.1-90 . 129.Sh CAVEAT 130.Fn Access 131is a potential security hole and 132should never be used. 133.Sh HISTORY 134An 135.Fn access 136function call appeared in 137.At v7 . 138