access man page on BSDi

Man page or keyword search:  
man Server   6284 pages
apropos Keyword Search (all sections)
Output format
BSDi logo
[printable version]

ACCESS(2)		    BSD Programmer's Manual		     ACCESS(2)

NAME
     access - check access permissions of a file or pathname

SYNOPSIS
     #include <unistd.h>

     int
     access(const char *path, int mode);

DESCRIPTION
     The access() function checks the accessibility of the file named by path
     for the access permissions indicated by mode. The value of mode is the
     bitwise inclusive OR of the access permissions to be checked (R_OK for
     read permission, W_OK for write permission and X_OK for execute/search
     permission) or the existence test, F_OK. All components of the pathname
     path are checked for access permissions (including F_OK).

     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.

     Even if a process has appropriate privileges and indicates success for
     X_OK, the file may not actually have execute permission bits set.	Like-
     wise for R_OK and W_OK.

RETURN VALUES
     If 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.

ERRORS
     Access to the file is denied if:

     [ENOTDIR]	   A component of the path prefix is not a directory.

     [EINVAL]	   The pathname contains a character with the high-order bit
		   set.

     [ENAMETOOLONG]
		   A component of a pathname exceeded 255 characters, or an
		   entire path name exceeded 1023 characters.

     [ENOENT]	   The named file does not exist.

     [ELOOP]	   Too many symbolic links were encountered in translating the
		   pathname.

     [EROFS]	   Write access is requested for a file on a read-only file
		   system.

     [ETXTBSY]	   Write access is requested for a pure procedure (shared
		   text) file presently being executed.

     [EACCES]	   Permission bits of the file mode do not permit the request-
		   ed 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 exe-
		   cute 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 re-
		   spect to the ``other'' mode bits.

     [EFAULT]	   Path points outside the process's allocated address space.

     [EIO]	   An I/O error occurred while reading from or writing to the
		   file system.

SEE ALSO
     chmod(2),	stat(2)

STANDARDS
     Access() conforms to IEEE Std 1003.1-1988 (``POSIX'').

CAVEAT
     The access() function should be used rarely, if ever.  Specifically,
     access() should never be used by any program whose user real and effec-
     tive IDs, or group real and effective IDs, differ.	 At best, using
     access() in this situation can produce a misleading result, because the
     system call permission checks are based on effective IDs.	Thus, access()
     might return that the file is accessible, when the corresponding open(2)
     or exec(2) call would fail, or vice-versa.	 In addition, the permissions
     on the file, or the path leading to the file, may change between the time
     access() makes its test and the eventual system call.  This timing race
     applies to all uses of access(), so it is better to attempt the operation
     itself to see if it will succeed.	(Processes designed to run setuid or
     setgid should call seteuid(2) or setegid(2) as needed to suspend their
     special privileges.)

4th Berkeley Distribution	 April 1, 1994				     2
[top]

List of man pages available for BSDi

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
....................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net