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- Bump document date for eaccess(2) addition.

- Mention ``eaccess'' in the NAME section.
- Use intro(2) terminology.
- Markup fixes.

Reviewed by:	rwatson
This commit is contained in:
Ruslan Ermilov 2001-10-11 15:27:53 +00:00
parent 146db49f97
commit 506d9c18e9
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=84805

View File

@ -32,12 +32,12 @@
.\" @(#)access.2 8.2 (Berkeley) 4/1/94
.\" $FreeBSD$
.\"
.Dd April 1, 1994
.Dd September 21, 2001
.Dt ACCESS 2
.Os
.Sh NAME
.Nm access
.Nd check access permissions of a file or pathname
.Nm access , eaccess
.Nd check accessibility of a file
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
@ -53,35 +53,42 @@ and
.Fn eaccess
functions check the accessibility of the
file named by
the
.Fa path
argument
for the access permissions indicated by
.Fa mode .
the
.Fa mode
argument.
The value of
.Fa mode
is the bitwise inclusive OR of the access permissions to be
is either the bitwise-inclusive OR of the access permissions to be
checked
.Pf ( Dv R_OK
.Dv ( R_OK
for read permission,
.Dv W_OK
for write permission and
for write permission, and
.Dv X_OK
for execute/search permission) or the existence test,
.Dv F_OK .
for execute/search permission),
or the existence test
.Pq Dv F_OK .
.Pp
For additional information, see the
.Dq File Access Permission
.Sx "File Access Permission"
section of
.Xr intro 2 .
.Pp
The
.Fn eaccess
uses the effective user ID, group ID, and additional groups to authorize
the request.
call uses
the effective user ID and the group access list
to authorize the request;
the
.Fn access
uses
the real user ID 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.
call uses
the real user ID in place of the effective user ID,
the real group ID in place of the effective group ID,
and the rest of the group access list.
.Pp
Even if a process's real or effective user has appropriate privileges
and indicates success for
@ -92,11 +99,7 @@ Likewise for
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.
.Rv -std
.Sh ERRORS
Access to the file is denied if:
.Bl -tag -width Er
@ -119,7 +122,7 @@ Permission bits of the file mode do not permit the requested
access, or search permission is denied on a component of the
path prefix.
.It Bq Er EFAULT
.Fa Path
.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.
@ -134,14 +137,19 @@ The
function call is expected to conform to
.St -p1003.1-90 .
.Sh CAVEAT
.Fn Access
The
.Fn access
call
is a potential security hole due to race conditions and
should never be used.
Setuid and setgid applications should restore the effective uid or gid
Set-user-ID and set-group-ID applications should restore the
effective user or group ID,
and perform actions directly rather than use
.Fn access
to simulate access checks for the real user of group id.
.Fn Eaccess
to simulate access checks for the real user or group ID.
The
.Fn eaccess
call
likewise may be subject to races if used inappropriately.
.Sh HISTORY
An