NAME

access − determine accessibility of file

SYNOPSIS

­#include <u.h>
­#include <libc.h>

int access(char ∗name, int mode)

DESCRIPTION

­Access evaluates the given file ­name for accessibility.  If mode&4 is nonzero, read permission is expected; if mode&2, write permission; if mode&1, execute permission.  If mode==0, the file merely need exist.  In any case all directories leading to the file must permit searches.  Zero is returned if the desired access is permitted, −1 if not. 

Only access for open is checked.  A file may look executable, but exec(2) will fail unless it is in proper format.

The include file defines AEXIST=0, AEXEC=1, AWRITE=2, and AREAD=4. 

SOURCE

­/sys/src/libc/9sys/access.c

SEE ALSO

stat(2)

DIAGNOSTICS

Sets errstr.

BUGS

Since file permissions are checked by the server and group information is not known to the client, ­access must open the file to check permissions.  (It calls stat(2) to check simple existence.)

Plan 9  —  March 02, 2003