share(1Mnfs)
share --
make local NFS resource available for mounting by remote systems
Synopsis
share -F nfs [-o specific_options] [-d description] pathname [resource]
Description
The NFS®-specific share command makes local resources
available for mounting by remote systems.
Options
The following options are available to the share command:
- -F
-
Specifies the File System Type (FSType). This option may be omitted if NFS
is the first filesystem type listed in the /etc/dfs/fstypes file.
- -o specific_options
-
Specify options in a comma-separated list of keywords and
attribute-value-assertions for interpretation by the
file-system-type-specific command.
specific_options can be any combination of the following:
- rw
-
Sharing will be read-write to all clients.
- rw=client[:client] ...
-
Sharing will be read-write to the listed clients; overrides the
ro suboption for the clients specified.
- ro
-
Sharing will be read-only to all clients.
- ro=client[:client] ...
-
Sharing will be read-only to the listed clients; overrides the
rw suboption for the clients specified.
- asyncwrites
-
All writes to the shared filesystem will be asynchronous. This will
significantly improve server write performance, but carries with it the
risk of data loss on server crashes.
- anon=uid
-
Set uid to be the effective user ID of unauthenticated
users if AUTH_DES authentication is used, or to be root if
AUTH_UNIX authentication is used. By default, unknown users are
given the effective user ID UID_NOBODY. If uid
is set to -1, access is denied.
- root=host[:host] ...
-
Only root users from the specified hosts will have root access. By default,
no host has root access.
- secure
-
Clients must use the AUTH_DES authentication of RPC.
AUTH_UNIX authentication is the default.
If specific_options is not specified, then by default sharing
will be read-write to all clients.
- -d description
-
Provides a comment that describes the resource to be shared.
- pathname
-
Specifies the pathname of the resource to be shared.
- resource
-
Specifies the name of the resource to be shared.
Files
- /etc/dfs/fstypes
-
- /etc/dfs/sharetab
-
Usage
If no argument is specified, then share displays all of the
NFS resources currently shared.
NOTE:
The specific_options ro=, rw=, and
root= are guaranteed to work over UDP and TCP
but may not work over other transport providers.
In addition, if a resource is shared with a ro= list and a
root= list, any host that is on the root= list will be
given read-only access, regardless of whether that host is specified in
the ro= list, unless rw is declared as the default,
or the host is mentioned in a rw= list. The same is true if the
resource is shared with ro as the default.
This command advertises its resources on applicable transports specified
by the NETPATH environment variable if the variable is not
set to NULL. Otherwise, the share command scans
the /etc/netconfig file to find all appropriate transports.
The recommended use of the NETPATH variable with the
share command is as follows:
# NETPATH=udp share -F nfs ...
Specifying NETPATH in this manner affects only the execution of
the share command and does not affect the shell environment.
Exit codes
- 0
-
Successful exit
- 33
-
Usage error
- 34
-
Could not add to sharetab
- 35
-
Could not delete from sharetab
- 36
-
Could not share
- 37
-
Error in options parsing
Warnings
The share command will fail if both ro and
rw (with no qualifiers) are specified. If the same client name
exists in both the ro= and rw= lists, the rw
will override the ro, giving read/write access to the client
specified.
Granting root access to other hosts has far reaching security implications;
use the root= option with extreme caution.
Examples
The following share commands will give read-only permissions to
hostb:
share -F nfs -oro=hosta,root=hostb /var
share -F nfs -oro,root=hostb /var
While the following will give read/write permissions to hostb:
share -F nfs -oro=hosta,rw=hostb,root=hostb /var
share -F nfs -oroot=hostb /var
References
share(1M),
unshare(1M),
unshare(1Mnfs)
30 January 1998
© 1998 The Santa Cruz Operation, Inc. All rights reserved.