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.