fam - file alteration monitor


SYNOPSIS

       /usr/etc/fam [ -f | -v | -d ] [ -l | -t NFS_polling_interval ]
            [ -T idle_timeout ] [ -p program.version ] [ -L ] [ -C ]
            [ -c config_file ]


DESCRIPTION

       fam  is a server that tracks changes to the filesystem and
       relays these changes to interested applications.  Applica­
       tions  such as fm(1G) and mailbox(1) present an up-to-date
       view of the filesystem.  In  the  absence  of  fam,  these
       applications  and  others like them are forced to poll the
       filesystem to detect changes.  fam is more efficient.

       Applications can request  fam  to  monitor  any  files  or
       directories  in  any filesystem.  When fam detects changes
       to monitored files, it notifies the  appropriate  applica­
       tion.   The  FAM  API provides a programmatic interface to
       fam; see fam(3X).

       fam is informed of filesystem changes as  they  happen  by
       the  kernel through the imon(7M) pseudo device driver.  If
       asked to monitor files on an NFS mounted  filesystem,  fam
       tries  to  use fam on the NFS server to monitor files.  If
       fam cannot contact  a  remote  fam,  it  polls  the  files
       instead.  fam also polls special files.

       Normally,  fam  is started by inetd(1M).  It is registered
       with portmap(1M) as performing the sgi_fam service.


OPTIONS

       -l                        Disable polling  of  NFS  files.
                                 It   does  not  disable  use  of
                                 remote fam on NFS  servers,  nor
                                 does it disable polling of local
                                 files.

       -t NFS_polling_interval   Set  the  interval  for  polling
                                 files   to  NFS_polling_interval
                                 seconds.   The  default  is  six
                                 seconds.

       -T idle_timeout           Set the idle timeout interval to
                                 idle_timeout.      fam     exits
                                 idle_timeout  seconds  after its
                                 last  client   disconnects.    A
                                 value  of  0  causes fam to wait
                                 indefinitely  for  new   connec­
                                 tions.  The default is five sec­
                                 onds.

       -f                        Remain in the foreground instead

                                 This option is ignored if fam is
                                 started by inetd.

       -v                        Turn on verbose messages.

       -d                        Enable   verbose   messages  and
                                 debug messages.

       -p program.version        Use the  specified  RPC  program
                                 and version numbers.

       -L                        Local-only  mode.  fam will only
                                 accept  requests  from   clients
                                 running  on  the  local machine.
                                 This  overrides  the  local_only
                                 flag  in the configuration file.
                                 This option is ignored if fam is
                                 started by inetd.

       -C                        Compatibility  mode.   This dis­
                                 ables authentication and reduces
                                 access   security  as  described
                                 under  SECURITY   below.    This
                                 overrides  the insecure_compati­
                                 bility flag in the configuration
                                 file.

       -c config_file            Read  configuration  information
                                 from the given file rather  than
                                 the     default,     which    is
                                 /etc/fam.conf.


CONFIGURATION FILE

       In addition to its command-line  options,  fam's  behavior
       can also be controlled through its configuration file.  By
       default, this is /etc/fam.conf; the -c command-line option
       can  be  used to specify an alternate file.  Configuration
       lines are in the  format  option=value.   Lines  beginning
       with  #  or  !  are ignored.  fam recognizes the following
       options:

       insecure_compatibility    If set to  true,  this  disables
                                 authentication    and    reduces
                                 access  security  as   described
                                 under  SECURITY  below.  This is
                                 false by default.  Setting  this
                                 option  to  true  is the same as
                                 using   the   -C    command-line
                                 option.

       untrusted_user            This  is the user name or UID of
                                 the user account which fam  will
                                 use for unauthenticated clients.

                                 this  user,  fam  will  not tell
                                 unauthenticated  clients   about
                                 the  file's  existence.   If  an
                                 untrusted user is not  given  in
                                 the configuration file, fam will
                                 write an error  message  to  the
                                 system log and terminate.

       local_only                If  set to true, fam will ignore
                                 requests from remote fams.  This
                                 is  false  by  default.  Setting
                                 this option to true is the  same
                                 as  using  the  -L  command-line
                                 option.  This option is  ignored
                                 if fam is started by inetd.

       xtab_verification         If  set  to true, fam will check
                                 the list of exported filesystems
                                 when    remote    requests   are
                                 received  to  verify  that   the
                                 requests   fall  on  filesystems
                                 which  are   exported   to   the
                                 requesting  hosts.  This is true
                                 by default.  If this  option  is
                                 set  to  false, fam will service
                                 remote requests without attempt­
                                 ing to perform the verification.
                                 If the local_only  configuration
                                 option or -L command-line option
                                 is used,  xtab_verification  has
                                 no effect.


SECURITY

       For backward compatibility, the -C command-line option and
       insecure_compatibility configuration option can be used to
       disable  authentication.  Configuring fam this way opens a
       publically  known  security  weakness  whereby  a   "rogue
       client" can obtain the names of all the files and directo­
       ries on the system.

       Note that fam never opens the files it's  monitoring,  and
       cannot  be  used by a rogue client to read the contents of
       any file on the system.  fam only gives out the  names  of
       monitored  files, and only monitors files which the client
       can stat(1M).  Users can stat a file without  having  read
       permission on it as long as they have search permission on
       the directory containing it.


FILES

       /etc/fam.conf


SEE ALSO

       inetd(1M), portmap(1M), fam(3X), imon(7M), stat(1M).


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