FAM(1M) FAM(1M) NAME fam - file alteration monitor SYNOPSIS /usr/etc/fam [ -t NFS polling interval ] DESCRIPTION Fam is a server that tracks changes to the file system and relays these changes to interested applications. Applications such as WorkSpace(1G) and Mailbox(1G) present an up-to-date view of the file system. In the absence of fam, these applications and others like them would be forced to poll the file system to detect changes. Fam is considerably more efficient. Applications can request fam to monitor any files or directories in the file system. When fam detects changes to these files, it notifies the appropriate application. Fam(3X) provides a programmatic interface to fam. Fam is informed of file system changes as they happen by the IRIX kernel through the imon(1M) pseudo device driver. Currently, fam servers do not communicate with each other and consequently, they poll to determine the state of NFS mounted file systems. The -t option specifies the polling interval in seconds. The default polling interval is 3 seconds. Since fam is invoked by inetd(1M), you must edit the /etc/inetd.conf file to change the polling interval. SEE ALSO imon(1M), fam(3X), inetd(1M), workspace(1G), mailbox(1G)
fam(1M) fam(1M) NAME fam - file alteration monitor SYNOPSIS /usr/etc/fam [ -f | -v | -d ] [ -l ] [ -t NFS_polling_interval ] [ -T idle_timeout ] [ -p program.version ] DESCRIPTION fam is a server that tracks changes to the filesystem and relays these changes to interested applications. Applications 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 the filesystem. When fam detects changes to these files, it notifies the appropriate application. fam(3X) provides a programmatic interface to fam. fam is informed of filesystem changes as they happen by the IRIX 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. -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. The default is five seconds. -f If fam is not started by inetd, it remains in the foreground instead of spawning a child and exiting. -v Turn on verbose messages. -d Enable verbose messages and debug messages. -p program.version Use the specified RPC program and version numbers. Page 1 fam(1M) fam(1M) SEE ALSO fm(1G), inetd(1M), mailbox(1), portmap(1M), fam(3X), imon(7M).
FAM(3X) FAM(3X) NAME fam - File Alteration Monitor (FAM) library routines SYNOPSIS #includeextern int FAMOpen(FAMConnection* fc); extern int FAMClose(FAMConnection* fc); extern int FAMMonitorDirectory(FAMConnection *fc, char *filename, FAMRequest* fr, void* userData); extern int FAMMonitorFile(FAMConnection *fc, char *filename, FAMRequest* fr, void* userData); extern int FAMMonitorRemoteDirectory(FAMConnection *fc, char *hostname, char *filename, FAMRequest* fr, void* userdata); extern int FAMMonitorRemoteFile(FAMConnection *fc, char *hostname, char *filename, FAMRequest* fr, void* userdata); int FAMSuspendMonitor(FAMConnection *fc, FAMRequest *fr); int FAMResumeMonitor(FAMConnection *fc, FAMRequest *fr); int FAMCancelMonitor(FAMConnection *fc, FAMRequest *fr); int FAMNextEvent(FAMConnection *fc, FAMEvent *fe); int FAMPending(FAMConnection* fc); typedef struct { int fd; } FAMConnection; #define FAMCONNECTION_GETFD(fc) (fc->fd) typedef struct { int reqnum; } FAMRequest; Page 1 FAM(3X) FAM(3X) enum FAMCodes { FAMChanged=1, FAMDeleted=2, FAMStartExecuting=3, FAMStopExecuting=4, FAMCreated=5, FAMMoved=6, FAMAcknowledge=7, FAMExists=8, FAMEndExist=9 }; typedef struct { FAMConnection* fc; FAMRequest fr; char hostname[MAXHOSTNAMELEN]; char filename[NAME_MAX]; void *userdata; FAMCodes code; } FAMEvent; extern int FAMErrno; extern char *FamErrlist[]; DESCRIPTION FAM monitors files and directories, notifying interested applications of changes. Routines for communicating with the fam(1M) server process are found in ``libfam.a'', which is loaded if the option ``-lfam'' is used with cc(1) or ld(1). The library ``libC.a'' (``-lC'') must also be specified. An application calls routines described here to establish a list of files for fam to monitor. Fam generates events on a socket to communicate with the application. The fam process is started when the first connection from any application to it is opened. It exits after all connections to it have been closed. USING FAM Here are the steps required to use FAM in an application: 1. Create a connection to fam by calling FAMOpen. This routine will pass back a FAMConnection structure used in all fam procedures. 2. Tell fam which files and directories to monitor by calling FAMMonitorFile and FAMMonitorDirectory to express interest in files and directories, respectively. 3. Select on the fam socket file descriptor and call FAMNextEvent when the fam socket is active. Alternatively, the application must call FAMNextEvent (or FAMPending) periodically to check the socket connection to fam to see if any new information has arrived. If there are no events pending, FAMNextEvent blocks until an event occurs. 4. When the application is through monitoring a file or directory, it should call FAMCancelMonitor. If the application wants to temporarily suspend monitoring of a file or directory, it may call FAMSuspendMonitor. When the application is ready to start Page 2 FAM(3X) FAM(3X) monitoring again, it calls FAMResumeMonitor. 5. Before the application exits, it should call FAMClose to free resources associated with files still being monitored and to close connection to fam. DATA STRUCTURES The FAMConnection Structure The FAMConnection data structure is created when opening a connection to FAM. Subsequently it is passed into all FAM procedures. This structure has all the information in it to communicate to fam. Use the macro FAMCONNECTION_GETFD to access the file descriptor inside the FAMConnection, rather than accessing it directly. The FAMRequest Structure When fam is called on to monitor a file, it passes back a FAMRequest structure. This structure uniquely identifies the request so that it may be cancelled, using FAMCancelMonitor or suspended, using FAMSuspendMonitor. The FAMEvent Structure Changes to files and directories are encoded in the FAMEvent structure. The code field of this structure contains one of the following enumeration constants: FAMChanged Some value which can be obtained with fstat(1) changed for a file or directory being monitored. FAMDeleted A file or directory being monitored was deleted or its name was changed. FAMStartExecuting An executable file being monitored started executing. This event occurs every time the file is run, even if older processes are still running. FAMStopExecuting An executable file being monitored which was running finished. If multiple processes from an executable are running, this event is only generated when the last one finishes. FAMCreated A file was created in a directory being monitored. Note: this event is only generated for files created directly in a directory being monitored; subdirectories are not automatically monitored. Page 3 FAM(3X) FAM(3X) FAMMoved FAMMoved events never occur. The name remains defined so that programs that reference it will still compile. FAMAcknowledge After a FAMCancelMonitor, fam generates a FAMAcknowledge event. FAMExists When the application requests a file be monitored, fam generates a FAMExists event for that file. When the application requests a directory be monitored, fam generates a FAMExists event for that directory and every file directly contained in that directory. FAMEndExist When the application requests a directory be monitored, a series of FAMExists events are generated as described above. After the last FAMExists message, fam generates a FAMEndExist messsage. ERROR HANDLING If an error occurs inside of FAM, a global named FAMErrno is set to a non-zero value and the routine that generated the error in will return an error value. The value of FAMErrno is valid until the next FAM routine is called. The FAMErrno can be translated in to a character string using the global array FAMErrlist. PROCEDURES FAMOpen, FAMClose The application opens a connection to fam by calling FAMOpen. FAMOpen initializes the FAMConnection structure passed in to it and returns 0 if successful, otherwise -1. The variable char* appName should be set to the name of your application. The FAMConnection structure is passed to all subsequent FAM procedure calls. FAMClose frees resources associated with files still being monitored and closes a fam connection. It returns 0 if successful and -1 otherwise. FAMMonitorDirectory, FAMMonitorFile FAMMonitorDirectory and FAMMonitorFile tell FAM to start monitoring a directory or file, respectively. The parameters to this function are a FAMConnection (initialized by FAMOpen), a FAMRequest structure, a filename and a user data pointer. The FAMRequest structure is modified to subsequently identify this request. When the file or directory changes, a FAM event structure will be generated. The application can retrieve this structure by calling FAMNextEvent (see description under FAMNextEvent). FAMMonitorDirectory monitors changes that happens to the contents of the directory (as well as the directory file itself); FAMMonitorFile monitors only what happens to a particular file. Both routines return 0 if successful and -1 otherwise. Page 4 FAM(3X) FAM(3X) The filename argument must be a full pathname. FAMMonitorRemoteDirectory, FAMMonitorRemoteFile FAMMonitorRemoteDirectory and FAMMonitorRemoteFile are analogous to FAMMonitorDirectory and FAMMonitorFile. They take an additional hostname parameter (as returned by gethostname(2), for example) to connect to a fam process running on a remote processor. Both routines return 0 if successful and -1 otherwise. FAMSuspendMonitor, FAMResumeMonitor FAMSuspendMonitor temporarily suspends monitoring of files or directories. This is useful when an application is not displaying information about files, when it is iconified, for example. FAMResumeMonitor signals fam to start monitoring the file or directory again. Changes which occur while monitoring is suspended are discarded, not enqueued. Both of these routines take a FAMConnection and a FAMRequest structure. The FAMRequest Structure is returned from the FAMMonitorFile or FAMMonitorDirectory routines and return 0 if successful and -1 otherwise. FAMCancelMonitor When an application is through monitoring a file or directory, it should call FAMCancelMonitor. This routine will signal fam not to monitor this directory anymore. The FAMRequest structure is returned from the FAMMonitorFile or FAMMonitorDirectory routines. FAMCancelMonitor returns 0 if successful and -1 otherwise. FAMPending, FAMNextEvent FAMPending returns 1 if an event waiting, 0 if no event is waiting, and -1 if there is an error. This routine returns immediately to the caller. FAMNextEvent will get the next FAM event (file or directory change). If there are no FAM events waiting, then the calling application blocks until a FAM event is received (from fam). There are two ways to for applications to receive FAM events: 1. The Select approach - The application selects on the file descriptor returned from FAMOpen, in the FAMConnection structure. When this file descriptor becomes active, the application calls FAMNextEvent to retrieve the pending FAM event. 2. The Polling approach - The application calls FAMPending periodically (usually when the system is waiting for input). When FAMPending returns with a positive return value, the application calls FAMNextEvent to retrieve the pending FAM Pevents. Page 5 FAM(3X) FAM(3X) FAMNextEvent reads any information that is on the fam socket, and returns it to the application in the form of a FAMEvent. FAMNextEvent returns 1 if successful and -1 otherwise. SEE ALSO fam(1M). BUGS The FAMMoved event is not currently supported. FAMNextEvent may not initialize the FAMEvent's filename field for FAMEndExist and FAMAcknowledge events. Use the request number to determine the file or directory to which those events refer. The current fam does not support networking. FAMMonitorRemoteDirectory and FAMMonitorRemoteFile are not implemented yet. The FAMErrno variable is not set when errors occur. When a shell script is run, notification is generated for the shell executing the script, typically sh(1) or csh(1). Each process is limited to 1000 active requests at a time.
FAM(3X) FAM(3X) NAME fam - File Alteration Monitor (FAM) library routines SYNOPSIS #includeextern int FAMOpen(FAMConnection* fc); extern int FAMClose(FAMConnection* fc); extern int FAMMonitorDirectory(FAMConnection *fc, char *filename, FAMRequest* fr, void* userData); extern int FAMMonitorFile(FAMConnection *fc, char *filename, FAMRequest* fr, void* userData); extern int FAMMonitorRemoteDirectory(FAMConnection *fc, char *hostname, char *filename, FAMRequest* fr, void* userdata); extern int FAMMonitorRemoteFile(FAMConnection *fc, char *hostname, char *filename, FAMRequest* fr, void* userdata); int FAMSuspendMonitor(FAMConnection *fc, FAMRequest *fr); int FAMResumeMonitor(FAMConnection *fc, FAMRequest *fr); int FAMCancelMonitor(FAMConnection *fc, FAMRequest *fr); int FAMNextEvent(FAMConnection *fc, FAMEvent *fe); int FAMPending(FAMConnection* fc); typedef struct { int fd; } FAMConnection; #define FAMCONNECTION_GETFD(fc) (fc->fd) typedef struct { int reqnum; } FAMRequest; Page 1 FAM(3X) FAM(3X) enum FAMCodes { FAMChanged=1, FAMDeleted=2, FAMStartExecuting=3, FAMStopExecuting=4, FAMCreated=5, FAMMoved=6, FAMAcknowledge=7, FAMExists=8, FAMEndExist=9 }; typedef struct { FAMConnection* fc; FAMRequest fr; char hostname[MAXHOSTNAMELEN]; char filename[NAME_MAX]; void *userdata; FAMCodes code; } FAMEvent; extern int FAMErrno; extern char *FamErrlist[]; DESCRIPTION FAM monitors files and directories, notifying interested applications of changes. Routines for communicating with the fam(1M) server process are found in ``libfam.a'', which is loaded if the option ``-lfam'' is used with cc(1) or ld(1). The library ``libC.a'' (``-lC'') must also be specified. An application calls routines described here to establish a list of files for fam to monitor. Fam generates events on a socket to communicate with the application. The fam process is started when the first connection from any application to it is opened. It exits after all connections to it have been closed. USING FAM Here are the steps required to use FAM in an application: 1. Create a connection to fam by calling FAMOpen. This routine will pass back a FAMConnection structure used in all fam procedures. 2. Tell fam which files and directories to monitor by calling FAMMonitorFile and FAMMonitorDirectory to express interest in files and directories, respectively. 3. Select on the fam socket file descriptor and call FAMNextEvent when the fam socket is active. Alternatively, the application must call FAMNextEvent (or FAMPending) periodically to check the socket connection to fam to see if any new information has arrived. If there are no events pending, FAMNextEvent blocks until an event occurs. 4. When the application is through monitoring a file or directory, it should call FAMCancelMonitor. If the application wants to temporarily suspend monitoring of a file or directory, it may call FAMSuspendMonitor. When the application is ready to start monitoring again, it calls FAMResumeMonitor. Page 2 FAM(3X) FAM(3X) 5. Before the application exits, it should call FAMClose to free resources associated with files still being monitored and to close the connection to fam. DATA STRUCTURES The FAMConnection Structure The FAMConnection data structure is created when opening a connection to FAM. Subsequently it is passed into all FAM procedures. This structure has all the information in it to communicate to fam. Use the macro FAMCONNECTION_GETFD to access the file descriptor inside the FAMConnection, rather than accessing it directly. The FAMRequest Structure When fam is called on to monitor a file, it passes back a FAMRequest structure. This structure uniquely identifies the request so that it may be cancelled, using FAMCancelMonitor or suspended, using FAMSuspendMonitor. The FAMEvent Structure Changes to files and directories are encoded in the FAMEvent structure. The code field of this structure contains one of the following enumeration constants: FAMChanged Some value which can be obtained with fstat(1) changed for a file or directory being monitored. FAMDeleted A file or directory being monitored was deleted or its name was changed. This event is also generated when monitoring starts on a nonexistent file or directory. FAMStartExecuting An executable file or shared library being monitored started executing. If multiple processes execute the same file, this event only occurs when the first process starts. FAMStopExecuting An executable file being monitored which was running finished. If multiple processes from an executable are running, this event is only generated when the last one finishes. FAMCreated A file was created in a directory being monitored. Note: this event is only generated for files created directly in a directory being monitored; subdirectories are not automatically monitored. Page 3 FAM(3X) FAM(3X) FAMMoved FAMMoved events never occur. The name remains defined so that programs that reference it will still compile. FAMAcknowledge After a FAMCancelMonitor, fam generates a FAMAcknowledge event. Also, if an invalid pathname is specified, fam generates a FAMAcknowledge event. FAMExists When the application requests a file be monitored, fam generates a FAMExists event for that file. When the application requests a directory be monitored, fam generates a FAMExists event for that directory and every file directly contained in that directory. FAMEndExist When the application requests a file directory be monitored, a series of FAMExists events is generated as described above. After the last FAMExists message, fam generates a FAMEndExist messsage. If a FAM event applies to a file or directory being monitored, the FAMEvent's filename field contains the full pathname that was passed to fam. If an event applies to an entry in a monitored directory, the filename field contains the relative path only. For example, if the directory /usr/tmp/xyzzy were monitored, and the file /usr/tmp/xyzzy/plugh were deleted, a FAMDeleted event would be generated containing "plugh" in filename. If the directory itself were deleted, filename would contain "/usr/tmp/xyzzy". ERROR HANDLING If an error occurs inside of FAM, a global named FAMErrno is set to a non-zero value and the routine that generated the error in will return an error value. The value of FAMErrno is valid until the next FAM routine is called. The FAMErrno can be translated in to a character string using the global array FAMErrlist. PROCEDURES FAMOpen, FAMClose The application opens a connection to fam by calling FAMOpen. FAMOpen initializes the FAMConnection structure passed in to it and returns 0 if successful, otherwise -1. The variable char* appName should be set to the name of your application. The FAMConnection structure is passed to all subsequent FAM procedure calls. FAMClose frees resources associated with files still being monitored and closes a fam connection. It returns 0 if successful and -1 otherwise. FAMMonitorDirectory, FAMMonitorFile Page 4 FAM(3X) FAM(3X) FAMMonitorDirectory and FAMMonitorFile tell FAM to start monitoring a directory or file, respectively. The parameters to this function are a FAMConnection (initialized by FAMOpen), a FAMRequest structure, a filename and a user data pointer. The FAMRequest structure is modified to subsequently identify this request. When the file or directory changes, a FAM event structure will be generated. The application can retrieve this structure by calling FAMNextEvent (see description under FAMNextEvent). FAMMonitorDirectory monitors changes that happens to the contents of the directory (as well as the directory file itself); FAMMonitorFile monitors only what happens to a particular file. Both routines return 0 if successful and -1 otherwise. The filename argument must be a full pathname. FAMMonitorRemoteDirectory, FAMMonitorRemoteFile FAMMonitorRemoteDirectory and FAMMonitorRemoteFile are obsolete. Remote files and directories on mounted NFS filesystems may be monitored using FAMMonitorDirectory and FAMMonitorFile. There is not supported way to monitor files or directories that are not mounted. FAMSuspendMonitor, FAMResumeMonitor FAMSuspendMonitor temporarily suspends monitoring of files or directories. This is useful when an application is not displaying information about files, when it is iconified, for example. FAMResumeMonitor signals fam to start monitoring the file or directory again. Changes which occur while monitoring is suspended are enqueued and delivered when monitoring is resumed. Both of these routines take a FAMConnection and a FAMRequest structure. The FAMRequest Structure is returned from the FAMMonitorFile or FAMMonitorDirectory routines and return 0 if successful and -1 otherwise. Because fam runs as an asynchronous process, FAMNextEvent may return a few events regarding a given request after that request has been suspended. FAMCancelMonitor When an application is through monitoring a file or directory, it should call FAMCancelMonitor. This routine will signal fam not to monitor this directory anymore. The FAMRequest structure is returned from the FAMMonitorFile or FAMMonitorDirectory routines. FAMCancelMonitor returns 0 if successful and -1 otherwise. FAMPending, FAMNextEvent Page 5 FAM(3X) FAM(3X) FAMPending returns 1 if an event waiting, 0 if no event is waiting, and -1 if there is an error. This routine returns immediately to the caller. FAMNextEvent will get the next FAM event (file or directory change). If there are no FAM events waiting, then the calling application blocks until a FAM event is received (from fam). There are two ways to for applications to receive FAM events: 1. The Select approach - The application selects on the file descriptor returned from FAMOpen, in the FAMConnection structure. When this file descriptor becomes active, the application calls FAMNextEvent to retrieve the pending FAM event. 2. The Polling approach - The application calls FAMPending periodically (usually when the system is waiting for input). When FAMPending returns with a positive return value, the application calls FAMNextEvent to retrieve the pending FAM Pevents. FAMNextEvent reads any information that is on the fam socket, and returns it to the application in the form of a FAMEvent. FAMNextEvent returns 1 if successful and -1 otherwise. SEE ALSO fam(1M). BUGS The FAMMoved event is not currently supported. FAMNextEvent may not initialize the FAMEvent's filename field for FAMEndExist and FAMAcknowledge events. Use the request number to determine the file or directory to which those events refer. The FAMErrno variable is not set when errors occur. When a shell script is run, notification is generated for the shell executing the script, typically sh(1) or csh(1). Each process is limited to 1000 active requests at a time.
Schneider Lab.
origin: 1997 April 18
updated: 1998 Jan 8