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danfruehauf/incron

inotify cron system

Authors

  • (c) Lukas Jelinek, 2006, 2007, 2008, 2009, 2012
  • (c) Dan Fruehauf, 2015

Content

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1. About

This program is the "inotify cron" system. It consist of a daemon and a table manipulator. You can use it a similar way as the regular cron. The difference is that the inotify cron handles filesystem events rather than time periods.

2. Requirements

  • Linux kernel 2.6.13 or later (with inotify compiled in)
  • inotify headers (inotify.h, sometimes inotify-syscalls.h) installed in <INCLUDE_DIR>/sys. The most common place is /usr/include/sys.
  • GCC 4.x compiler (probably works also with GCC 3.4, possibly with older versions too)

3. How to build

Because this version is very early it does not contain a standard portable build mechanism. There is only a Makefile which must be modified manually. On many Linux systems you need not to change anything.

Please review the Makefile BEFORE you type make. Especially check the PREFIX and other common variables. If done you can now build the files (make).

The binaries must be installed as root.

If you want to use (after editing) the example configuration file simply rename it from /etc/incron.conf.example to /etc/incron.conf (you can also use -f <config> for one-time use of a custom configuration file).

Making a release

Making a release of the source tree relies on the VERSION file. The file should contain only a simple version string such as '0.5.9' or (if you wish) something more complex (e.g. '0.5.9-improved'). The doxygen program must be installed and its control file 'Doxygen' created for generating the API documentation.

4. How to use

The incron daemon (incrond) must be run under root (typically from runlevel script etc.). It loads the current user tables and hooks them for later changes.

The incron table manipulator may be run under any regular user since it SUIDs. For manipulation with the tables use basically the same syntax as for the crontab program. You can import a table, remove and edit the current table.

The user table rows have the following syntax:

<path> <mask> <command>

Where:

  <path> is a filesystem path (currently avoid whitespaces!)
  <mask> is a symbolic (see inotify.h; use commas for separating
         symbols) or numeric mask for events
  <command> is an application or script to run on the events

The command may contain these wildcards:

  $$ - a dollar sign
  $@ - the watched filesystem path (see above)
  $# - the event-related file name
  $% - the event flags (textually)
  $& - the event flags (numerically)

The mask may additionaly contain a special symbol IN_NO_LOOP which disables events occurred during the event handling (to avoid loops).

Examples

Example 1: You need to run program abc with the full file path as an argument every time a file is changed in /var/mail. One of the solutions follows:

/var/mail IN_CLOSE_WRITE abc $@/$#

Example 2: You need to run program efg with the full file path as the first argument and the numeric event flags as the second one. It have to monitor all events on files in /tmp. Here is it:

/tmp IN_ALL_EVENTS efg $@/$# $&

Since 0.4.0 also system tables are supported. They are located in /etc/incron.d and their commands use root privileges. System tables are intended to be changed directly (without incrontab).

Some parameters of both incrontab and incrond can be changed by the configuration. See the example file for more information.

5. Bugs, suggestions

If you find a bug or have a suggestion how to improve the program, please use the issue tracking system at https://github.com/danfruehauf/incron/issues

6. Licensing

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License, version 2 (see LICENSE-GPL).

Some parts may be also covered by other licenses. Please look into the source files for detailed information.