139 lines
3.7 KiB
Plaintext
139 lines
3.7 KiB
Plaintext
How to Add a New Applet to BusyBox
|
|
==================================
|
|
|
|
This document details the steps you must take to add a new applet to BusyBox.
|
|
|
|
Credits:
|
|
Matt Kraai - initial writeup
|
|
Mark Whitley - the remix
|
|
|
|
|
|
Initial Write
|
|
-------------
|
|
|
|
First, write your applet. Be sure to include copyright information at the
|
|
top, such as who you stole the code from and so forth. Also include the
|
|
mini-GPL boilerplate. Be sure to name the main function <applet>_main instead
|
|
of main. And be sure to put it in <applet>.c. For a new applet mu, here is
|
|
the code that would go in mu.c:
|
|
|
|
----begin example code------
|
|
|
|
/* vi: set sw=4 ts=4: */
|
|
/*
|
|
* Mini mu implementation for busybox
|
|
*
|
|
*
|
|
* Copyright (C) [YEAR] by [YOUR NAME] <YOUR EMAIL>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
|
|
* 02111-1307 USA
|
|
*
|
|
*/
|
|
|
|
#include "busybox.h"
|
|
|
|
int mu_main(int argc, char **argv)
|
|
{
|
|
int fd;
|
|
char mu;
|
|
|
|
if ((fd = open("/dev/random", O_RDONLY)) < 0)
|
|
perror_msg_and_die("/dev/random");
|
|
|
|
if ((n = safe_read(fd, &mu, 1)) < 1)
|
|
perror_msg_and_die("/dev/random");
|
|
|
|
return mu;
|
|
}
|
|
|
|
----end example code------
|
|
|
|
|
|
Coding Style
|
|
------------
|
|
|
|
Before you submit your applet for inclusion in BusyBox, (or better yet, before
|
|
you _write_ your applet) please read through the style guide in the docs
|
|
directory and make your program compliant.
|
|
|
|
|
|
Some Words on libbb
|
|
-------------------
|
|
|
|
As you are writing your applet, please be aware of the body of pre-existing
|
|
useful functions in libbb. Use these instead of reinventing the wheel.
|
|
|
|
Additionally, if you have any useful, general-purpose functions in your
|
|
program that could be useful in another program, consider putting them in
|
|
libbb.
|
|
|
|
|
|
Usage String(s)
|
|
---------------
|
|
|
|
Next, add usage information for you applet to usage.h. This should look like
|
|
the following:
|
|
|
|
#define mu_trivial_usage \
|
|
"-[abcde] FILES"
|
|
#define mu_full_usage \
|
|
"Returns an indeterminate value.\n\n" \
|
|
"Options:\n" \
|
|
"\t-a\t\tfirst function\n" \
|
|
"\t-b\t\tsecond function\n" \
|
|
|
|
If your program supports flags, the flags should be mentioned on the first
|
|
line (-[abcde]) and a detailed description of each flag should go in the
|
|
mu_full_usage section, one flag per line. (Numerous examples of this
|
|
currently exist in usage.h.)
|
|
|
|
|
|
Header Files
|
|
------------
|
|
|
|
Next, add an entry to applets.h. Be *sure* to keep the list in alphabetical
|
|
order, or else it will break the binary-search lookup algorithm in busybox.c
|
|
and the Gods of BusyBox smite you. Yea, verily:
|
|
|
|
/* all programs above here are alphabetically "less than" 'mu' */
|
|
#ifdef BB_MU
|
|
APPLET("mu", mu_main, _BB_DIR_USR_BIN, mu_usage)
|
|
#endif
|
|
/* all programs below here are alphabetically "greater than" 'mu' */
|
|
|
|
|
|
Finally, add a define for your applet to Config.h:
|
|
|
|
#define BB_MU
|
|
|
|
|
|
Documentation
|
|
-------------
|
|
|
|
If you're feeling especially nice, you should also document your applet in the
|
|
docs directory (but nobody ever does that).
|
|
|
|
|
|
The Grand Announcement
|
|
----------------------
|
|
|
|
Then create a diff -urN of the files you added (<applet>.c, usage.c,
|
|
applets.h, Config.h) and send it to the mailing list:
|
|
busybox@opensource.lineo.com. Sending patches as attachments is preferred, but
|
|
not required.
|
|
|
|
|