1 How to Add a New Applet to BusyBox
2 ==================================
4 This document details the steps you must take to add a new applet to BusyBox.
7 Matt Kraai - initial writeup
8 Mark Whitley - the remix
14 First, write your applet. Be sure to include copyright information at the
15 top, such as who you stole the code from and so forth. Also include the
16 mini-GPL boilerplate. Be sure to name the main function <applet>_main instead
17 of main. And be sure to put it in <applet>.c. For a new applet mu, here is
18 the code that would go in mu.c:
20 ----begin example code------
22 /* vi: set sw=4 ts=4: */
24 * Mini mu implementation for busybox
27 * Copyright (C) [YEAR] by [YOUR NAME] <YOUR EMAIL>
29 * This program is free software; you can redistribute it and/or modify
30 * it under the terms of the GNU General Public License as published by
31 * the Free Software Foundation; either version 2 of the License, or
32 * (at your option) any later version.
34 * This program is distributed in the hope that it will be useful,
35 * but WITHOUT ANY WARRANTY; without even the implied warranty of
36 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
37 * General Public License for more details.
39 * You should have received a copy of the GNU General Public License
40 * along with this program; if not, write to the Free Software
41 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
48 int mu_main(int argc, char **argv)
53 if ((fd = open("/dev/random", O_RDONLY)) < 0)
54 perror_msg_and_die("/dev/random");
56 if ((n = safe_read(fd, &mu, 1)) < 1)
57 perror_msg_and_die("/dev/random");
62 ----end example code------
64 As you are writing your applet, please be aware of the body of pre-existing
65 useful functions in utility.c. Use these instead of reinventing the wheel.
66 Additionally, if you have any useful, general-purpose functions in your
67 program that could be useful in another program, consider putting them in
70 Furthermore, please read through the style guide in the docs directory and
71 make your program compliant.
77 Next, add usage information for you applet to usage.c. This should look like
81 const char mu_usage[] =
83 #ifndef BB_FEATURE_TRIVIAL_HELP
84 "\nReturns an indeterminate value.\n"
88 If your program supports flags, the flags should be mentioned on the first
89 line (mu -[bcRovma]) and a detailed description of each flag should go in the
90 BB_FEATURE_TRIVIAL_HELP section, one flag per line. (Numerous examples of this
91 currently exist in utility.c.)
97 Next, add an entry to applets.h. Be *sure* to keep the list in alphabetical
98 order, or else it will break the binary-search lookup algorithm in busybox.c
99 and the Gods of BusyBox smite you. Yea, verily:
101 /* all programs above here are alphabetically "less than" 'mu' */
103 APPLET("mu", mu_main, _BB_DIR_USR_BIN, mu_usage)
105 /* all programs below here are alphabetically "greater than" 'mu' */
108 Finally, add a define for your applet to Config.h:
116 If you're feeling especially nice, you should also document your applet in the
117 docs directory (but nobody ever does that).
120 The Grand Announcement
121 ----------------------
123 Then create a diff -urN of the files you added (<applet>.c, usage.c,
124 applets.h, Config.h) and send it to the mailing list:
125 busybox@opensource.lineo.com. Sending patches as attachments is preferred, but