[821] | 1 | How to Add a New Applet to BusyBox
|
---|
| 2 | ==================================
|
---|
| 3 |
|
---|
| 4 | This document details the steps you must take to add a new applet to BusyBox.
|
---|
| 5 |
|
---|
| 6 | Credits:
|
---|
| 7 | Matt Kraai - initial writeup
|
---|
| 8 | Mark Whitley - the remix
|
---|
[1770] | 9 | Thomas Lundquist - Trying to keep it updated.
|
---|
[821] | 10 |
|
---|
[1770] | 11 | When doing this you should consider using the latest svn trunk.
|
---|
| 12 | This is a good thing if you plan to getting it commited into mainline.
|
---|
| 13 |
|
---|
[821] | 14 | Initial Write
|
---|
| 15 | -------------
|
---|
| 16 |
|
---|
| 17 | First, write your applet. Be sure to include copyright information at the top,
|
---|
| 18 | such as who you stole the code from and so forth. Also include the mini-GPL
|
---|
| 19 | boilerplate. Be sure to name the main function <applet>_main instead of main.
|
---|
| 20 | And be sure to put it in <applet>.c. Usage does not have to be taken care of by
|
---|
| 21 | your applet.
|
---|
[1770] | 22 | Make sure to #include "libbb.h" as the first include file in your applet so
|
---|
[821] | 23 | the bb_config.h and appropriate platform specific files are included properly.
|
---|
| 24 |
|
---|
| 25 | For a new applet mu, here is the code that would go in mu.c:
|
---|
| 26 |
|
---|
[1770] | 27 | (busybox.h already includes most usual header files. You do not need
|
---|
| 28 | #include <stdio.h> etc...)
|
---|
| 29 |
|
---|
| 30 |
|
---|
[821] | 31 | ----begin example code------
|
---|
| 32 |
|
---|
| 33 | /* vi: set sw=4 ts=4: */
|
---|
| 34 | /*
|
---|
| 35 | * Mini mu implementation for busybox
|
---|
| 36 | *
|
---|
| 37 | * Copyright (C) [YEAR] by [YOUR NAME] <YOUR EMAIL>
|
---|
| 38 | *
|
---|
| 39 | * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
|
---|
| 40 | */
|
---|
| 41 |
|
---|
[1770] | 42 | #include "libbb.h"
|
---|
| 43 | #include "other.h"
|
---|
[821] | 44 |
|
---|
[1770] | 45 | int mu_main(int argc, char **argv);
|
---|
[821] | 46 | int mu_main(int argc, char **argv)
|
---|
| 47 | {
|
---|
| 48 | int fd;
|
---|
| 49 | char mu;
|
---|
| 50 |
|
---|
[1770] | 51 | fd = xopen("/dev/random", O_RDONLY);
|
---|
[821] | 52 |
|
---|
| 53 | if ((n = safe_read(fd, &mu, 1)) < 1)
|
---|
| 54 | bb_perror_msg_and_die("/dev/random");
|
---|
| 55 |
|
---|
| 56 | return mu;
|
---|
| 57 | }
|
---|
| 58 |
|
---|
| 59 | ----end example code------
|
---|
| 60 |
|
---|
| 61 |
|
---|
| 62 | Coding Style
|
---|
| 63 | ------------
|
---|
| 64 |
|
---|
| 65 | Before you submit your applet for inclusion in BusyBox, (or better yet, before
|
---|
| 66 | you _write_ your applet) please read through the style guide in the docs
|
---|
| 67 | directory and make your program compliant.
|
---|
| 68 |
|
---|
| 69 |
|
---|
| 70 | Some Words on libbb
|
---|
| 71 | -------------------
|
---|
| 72 |
|
---|
| 73 | As you are writing your applet, please be aware of the body of pre-existing
|
---|
| 74 | useful functions in libbb. Use these instead of reinventing the wheel.
|
---|
| 75 |
|
---|
| 76 | Additionally, if you have any useful, general-purpose functions in your
|
---|
| 77 | applet that could be useful in other applets, consider putting them in libbb.
|
---|
| 78 |
|
---|
[1770] | 79 | And it may be possible that some of the other applets uses functions you
|
---|
| 80 | could use. If so, you have to rip the function out of the applet and make
|
---|
| 81 | a libbb function out of it.
|
---|
[821] | 82 |
|
---|
[1770] | 83 | Adding a libbb function:
|
---|
| 84 | ------------------------
|
---|
| 85 |
|
---|
| 86 | Make a new file named <function_name>.c
|
---|
| 87 |
|
---|
| 88 | ----start example code------
|
---|
| 89 |
|
---|
| 90 | #include "libbb.h"
|
---|
| 91 | #include "other.h"
|
---|
| 92 |
|
---|
| 93 | int function(char *a)
|
---|
| 94 | {
|
---|
| 95 | return *a;
|
---|
| 96 | }
|
---|
| 97 |
|
---|
| 98 | ----end example code------
|
---|
| 99 |
|
---|
| 100 | Add <function_name>.o in the right alphabetically sorted place
|
---|
| 101 | in libbb/Kbuild. You should look at the conditional part of
|
---|
| 102 | libbb/Kbuild aswell.
|
---|
| 103 |
|
---|
| 104 | You should also try to find a suitable place in include/libbb.h for
|
---|
| 105 | the function declaration. If not, add it somewhere anyway, with or without
|
---|
| 106 | ifdefs to include or not.
|
---|
| 107 |
|
---|
| 108 | You can look at libbb/Config.in and try to find out if the function is
|
---|
| 109 | tuneable and add it there if it is.
|
---|
| 110 |
|
---|
| 111 |
|
---|
[821] | 112 | Placement / Directory
|
---|
| 113 | ---------------------
|
---|
| 114 |
|
---|
| 115 | Find the appropriate directory for your new applet.
|
---|
| 116 |
|
---|
| 117 | Make sure you find the appropriate places in the files, the applets are
|
---|
| 118 | sorted alphabetically.
|
---|
| 119 |
|
---|
[1770] | 120 | Add the applet to Kbuild in the chosen directory:
|
---|
[821] | 121 |
|
---|
[1770] | 122 | lib-$(CONFIG_MU) += mu.o
|
---|
[821] | 123 |
|
---|
| 124 | Add the applet to Config.in in the chosen directory:
|
---|
| 125 |
|
---|
| 126 | config CONFIG_MU
|
---|
| 127 | bool "MU"
|
---|
| 128 | default n
|
---|
| 129 | help
|
---|
| 130 | Returns an indeterminate value.
|
---|
| 131 |
|
---|
| 132 |
|
---|
| 133 | Usage String(s)
|
---|
| 134 | ---------------
|
---|
| 135 |
|
---|
| 136 | Next, add usage information for you applet to include/usage.h.
|
---|
| 137 | This should look like the following:
|
---|
| 138 |
|
---|
| 139 | #define mu_trivial_usage \
|
---|
| 140 | "-[abcde] FILES"
|
---|
| 141 | #define mu_full_usage \
|
---|
| 142 | "Returns an indeterminate value.\n\n" \
|
---|
| 143 | "Options:\n" \
|
---|
| 144 | "\t-a\t\tfirst function\n" \
|
---|
| 145 | "\t-b\t\tsecond function\n" \
|
---|
| 146 | ...
|
---|
| 147 |
|
---|
| 148 | If your program supports flags, the flags should be mentioned on the first
|
---|
| 149 | line (-[abcde]) and a detailed description of each flag should go in the
|
---|
| 150 | mu_full_usage section, one flag per line. (Numerous examples of this
|
---|
| 151 | currently exist in usage.h.)
|
---|
| 152 |
|
---|
| 153 |
|
---|
| 154 | Header Files
|
---|
| 155 | ------------
|
---|
| 156 |
|
---|
| 157 | Next, add an entry to include/applets.h. Be *sure* to keep the list
|
---|
| 158 | in alphabetical order, or else it will break the binary-search lookup
|
---|
| 159 | algorithm in busybox.c and the Gods of BusyBox smite you. Yea, verily:
|
---|
| 160 |
|
---|
[1770] | 161 | Be sure to read the top of applets.h before adding your applet.
|
---|
| 162 |
|
---|
[821] | 163 | /* all programs above here are alphabetically "less than" 'mu' */
|
---|
[1770] | 164 | USE_MU(APPLET(mu, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
|
---|
[821] | 165 | /* all programs below here are alphabetically "greater than" 'mu' */
|
---|
| 166 |
|
---|
| 167 |
|
---|
| 168 | The Grand Announcement
|
---|
| 169 | ----------------------
|
---|
| 170 |
|
---|
[1770] | 171 | Then create a diff by adding the new files with svn (remember your libbb files)
|
---|
| 172 | svn add <where you put it>/mu.c
|
---|
| 173 | eventually also:
|
---|
| 174 | svn add libbb/function.c
|
---|
| 175 | then
|
---|
| 176 | svn diff
|
---|
[821] | 177 | and send it to the mailing list:
|
---|
| 178 | busybox@busybox.net
|
---|
| 179 | http://busybox.net/mailman/listinfo/busybox
|
---|
| 180 |
|
---|
| 181 | Sending patches as attachments is preferred, but not required.
|
---|