Credits:
Matt Kraai - initial writeup
Mark Whitley - the remix
-
+Thomas Lundquist - Added stuff for the new directory layout.
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:
+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. Usage does not have to be taken care of by
+your applet.
+
+For a new applet mu, here is the code that would go in mu.c:
----begin example code------
char mu;
if ((fd = open("/dev/random", O_RDONLY)) < 0)
- perror_msg_and_die("/dev/random");
+ bb_perror_msg_and_die("/dev/random");
if ((n = safe_read(fd, &mu, 1)) < 1)
- perror_msg_and_die("/dev/random");
+ bb_perror_msg_and_die("/dev/random");
return mu;
}
directory and make your program compliant.
-Some Words on utility.c
------------------------
+Some Words on libbb
+-------------------
As you are writing your applet, please be aware of the body of pre-existing
-useful functions in utility.c. Use these instead of reinventing the wheel.
-
-If you use functions from utility.c, you may need to add to the preprocessor
-conditionals in that file, to make sure the routines you need are included.
-So, since your mu implementation used safe_read(), append "|| defined BB_MU" to
-the #if instruction that precedes the safe_read() function in utility.c .
+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
-utility.c.
+applet that could be useful in other applets, consider putting them in libbb.
+
+
+Placement / Directory
+---------------------
+
+Find the appropriate directory for your new applet.
+
+Make sure you find the appropriate places in the files, the applets are
+sorted alphabetically.
+
+Add the applet to Makefile.in in the chosen directory:
+
+obj-$(CONFIG_MU) += mu.o
+
+Add the applet to Config.in in the chosen directory:
+
+config CONFIG_MU
+ bool "MU"
+ default n
+ help
+ Returns an indeterminate value.
Usage String(s)
---------------
-Next, add usage information for you applet to usage.c. This should look like
-the following:
+Next, add usage information for you applet to include/usage.h.
+This should look like the following:
- #if defined BB_MU
- const char mu_usage[] =
- "mu\n"
- #ifndef BB_FEATURE_TRIVIAL_HELP
- "\nReturns an indeterminate value.\n"
- #endif
- ;
+ #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 (mu -[bcRovma]) and a detailed description of each flag should go in the
-BB_FEATURE_TRIVIAL_HELP section, one flag per line. (Numerous examples of this
-currently exist in usage.c.)
+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:
+Next, add an entry to include/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
+ #ifdef CONFIG_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).
+Adding some text to docs/Configure.help is a nice start.
+
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.
-
-
+Then create a diff -urN of the files you added and/or modified. Typically:
+ <appletdir>/<applet>.c
+ include/usage.c
+ include/applets.h
+ <appletdir>/Makefile.in
+ <appletdir>/config.in
+and send it to the mailing list:
+ busybox@busybox.net
+ http://busybox.net/mailman/listinfo/busybox
+
+Sending patches as attachments is preferred, but not required.
projects / oweals / busybox.git / blobdiff