X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=docs%2Fnew-applet-HOWTO.txt;h=24bc1d824111419502c802e28e02c591171091db;hb=0612b5fa68a1c41656031c7318b0347bdbdeeb89;hp=90e124d01cb8dcd7fe155edddb48035348241f03;hpb=8eb5985f94a3f8a08c9e80274019175ea87c76b9;p=oweals%2Fbusybox.git diff --git a/docs/new-applet-HOWTO.txt b/docs/new-applet-HOWTO.txt index 90e124d01..24bc1d824 100644 --- a/docs/new-applet-HOWTO.txt +++ b/docs/new-applet-HOWTO.txt @@ -6,16 +6,18 @@ This document details the steps you must take to add a new applet to BusyBox. 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 _main instead -of main. And be sure to put it in .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 _main instead of main. +And be sure to put it in .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------ @@ -51,10 +53,10 @@ int mu_main(int argc, char **argv) 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; } @@ -70,74 +72,92 @@ you _write_ your applet) please read through the style guide in the docs 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 (.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: + /.c + include/usage.c + include/applets.h + /Makefile.in + /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.