Changeset 1765 in MondoRescue for branches/2.2.5/mindi-busybox/docs/new-applet-HOWTO.txt

Timestamp:

Nov 4, 2007, 3:16:40 AM (16 years ago)

Author:

Bruno Cornec

Message:

Update to busybox 1.7.2

File:

• branches/2.2.5/mindi-busybox/docs/new-applet-HOWTO.txt (modified) (8 diffs)

branches/2.2.5/mindi-busybox/docs/new-applet-HOWTO.txt

@@ -7 +7 @@
 Matt Kraai - initial writeup
 Mark Whitley - the remix
-Thomas Lundquist - Added stuff for the new directory layout.
+Thomas Lundquist - Trying to keep it updated.
+
+When doing this you should consider using the latest svn trunk.
+This is a good thing if you plan to getting it commited into mainline.
 
 Initial Write
@@ -17 +20 @@
 And be sure to put it in <applet>.c. Usage does not have to be taken care of by
 your applet.
-Make sure to #include "busybox.h" as the first include file in your applet so
+Make sure to #include "libbb.h" as the first include file in your applet so
 the bb_config.h and appropriate platform specific files are included properly.
 
 For a new applet mu, here is the code that would go in mu.c:
+
+(busybox.h already includes most usual header files. You do not need
+#include <stdio.h> etc...)
+
 
 ----begin example code------
@@ -33 +40 @@
  */
 
-#include "busybox.h"
-#include <other.h>
+#include "libbb.h"
+#include "other.h"
 
+int mu_main(int argc, char **argv);
 int mu_main(int argc, char **argv)
 {
@@ -41 +49 @@
     char mu;
 
-    fd = bb_xopen("/dev/random", O_RDONLY);
+    fd = xopen("/dev/random", O_RDONLY);
 
     if ((n = safe_read(fd, &mu, 1)) < 1)
@@ -69 +77 @@
 applet that could be useful in other applets, consider putting them in libbb.
 
+And it may be possible that some of the other applets uses functions you
+could use. If so, you have to rip the function out of the applet and make
+a libbb function out of it.
+
+Adding a libbb function:
+------------------------
+
+Make a new file named <function_name>.c
+
+----start example code------
+
+#include "libbb.h"
+#include "other.h"
+
+int function(char *a)
+{
+    return *a;
+}
+
+----end example code------
+
+Add <function_name>.o in the right alphabetically sorted place
+in libbb/Kbuild. You should look at the conditional part of
+libbb/Kbuild aswell.
+
+You should also try to find a suitable place in include/libbb.h for
+the function declaration. If not, add it somewhere anyway, with or without
+ifdefs to include or not.
+
+You can look at libbb/Config.in and try to find out if the function is
+tuneable and add it there if it is.
+
 
 Placement / Directory
@@ -78 +118 @@
 sorted alphabetically.
 
-Add the applet to Makefile.in in the chosen directory:
+Add the applet to Kbuild in the chosen directory:
 
-obj-$(CONFIG_MU)               += mu.o
+lib-$(CONFIG_MU)               += mu.o
 
 Add the applet to Config.in in the chosen directory:
@@ -119 +159 @@
 algorithm in busybox.c and the Gods of BusyBox smite you. Yea, verily:
 
+Be sure to read the top of applets.h before adding your applet.
+
     /* all programs above here are alphabetically "less than" 'mu' */
-    #ifdef CONFIG_MU
-        APPLET("mu", mu_main, _BB_DIR_USR_BIN, mu_usage)
-    #endif
+    USE_MU(APPLET(mu, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
     /* all programs below here are alphabetically "greater than" '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.
 
 
@@ -138 +169 @@
 ----------------------
 
-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
+Then create a diff by adding the new files with svn (remember your libbb files)
+    svn add <where you put it>/mu.c
+eventually also:
+    svn add libbb/function.c
+then
+    svn diff
 and send it to the mailing list:
     busybox@busybox.net