commit bash-20150807 snapshot

examples/loadables/README

@@ -34,18 +34,17 @@ new loadable builtins.
 
 basename.c	Return non-directory portion of pathname.
 cat.c		cat(1) replacement with no options - the way cat was intended.
-cut.c		cut(1) replacement.
 dirname.c	Return directory portion of pathname.
 finfo.c		Print file info.
-getconf.c	POSIX.2 getconf utility.
-getconf.h	Replacement definitions for ones the system doesn't provide.
 head.c		Copy first part of files.
 hello.c		Obligatory "Hello World" / sample loadable.
 id.c		POSIX.2 user identity.
 ln.c		Make links.
+loadables.h	Start at a file loadable builtins can include for shell definitions
 logname.c	Print login name of current user.
 Makefile.in	Simple makefile for the sample loadable builtins.
 mkdir.c		Make directories.
+mypid.c		Add $MYPID variable, demonstrate use of unload hook function
 necho.c		echo without options or argument interpretation.
 pathchk.c	Check pathnames for validity and portability.
 print.c		Loadable ksh-93 style print builtin.

examples/loadables/hello.c

@@ -56,6 +56,23 @@ hello_builtin (list)
   return (EXECUTION_SUCCESS);
 }
 
+int
+hello_builtin_load (s)
+     char *s;
+{
+  printf ("hello builtin loaded\n");
+  fflush (stdout);
+  return (1);
+}
+
+void
+hello_builtin_unload (s)
+     char *s;
+{
+  printf ("hello builtin unloaded\n");
+  fflush (stdout);
+}
+
 /* An array of strings forming the `long' documentation for a builtin xxx,
    which is printed by `help xxx'.  It must end with a NULL.  By convention,
    the first line is a short description. */

examples/loadables/mypid.c

@@ -5,6 +5,11 @@
  * Then, from within bash, enable -f ./mypid enable_mypid, where ./mypid
  * is the binary obtained from running make. Hereafter, `${MYPID}'
  * is a shell builtin variable.
+ *
+ * This defines an unload hook function that is called when the builtin is
+ * deleted with enable -d that will unbind the MYPID variable so future
+ * references to it do not attempt to access memory that is no longer part
+ * of this process's address space.
  */
 
 #include <stdio.h>
@@ -56,6 +61,12 @@ enable_mypid_builtin(WORD_LIST *list)
   return 0;
 }
 
+void
+enable_mypid_builtin_unload (char *s)
+{
+  unbind_variable ("MYPID");
+}
+
 char const *enable_mypid_doc[] = {
   "Enable $MYPID.",
   "",

examples/loadables/template.c

@@ -41,6 +41,22 @@ template_builtin (list)
   return (rval);
 }
 
+/* Called when `template' is enabled and loaded from the shared object.  If this
+   function returns 0, the load fails. */
+int
+template_builtin_load (name)
+     char *name;
+{
+  return (1);
+}
+
+/* Called when `template' is disabled. */
+void
+template_builtin_unload (name)
+     char *name;
+{
+}
+
 char *template_doc[] = {
 	"Short description.",
 	""