Load 'r' and 'history' default aliases on interactive only

These two default aliases are useful on interactive shells. In
scripts, they interfere with possible function or command names.

As of this commit, these final two default aliases are only loaded
for interactive shells, leaving zero default aliases for scripts.
This completes the project to get rid of misguided default aliases.

src/cmd/ksh93/include/shtable.h,
src/cmd/ksh93/data/aliases.c:
src/cmd/ksh93/sh/init.c:
- Add empty alias table shtab_noaliases[] for scripts.
- Rename inittree() to sh_inittree() and make it external.
- nv_init(), sh_reinit(): Initialise empty alias tree for scripts.

src/cmd/ksh93/sh/main.c: sh_main():
- If interactive, reinitialise alias tree for interactive shells.

src/cmd/ksh93/tests/alias.sh:
- To test default alias removal, launch shell with -i.

src/cmd/ksh93/data/aliases.c

@@ -24,7 +24,7 @@
 #include	"FEATURE/dynamic"
 
 /*
- * This is the table of built-in aliases.  These should be exported.
+ * Table of built-in aliases for interactive shells.
  */
 
 const struct shtable2 shtab_aliases[] =
@@ -34,3 +34,12 @@ const struct shtable2 shtab_aliases[] =
 	"",		0,			(char*)0
 };
 
+/*
+ * Empty table of built-in aliases for non-interactive shells.
+ */
+
+const struct shtable2 shtab_noaliases[] =
+{
+	"",		0,			(char*)0
+};
+

src/cmd/ksh93/include/shtable.h

@@ -56,10 +56,12 @@ extern const Shtable_t		shtab_options[];
 extern const Shtable_t		shtab_attributes[];
 extern const struct shtable2	shtab_variables[];
 extern const struct shtable2	shtab_aliases[];
+extern const struct shtable2	shtab_noaliases[];
 extern const struct shtable2	shtab_signals[];
 extern const struct shtable3	shtab_builtins[];
 extern const Shtable_t		shtab_reserved[];
 extern const Shtable_t		*sh_locate(const char*, const Shtable_t*, int);
 extern int			sh_lookopt(const char*, int*);
+extern Dt_t			*sh_inittree(Shell_t*, const struct shtable2*);
 
 #endif /* SH_TABLE_H */

src/cmd/ksh93/sh/init.c

@@ -217,7 +217,6 @@ static int		lctype;
 static int		nbltins;
 static void		env_init(Shell_t*);
 static Init_t		*nv_init(Shell_t*);
-static Dt_t		*inittree(Shell_t*,const struct shtable2*);
 static int		shlvl;
 
 #ifdef _WINIX
@@ -1561,7 +1560,7 @@ int sh_reinit(char *argv[])
 		nv_delete(np,dp,NV_NOFREE);
 	}
 	dtclose(shp->alias_tree);
-	shp->alias_tree = inittree(shp,shtab_aliases);
+	shp->alias_tree = sh_inittree(shp,shtab_noaliases);
 	shp->last_root = shp->var_tree;
 	shp->inuse_bits = 0;
 	if(shp->userinit)
@@ -1760,7 +1759,7 @@ static Init_t *nv_init(Shell_t *shp)
 	shp->nvfun.last = (char*)shp;
 	shp->nvfun.nofree = 1;
 	ip->sh = shp;
-	shp->var_base = shp->var_tree = inittree(shp,shtab_variables);
+	shp->var_base = shp->var_tree = sh_inittree(shp,shtab_variables);
 	SHLVL->nvalue.ip = &shlvl;
 	ip->IFS_init.hdr.disc = &IFS_disc;
 	ip->PATH_init.disc = &RESTRICTED_disc;
@@ -1853,9 +1852,9 @@ static Init_t *nv_init(Shell_t *shp)
 	(MCHKNOD)->nvalue.lp = (&sh_mailchk);
 	(OPTINDNOD)->nvalue.lp = (&shp->st.optindex);
 	/* set up the seconds clock */
-	shp->alias_tree = inittree(shp,shtab_aliases);
+	shp->alias_tree = sh_inittree(shp,shtab_noaliases);
 	shp->track_tree = dtopen(&_Nvdisc,Dtset);
-	shp->bltin_tree = inittree(shp,(const struct shtable2*)shtab_builtins);
+	shp->bltin_tree = sh_inittree(shp,(const struct shtable2*)shtab_builtins);
 	shp->fun_tree = dtopen(&_Nvdisc,Dtoset);
 	dtview(shp->fun_tree,shp->bltin_tree);
 	nv_mount(DOTSHNOD, "type", shp->typedict=dtopen(&_Nvdisc,Dtoset));
@@ -1878,7 +1877,7 @@ static Init_t *nv_init(Shell_t *shp)
  * initialize name-value pairs
  */
 
-static Dt_t *inittree(Shell_t *shp,const struct shtable2 *name_vals)
+Dt_t *sh_inittree(Shell_t *shp,const struct shtable2 *name_vals)
 {
 	register Namval_t *np;
 	register const struct shtable2 *tp;

src/cmd/ksh93/sh/main.c

@@ -176,6 +176,8 @@ int sh_main(int ac, char *av[], Shinit_f userinit)
 		{
 			sh_onoption(SH_BGNICE);
 			sh_onoption(SH_RC);
+			free(shp->alias_tree);
+			shp->alias_tree = sh_inittree(shp,shtab_aliases);
 		}
 		if(!sh_isoption(SH_RC) && (sh_isoption(SH_BASH) && !sh_isoption(SH_POSIX)
 #if SHOPT_REMOTE

src/cmd/ksh93/tests/alias.sh

@@ -110,7 +110,7 @@ unalias foo
 unalias foo && err_exit 'unalias should return non-zero when a previously set alias is unaliased twice'
 
 # Removing a predefined alias should work without an error from free(3)
-$SHELL -c 'unalias history' 2> /dev/null || err_exit 'removing a predefined alias does not work'
+$SHELL -i -c 'unalias history' 2> /dev/null || err_exit 'removing a predefined alias does not work'
 
 # ======
 exit $((Errors<125?Errors:125))